/**
 * Offline Cast Overlay Asset & Data Baking Script.
 *
 * Extracts authentic Diablo II v1.13c cast overlay DCC sprites from d2data.mpq:
 * - FireCast_for_Sorceress.dcc (fire_cast_1, 14 frames, box: [-55, -127, 117, 164])
 * - FireCast2.dcc (fire_cast_2, 16 frames, box: [-74, -89, 145, 133])
 * - IceCastNew01.dcc (ice_cast_1, 15 frames, box: [-49, -90, 97, 55])
 * - IceCastNew02.dcc (ice_cast_2, 15 frames, box: [-58, -100, 115, 123])
 * - IceCastNew03.dcc (ice_cast_3, 16 frames, box: [-63, -113, 127, 148])
 * - LightningCast.dcc (light_cast_1, 10 frames, box: [-79, -107, 164, 144])
 * - LightningCastRunesFront.dcc (light_cast_2, 10 frames, box: [-73, -154, 147, 190])
 * - Teleport.dcc (teleport, 18 frames, box: [-61, -108, 136, 154])
 *
 * Bakes them into indexed-color PNG atlases and JSON metadata under:
 * - public/overlays/
 * - samples/d2-packs/overlays/
 *
 * And generates typed metadata in src/render/overlays-meta.ts.
 * Enforces Zero Runtime MPQ/DLL Architectural Invariant.
 */

import { mkdirSync, writeFileSync } from 'node:fs'
import { join } from 'node:path'
import { MpqArchive } from '../src/mpq/archive.ts'
import { fileSource } from '../src/mpq/file-source.ts'
import { decodeDcc } from '../src/formats/dcc.ts'
import { decodePl2 } from '../src/formats/pl2.ts'
import { packSheetToPng } from './pack-entity-assets.ts'
import type { SpriteFrame, SpriteSheet } from '../src/formats/sprite.ts'

export interface OverlayFrameMeta {
  readonly x: number
  readonly y: number
  readonly w: number
  readonly h: number
  readonly anchorX: number
  readonly anchorY: number
}

export type OverlayFrameTuple = readonly [
  x: number,
  y: number,
  width: number,
  height: number,
  anchorX: number,
  anchorY: number,
]

export interface OverlayBox {
  readonly left: number
  readonly top: number
  readonly width: number
  readonly height: number
}

export interface OverlayMeta {
  readonly name: string
  readonly celFile: string
  readonly width: number
  readonly height: number
  readonly directions: number
  readonly frames: number
  readonly framesPerDirection: number
  readonly animRate: number
  readonly trans: number
  readonly preDraw: boolean
  readonly lightRadius: number
  readonly lightColor: readonly [number, number, number]
  readonly box: OverlayBox
  readonly groups: readonly (readonly OverlayFrameTuple[])[]
}

export const OVERLAY_TARGETS = [
  {
    name: 'fire_cast_1',
    celFile: 'FireCast_for_Sorceress',
    animRate: 16,
    trans: 3,
    preDraw: false,
    lightRadius: 9,
    lightColor: [255, 178, 64] as const,
  },
  {
    name: 'fire_cast_2',
    celFile: 'FireCast2',
    animRate: 16,
    trans: 3,
    preDraw: false,
    lightRadius: 9,
    lightColor: [255, 178, 64] as const,
  },
  {
    name: 'ice_cast_1',
    celFile: 'IceCastNew01',
    animRate: 16,
    trans: 3,
    preDraw: false,
    lightRadius: 9,
    lightColor: [81, 81, 255] as const,
  },
  {
    name: 'ice_cast_2',
    celFile: 'IceCastNew02',
    animRate: 16,
    trans: 3,
    preDraw: false,
    lightRadius: 9,
    lightColor: [81, 81, 255] as const,
  },
  {
    name: 'ice_cast_3',
    celFile: 'IceCastNew03',
    animRate: 16,
    trans: 3,
    preDraw: false,
    lightRadius: 9,
    lightColor: [81, 81, 255] as const,
  },
  {
    name: 'light_cast_1',
    celFile: 'LightningCast',
    animRate: 16,
    trans: 3,
    preDraw: false,
    lightRadius: 9,
    lightColor: [255, 255, 255] as const,
  },
  {
    name: 'light_cast_2',
    celFile: 'LightningCastRunesFront',
    animRate: 16,
    trans: 3,
    preDraw: false,
    lightRadius: 9,
    lightColor: [255, 255, 255] as const,
  },
  {
    name: 'teleport',
    celFile: 'Teleport',
    animRate: 16,
    trans: 3,
    preDraw: false,
    lightRadius: 5,
    lightColor: [255, 255, 200] as const,
  },
] as const

