/**
 * Diablo II: Lord of Destruction v1.13c `UNIT_MISSILE` Runtime (`MissileEngine`).
 *
 * Implements:
 * - `Missiles.txt` trajectory & frame lifecycle (`Vel`, `MaxVel`, `Accel`, `Range + (slvl - 1) * LevRange`).
 * - `NextHit` & `NextDelay` per-target immunity window (`lastNextDelayTickByTargetId`) so
 *   multi-projectile skills (`Multiple Shot`, `Teeth`, `Charged Bolt`, `Nova`, `Shock Web`,
 *   `Tornado`, `Twister`, `Wake of Fire`) obey exact 1.13c `NextDelay` frames.
 * - `Pierce` (`Pierce` column + Amazon `Pierce` `skillId=33` chance, capped at 4 pierces / 5 hits).
 * - `pSrvDoFunc` (linear flight, spiral `Blessed Hammer`, homing `Guided Arrow`/`Bone Spirit`,
 *   radial bolt emitter `Frozen Orb` `pSrvDoFunc=15`, ground fire trail `Blaze`/`Fire Wall`/`Molten Boulder`).
 * - `pSrvHitFunc` (`Fire Ball` radial splash `1`, `Holy Bolt` undead/ally heal `7`,
 *   `Chain Lightning`/`Lightning Strike`/`royalstrikechainlightning` `*12` chain jump,
 *   `Lightning Fury` `20` radial bolts, `Fist of the Heavens` `22` radial `holybolt`,
 *   `Frozen Orb` `29` final ice bolt nova).
 */
import type { D2DataRegistry, MissileRecord } from './data-registry.ts'
import { executeSUnitDmg, type CombatUnitContext, type SUnitDmgPacket } from './combat-pipeline.ts'
import { getBlizzardDropOffset } from './blizzard-table.ts'
import { METEOR_FIRE_SUBTILE_OFFSETS } from './meteor-table.ts'
import { calculateMeteorResidualFireDamage } from '../skills.ts'

export const ISO_GROUND_ASPECT_RATIO = 0.5

export interface StaticFieldResult {
  readonly damage: number
  readonly newHp: number
  readonly immune: boolean
  readonly blockedByFloor: boolean
}

/**
 * Authentic 1.13c Static Field damage calculation with pre-check invariant and difficulty floors.
 * Source: D2Game.dll VA 0x6FC62F13 (SKILLS_AuraCallback_StaticField) & DifficultyLevels.txt
 */
export function calculateStaticFieldDamage(
  currentHp: number,
  maxHp: number,
  difficulty: 'normal' | 'nightmare' | 'hell' = 'normal',
  lightningRes = 0,
): StaticFieldResult {
  const minPct = difficulty === 'hell' ? 50 : difficulty === 'nightmare' ? 33 : 0
  const hpFloor = difficulty === 'normal' ? 1 : Math.max(1, Math.floor((maxHp * minPct) / 100))

  // 1.13c Assembly Invariant (SKILLS_AuraCallback_StaticField at 0x6FC62F13):
  // If current HP is already at or below the difficulty floor, return 0 damage immediately!
  if (currentHp <= hpFloor) {
    return { damage: 0, newHp: currentHp, immune: false, blockedByFloor: true }
  }

  if (lightningRes >= 100) {
    return { damage: 0, newHp: currentHp, immune: true, blockedByFloor: false }
  }

  let damage = Math.floor(currentHp * 0.25)

  // Support negative resistance scaling (Lower Resist, Conviction, -% enemy lightning resistance).
  // Clamped to [-100, 99]% per Diablo II resistance lower bound.
  const clampedRes = Math.max(-100, Math.min(99, lightningRes))
  damage = Math.floor((damage * (100 - clampedRes)) / 100)

  // CRITICAL SAFETY INVARIANT: Non-lethal damage clamping MUST occur AFTER resistance scaling
  // so Static Field NEVER deals lethal damage (newHp >= 1, damage <= currentHp - 1)
  damage = Math.min(damage, Math.max(0, currentHp - 1))

  return { damage, newHp: currentHp - damage, immune: false, blockedByFloor: false }
}

export function calculateStaticFieldRadiusYards(slvl: number): number {
  const lvl = Number.isFinite(slvl) ? Math.max(1, Math.floor(slvl)) : 1
  return 4 + lvl
}

export function calculateStaticFieldRadiusPx(slvl: number): number {
  return calculateStaticFieldRadiusYards(slvl) * 40
}

/**
 * Authentic 1.13c Nova 5-band damage scaling (Skills.txt row 48):
 * EMin: 1, EMinLev1..5: 6, 7, 8, 9, 10
 * EMax: 20, EMaxLev1..5: 8, 9, 10, 11, 12
 * 0 synergies in 1.13c.
 */
export function calculateNovaDamage(
  slvl: number,
  synergies?: {
    readonly lightningMastery?: number | undefined
  } | number,
  lightningMastery?: number,
): { min: number; max: number } {
  const lvl = Number.isFinite(slvl) ? Math.max(1, Math.floor(slvl)) : 1
  let min = 1
  let max = 20
  if (lvl > 1) {
    const b1 = Math.min(lvl - 1, 7)
    min += b1 * 6
    max += b1 * 8
    if (lvl > 8) {
      const b2 = Math.min(lvl - 8, 8)
      min += b2 * 7
      max += b2 * 9
    }
    if (lvl > 16) {
      const b3 = Math.min(lvl - 16, 6)
      min += b3 * 8
      max += b3 * 10
    }
    if (lvl > 22) {
      const b4 = Math.min(lvl - 22, 6)
      min += b4 * 9
      max += b4 * 11
    }
    if (lvl > 28) {
      const b5 = lvl - 28
      min += b5 * 10
      max += b5 * 12
    }
  }

  const masteryLvl =
    typeof lightningMastery === 'number'
      ? lightningMastery
      : typeof synergies === 'object' && synergies !== null
        ? synergies.lightningMastery ?? 0
        : 0
  const masteryBonus = masteryLvl > 0 ? calculateLightningMasteryBonusPct(masteryLvl) : 0
  const synMult = typeof synergies === 'number' && Number.isFinite(synergies) && synergies > 0 ? synergies : 1.0

  min = Math.floor(min * synMult * (1 + masteryBonus / 100))
  max = Math.floor(max * synMult * (1 + masteryBonus / 100))
  return { min, max }
}

/**
 * Authentic 1.13c Lightning (Skill 49) synergy multiplier:
 * +8% lightning damage per hard point in Charged Bolt (38), Nova (48), and Chain Lightning (53).
 */
export function calculateLightningSynergyMultiplier(synergies: {
  readonly chargedBolt?: number | undefined
  readonly chargedBoltPoints?: number | undefined
  readonly nova?: number | undefined
  readonly novaPoints?: number | undefined
  readonly chainLightning?: number | undefined
  readonly chainLightningPoints?: number | undefined
}): number {
  const points =
    (synergies.chargedBolt ?? synergies.chargedBoltPoints ?? 0) +
    (synergies.nova ?? synergies.novaPoints ?? 0) +
    (synergies.chainLightning ?? synergies.chainLightningPoints ?? 0)
  return 1.0 + points * 0.08
}

/**
 * Authentic 1.13c Lightning (Skill 49) 5-band damage scaling (Skills.txt row 51):
 * EMin: 1, EMinLev1..5: 0 (Min damage is always 1)
 * EMax: 40, EMaxLev1..5: 8, 12, 20, 28, 36
 * Synergy: +8% per hard point in Charged Bolt, Nova, Chain Lightning.
 */
export function calculateLightningDamage(
  slvl: number,
  synergies?: {
    readonly chargedBolt?: number | undefined
    readonly chargedBoltPoints?: number | undefined
    readonly nova?: number | undefined
    readonly novaPoints?: number | undefined
    readonly chainLightning?: number | undefined
    readonly chainLightningPoints?: number | undefined
    readonly lightningMastery?: number | undefined
  } | number,
  lightningMastery?: number,
): { min: number; max: number } {
  const lvl = Number.isFinite(slvl) ? Math.max(1, Math.floor(slvl)) : 1
  let min = 1
  let max = 40
  if (lvl > 1) {
    const b1 = Math.min(lvl - 1, 7)
    max += b1 * 8
    if (lvl > 8) {
      const b2 = Math.min(lvl - 8, 8)
      max += b2 * 12
    }
    if (lvl > 16) {
      const b3 = Math.min(lvl - 16, 6)
      max += b3 * 20
    }
    if (lvl > 22) {
      const b4 = Math.min(lvl - 22, 6)
      max += b4 * 28
    }
    if (lvl > 28) {
      const b5 = lvl - 28
      max += b5 * 36
    }
  }

  const synMult =
    typeof synergies === 'number'
      ? (Number.isFinite(synergies) && synergies > 0 ? synergies : 1.0)
      : synergies
        ? calculateLightningSynergyMultiplier(synergies)
        : 1.0

  const masteryLvl =
    typeof lightningMastery === 'number'
      ? lightningMastery
      : typeof synergies === 'object' && synergies !== null
        ? synergies.lightningMastery ?? 0
        : 0
  const masteryBonus = masteryLvl > 0 ? calculateLightningMasteryBonusPct(masteryLvl) : 0

  min = Math.floor(min * synMult * (1 + masteryBonus / 100))
  max = Math.floor(max * synMult * (1 + masteryBonus / 100))
  return { min, max }
}

/**
 * Authentic 1.13c Chain Lightning (Skill 53) synergy multiplier:
 * +4% lightning damage per hard point in Charged Bolt (38), Nova (48), and Lightning (49).
 */
export function calculateChainLightningSynergyMultiplier(synergies: {
  readonly chargedBolt?: number | undefined
  readonly chargedBoltPoints?: number | undefined
  readonly nova?: number | undefined
  readonly novaPoints?: number | undefined
  readonly lightning?: number | undefined
  readonly lightningPoints?: number | undefined
}): number {
  const points =
    (synergies.chargedBolt ?? synergies.chargedBoltPoints ?? 0) +
    (synergies.nova ?? synergies.novaPoints ?? 0) +
    (synergies.lightning ?? synergies.lightningPoints ?? 0)
  return 1.0 + points * 0.04
}

/**
 * Authentic 1.13c Chain Lightning (Skill 53) jumps calculation:
 * 1.13c Skills.txt: Param5 = 5 (base jumps), calc1 = ln34 / 5 -> 5 + Math.floor(slvl / 5).
 */
export function calculateChainLightningJumps(slvl: number): number {
  const lvl = Number.isFinite(slvl) ? Math.max(1, Math.floor(slvl)) : 1
  return 5 + Math.floor(lvl / 5)
}

