import { describe, expect, it } from 'vitest'
import { existsSync, readFileSync } from 'node:fs'
import { join } from 'node:path'
import { MONSTER_ART_MAP } from '../src/game/monster-mapping.ts'

describe('offline pre-baked entity atlases (Issue #30)', () => {
  const packRoot = join(process.cwd(), 'samples', 'd2-packs')
  const hasPacks = existsSync(join(packRoot, 'act1', 'entities', 'char-so.json'))

  it.skipIf(!hasPacks)('bakes Sorceress char-so PNG + JSON for Acts 1..5', () => {
    for (let act = 1; act <= 5; act += 1) {
      const dir = join(packRoot, `act${act}`, 'entities')
      const jsonPath = join(dir, 'char-so.json')
      const pngPath = join(dir, 'char-so.png')
      expect(existsSync(jsonPath)).toBe(true)
      expect(existsSync(pngPath)).toBe(true)

      const meta = JSON.parse(readFileSync(jsonPath, 'utf8'))
      expect(meta.file).toBe('char-so.png')
      expect(meta.directions).toBe(16)
      expect(meta.walk).toBe(0)
      expect(meta.stand).toBe(16)
      expect(meta.members).toBeGreaterThanOrEqual(16)
      expect(meta.groups.length).toBe(32) // 16 walk + 16 stand

      const png = readFileSync(pngPath)
      // Check PNG magic header
      expect(png[0]).toBe(137)
      expect(png[1]).toBe(80) // P
      expect(png[2]).toBe(78) // N
      expect(png[3]).toBe(71) // G
      // Read IHDR width and height
      const view = new DataView(png.buffer, png.byteOffset, png.byteLength)
      expect(view.getUint32(16)).toBe(meta.width)
      expect(view.getUint32(20)).toBe(meta.height)
    }
  })

  it.skipIf(!hasPacks)('bakes monster PNG + JSON atlases for all mapped monster specs across Acts 1..5', () => {
    const uniqueSpecs = new Map<string, { token: string; weapon: string }>()
    for (const spec of Object.values(MONSTER_ART_MAP)) {
      const key = `${spec.token}-${spec.weapon}`
      if (!uniqueSpecs.has(key)) uniqueSpecs.set(key, spec)
    }

    for (let act = 1; act <= 5; act += 1) {
      const dir = join(packRoot, `act${act}`, 'entities')
      for (const spec of uniqueSpecs.values()) {
        const slug = `monster-${spec.token.toLowerCase()}-${spec.weapon.toLowerCase()}`
        const jsonPath = join(dir, `${slug}.json`)
        const pngPath = join(dir, `${slug}.png`)
        expect(existsSync(jsonPath), `missing ${jsonPath}`).toBe(true)
        expect(existsSync(pngPath), `missing ${pngPath}`).toBe(true)

        const meta = JSON.parse(readFileSync(jsonPath, 'utf8'))
        expect(meta.token).toBe(spec.token)
        expect(meta.weapon).toBe(spec.weapon)
        expect(meta.directions).toBe(8)
        expect(meta.walkOffset).toBe(0)
        expect(meta.standOffset).toBe(8)
        expect(meta.groups.length).toBe(16) // 8 walk + 8 stand

        const png = readFileSync(pngPath)
        const view = new DataView(png.buffer, png.byteOffset, png.byteLength)
        expect(view.getUint32(16)).toBe(meta.width)
        expect(view.getUint32(20)).toBe(meta.height)
      }
    }
  })
})