export async function bakeOverlays(projectRoot: string = process.cwd()): Promise<Record<string, OverlayMeta>> {
  const mpqPath = join(projectRoot, 'samples', 'd2', 'd2data.mpq')
  const mpq = await MpqArchive.open(await fileSource(mpqPath))

  const palFile = mpq.find('data/global/palette/ACT1/pal.pl2')
  if (!palFile) throw new Error('data/global/palette/ACT1/pal.pl2 not found in d2data.mpq')
  const pl2 = decodePl2(await mpq.read(palFile))

  const publicOutDir = join(projectRoot, 'public', 'overlays')
  const packOutDir = join(projectRoot, 'samples', 'd2-packs', 'overlays')
  mkdirSync(publicOutDir, { recursive: true })
  mkdirSync(packOutDir, { recursive: true })

  const metaRecord: Record<string, OverlayMeta> = {}

  for (const target of OVERLAY_TARGETS) {
    const f = mpq.find(`data/global/overlays/${target.celFile}.dcc`)
    if (!f) throw new Error(`Overlay DCC not found: data/global/overlays/${target.celFile}.dcc`)

    const dcc = decodeDcc(await mpq.read(f))
    const firstDir = dcc.directions[0]
    if (!firstDir) throw new Error(`Overlay DCC has no directions: ${target.celFile}`)

    const box: OverlayBox = {
      left: firstDir.box.left,
      top: firstDir.box.top,
      width: firstDir.box.width,
      height: firstDir.box.height,
    }

    const groups = dcc.directions.map(dir => ({
      frames: dir.frames.map(
        (frame): SpriteFrame => ({
          width: frame.frame.width,
          height: frame.frame.height,
          indices: frame.frame.indices,
          mask: frame.frame.mask,
          anchorX: dir.box.left,
          anchorY: dir.box.top,
        }),
      ),
    }))

    const sheet: SpriteSheet = { groups, width: null }
    const packed = packSheetToPng(sheet, pl2.rgb)

    const meta: OverlayMeta = {
      name: target.name,
      celFile: target.celFile,
      width: packed.width,
      height: packed.height,
      directions: dcc.directions.length,
      frames: firstDir.frames.length,
      framesPerDirection: firstDir.frames.length,
      animRate: target.animRate,
      trans: target.trans,
      preDraw: target.preDraw,
      lightRadius: target.lightRadius,
      lightColor: target.lightColor,
      box,
      groups: packed.groups,
    }

    metaRecord[target.name] = meta
    metaRecord[target.celFile] = meta

    const jsonStr = JSON.stringify(meta, null, 2)

    // Write primary name (e.g. fire_cast_1.png) and celFile alias (e.g. FireCast_for_Sorceress.png)
    for (const fileKey of [target.name, target.celFile]) {
      writeFileSync(join(publicOutDir, `${fileKey}.png`), packed.png)
      writeFileSync(join(publicOutDir, `${fileKey}.json`), jsonStr, 'utf-8')
      writeFileSync(join(packOutDir, `${fileKey}.png`), packed.png)
      writeFileSync(join(packOutDir, `${fileKey}.json`), jsonStr, 'utf-8')
    }

    console.log(
      `[Overlay Packer] Baked ${target.name} (${target.celFile}.dcc): ` +
      `${meta.frames} frames, box [${box.left}, ${box.top}, ${box.width}, ${box.height}], ` +
      `${packed.width}x${packed.height}, ${packed.png.byteLength} bytes PNG`,
    )
  }