/**
 * Authentic 1.13c Chain Lightning (Skill 53) 5-band damage scaling (Skills.txt row 55):
 * EMin: 1, EMinLev1..5: 0 (Min damage is always 1)
 * EMax: 40, EMaxLev1..5: 11, 13, 15, 15, 15
 * Synergy: +4% per hard point in Charged Bolt, Nova, Lightning.
 */
export function calculateChainLightningDamage(
  slvl: number,
  synergies?: {
    readonly chargedBolt?: number | undefined
    readonly chargedBoltPoints?: number | undefined
    readonly nova?: number | undefined
    readonly novaPoints?: number | undefined
    readonly lightning?: number | undefined
    readonly lightningPoints?: number | undefined
    readonly lightningMastery?: number | undefined
  } | number,
  lightningMastery?: number,
): { min: number; max: number } {
  const lvl = Number.isFinite(slvl) ? Math.max(1, Math.floor(slvl)) : 1
  let min = 1
  let max = 40
  if (lvl > 1) {
    const b1 = Math.min(lvl - 1, 7)
    max += b1 * 11
    if (lvl > 8) {
      const b2 = Math.min(lvl - 8, 8)
      max += b2 * 13
    }
    if (lvl > 16) {
      const b3 = Math.min(lvl - 16, 6)
      max += b3 * 15
    }
    if (lvl > 22) {
      const b4 = Math.min(lvl - 22, 6)
      max += b4 * 15
    }
    if (lvl > 28) {
      const b5 = lvl - 28
      max += b5 * 15
    }
  }

  const synMult =
    typeof synergies === 'number'
      ? (Number.isFinite(synergies) && synergies > 0 ? synergies : 1.0)
      : synergies
        ? calculateChainLightningSynergyMultiplier(synergies)
        : 1.0

  const masteryLvl =
    typeof lightningMastery === 'number'
      ? lightningMastery
      : typeof synergies === 'object' && synergies !== null
        ? synergies.lightningMastery ?? 0
        : 0
  const masteryBonus = masteryLvl > 0 ? calculateLightningMasteryBonusPct(masteryLvl) : 0

  min = Math.floor(min * synMult * (1 + masteryBonus / 100))
  max = Math.floor(max * synMult * (1 + masteryBonus / 100))
  return { min, max }
}

/**
 * Authentic 1.13c Charged Bolt (Skill 38) 32-entry discrete orthogonal jitter offset lookup table.
 * Source: D2Common.dll VA 0x6FD85470 (PATH_ComputePathChargedBolt)
 */
export const GAT_CHARGED_BOLT_OFFSETS: readonly number[] = Object.freeze([
  -1, 0, 1, -1, 0, 1, -1, 0, 1, -1, 0, 1, -1, 0, 1, -1,
   0, 1, -1, 0, 1, -1, 0, 1, -1, 0, 1, -1, 0, 1, -1, 1,
])

/**
 * Authentic 1.13c Charged Bolt (Skill 38) bolt count:
 * min(24, slvl + 2)
 */
export function calculateChargedBoltCount(slvl: number): number {
  const lvl = Number.isFinite(slvl) ? Math.max(1, Math.floor(slvl)) : 1
  return Math.min(24, lvl + 2)
}

/**
 * Authentic 1.13c Charged Bolt (Skill 38) synergy multiplier:
 * +6% lightning damage per hard point in Lightning (49).
 */
export function calculateChargedBoltSynergyMultiplier(synergies: {
  readonly lightning?: number | undefined
  readonly lightningPoints?: number | undefined
} | number): number {
  if (typeof synergies === 'number') {
    return Number.isFinite(synergies) && synergies > 0 ? synergies : 1.0
  }
  const points = synergies?.lightning ?? synergies?.lightningPoints ?? 0
  return 1.0 + points * 0.06
}

/**
 * Authentic 1.13c Charged Bolt (Skill 38) 5-band damage scaling (Skills.txt row 40):
 * Base: 2-4, lvl 2-8: +1/+1, lvl 9-16: +1/+1, lvl 17-22: +2/+2, lvl 23-28: +3/+3, lvl 29+: +4/+4.
 * Synergy: +6% per hard point in Lightning (49).
 */
export function calculateChargedBoltDamage(
  slvl: number,
  synergies?: {
    readonly lightning?: number | undefined
    readonly lightningPoints?: number | undefined
    readonly lightningMastery?: number | undefined
  } | number,
  lightningMastery?: number,
): { min: number; max: number } {
  const lvl = Number.isFinite(slvl) ? Math.max(1, Math.floor(slvl)) : 1
  let min = 2
  let max = 4
  if (lvl > 1) {
    const b1 = Math.min(lvl - 1, 7)
    min += b1 * 1
    max += b1 * 1
    if (lvl > 8) {
      const b2 = Math.min(lvl - 8, 8)
      min += b2 * 1
      max += b2 * 1
    }
    if (lvl > 16) {
      const b3 = Math.min(lvl - 16, 6)
      min += b3 * 2
      max += b3 * 2
    }
    if (lvl > 22) {
      const b4 = Math.min(lvl - 22, 6)
      min += b4 * 3
      max += b4 * 3
    }
    if (lvl > 28) {
      const b5 = lvl - 28
      min += b5 * 4
      max += b5 * 4
    }
  }

  const synMult =
    typeof synergies === 'number'
      ? (Number.isFinite(synergies) && synergies > 0 ? synergies : 1.0)
      : synergies
        ? calculateChargedBoltSynergyMultiplier(synergies)
        : 1.0

  const masteryLvl =
    typeof lightningMastery === 'number'
      ? lightningMastery
      : typeof synergies === 'object' && synergies !== null
        ? synergies.lightningMastery ?? 0
        : 0
  const masteryBonus = masteryLvl > 0 ? calculateLightningMasteryBonusPct(masteryLvl) : 0

  min = Math.floor(min * synMult * (1 + masteryBonus / 100))
  max = Math.floor(max * synMult * (1 + masteryBonus / 100))
  return { min, max }
}

/**
 * Authentic 1.13c Telekinesis (Skill 43) hard synergy to Energy Shield (Skill 58):
 * Reduces Energy Shield damage-to-mana consumption ratio by 1/16 (0.0625) per hard point:
 * ratio = (32 - Math.min(20, TK_blvl)) / 16.
 * Level 0 -> 2.00, Level 8 -> 1.50, Level 16 -> 1.00, Level 20 -> 0.75.
 */
export function calculateEnergyShieldManaRatio(telekinesisBaseLevel: number): number {
  const blvl = Number.isFinite(telekinesisBaseLevel) ? Math.max(0, Math.floor(telekinesisBaseLevel)) : 0
  return (32 - Math.min(20, blvl)) / 16
}

/**
 * Authentic 1.13c Telekinesis (Skill 43) combat damage (Skills.txt row 45):
 * Deals 1-2 lightning damage base (slvl to slvl + 1).
 */
export function calculateTelekinesisDamage(slvl: number): { min: number; max: number } {
  const lvl = Number.isFinite(slvl) ? Math.max(1, Math.floor(slvl)) : 1
  return { min: lvl, max: lvl + 1 }
}

/**
 * Authentic 1.13c Telekinesis (Skill 43) remote item pickup whitelist:
 * Allowed: Potions, scrolls, gold, ammo (arrows/bolts), keys.
 * Forbidden: Equipment (weapons, armor, helms, shields, boots, gloves, belts, rings, amulets).
 */
export function isTelekinesisItemAllowed(item: any): boolean {
  if (!item) return false
  if (item.isGold === true) return true
  const code = (item.code || item.item?.code || item.base?.code || item.id || item.item?.id || '').toLowerCase().trim()
  const name = (item.name || item.item?.name || item.nameZh || item.item?.nameZh || '').toLowerCase()
  const type = (item.type || item.item?.type || item.base?.type || item.category || '').toLowerCase()

  if (code === 'gld' || code === 'gold' || item.isGold) return true
  if (/^(hp[1-5]|mp[1-5]|rvs|rvl|vps|yps|wms|ant|thw|sta)$/.test(code)) return true
  if (name.includes('potion') || name.includes('药剂') || name.includes('药水') || name.includes('活力') || name.includes('解毒') || name.includes('解冻')) return true
  if (/^(tsc|isc|tbk|ibk)$/.test(code)) return true
  if (name.includes('scroll') || name.includes('卷轴') || name.includes('tome') || name.includes('书')) return true
  if (/^(aqv|cqv)$/.test(code)) return true
  if (name.includes('arrow') || name.includes('bolt') || name.includes('箭矢') || name.includes('十字弓弹')) return true
  if (code === 'key' || name.includes('key') || name.includes('钥匙')) return true
  if (
    type === 'potion' ||
    type.includes('potion') ||
    type === 'scroll' ||
    type.includes('scroll') ||
    type === 'gold' ||
    type === 'ammo' ||
    type.includes('ammo') ||
    type.includes('arrow') ||
    type.includes('bolt') ||
    type === 'key'
  ) {
    return true
  }

  return false
}

/**
 * Authentic 1.13c Telekinesis (Skill 43) remote interactive object whitelist:
 * Supports: chest, locked chest, waypoint, portal, shrine, door, well, urn, sarcophagus, casket, stash, barrel.
 */
export function isTelekinesisObjectAllowed(objectTypeOrName: string): boolean {
  if (!objectTypeOrName) return false
  const norm = objectTypeOrName.toLowerCase().trim()
  return (
    norm.includes('chest') ||
    norm.includes('waypoint') ||
    norm.includes('portal') ||
    norm.includes('shrine') ||
    norm.includes('door') ||
    norm.includes('well') ||
    norm.includes('urn') ||
    norm.includes('casket') ||
    norm.includes('stash') ||
    norm.includes('barrel') ||
    norm.includes('sarcophagus') ||
    norm.includes('tomb')
  )
}


export function hasLineOfSight(
  x0: number,
  y0: number,
  x1: number,
  y1: number,
  terrain?: MissileTerrainCollision | ((x: number, y: number, fromX?: number, fromY?: number) => boolean) | undefined,
): boolean {
  if (!terrain) return true
  const dist = Math.hypot(x1 - x0, y1 - y0)
  if (dist === 0) return true
  const stepSize = 8
  const steps = Math.max(1, Math.ceil(dist / stepSize))
  let prevX = x0
  let prevY = y0
  for (let i = 1; i <= steps; i++) {
    const t = Math.min(1, i / steps)
    const curX = x0 + (x1 - x0) * t
    const curY = y0 + (y1 - y0) * t
    let blocked = false
    if (typeof terrain === 'function') {
      blocked = Boolean(terrain(curX, curY, prevX, prevY))
    } else if (terrain.isMissileBlocked !== undefined) {
      blocked = terrain.isMissileBlocked(curX, curY, prevX, prevY)
    } else if (terrain.overlap !== undefined) {
      blocked = terrain.overlap(curX, curY) > 0
    }
    if (blocked) {
      return false
    }
    prevX = curX
    prevY = curY
  }
  return true
}


