diablo2-web/tests/parity-1.13c.test.ts

import { describe, it, expect, beforeAll } from 'vitest'
import { ACT_BOSSES, BOSS_LIST, type BossDefinition } from '../src/boss.ts'
import { getEmbeddedDropTables } from '../src/game/embedded-drop-tables.ts'
import { executeDropPipeline, type DropTables } from '../src/game/drop-pipeline.ts'
import type { UpgradableItemBase } from '../src/game/item-upgrade.ts'
import type { Item } from '../src/game/items.ts'
import { runParityAudit } from '../scripts/audit-parity.ts'

export type BaseTier = 'normal' | 'exceptional' | 'elite'

export function classifyItemBaseTier(item: Item): BaseTier | null {
  if (item.base.kind !== 'weapon' && item.base.kind !== 'armor') {
    return null
  }
  const b = item.base as UpgradableItemBase
  const id = (b.id ?? '').trim().toLowerCase()
  const uber = (b.ubercode ?? '').trim().toLowerCase()
  const ultra = (b.ultracode ?? '').trim().toLowerCase()

  if (ultra && ultra !== 'xxx' && id === ultra) {
    return 'elite'
  }
  if (uber && uber !== 'xxx' && id === uber) {
    return 'exceptional'
  }
  return 'normal'
}

describe('Diablo II 1.13c Parity Baseline & Boss monsterType=4 Upgrade Odds (Issue #126)', () => {
  let dropTables: DropTables

  beforeAll(() => {
    dropTables = getEmbeddedDropTables()
  })

  it('1. BOSS_LIST and ACT_BOSSES define monsterType === 4 for all 5 Act Bosses', () => {
    expect(BOSS_LIST).toBeDefined()
    expect(BOSS_LIST).toHaveLength(5)
    expect(BOSS_LIST).toBe(ACT_BOSSES)

    for (const boss of BOSS_LIST) {
      const def: BossDefinition = boss
      expect(def.monsterType, `Boss ${def.id} must explicitly set monsterType: 4`).toBe(4)
    }
  })

  it('2. Difficultylevels.txt Good odds (UberCodeOddsGood / UltraCodeOddsGood) exceed Normal odds in Nightmare and Hell', () => {
    const nmOdds = dropTables.difficultyLevels.get('Nightmare')!
    const hellOdds = dropTables.difficultyLevels.get('Hell')!

    expect(nmOdds.uberCodeOddsGood).toBeGreaterThan(nmOdds.uberCodeOddsNormal)
    expect(hellOdds.uberCodeOddsGood).toBeGreaterThan(hellOdds.uberCodeOddsNormal)
    expect(hellOdds.ultraCodeOddsGood).toBeGreaterThan(hellOdds.ultraCodeOddsNormal)
  })

  it('3. monsterType=4 (Boss) yields significantly higher Exceptional/Elite base upgrades than monsterType=1 (Normal) over identical seeds', () => {
    const sampleKills = 400
    let normalMonsterUpgraded = 0
    let normalMonsterEquipCount = 0
    let bossMonsterUpgraded = 0
    let bossMonsterEquipCount = 0

    for (let i = 0; i < sampleKills; i++) {
      const seed = (0x12600000 + i * 7919) >>> 0

      // Run with monsterType = 1 (Normal monster: uses uberCodeOddsNormal=20, ultraCodeOddsNormal=30)
      const dropsNormalType = executeDropPipeline({
        tcName: 'Mephistoq (H)',
        nLevel: 87,
        monsterType: 1,
        dropTables,
        difficulty: 'hell',
        playerMf: 250,
        gamePlayers: 1,
        partyPlayers: 1,
        monsterRng: seed,
      })

      for (const item of dropsNormalType) {
        const tier = classifyItemBaseTier(item)
        if (tier !== null) {
          normalMonsterEquipCount++
          if (tier === 'exceptional' || tier === 'elite') {
            normalMonsterUpgraded++
          }
        }
      }

      // Run with monsterType = 4 (Act Boss: uses uberCodeOddsGood=40, ultraCodeOddsGood=40)
      const dropsBossType = executeDropPipeline({
        tcName: 'Mephistoq (H)',
        nLevel: 87,
        monsterType: 4,
        dropTables,
        difficulty: 'hell',
        playerMf: 250,
        gamePlayers: 1,
        partyPlayers: 1,
        monsterRng: seed,
      })

      for (const item of dropsBossType) {
        const tier = classifyItemBaseTier(item)
        if (tier !== null) {
          bossMonsterEquipCount++
          if (tier === 'exceptional' || tier === 'elite') {
            bossMonsterUpgraded++
          }
        }
      }
    }

    expect(normalMonsterEquipCount).toBeGreaterThan(500)
    expect(bossMonsterEquipCount).toBe(normalMonsterEquipCount)

    const normalUpgradeRate = normalMonsterUpgraded / normalMonsterEquipCount
    const bossUpgradeRate = bossMonsterUpgraded / bossMonsterEquipCount

    // Boss (Good odds: 40/1024 + 40/1024) must strictly exceed Normal (20/1024 + 30/1024)
    expect(bossMonsterUpgraded).toBeGreaterThan(normalMonsterUpgraded)
    expect(bossUpgradeRate).toBeGreaterThan(normalUpgradeRate)
  })

  it('4. executeDropPipeline works properly with monsterType: 4 across all 5 Act Bosses in Hell', () => {
    for (const boss of BOSS_LIST) {
      const drops = executeDropPipeline({
        tcName: boss.questTc.hell,
        nLevel: boss.mlvl.hell,
        monsterType: boss.monsterType ?? 4,
        dropTables,
        difficulty: 'hell',
        playerMf: 250,
        gamePlayers: 1,
        partyPlayers: 1,
        monsterRng: 1337 + boss.act,
      })

      expect(drops.length).toBeGreaterThan(0)
      for (const item of drops) {
        expect(item.ilvl).toBe(boss.mlvl.hell)
      }
    }
  })

  it('5. runParityAudit generates structured JSON summary of quality, base upgrade, and affix distributions', () => {
    const summary = runParityAudit({
      kills: 100,
      bossId: 'mephisto',
      difficulty: 'hell',
      playerMf: 250,
      gamePlayers: 1,
    })

    expect(summary.config.boss).toBe('mephisto')
    expect(summary.config.monsterType).toBe(4)
    expect(summary.totalItems).toBeGreaterThan(0)
    expect(summary.baseTierUpgrade.totalEquipment).toBeGreaterThan(0)
    expect(summary.baseTierUpgrade.upgradedRatio).toBeGreaterThan(0)
  })
})