/**
 * Issue #436: Hydra (#62) Summon Cap & Entity Visuals
 *
 * 1.13c Ground Truth Invariants Verification Suite:
 * 1. Summon Cap: Maximum 6 active Hydra groups (18 heads total) concurrently active.
 * 2. FIFO Eviction: When 7th group is cast, the oldest 1st group is automatically evicted (pruned to 0 ttl).
 * 3. Exact 3-Head Offsets: Offsets [(-6, -11), (0, -7), (4, -15)] correctly assigned per group.
 * 4. Slvl Scaling: Hydra damage properly respects caster skill level instead of hardcoded slvl 1.
 */
import { describe, expect, it } from 'vitest'
import { GameEngine } from '../../../src/server/engine/engine.ts'
import { castSkill } from '../../../src/server/scene/skill-caster.ts'

describe('Issue #436: Hydra (#62) Summon Cap & Entity Visuals', () => {
  it('enforces maximum 6 groups (18 heads) and FIFO eviction on successive casts', () => {
    const engine = new GameEngine(
      { widthPx: 1000, heightPx: 1000, overlap: () => 0 },
      { spawn: { x: 200, y: 200 }, stats: [], questDefs: [], npcDefs: [] } as any,
    )
    engine.world.player.x = 200
    engine.world.player.y = 200
    engine.world.player.mana = 1000

    const statusEl = { textContent: '' } as HTMLElement
    const dummyRuntime = {
      walkable: { isWalkable: () => true },
      collision: { isWalkable: () => true },
    } as any

    // Cast Hydra 6 times (filling cap to 6 groups = 18 heads)
    for (let c = 1; c <= 6; c++) {
      engine.world.player.cooldown = 0
      const ok = castSkill(62, 300 + c * 20, 300, {
        engine,
        runtime: dummyRuntime,
        hudManager: null,
        status: statusEl,
      })
      expect(ok).toBe(true)
      expect(engine.projectiles.length).toBe(c * 3)
    }

    expect(engine.projectiles.length).toBe(18)
    const firstGroupHeadX = engine.projectiles[0]!.x

    // Cast 7th time -> triggers FIFO eviction of group 1
    engine.world.player.cooldown = 0
    const ok7 = castSkill(62, 500, 300, {
      engine,
      runtime: dummyRuntime,
      hudManager: null,
      status: statusEl,
    })
    expect(ok7).toBe(true)

    // Total active heads must be capped at 18 (6 groups * 3 heads)
    expect(engine.projectiles.length).toBe(18)

    // First group must have been evicted and no longer present in engine.projectiles
    const containsOldHead = engine.projectiles.some(p => p.x === firstGroupHeadX)
    expect(containsOldHead).toBe(false)
  })

  it('correctly reads slvl from hudManager for damage calculation', () => {
    const engine = new GameEngine(
      { widthPx: 1000, heightPx: 1000, overlap: () => 0 },
      { spawn: { x: 200, y: 200 }, stats: [], questDefs: [], npcDefs: [] } as any,
    )
    engine.world.player.x = 200
    engine.world.player.y = 200
    engine.world.player.mana = 1000
    engine.world.player.cooldown = 0

    const mockHudManager = {
      getSkillLevel: (skillId: number) => (skillId === 62 ? 20 : 0),
      syncPublishedState: () => {},
    }

    const statusEl = { textContent: '' } as HTMLElement
    const dummyRuntime = {
      walkable: { isWalkable: () => true },
      collision: { isWalkable: () => true },
    } as any

    castSkill(62, 350, 250, {
      engine,
      runtime: dummyRuntime,
      hudManager: mockHudManager as any,
      status: statusEl,
    })

    expect(engine.projectiles.length).toBe(3)
    // At slvl 20, damage is ~162 (150-175 range), much higher than slvl 1 (14-19)
    const head = engine.projectiles[0]!
    expect(head.damage).toBeGreaterThan(100)
  })
})