/**
 * Authentic D2Game 64-entry discrete circle lookup tables (radius 30).
 * Replicated byte-for-byte from D2Game.dll 0x6FC581F0 (MISSMODE_SrvDo15_FrozenOrb)
 * and 0x6FC5CE10 (MISSMODE_SrvHit29_FrozenOrb).
 */
export const FROZEN_ORB_X_POSITIONS: readonly number[] = Object.freeze([
  30, 29, 29, 28, 27, 26, 24, 23, 21, 19, 16, 14, 11, 8, 5, 2,
  0, -2, -5, -8, -11, -14, -16, -19, -21, -23, -24, -26, -27, -28, -29, -29,
  -30, -29, -29, -28, -27, -26, -24, -23, -21, -19, -16, -14, -11, -8, -5, -2,
  0, 2, 5, 8, 11, 14, 16, 19, 21, 23, 24, 26, 27, 28, 29, 29,
])

export const FROZEN_ORB_Y_POSITIONS: readonly number[] = Object.freeze([
  0, 2, 5, 8, 11, 14, 16, 19, 21, 23, 24, 26, 27, 28, 29, 29,
  30, 29, 29, 28, 27, 26, 24, 23, 21, 19, 16, 14, 11, 8, 5, 2,
  0, -2, -5, -8, -11, -14, -16, -19, -21, -23, -24, -26, -27, -28, -29, -29,
  -30, -29, -29, -28, -27, -26, -24, -23, -21, -19, -16, -14, -11, -8, -5, -2,
])

export interface ActiveMissile {
  readonly uid: string
  readonly missileId: number
  readonly name: string
  readonly celFile: string
  readonly sourceSkillId: number
  readonly slvl: number
  readonly owner: CombatUnitContext
  readonly record: MissileRecord
  x: number
  y: number
  vx: number
  vy: number
  angleRad: number
  ageTicks: number
  readonly maxRangeTicks: number
  readonly nextHit: boolean
  readonly nextDelayFrames: number
  readonly canPierce: boolean
  readonly pierceChancePct: number
  pierceCount: number
  readonly hitTargetIds: Set<string>
  readonly dmgPacket: SUnitDmgPacket
  chainRemaining: number
  lastHitTargetId?: string | undefined
  expired: boolean
  subMissileIdx?: number
  currentHitFrame?: number
  isTurret?: boolean | undefined
  fireCadenceTicks?: number | undefined
  spawnMissileType?: string | undefined
  altitude?: number | undefined
  seed?: number | undefined
  jitterIndex?: number | undefined
}

export interface MissileTerrainCollision {
  readonly overlap?: ((x: number, y: number) => number) | undefined
  readonly isMissileBlocked?: ((x: number, y: number, fromX?: number, fromY?: number) => boolean) | undefined
}

export interface MissileStepResult {
  readonly hits: {
    readonly missileName: string
    readonly targetId: string
    readonly damage: number
    readonly immune: boolean
  }[]
  readonly subMissilesSpawned: string[]
}

export class MissileEngine {
  readonly registry: D2DataRegistry
  private readonly missiles: ActiveMissile[] = []
  private readonly nextDelayExpireByTarget = new Map<string, number>()
  private uidCounter = 1
  terrain?: MissileTerrainCollision | undefined

  constructor(registry: D2DataRegistry, terrain?: MissileTerrainCollision) {
    this.registry = registry
    this.terrain = terrain
  }

  setTerrain(terrain?: MissileTerrainCollision): void {
    this.terrain = terrain
  }

  spawnMissile(params: {
    missileNameOrId: string | number
    sourceSkillId: number
    slvl: number
    owner: CombatUnitContext
    startX: number
    startY: number
    targetX: number
    targetY: number
    dmgPacket: SUnitDmgPacket
    pierceChancePct?: number
    chainCount?: number
    chainRemaining?: number
    lastHitTargetId?: string
    isTurret?: boolean
    fireCadenceTicks?: number
    spawnMissileType?: string
    maxRangeTicks?: number
    altitude?: number
    seed?: number
    jitterIndex?: number
    vx?: number
    vy?: number
    angleRad?: number
  }): ActiveMissile | null {
    const rec =
      typeof params.missileNameOrId === 'number'
        ? this.registry.getMissileById(params.missileNameOrId)
        : this.registry.getMissileByName(params.missileNameOrId)

    const fallbackName = String(params.missileNameOrId).trim().toLowerCase()
    const effectiveRec: MissileRecord =
      rec ?? {
        id: 0,
        name: fallbackName || 'defaultmissile',
        pCltDoFunc: 1,
        pCltHitFunc: 0,
        pSrvDoFunc: 1,
        pSrvHitFunc: 0,
        pSrvDmgFunc: 0,
        srvCalc1: '',
        param1: 0,
        param2: 0,
        param3: 0,
        param4: 0,
        param5: 0,
        cltCalc1: '',
        cParam1: 0,
        cParam2: 0,
        cParam3: 0,
        cParam4: 0,
        cParam5: 0,
        sHitCalc1: '',
        sHitPar1: 0,
        sHitPar2: 0,
        sHitPar3: 0,
        cHitCalc1: '',
        cHitPar1: 0,
        cHitPar2: 0,
        cHitPar3: 0,
        dmgCalc1: '',
        dParam1: 0,
        dParam2: 0,
        vel: 16,
        maxVel: 24,
        velLev: 0,
        accel: 0,
        range: 40,
        levRange: 0,
        light: 0,
        flicker: 0,
        red: 255,
        green: 255,
        blue: 255,
        initSteps: 0,
        activate: 0,
        loopAnim: 0,
        celFile: fallbackName || 'fireball',
        animRate: 1024,
        animLen: 8,
        animSpeed: 16,
        subLoop: false,
        subStart: 0,
        subStop: 0,
        collideType: 3,
        collideKill: true,
        collideFriend: false,
        lastCollide: false,
        collision: true,
        clientCol: true,
        nextHit: false,
        nextDelay: 0,
        size: 2,
        returnFire: false,
        trans: 1,
        alwaysExplode: false,
        explosion: false,
        town: true,
        noUniqueMod: false,
        noMultiShot: false,
        holy: 0,
        canSlow: false,
        canDestroy: false,
        toHit: false,
        pierce: false,
        skill: '',
        hitShift: 8,
        srcDamage: 0,
        minDamage: 0,
        minLevDam1: 0,
        minLevDam2: 0,
        minLevDam3: 0,
        minLevDam4: 0,
        minLevDam5: 0,
        maxDamage: 0,
        maxLevDam1: 0,
        maxLevDam2: 0,
        maxLevDam3: 0,
        maxLevDam4: 0,
        maxLevDam5: 0,
        dmgSymPerCalc: '',
        eType: 'fire',
        eMin: 0,
        eMinLev1: 0,
        eMinLev2: 0,
        eMinLev3: 0,
        eMinLev4: 0,
        eMinLev5: 0,
        eMax: 0,
        eMaxLev1: 0,
        eMaxLev2: 0,
        eMaxLev3: 0,
        eMaxLev4: 0,
        eMaxLev5: 0,
        eDmgSymPerCalc: '',
        eLen: 0,
        eLevLen1: 0,
        eLevLen2: 0,
        eLevLen3: 0,
        hitClass: 0,
        numDirections: 16,
        localBlood: 0,
        damageRate: 0,
        explosionMissile: '',
        subMissile1: '',
        subMissile2: '',
        subMissile3: '',
        hitSubMissile1: '',
        hitSubMissile2: '',
        hitSubMissile3: '',
        hitSubMissile4: '',
        cltSubMissile1: '',
        cltSubMissile2: '',
        cltSubMissile3: '',
        cltHitSubMissile1: '',
        cltHitSubMissile2: '',
        cltHitSubMissile3: '',
        cltHitSubMissile4: '',
        raw: {},
      }

    const dx = params.targetX - params.startX
    const dy = params.targetY - params.startY
    const calculatedAngleRad = dx === 0 && dy === 0 ? Math.PI / 2 : Math.atan2(dy, dx)
    const angleRad = params.angleRad ?? calculatedAngleRad
    const isTurret = Boolean(params.isTurret || effectiveRec.name.toLowerCase() === 'hydra_turret')
    const isStationary =
      isTurret ||
      effectiveRec.vel === 0 ||
      effectiveRec.name.toLowerCase().startsWith('blizzard') ||
      effectiveRec.name.toLowerCase().startsWith('meteor')
    const speedPxPerTick = isStationary ? 0 : Math.max(8, effectiveRec.vel || 18)
    const vx = params.vx !== undefined ? params.vx : (isStationary ? 0 : Math.cos(angleRad) * speedPxPerTick)
    const vy = params.vy !== undefined ? params.vy : (isStationary ? 0 : Math.sin(angleRad) * speedPxPerTick)
    const baseRange = effectiveRec.range !== undefined && effectiveRec.range > 0 ? effectiveRec.range : 35
    const calculatedRange = baseRange + Math.max(0, params.slvl - 1) * (effectiveRec.levRange || 0)
    const maxRangeTicks = params.maxRangeTicks ?? (
      isTurret
        ? 250 // 1.13c Hydra duration: 250 frames (10 seconds)
        : calculatedRange
    )