  // Generate src/render/overlays-meta.ts
  const metaTsContent = `/**
 * Authentic Diablo II v1.13c Cast Overlay Atlas Metadata.
 * Auto-generated by scripts/pack-overlays.ts.
 * Enforces Zero Runtime MPQ/DLL Architectural Invariant.
 */

export interface OverlayFrameMeta {
  readonly x: number
  readonly y: number
  readonly w: number
  readonly h: number
  readonly anchorX: number
  readonly anchorY: number
}

export type OverlayFrameTuple = readonly [
  x: number,
  y: number,
  width: number,
  height: number,
  anchorX: number,
  anchorY: number,
]

export interface OverlayBox {
  readonly left: number
  readonly top: number
  readonly width: number
  readonly height: number
}

export interface OverlayMeta {
  readonly name: string
  readonly celFile: string
  readonly width: number
  readonly height: number
  readonly directions: number
  readonly frames: number
  readonly framesPerDirection: number
  readonly animRate: number
  readonly trans: number
  readonly preDraw: boolean
  readonly lightRadius: number
  readonly lightColor: readonly [number, number, number]
  readonly box: OverlayBox
  readonly groups: readonly (readonly OverlayFrameTuple[])[]
}

export const FIRE_CAST_1_META: OverlayMeta = ${JSON.stringify(metaRecord['fire_cast_1'], null, 2)}

export const FIRE_CAST_2_META: OverlayMeta = ${JSON.stringify(metaRecord['fire_cast_2'], null, 2)}

export const ICE_CAST_1_META: OverlayMeta = ${JSON.stringify(metaRecord['ice_cast_1'], null, 2)}

export const ICE_CAST_2_META: OverlayMeta = ${JSON.stringify(metaRecord['ice_cast_2'], null, 2)}

export const ICE_CAST_3_META: OverlayMeta = ${JSON.stringify(metaRecord['ice_cast_3'], null, 2)}

export const LIGHT_CAST_1_META: OverlayMeta = ${JSON.stringify(metaRecord['light_cast_1'], null, 2)}

export const LIGHT_CAST_2_META: OverlayMeta = ${JSON.stringify(metaRecord['light_cast_2'], null, 2)}

export const TELEPORT_META: OverlayMeta = ${JSON.stringify(metaRecord['teleport'], null, 2)}

export const OVERLAY_METAS: Readonly<Record<string, OverlayMeta>> = {
  fire_cast_1: FIRE_CAST_1_META,
  FireCast_for_Sorceress: FIRE_CAST_1_META,
  fire_cast_2: FIRE_CAST_2_META,
  FireCast2: FIRE_CAST_2_META,
  ice_cast_1: ICE_CAST_1_META,
  IceCastNew01: ICE_CAST_1_META,
  ice_cast_2: ICE_CAST_2_META,
  IceCastNew02: ICE_CAST_2_META,
  ice_cast_3: ICE_CAST_3_META,
  IceCastNew03: ICE_CAST_3_META,
  light_cast_1: LIGHT_CAST_1_META,
  LightningCast: LIGHT_CAST_1_META,
  light_cast_2: LIGHT_CAST_2_META,
  LightningCastRunesFront: LIGHT_CAST_2_META,
  teleport: TELEPORT_META,
  Teleport: TELEPORT_META,
}
`
  const metaTsPath = join(projectRoot, 'src', 'render', 'overlays-meta.ts')
  writeFileSync(metaTsPath, metaTsContent, 'utf-8')
  console.log(`[Overlay Packer] Wrote ${metaTsPath}`)

  return metaRecord
}

// Execute standalone if called from CLI
if (process.argv[1]?.endsWith('pack-overlays.ts')) {
  bakeOverlays().catch((err: unknown) => {
    console.error('Bake overlays failed:', err)
    process.exit(1)
  })
}