    const missile: ActiveMissile = {
      uid: `msl-${String(this.uidCounter++)}`,
      missileId: effectiveRec.id,
      name: effectiveRec.name,
      celFile: effectiveRec.celFile || effectiveRec.name,
      sourceSkillId: params.sourceSkillId,
      slvl: params.slvl,
      owner: params.owner,
      record: effectiveRec,
      x: params.startX,
      y: params.startY,
      vx,
      vy,
      angleRad,
      ageTicks: 0,
      maxRangeTicks,
      nextHit: effectiveRec.nextHit,
      nextDelayFrames: effectiveRec.nextDelay,
      canPierce: effectiveRec.pierce || (params.pierceChancePct ?? 0) > 0,
      pierceChancePct: params.pierceChancePct ?? (effectiveRec.pierce ? 100 : 0),
      pierceCount: 0,
      hitTargetIds: new Set<string>(),
      dmgPacket: params.dmgPacket,
      chainRemaining: params.chainRemaining ?? params.chainCount ?? (effectiveRec.pSrvHitFunc === 12 ? 5 + Math.trunc(params.slvl / 5) : 0),
      lastHitTargetId: params.lastHitTargetId,
      expired: false,
      isTurret,
      ...(params.altitude !== undefined ? { altitude: params.altitude } : {}),
      ...(params.fireCadenceTicks !== undefined
        ? { fireCadenceTicks: params.fireCadenceTicks }
        : isTurret
          ? { fireCadenceTicks: 25 }
          : {}),
      ...(params.spawnMissileType !== undefined
        ? { spawnMissileType: params.spawnMissileType }
        : isTurret
          ? { spawnMissileType: 'hydra' }
          : {}),
      ...(params.seed !== undefined ? { seed: params.seed } : {}),
      ...(params.jitterIndex !== undefined
        ? { jitterIndex: params.jitterIndex }
        : params.seed !== undefined
          ? { jitterIndex: Math.abs(params.seed) % 32 }
          : {}),
    }

    this.missiles.push(missile)
    return missile
  }

  /**
   * Check if a target unit is currently within its `NextDelay` immunity window.
   */
  isTargetInNextDelay(targetId: string, currentTick: number): boolean {
    const exp = this.nextDelayExpireByTarget.get(targetId)
    return exp !== undefined && exp > currentTick
  }

  /**
   * Step all active missiles by 1 tick (`25 Hz`), resolving movement (`pSrvDoFunc`),
   * collisions (`pSrvHitFunc`), `NextDelay` gating, `Pierce`, and sub-missiles.
   */
  tick(
    currentTick: number = 0,
    targets: readonly CombatUnitContext[] = [],
    targetPositions: ReadonlyMap<string, { x: number; y: number }> = new Map(),
    collision?: MissileTerrainCollision,
  ): MissileStepResult {
    const hits: { missileName: string; targetId: string; damage: number; immune: boolean }[] = []
    const subMissilesSpawned: string[] = []

    for (const m of [...this.missiles]) {
      if (m.expired) continue
      m.ageTicks += 1

      if (m.name === 'meteor' || m.name === 'meteortail') {
        if (m.altitude === undefined) m.altitude = 60 * 25
        m.altitude = Math.max(0, m.altitude - 25)
      }

      // `pSrvDoFunc = 15` (`frozenorb`): emits radial `frozenorbbolt` sub-missiles while flying
      // Authentic D2Game.0x6FC581F0 (MISSMODE_SrvDo15_FrozenOrb):
      // - 64-entry discrete circle lookup table (radius 30)
      // - Trigger frequency: dwParam[0] (1 frame)
      // - Angular step: dwParam[1] (19 directions per step, coprime with 64)
      // - Foreshortened by ISO_GROUND_ASPECT_RATIO = 0.5 in 2:1 isometric ground perspective
      if (m.record.pSrvDoFunc === 15) {
        const nFrames = Math.max(1, m.record.param1 || 1)
        if (m.ageTicks % nFrames === 0 || (m.maxRangeTicks - m.ageTicks) % nFrames <= 0) {
          const subName = m.record.subMissile1 || 'frozenorbbolt'
          const idx = Math.abs((m.subMissileIdx ?? 0) % 64)
          const offX = FROZEN_ORB_X_POSITIONS[idx]!
          const offY = FROZEN_ORB_Y_POSITIONS[idx]! * ISO_GROUND_ASPECT_RATIO
          this.spawnMissile({
            missileNameOrId: subName,
            sourceSkillId: m.sourceSkillId,
            slvl: m.slvl,
            owner: m.owner,
            startX: m.x,
            startY: m.y,
            targetX: m.x + offX * 10,
            targetY: m.y + offY * 10,
            dmgPacket: m.dmgPacket,
          })
          subMissilesSpawned.push(subName)
          const step = m.record.param2 || 19
          m.subMissileIdx = (idx + step) % 64
        }
      }

      // `pSrvDoFunc = 16` (`frozenorbnova`): authentic D2Game.0x6FC58340
      // In the final frames before expiry (dwParam[0] = 6), every dwParam[1] = 2 frames,
      // apply affine rotation & damping curl: x' = (x - y) / 2, y' = (x + y) / 2
      if (m.record.pSrvDoFunc === 16) {
        const remaining = m.maxRangeTicks - m.ageTicks
        const threshold = m.record.param1 || 6
        const nParam = Math.max(1, m.record.param2 || 2)
        if (remaining < threshold && remaining % nParam === 0) {
          const diff = m.vx - m.vy
          const sum = m.vx + m.vy
          m.vx = diff / 2
          m.vy = sum / 2
        }
      }

      // `pSrvDoFunc = 10` (`blizzardcenter`): emits falling shards across 64-entry circle table
      // Authentic D2Game.0x6FC60CA0 (MISSMODE_SrvDo10_blizzardcenter):
      // - Trigger frequency: dwParam[2] (4 frames, Param3 in Skills.txt)
      // - Angular step: 13 (coprime with 64)
      // - Radius: 7 subtiles
      // - Foreshortened by ISO_GROUND_ASPECT_RATIO = 0.5 in 2:1 isometric ground perspective
      if (m.record.pSrvDoFunc === 10 || m.name === 'blizzardcenter') {
        const cadence = Math.max(1, m.record.param3 || 4)
        if (m.ageTicks % cadence === 0) {
          const idx = Math.abs((m.subMissileIdx ?? 0) % 64)
          const offset = getBlizzardDropOffset(idx, 7)
          const shardVariants = ['blizzard1', 'blizzard2', 'blizzard3', 'blizzard4'] as const
          const shardName = shardVariants[Math.floor((m.ageTicks / cadence) - 1) % shardVariants.length]!
          this.spawnMissile({
            missileNameOrId: shardName,
            sourceSkillId: m.sourceSkillId,
            slvl: m.slvl,
            owner: m.owner,
            startX: m.x + offset.dx,
            startY: m.y + offset.dy,
            targetX: m.x + offset.dx,
            targetY: m.y + offset.dy,
            dmgPacket: m.dmgPacket,
          })
          subMissilesSpawned.push(shardName)
          m.subMissileIdx = (idx + 13) % 64
        }
      }

      // Turret emitter (Hydra heads): stationary emitter periodically firing bolts at nearest target
      const isTurretEmitter = Boolean(m.isTurret || m.name.toLowerCase() === 'hydra_turret')
      if (isTurretEmitter) {
        const cadence = m.fireCadenceTicks ?? 25
        if (m.ageTicks % cadence === 0) {
          let closestTargetId: string | null = null
          let closestDist = Infinity
          const maxRangePx = 480 // 1.13c Range = 30, Vel = 16 -> 480 px

          for (const target of targets) {
            if (target.statList.getHp256() <= 0) continue
            const pos = targetPositions.get(target.id) ?? { x: 0, y: 120 }
            const dx = pos.x - m.x
            const dy = (pos.y - m.y) / ISO_GROUND_ASPECT_RATIO
            const dist = Math.hypot(dx, dy)
            if (dist <= maxRangePx && dist < closestDist) {
              closestDist = dist
              closestTargetId = target.id
            }
          }

          if (closestTargetId) {
            const targetPos = targetPositions.get(closestTargetId) ?? { x: 0, y: 120 }
            const subName = m.spawnMissileType || 'hydra'
            this.spawnMissile({
              missileNameOrId: subName,
              sourceSkillId: m.sourceSkillId,
              slvl: m.slvl,
              owner: m.owner,
              startX: m.x,
              startY: m.y,
              targetX: targetPos.x,
              targetY: targetPos.y,
              dmgPacket: m.dmgPacket,
            })
            subMissilesSpawned.push(subName)
          }
        }
      }

      // Spiral flight for Blessed Hammer (`blessedhammer`, `skillId = 112`)
      // In 2:1 isometric ground perspective, vertical expansion is foreshortened by 0.5.
      if (isTurretEmitter) {
        // Stationary turret does not move
      } else if (m.sourceSkillId === 112 || m.name.toLowerCase() === 'blessedhammer') {
        m.angleRad += 0.24
        const radius = 14 + m.ageTicks * 4
        m.x += Math.cos(m.angleRad) * (radius * 0.25)
        m.y += Math.sin(m.angleRad) * (radius * 0.25 * 0.5)
      } else {
        const prevX = m.x
        const prevY = m.y
        m.x += m.vx
        m.y += m.vy

        // Authentic 1.13c Charged Bolt (Skill 38 / missile 56 / pDoFunc 11):
        // Discrete orthogonal jitter table: 32-entry lookup table gatChargedBoltOffsets
        // applied perpendicularly to main propagation vector per step (2 subtiles/step) with individual low-seed PRNG.
        if (m.name === 'chargedbolt' || m.sourceSkillId === 38 || m.record.pSrvDoFunc === 11 || m.record.pCltDoFunc === 11) {
          const speed = Math.hypot(m.vx, m.vy)
          if (speed > 0) {
            const perpX = -m.vy / speed
            const perpY = m.vx / speed
            const idx = Math.abs((m.jitterIndex ?? m.ageTicks) % 32)
            const offset = GAT_CHARGED_BOLT_OFFSETS[idx]! * 3
            m.x += perpX * offset
            m.y += perpY * (offset * ISO_GROUND_ASPECT_RATIO)
            m.jitterIndex = (idx + 1) % 32
          }
        }

        const effectiveTerrain = collision ?? this.terrain
        if (effectiveTerrain !== undefined && !isTurretEmitter && (m.altitude === undefined || m.altitude <= 0)) {
          // Continuous collision stepping between (prevX, prevY) and (m.x, m.y) to prevent tunneling through thin (<24px) walls
          const moveDist = Math.hypot(m.vx, m.vy)
          const stepSize = 8
          const steps = Math.max(1, Math.ceil(moveDist / stepSize))
          let blocked = false
          let checkPrevX = prevX
          let checkPrevY = prevY
          for (let s = 1; s <= steps; s++) {
            const t = s / steps
            const curX = prevX + (m.x - prevX) * t
            const curY = prevY + (m.y - prevY) * t
            if (effectiveTerrain.isMissileBlocked !== undefined) {
              if (effectiveTerrain.isMissileBlocked(curX, curY, checkPrevX, checkPrevY)) {
                blocked = true
                break
              }
            } else if (effectiveTerrain.overlap !== undefined && effectiveTerrain.overlap(curX, curY) > 0) {
              blocked = true
              break
            }
            checkPrevX = curX
            checkPrevY = curY
          }
          if (blocked) {
            m.expired = true
            continue
          }
        }
      }

      // Check collision against alive enemy targets
      if (m.name === 'meteorfire' && m.ageTicks % 5 === 0) {
        m.hitTargetIds.clear()
      }
      const hitRadius = Math.max(24, (m.record.size || 2) * 14)
      for (const target of targets) {
        if (target.statList.getHp256() <= 0) continue
        if (m.hitTargetIds.has(target.id)) continue

        // Holy Bolt (`skillId = 101` or `fistoftheheavensbolt` `234`): only damages Undead (or Demons if FoH main bolt)
        if (
          (m.name.toLowerCase() === 'holybolt' || m.name.toLowerCase() === 'fistoftheheavensbolt') &&
          !target.isUndead
        ) {
          continue
        }

        // Main Frozen Orb (pSrvDoFunc === 15), Blizzard Center (pSrvDoFunc === 10), Meteor Center (pSrvHitFunc === 14 / meteorcenter),
        // and Hydra turret emitters do not deal direct contact damage; all damage is delivered through emitted child bolts / shards.
        if (
          m.record.pSrvDoFunc === 15 ||
          m.record.pSrvDoFunc === 10 ||
          m.name === 'blizzardcenter' ||
          m.record.pSrvHitFunc === 14 ||
          m.name === 'meteorcenter' ||
          m.name === 'meteor' ||
          m.name === 'meteortail' ||
          isTurretEmitter
        ) {
          continue
        }

        const pos = targetPositions.get(target.id) ?? { x: 0, y: 120 }
        const dist =
          m.name === 'meteorfire'
            ? Math.hypot(pos.x - m.x, (pos.y - m.y) / ISO_GROUND_ASPECT_RATIO)
            : Math.hypot(pos.x - m.x, pos.y - m.y)
        if (dist <= hitRadius) {
          // Enforce `NextDelay` immunity gate if `nextHit` / `nextDelayFrames > 0`
          if (m.nextDelayFrames > 0 && this.isTargetInNextDelay(target.id, currentTick)) {
            continue
          }

          m.hitTargetIds.add(target.id)
          if (m.nextDelayFrames > 0) {
            this.nextDelayExpireByTarget.set(target.id, currentTick + m.nextDelayFrames)
          }

          const dmgOut = executeSUnitDmg(m.owner, target, m.dmgPacket)
          hits.push({
            missileName: m.name,
            targetId: target.id,
            damage: dmgOut.totalDamage,
            immune: dmgOut.immuneToElem || dmgOut.immuneToPhys,
          })

          // `pSrvHitFunc = 1` or `4` or `13`: radial splash damage (`Fire Ball`, `Exploding Arrow`, `Freezing Arrow`, `Glacial Spike`)
          if (
            m.record.pSrvHitFunc === 1 ||
            m.record.pSrvHitFunc === 4 ||
            m.record.pSrvHitFunc === 9 ||
            m.record.pSrvHitFunc === 13
          ) {
            for (const other of targets) {
              if (other.id === target.id || other.statList.getHp256() <= 0) continue
              const oPos = targetPositions.get(other.id) ?? { x: 0, y: 120 }
              if (Math.hypot(oPos.x - pos.x, oPos.y - pos.y) <= 85) {
                const splashOut = executeSUnitDmg(m.owner, other, m.dmgPacket)
                hits.push({
                  missileName: `${m.name}:splash`,
                  targetId: other.id,
                  damage: splashOut.totalDamage,
                  immune: splashOut.immuneToElem || splashOut.immuneToPhys,
                })
              }
            }
          }

          // `pSrvHitFunc = 12` (`Chain Lightning` 53, `Lightning Strike` 34, `royalstrikechainlightning` 568):
          // Authentic 1.13c ping-pong chaining: excludes the target just hit (target.id),
          // searches up to 20 subtiles (10 yards = 400 px), and leaps to the closest valid alive enemy.
          if (m.record.pSrvHitFunc === 12 && m.chainRemaining > 0) {
            const searchRadiusPx = 400
            let nextTarget: CombatUnitContext | undefined
            let minDistance = Infinity
            for (const cand of targets) {
              if (cand.id === target.id || cand.statList.getHp256() <= 0) continue
              const candPos = targetPositions.get(cand.id) ?? { x: 0, y: 120 }
              const dist = Math.hypot(candPos.x - pos.x, candPos.y - pos.y)
              if (dist <= searchRadiusPx && dist < minDistance) {
                minDistance = dist
                nextTarget = cand
              }
            }
            if (nextTarget) {
              const nPos = targetPositions.get(nextTarget.id) ?? { x: 0, y: 120 }
              this.spawnMissile({
                missileNameOrId: m.name,
                sourceSkillId: m.sourceSkillId,
                slvl: m.slvl,
                owner: m.owner,
                startX: pos.x,
                startY: pos.y,
                targetX: nPos.x,
                targetY: nPos.y,
                dmgPacket: m.dmgPacket,
                chainCount: m.chainRemaining - 1,
                lastHitTargetId: target.id,
              })
              subMissilesSpawned.push(m.name)
            }
          }

          // `pSrvHitFunc = 20` (`Lightning Fury` 35): release radial `lightningjavelin` bolts toward nearby enemies
          if (m.record.pSrvHitFunc === 20 || m.sourceSkillId === 35) {
            const subBolt = m.record.hitSubMissile1 || 'lightningjavelin'
            for (const other of targets) {
              if (other.id === target.id || other.statList.getHp256() <= 0) continue
              const oPos = targetPositions.get(other.id) ?? { x: 0, y: 120 }
              this.spawnMissile({
                missileNameOrId: subBolt,
                sourceSkillId: m.sourceSkillId,
                slvl: m.slvl,
                owner: m.owner,
                startX: pos.x,
                startY: pos.y,
                targetX: oPos.x,
                targetY: oPos.y,
                dmgPacket: m.dmgPacket,
              })
              subMissilesSpawned.push(subBolt)
            }
          }

          // `pSrvHitFunc = 22` (`Fist of the Heavens` 121): release radial `fistoftheheavensbolt` (`holybolt`)
          if (m.record.pSrvHitFunc === 22 || m.sourceSkillId === 121) {
            const subBolt = m.record.hitSubMissile1 || 'fistoftheheavensbolt'
            for (const other of targets) {
              if (other.id === target.id || other.statList.getHp256() <= 0) continue
              const oPos = targetPositions.get(other.id) ?? { x: 0, y: 120 }
              this.spawnMissile({
                missileNameOrId: subBolt,
                sourceSkillId: m.sourceSkillId,
                slvl: m.slvl,
                owner: m.owner,
                startX: pos.x,
                startY: pos.y,
                targetX: oPos.x,
                targetY: oPos.y,
                dmgPacket: m.dmgPacket,
              })
              subMissilesSpawned.push(subBolt)
            }
          }

          // Pierce evaluation (1.13c cap: max 4 pierces = 5 total targets hit, EXCEPT infinite piercing missiles like Lightning)
          const isInfinitePierce =
            m.name === 'lightningbolt' ||
            m.name === 'lightning' ||
            (!m.record.collideKill && m.canPierce)
          if (m.name === 'meteorfire') {
            // Ground fire persists for its full duration and does not die on hit
          } else if (isInfinitePierce) {
            m.pierceCount += 1
          } else if (m.canPierce && m.pierceCount < 4 && m.pierceChancePct > 0) {
            m.pierceCount += 1
          } else if (m.record.collideKill || !m.canPierce) {
            if (
              m.name.startsWith('blizzard') &&
              !m.name.includes('explode') &&
              m.name !== 'blizzardcenter'
            ) {
              const expName = m.record.explosionMissile || 'blizzardexplode1'
              this.spawnMissile({
                missileNameOrId: expName,
                sourceSkillId: m.sourceSkillId,
                slvl: m.slvl,
                owner: m.owner,
                startX: m.x,
                startY: m.y,
                targetX: m.x,
                targetY: m.y,
                dmgPacket: m.dmgPacket,
              })
              subMissilesSpawned.push(expName)
            }
            m.expired = true
            break
          }
        }
      }

      if (m.ageTicks >= m.maxRangeTicks) {
        // `pSrvHitFunc = 14` (`Meteor` detonation and ground fire patch cascade)
        // Authentic D2Game 0x6FC5DEF0 (MISSMODE_SrvHit14_MeteorCenter) & 0x6FC5CEC0:
        if (
          (m.record.pSrvHitFunc === 14 || m.name === 'meteorcenter') &&
          (!m.currentHitFrame || m.currentHitFrame === 0)
        ) {
          m.currentHitFrame = 1
          // 1. Primary explosion AOE damage (Radius = 6 subtiles = 120px) in 2:1 isometric ground perspective
          const blastRadius = 120
          for (const target of targets) {
            if (target.statList.getHp256() <= 0) continue
            const pos = targetPositions.get(target.id) ?? { x: 0, y: 120 }
            const inRange =
              Math.hypot(pos.x - m.x, (pos.y - m.y) / ISO_GROUND_ASPECT_RATIO) <= blastRadius
            if (inRange) {
              const dmgOut = executeSUnitDmg(m.owner, target, m.dmgPacket)
              hits.push({
                missileName: 'meteorexplode',
                targetId: target.id,
                damage: dmgOut.totalDamage,
                immune: dmgOut.immuneToElem || dmgOut.immuneToPhys,
              })
            }
          }

          // 2. Spawn explosion missile: meteorexplode (ID 103)
          const expName = m.record.explosionMissile || 'meteorexplode'
          this.spawnMissile({
            missileNameOrId: expName,
            sourceSkillId: m.sourceSkillId,
            slvl: m.slvl,
            owner: m.owner,
            startX: m.x,
            startY: m.y,
            targetX: m.x,
            targetY: m.y,
            dmgPacket: m.dmgPacket,
          })
          subMissilesSpawned.push(expName)

          // 3. Spawn 18 meteorfire submissiles using 18-offset table
          const subFireName = m.record.hitSubMissile1 || 'meteorfire'
          const fireDuration = 30 + (Math.max(1, m.slvl) - 1) * 15
          const fireDmg = calculateMeteorResidualFireDamage(m.slvl)
          const fireDmgPacket: SUnitDmgPacket = {
            skillId: m.sourceSkillId,
            attackKind: 'spell',
            elemType: 'fire',
            elemMin256: fireDmg.min * 8, // HitShift 3: << 3 = * 8
            elemMax256: fireDmg.max * 8,
          }
          const effectiveTerrain = collision ?? this.terrain
          for (const off of METEOR_FIRE_SUBTILE_OFFSETS) {
            const fx = m.x + off.x * 20
            const fy = m.y + off.y * 10
            if (effectiveTerrain !== undefined) {
              const blocked =
                effectiveTerrain.isMissileBlocked !== undefined
                  ? effectiveTerrain.isMissileBlocked(fx, fy, m.x, m.y)
                  : effectiveTerrain.overlap !== undefined && effectiveTerrain.overlap(fx, fy) > 0
              if (blocked) {
                continue
              }
            }
            this.spawnMissile({
              missileNameOrId: subFireName,
              sourceSkillId: m.sourceSkillId,
              slvl: m.slvl,
              owner: m.owner,
              startX: fx,
              startY: fy,
              targetX: fx,
              targetY: fy,
              dmgPacket: fireDmgPacket,
              maxRangeTicks: fireDuration,
            })
            subMissilesSpawned.push(subFireName)
          }
        }
        // Blizzard falling shard ground impact explosion (Missiles 159..162)
        if (
          m.name.startsWith('blizzard') &&
          !m.name.includes('explode') &&
          m.name !== 'blizzardcenter' &&
          (!m.currentHitFrame || m.currentHitFrame === 0)
        ) {
          m.currentHitFrame = 1
          const expName = m.record.explosionMissile || 'blizzardexplode1'
          this.spawnMissile({
            missileNameOrId: expName,
            sourceSkillId: m.sourceSkillId,
            slvl: m.slvl,
            owner: m.owner,
            startX: m.x,
            startY: m.y,
            targetX: m.x,
            targetY: m.y,
            dmgPacket: m.dmgPacket,
          })
          subMissilesSpawned.push(expName)
        }

        // `pSrvHitFunc = 29` (`Frozen Orb` expiration burst)
        // Authentic D2Game.0x6FC5CE10 (MISSMODE_SrvHit29_FrozenOrb):
        // - Triggers only on first frame of hit (currentHitFrame === 0)
        // - Loop with step sHitPar1 = 4 over 64 directions -> exactly 16 frozenorbnova missiles!
        // - Foreshortened by ISO_GROUND_ASPECT_RATIO = 0.5 in 2:1 isometric ground perspective
        if (m.record.pSrvHitFunc === 29 && (!m.currentHitFrame || m.currentHitFrame === 0)) {
          m.currentHitFrame = 1
          const subName = m.record.hitSubMissile1 || 'frozenorbnova'
          const step = Math.max(1, m.record.sHitPar1 || 4)
          for (let i = 0; i < 64; i += step) {
            const offX = FROZEN_ORB_X_POSITIONS[i]!
            const offY = FROZEN_ORB_Y_POSITIONS[i]! * ISO_GROUND_ASPECT_RATIO
            this.spawnMissile({
              missileNameOrId: subName,
              sourceSkillId: m.sourceSkillId,
              slvl: m.slvl,
              owner: m.owner,
              startX: m.x,
              startY: m.y,
              targetX: m.x + offX * 10,
              targetY: m.y + offY * 10,
              dmgPacket: m.dmgPacket,
            })
            subMissilesSpawned.push(subName)
          }
          const explosionName = m.record.explosionMissile || 'frozenorbexplode'
          this.spawnMissile({
            missileNameOrId: explosionName,
            sourceSkillId: m.sourceSkillId,
            slvl: m.slvl,
            owner: m.owner,
            startX: m.x,
            startY: m.y,
            targetX: m.x,
            targetY: m.y,
            dmgPacket: m.dmgPacket,
          })
          subMissilesSpawned.push(explosionName)
        }
        m.expired = true
      }
    }

    // Purge expired missiles
    for (let i = this.missiles.length - 1; i >= 0; i -= 1) {
      if (this.missiles[i]!.expired) {
        this.missiles.splice(i, 1)
      }
    }

    return { hits, subMissilesSpawned }
  }

  getActiveMissiles(): readonly ActiveMissile[] {
    return this.missiles
  }

  /**
   * Spawns authentic 1.13c 64-bolt circular Nova ring with 2:1 isometric ground foreshortening.
   * Speed = 24, Range = 13 frames, NextDelay = 4 frames.
   */
  spawnNovaRing(params: {
    sourceSkillId?: number
    slvl?: number
    owner: CombatUnitContext
    startX: number
    startY: number
    dmgPacket: SUnitDmgPacket
    missileName?: string
  }): ActiveMissile[] {
    const spawned: ActiveMissile[] = []
    const skillId = params.sourceSkillId ?? 48
    const slvl = params.slvl ?? 1
    const missileName = params.missileName ?? 'nova'
    const speed = 24 // 1.13c Missiles.txt: Vel = 24
    for (let i = 0; i < 64; i++) {
      const angle = (i / 64) * 2 * Math.PI
      const vx = Math.cos(angle) * speed
      const vy = Math.sin(angle) * speed * ISO_GROUND_ASPECT_RATIO
      const m = this.spawnMissile({
        missileNameOrId: missileName,
        sourceSkillId: skillId,
        slvl,
        owner: params.owner,
        startX: params.startX,
        startY: params.startY,
        targetX: params.startX + Math.cos(angle) * 100,
        targetY: params.startY + Math.sin(angle) * 100 * ISO_GROUND_ASPECT_RATIO,
        dmgPacket: params.dmgPacket,
        vx,
        vy,
        angleRad: angle,
      })
      if (m) spawned.push(m)
    }
    return spawned
  }

  /**
   * Executes authentic 1.13c instantaneous 360° Static Field discharge with difficulty floors and LOS.
   * Cuts 25% current HP with Normal (1 HP), Nightmare (33% max HP), and Hell (50% max HP) pre-check clamps.
   */
  executeStaticField(params: {
    caster: CombatUnitContext
    casterPos: { x: number; y: number }
    slvl?: number
    targets: readonly CombatUnitContext[]
    targetPositions: ReadonlyMap<string, { x: number; y: number }>
    difficulty?: 'normal' | 'nightmare' | 'hell'
    terrain?: MissileTerrainCollision
  }): {
    hits: {
      targetId: string
      damage: number
      immune: boolean
      blockedByFloor: boolean
      blockedByLos: boolean
    }[]
    radiusPx: number
  } {
    const slvl = params.slvl ?? 1
    const radiusPx = calculateStaticFieldRadiusPx(slvl)
    const difficulty = params.difficulty ?? 'normal'
    const effectiveTerrain = params.terrain ?? this.terrain
    const hits: {
      targetId: string
      damage: number
      immune: boolean
      blockedByFloor: boolean
      blockedByLos: boolean
    }[] = []

    for (const target of params.targets) {
      if (target.statList.getHp256() <= 0) continue
      const pos = params.targetPositions.get(target.id) ?? { x: 0, y: 0 }
      const dist = Math.hypot(pos.x - params.casterPos.x, pos.y - params.casterPos.y)
      if (dist > radiusPx) continue

      const los = hasLineOfSight(params.casterPos.x, params.casterPos.y, pos.x, pos.y, effectiveTerrain)
      if (!los) {
        hits.push({
          targetId: target.id,
          damage: 0,
          immune: false,
          blockedByFloor: false,
          blockedByLos: true,
        })
        continue
      }

      const currentHp = target.statList.getHp()
      const maxHp = target.statList.getMaxHp() || currentHp
      const ltngRes = target.statList.getAccruedStat('lightresist') || 0
      const res = calculateStaticFieldDamage(currentHp, maxHp, difficulty, ltngRes)

      if (res.damage > 0) {
        target.statList.setHp256(target.statList.getHp256() - res.damage * 256)
      }

      hits.push({
        targetId: target.id,
        damage: res.damage,
        immune: res.immune,
        blockedByFloor: res.blockedByFloor,
        blockedByLos: false,
      })
    }

    return { hits, radiusPx }
  }
}

/**
 * Standalone helper to spawn 64 radial Projectile objects for Nova with 2:1 isometric ground foreshortening.
 */
export function spawnNovaRing(
  startX: number,
  startY: number,
  damage: number,
  options?: {
    skillId?: string
    missileType?: string
    fromPlayer?: boolean
  }
): {
  skillId: string
  missileType: string
  x: number
  y: number
  vx: number
  vy: number
  damage: number
  ttl: number
  fromPlayer: boolean
  nextDelay: number
}[] {
  const speed = 24 // 1.13c Missiles.txt: vel = 24 (600 px/s)
  const skillId = options?.skillId ?? '48'
  const missileType = options?.missileType ?? 'electricnova'
  const fromPlayer = options?.fromPlayer ?? true
  const bolts: {
    skillId: string
    missileType: string
    x: number
    y: number
    vx: number
    vy: number
    damage: number
    ttl: number
    fromPlayer: boolean
    nextDelay: number
  }[] = []

  for (let i = 0; i < 64; i++) {
    const angle = (i / 64) * 2 * Math.PI
    const vx = Math.cos(angle) * speed
    const vy = Math.sin(angle) * speed * ISO_GROUND_ASPECT_RATIO

    bolts.push({
      skillId,
      missileType,
      x: startX,
      y: startY,
      vx,
      vy,
      damage,
      ttl: 13,
      fromPlayer,
      nextDelay: 4,
    })
  }

  return bolts
}

export interface StaticFieldTarget {
  readonly id: string
  readonly x: number
  readonly y: number
  readonly currentHp: number
  readonly maxHp: number
  readonly lightResist?: number
}

/**
 * Standalone helper to execute 1.13c Static Field on target records.
 */
export function executeStaticField(params: {
  casterX: number
  casterY: number
  slvl: number
  targets: readonly StaticFieldTarget[]
  difficulty?: 'normal' | 'nightmare' | 'hell'
  isBlocked?: ((x: number, y: number, fromX?: number, fromY?: number) => boolean) | MissileTerrainCollision | undefined
}): {
  radiusPx: number
  hits: {
    targetId: string
    damage: number
    newHp: number
    immune: boolean
    blockedByFloor: boolean
    blockedByLos: boolean
  }[]
} {
  const radiusPx = calculateStaticFieldRadiusPx(params.slvl)
  const difficulty = params.difficulty ?? 'normal'
  const hits: {
    targetId: string
    damage: number
    newHp: number
    immune: boolean
    blockedByFloor: boolean
    blockedByLos: boolean
  }[] = []

  for (const t of params.targets) {
    const dist = Math.hypot(t.x - params.casterX, t.y - params.casterY)
    if (dist > radiusPx) continue

    if (params.isBlocked && !hasLineOfSight(params.casterX, params.casterY, t.x, t.y, params.isBlocked)) {
      hits.push({
        targetId: t.id,
        damage: 0,
        newHp: t.currentHp,
        immune: false,
        blockedByFloor: false,
        blockedByLos: true,
      })
      continue
    }

    const res = calculateStaticFieldDamage(t.currentHp, t.maxHp, difficulty, t.lightResist ?? 0)
    hits.push({
      targetId: t.id,
      damage: res.damage,
      newHp: res.newHp,
      immune: res.immune,
      blockedByFloor: res.blockedByFloor,
      blockedByLos: false,
    })
  }

  return { radiusPx, hits }
}

/**
 * Authentic 1.13c Lightning Mastery (Skill 63) passive bonus percentage:
 * Skills.txt row 63: Param1: 50, Param2: 12.
 * Formula: 50 + (slvl - 1) * 12 percent.
 * Level 1 -> 50%, Level 2 -> 62%, Level 10 -> 158%, Level 20 -> 278%.
 */
export function calculateLightningMasteryBonusPct(slvl: number): number {
  if (!Number.isFinite(slvl) || slvl <= 0) return 0
  const lvl = Math.floor(slvl)
  return 50 + (lvl - 1) * 12
}

/**
 * Authentic 1.13c Thunder Storm (Skill 57) duration in frames (Skills.txt row 57):
 * Param1: 800, Param2: 200.
 * Duration: 800 + (slvl - 1) * 200 frames (32s base + 8s/lvl).
 */
export function calculateThunderStormDuration(slvl: number): number {
  const lvl = Number.isFinite(slvl) ? Math.max(1, Math.floor(slvl)) : 1
  return 800 + (lvl - 1) * 200
}

/**
 * Authentic 1.13c Thunder Storm (Skill 57) strike interval in frames:
 * Param3: 25 (minimum floor), Param4: 100, Param6: 100.
 * Standard 1.13c hyperbolic cadence formula:
 * interval = Math.max(25, 125 - Math.floor((110 * slvl) / (slvl + 6))) frames.
 * Level 1 -> 110 frames (4.4s), Level 10 -> 57 frames (2.28s), Level 20 -> 41 frames (1.64s).
 */
export function calculateThunderStormInterval(slvl: number): number {
  const lvl = Number.isFinite(slvl) ? Math.max(1, Math.floor(slvl)) : 1
  return Math.max(25, 125 - Math.floor((110 * lvl) / (lvl + 6)))
}

/**
 * Authentic 1.13c Thunder Storm (Skill 57) 5-band damage scaling (Skills.txt row 57):
 * EMin: 1, EMinLev1..5: 10, 10, 11, 11, 11
 * EMax: 100, EMaxLev1..5: 10, 10, 11, 11, 11
 * 0 synergies in 1.13c.
 * Multiplicative scaling with Lightning Mastery:
 * Final = Base * (1 + MasteryBonusPct / 100)
 */
export function calculateThunderStormDamage(
  slvl: number,
  synergies?: {
    readonly lightningMastery?: number | undefined
  } | number,
  lightningMastery?: number,
): { min: number; max: number } {
  const lvl = Number.isFinite(slvl) ? Math.max(1, Math.floor(slvl)) : 1
  let min = 1
  let max = 100
  if (lvl > 1) {
    const b1 = Math.min(lvl - 1, 7)
    min += b1 * 10
    max += b1 * 10
    if (lvl > 8) {
      const b2 = Math.min(lvl - 8, 8)
      min += b2 * 10
      max += b2 * 10
    }
    if (lvl > 16) {
      const b3 = Math.min(lvl - 16, 6)
      min += b3 * 11
      max += b3 * 11
    }
    if (lvl > 22) {
      const b4 = Math.min(lvl - 22, 6)
      min += b4 * 11
      max += b4 * 11
    }
    if (lvl > 28) {
      const b5 = lvl - 28
      min += b5 * 11
      max += b5 * 11
    }
  }

  const masteryLvl =
    typeof lightningMastery === 'number'
      ? lightningMastery
      : typeof synergies === 'object' && synergies !== null
        ? synergies.lightningMastery ?? 0
        : 0
  const masteryBonus = masteryLvl > 0 ? calculateLightningMasteryBonusPct(masteryLvl) : 0
  const synMult = typeof synergies === 'number' && Number.isFinite(synergies) && synergies > 0 ? synergies : 1.0

  min = Math.floor(min * synMult * (1 + masteryBonus / 100))
  max = Math.floor(max * synMult * (1 + masteryBonus / 100))
  return { min, max }
}

/**
 * Authentic 1.13c Energy Shield (Skill 58) duration in frames (Skills.txt row 58):
 * Param1: 3600, Param2: 1500.
 * Duration: 3600 + (slvl - 1) * 1500 frames (144s base + 60s/lvl).
 */
export function calculateEnergyShieldDuration(slvl: number): number {
  const lvl = Number.isFinite(slvl) ? Math.max(1, Math.floor(slvl)) : 1
  return 3600 + (lvl - 1) * 1500
}

/**
 * Authentic 1.13c Energy Shield (Skill 58) damage absorption percentage (Skills.txt row 58):
 * EMin: 20, EMinLev1: 5 (lvl 2-8), EMinLev2: 2 (lvl 9-16), EMinLev3..5: 1 (lvl 17+).
 * Hard cap: 95% (achieved at level 40).
 */
export function calculateEnergyShieldAbsorbPct(slvl: number): number {
  const lvl = Number.isFinite(slvl) ? Math.max(1, Math.floor(slvl)) : 1
  let pct = 20
  if (lvl > 1) {
    const b1 = Math.min(lvl - 1, 7)
    pct += b1 * 5
    if (lvl > 8) {
      const b2 = Math.min(lvl - 8, 8)
      pct += b2 * 2
    }
    if (lvl > 16) {
      const b3 = lvl - 16
      pct += b3 * 1
    }
  }
  return Math.min(95, pct)
}

/**
 * Authentic 1.13c Frozen Armor (Skill 40) % Enhanced Defense:
 * Param1: 30 (% base), Param2: 5 (% per level).
 * Formula: 30 + (slvl - 1) * 5.
 * Level 1 -> 30%, Level 10 -> 75%, Level 20 -> 125%.
 */
export function calculateFrozenArmorDefense(slvl: number): number {
  const lvl = Number.isFinite(slvl) ? Math.max(1, Math.floor(slvl)) : 1
  return 30 + (lvl - 1) * 5
}

/**
 * Authentic 1.13c Frozen Armor (Skill 40) duration in frames:
 * Param3: 3000 (120s base), Param4: 300 (+12s/lvl), Param7: 250 (+10s/syn).
 * Default 1.13c: 3000 + (slvl - 1) * 300 + synPoints * 250.
 * If options.base1200 is set: 1200 + (slvl - 1) * 120 + synPoints * 120.
 */
export function calculateFrozenArmorDuration(
  slvl: number,
  synergies?: { shiverArmor?: number; chillingArmor?: number } | number,
  options?: { base1200?: boolean },
): number {
  const lvl = Number.isFinite(slvl) ? Math.max(1, Math.floor(slvl)) : 1
  const synPoints = Math.max(
    0,
    typeof synergies === 'number'
      ? synergies
      : (synergies?.shiverArmor ?? 0) + (synergies?.chillingArmor ?? 0),
  )
  if (options?.base1200) {
    return Math.floor((1200 + (lvl - 1) * 120) * (1 + (synPoints * 10) / 100))
  }
  return 3000 + (lvl - 1) * 300 + synPoints * 250
}

/**
 * Authentic 1.13c Frozen Armor (Skill 40) freeze length in frames (calc1):
 * Param5: 30 (1.2s base), Param6: 3 (+0.12s/lvl), Param8: 5 (+5% freeze length per synergy point).
 * Formula: Math.floor((30 + (slvl - 1) * 3) * (100 + synPoints * 5) / 100).
 * Level 1 -> 30 frames (1.20s), Level 10 -> 57 frames (2.28s), Level 20 -> 87 frames (3.48s).
 */
export function calculateFrozenArmorFreezeLength(
  slvl: number,
  synergies?: { shiverArmor?: number; chillingArmor?: number } | number,
): number {
  const lvl = Number.isFinite(slvl) ? Math.max(1, Math.floor(slvl)) : 1
  const synPoints = Math.max(
    0,
    typeof synergies === 'number'
      ? synergies
      : (synergies?.shiverArmor ?? 0) + (synergies?.chillingArmor ?? 0),
  )
  const baseFrames = 30 + (lvl - 1) * 3
  const synFactor = 100 + synPoints * 5
  return Math.floor((baseFrames * synFactor) / 100)
}

/**
 * Authentic 1.13c Shiver Armor (Skill 50) % Enhanced Defense:
 * Param1: 45 (% base), Param2: 6 (% per level).
 * Formula: 45 + (slvl - 1) * 6.
 * Level 1 -> 45%, Level 10 -> 99%, Level 20 -> 159%.
 */
export function calculateShiverArmorDefense(slvl: number): number {
  const lvl = Number.isFinite(slvl) ? Math.max(1, Math.floor(slvl)) : 1
  return 45 + (lvl - 1) * 6
}

/**
 * Authentic 1.13c Shiver Armor (Skill 50) duration in frames:
 * Param3: 3000 (120s base), Param4: 300 (+12s/lvl), Param7: 250 (+10s/syn).
 * Default 1.13c: 3000 + (slvl - 1) * 300 + synPoints * 250.
 */
export function calculateShiverArmorDuration(
  slvl: number,
  synergies?: { frozenArmor?: number; chillingArmor?: number } | number,
  options?: { base1200?: boolean },
): number {
  const lvl = Number.isFinite(slvl) ? Math.max(1, Math.floor(slvl)) : 1
  const synPoints = Math.max(
    0,
    typeof synergies === 'number'
      ? synergies
      : (synergies?.frozenArmor ?? 0) + (synergies?.chillingArmor ?? 0),
  )
  if (options?.base1200) {
    return Math.floor((1200 + (lvl - 1) * 120) * (1 + (synPoints * 10) / 100))
  }
  return 3000 + (lvl - 1) * 300 + synPoints * 250
}

/**
 * Authentic 1.13c Shiver Armor (Skill 50) 5-band cold damage scaling (HitShift = 7 -> divide by 2):
 * EMin: 12, EMax: 16 (HitShift 7 -> 6 - 8 at lvl 1)
 * EMinLev: [4, 6, 8, 10, 12], EMaxLev: [5, 7, 9, 11, 13]
 * Synergy: +9% (or +11% if specified) per point in Frozen Armor / Chilling Armor.
 */
export function calculateShiverArmorDamage(
  slvl: number,
  synergies?: { frozenArmor?: number; chillingArmor?: number; synPctPerLvl?: number } | number,
  options?: { synPctPerLvl?: number; synMultiplier?: number },
): { min: number; max: number } {
  const lvl = Number.isFinite(slvl) ? Math.max(1, Math.floor(slvl)) : 1
  let rawMin = 12
  let rawMax = 16
  if (lvl > 1) {
    const b1 = Math.min(lvl - 1, 7)
    rawMin += b1 * 4
    rawMax += b1 * 5
    if (lvl > 8) {
      const b2 = Math.min(lvl - 8, 8)
      rawMin += b2 * 6
      rawMax += b2 * 7
    }
    if (lvl > 16) {
      const b3 = Math.min(lvl - 16, 6)
      rawMin += b3 * 8
      rawMax += b3 * 9
    }
    if (lvl > 22) {
      const b4 = Math.min(lvl - 22, 6)
      rawMin += b4 * 10
      rawMax += b4 * 11
    }
    if (lvl > 28) {
      const b5 = lvl - 28
      rawMin += b5 * 12
      rawMax += b5 * 13
    }
  }

  let min = rawMin / 2
  let max = rawMax / 2

  let synMultiplier = 1.0
  if (typeof options?.synMultiplier === 'number' && Number.isFinite(options.synMultiplier)) {
    synMultiplier = Math.max(0, options.synMultiplier)
  } else if (typeof synergies === 'number') {
    const synPoints = Number.isFinite(synergies) ? Math.max(0, synergies) : 0
    const pctPerLvl = options?.synPctPerLvl ?? 9
    synMultiplier = 1.0 + (synPoints * pctPerLvl) / 100
  } else if (typeof synergies === 'object' && synergies !== null) {
    const synPoints = Math.max(0, (synergies.frozenArmor ?? 0) + (synergies.chillingArmor ?? 0))
    const pctPerLvl = options?.synPctPerLvl ?? synergies.synPctPerLvl ?? 9
    synMultiplier = 1.0 + (synPoints * pctPerLvl) / 100
  }

  min = Math.floor((min * synMultiplier + 1e-9) * 10) / 10
  max = Math.floor((max * synMultiplier + 1e-9) * 10) / 10
  return { min, max }
}

/**
 * Authentic 1.13c Shiver Armor (Skill 50) chill length in frames:
 * ELen: 100 frames base (4.0s). ELevLen1: 0, ELevLen2: 25 frames (lvl 9-16), ELevLen3: 50 frames (lvl 17+).
 * Level 1-8: 100 frames (4.0s), Level 10: 150 frames (6.0s), Level 20: 500 frames (20.0s).
 * Optional synergy: +7% chill length per synergy point.
 */
export function calculateShiverArmorChillLength(
  slvl: number,
  synergies?: { frozenArmor?: number; chillingArmor?: number } | number,
): number {
  const lvl = Number.isFinite(slvl) ? Math.max(1, Math.floor(slvl)) : 1
  let frames = 100
  if (lvl > 8) {
    const b2 = Math.min(lvl - 8, 8)
    frames += b2 * 25
  }
  if (lvl > 16) {
    const b3 = lvl - 16
    frames += b3 * 50
  }
  const synPoints = Math.max(
    0,
    typeof synergies === 'number'
      ? synergies
      : (synergies?.frozenArmor ?? 0) + (synergies?.chillingArmor ?? 0),
  )
  if (synPoints > 0) {
    frames = Math.floor((frames * (100 + synPoints * 7)) / 100)
  }
  return frames
}

/**
 * Authentic 1.13c Chilling Armor (Skill 60) % Enhanced Defense:
 * Param1: 45 (% base), Param2: 5 (% per level).
 * Formula: 45 + (slvl - 1) * 5.
 * Level 1 -> 45%, Level 10 -> 90%, Level 20 -> 140%.
 */
export function calculateChillingArmorDefense(slvl: number): number {
  const lvl = Number.isFinite(slvl) ? Math.max(1, Math.floor(slvl)) : 1
  return 45 + (lvl - 1) * 5
}

/**
 * Authentic 1.13c Chilling Armor (Skill 60) duration in frames:
 * Param3: 3600 (144s base), Param4: 150 (+6s/lvl), Param7: 250 (+10s/syn).
 * Default 1.13c: 3600 + (slvl - 1) * 150 + synPoints * 250.
 */
export function calculateChillingArmorDuration(
  slvl: number,
  synergies?: { frozenArmor?: number; shiverArmor?: number } | number,
  options?: { base1200?: boolean },
): number {
  const lvl = Number.isFinite(slvl) ? Math.max(1, Math.floor(slvl)) : 1
  const synPoints = Math.max(
    0,
    typeof synergies === 'number'
      ? synergies
      : (synergies?.frozenArmor ?? 0) + (synergies?.shiverArmor ?? 0),
  )
  if (options?.base1200) {
    return Math.floor((1200 + (lvl - 1) * 120) * (1 + (synPoints * 10) / 100))
  }
  return 3600 + (lvl - 1) * 150 + synPoints * 250
}

/**
 * Authentic 1.13c Chilling Armor (Skill 60) retaliatory ice bolt cold damage:
 * EMin: 8, EMax: 12 (HitShift 7 -> 4 - 6 at lvl 1)
 * EMinLev: [2, 4, 6, 8, 10], EMaxLev: [3, 5, 7, 9, 11]
 * Synergy: +7% per point in Frozen Armor / Shiver Armor.
 */
export function calculateChillingArmorDamage(
  slvl: number,
  synergies?: { frozenArmor?: number; shiverArmor?: number; synPctPerLvl?: number } | number,
  options?: { synPctPerLvl?: number; synMultiplier?: number },
): { min: number; max: number } {
  const lvl = Number.isFinite(slvl) ? Math.max(1, Math.floor(slvl)) : 1
  let rawMin = 8
  let rawMax = 12
  if (lvl > 1) {
    const b1 = Math.min(lvl - 1, 7)
    rawMin += b1 * 2
    rawMax += b1 * 3
    if (lvl > 8) {
      const b2 = Math.min(lvl - 8, 8)
      rawMin += b2 * 4
      rawMax += b2 * 5
    }
    if (lvl > 16) {
      const b3 = Math.min(lvl - 16, 6)
      rawMin += b3 * 6
      rawMax += b3 * 7
    }
    if (lvl > 22) {
      const b4 = Math.min(lvl - 22, 6)
      rawMin += b4 * 8
      rawMax += b4 * 9
    }
    if (lvl > 28) {
      const b5 = lvl - 28
      rawMin += b5 * 10
      rawMax += b5 * 11
    }
  }

  let min = rawMin / 2
  let max = rawMax / 2

  let synMultiplier = 1.0
  if (typeof options?.synMultiplier === 'number' && Number.isFinite(options.synMultiplier)) {
    synMultiplier = Math.max(0, options.synMultiplier)
  } else if (typeof synergies === 'number') {
    const synPoints = Number.isFinite(synergies) ? Math.max(0, synergies) : 0
    const pctPerLvl = options?.synPctPerLvl ?? 7
    synMultiplier = 1.0 + (synPoints * pctPerLvl) / 100
  } else if (typeof synergies === 'object' && synergies !== null) {
    const synPoints = Math.max(0, (synergies.frozenArmor ?? 0) + (synergies.shiverArmor ?? 0))
    const pctPerLvl = options?.synPctPerLvl ?? synergies.synPctPerLvl ?? 7
    synMultiplier = 1.0 + (synPoints * pctPerLvl) / 100
  }

  min = Math.floor((min * synMultiplier + 1e-9) * 10) / 10
  max = Math.floor((max * synMultiplier + 1e-9) * 10) / 10
  return { min, max }
}

/**
 * Authentic 1.13c Chilling Armor (Skill 60) chill length in frames:
 * ELen: 100 frames base (4.0s). ELevLen1: 0, ELevLen2: 25 frames, ELevLen3: 25 frames.
 * Level 1-8: 100 frames (4.0s), Level 10: 150 frames (6.0s), Level 20: 400 frames (16.0s).
 * Optional synergy: +10% chill length per synergy point.
 */
export function calculateChillingArmorChillLength(
  slvl: number,
  synergies?: { frozenArmor?: number; shiverArmor?: number } | number,
): number {
  const lvl = Number.isFinite(slvl) ? Math.max(1, Math.floor(slvl)) : 1
  let frames = 100
  if (lvl > 8) {
    const b2 = Math.min(lvl - 8, 8)
    frames += b2 * 25
  }
  if (lvl > 16) {
    const b3 = lvl - 16
    frames += b3 * 25
  }
  const synPoints = Math.max(
    0,
    typeof synergies === 'number'
      ? synergies
      : (synergies?.frozenArmor ?? 0) + (synergies?.shiverArmor ?? 0),
  )
  if (synPoints > 0) {
    frames = Math.floor((frames * (100 + synPoints * 10)) / 100)
  }
  return frames
}

/**
 * Standard Cold Armor base duration calculator (1200f base + 120f/lvl = 48s + 4.8s/lvl):
 */
export function calculateColdArmorDuration(
  slvl: number,
  baseFrames = 1200,
  perLvlFrames = 120,
  synBonusPct = 10,
  synPoints = 0,
): number {
  const lvl = Number.isFinite(slvl) ? Math.max(1, Math.floor(slvl)) : 1
  const safeSyn = Math.max(0, synPoints)
  return Math.floor((baseFrames + (lvl - 1) * perLvlFrames) * (1 + (safeSyn * synBonusPct) / 100))
}