/**
 * scripts/pack-ui.ts
 *
 * Complete Offline UI, Item Sprite, and Quest Icon Packer.
 * Extracts DC6/PL2 assets from 1.13c MPQs and generates:
 * 1. public/ui/*.png (all panels, globes, borders, fonts, items-atlas, quests-atlas)
 * 2. public/ui/manifest.json
 * 3. src/ui/baked-ui-meta.ts
 */

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 { MountedArchives } from '../src/mpq/mount.ts'
import { decodeDc6 } from '../src/formats/dc6.ts'
import type { SpriteFrame, SpriteSheet } from '../src/formats/sprite.ts'
import { decodePl2 } from '../src/formats/pl2.ts'
import { parseTable } from '../src/game/tables.ts'
import { encodeIndexedPng } from './png.ts'
import { packCursorAssets } from './pack-cursor.ts'

interface BlitPlacement {
  readonly frame: SpriteFrame
  readonly x: number
  readonly y: number
}

export interface SpriteRect {
  readonly x: number
  readonly y: number
  readonly w: number
  readonly h: number
}

export interface FontGlyphMetric {
  readonly code: number
  readonly width: number
  readonly height: number
  readonly x: number
  readonly y: number
  readonly frameW: number
  readonly frameH: number
}

export interface FontAtlasMeta {
  readonly name: string
  readonly lineHeight: number
  readonly capHeight: number
  readonly atlasWidth: number
  readonly atlasHeight: number
  readonly glyphs: readonly FontGlyphMetric[]
}

/**
 * Create an indexed pixel buffer and blit multiple DC6 frames onto it.
 * Index 0 is transparent in DC6 UI sprites.
 */
function stitchFrames(width: number, height: number, placements: readonly BlitPlacement[]): Uint8Array {
  const out = new Uint8Array(width * height)
  for (const { frame, x: dstX, y: dstY } of placements) {
    for (let sy = 0; sy < frame.height; sy++) {
      const ty = dstY + sy
      if (ty < 0 || ty >= height) continue
      for (let sx = 0; sx < frame.width; sx++) {
        const tx = dstX + sx
        if (tx < 0 || tx >= width) continue
        const srcIdx = sy * frame.width + sx
        if (frame.mask[srcIdx] === 0) continue
        const color = frame.indices[srcIdx] ?? 0
        if (color !== 0) {
          out[ty * width + tx] = color
        }
      }
    }
  }
  return out
}

/**
 * Apply a 256-byte PL2 color transformation table to a sprite frame.
 * Opaque pixels are mapped through table[orig].
 * Black dye guard: If mapped === 0, remap to index 172 (RGB [4, 4, 4]),
 * the darkest non-zero index in the D2 palette, ensuring opaque black pixels
 * are not rendered as transparent in indexed PNG (where index 0 is transparent).
 * Transparent pixels (mask === 0 or orig === 0) remain index 0.
 */
function transformSpriteFrame(frame: SpriteFrame, table: Uint8Array): SpriteFrame {
  const indices = new Uint8Array(frame.indices.length)
  for (let i = 0; i < frame.indices.length; i++) {
    if (frame.mask[i] !== 0 && frame.indices[i] !== 0) {
      const orig = frame.indices[i]!
      let mapped = table[orig] ?? 0
      if (mapped === 0) {
        mapped = 172
      }
      indices[i] = mapped
    } else {
      indices[i] = 0
    }
  }
  return {
    width: frame.width,
    height: frame.height,
    indices,
    mask: frame.mask,
  }
}

/**
 * Stitch a standard 2x2 320x432 Diablo II panel from 4 consecutive DC6 frames:
 * Frame +0: 256x256 (Top-Left)
 * Frame +1: 64x256  (Top-Right)
 * Frame +2: 256x176 (Bottom-Left)
 * Frame +3: 64x176  (Bottom-Right)
 */
function stitch320x432Panel(sheet: SpriteSheet, startFrame = 0): Uint8Array {
  const frames = sheet.groups[0]!.frames
  return stitchFrames(320, 432, [
    { frame: frames[startFrame + 0]!, x: 0, y: 0 },
    { frame: frames[startFrame + 1]!, x: 256, y: 0 },
    { frame: frames[startFrame + 2]!, x: 0, y: 256 },
    { frame: frames[startFrame + 3]!, x: 256, y: 256 },
  ])
}

/**
 * Stitch a horizontal strip of frames into a single sprite sheet.
 */
function stitchHorizontalStrip(frames: readonly SpriteFrame[]): {
  width: number
  height: number
  pixels: Uint8Array
  rects: SpriteRect[]
} {
  const height = Math.max(1, ...frames.map(f => f.height))
  let totalW = 0
  const rects: SpriteRect[] = []
  const placements: BlitPlacement[] = []
  for (const frame of frames) {
    rects.push({ x: totalW, y: 0, w: frame.width, h: frame.height })
    placements.push({ frame, x: totalW, y: 0 })
    totalW += frame.width
  }
  return {
    width: Math.max(1, totalW),
    height,
    pixels: stitchFrames(Math.max(1, totalW), height, placements),
    rects,
  }
}

/**
 * Parse a `Woo!\x01` font metric table (`data/local/font/latin/font*.tbl`)
 * and pack its 256 DC6 glyphs into a 16x16 grid PNG.
 */
function buildFontAtlas(name: string, dc6: SpriteSheet, tblBytes: Uint8Array): {
  meta: FontAtlasMeta
  pixels: Uint8Array
} {
  const magic = new TextDecoder().decode(tblBytes.slice(0, 4))
  if (magic !== 'Woo!') {
    throw new Error(`Invalid font tbl header for ${name}: ${magic}`)
  }
  const lineHeight = tblBytes[10] || 14
  const capHeight = tblBytes[11] || 16
  const frames = dc6.groups[0]!.frames
  const cellW = Math.max(16, ...frames.map(f => f.width))
  const cellH = Math.max(16, ...frames.map(f => f.height))
  const atlasWidth = cellW * 16
  const atlasHeight = cellH * 16

  const placements: BlitPlacement[] = []
  const glyphs: FontGlyphMetric[] = []

  for (let i = 0; i < 256; i++) {
    const recOff = 12 + i * 14
    const metricWidth = recOff + 3 < tblBytes.length ? (tblBytes[recOff + 3] || 6) : 6
    const metricHeight = recOff + 4 < tblBytes.length ? (tblBytes[recOff + 4] || lineHeight) : lineHeight
    const frameIdx = recOff + 8 < tblBytes.length ? (tblBytes[recOff + 8] ?? i) : i
    const frame = frames[frameIdx] ?? frames[i]
    const gx = (i % 16) * cellW
    const gy = Math.floor(i / 16) * cellH
    if (frame) {
      placements.push({ frame, x: gx, y: gy })
    }
    glyphs.push({
      code: i,
      width: metricWidth,
      height: metricHeight,
      x: gx,
      y: gy,
      frameW: frame?.width ?? 0,
      frameH: frame?.height ?? 0,
    })
  }

  return {
    meta: {
      name,
      lineHeight,
      capHeight,
      atlasWidth,
      atlasHeight,
      glyphs,
    },
    pixels: stitchFrames(atlasWidth, atlasHeight, placements),
  }
}

async function main(): Promise<void> {
  console.log('Mounting Diablo II v1.13c MPQ archives...')
  const archives = new MountedArchives()
  for (const m of ['d2char.mpq', 'd2data.mpq', 'd2exp.mpq', 'Patch_D2.mpq']) {
    archives.add(m, await MpqArchive.open(await fileSource(`samples/d2/${m}`)))
  }

  const pl2 = decodePl2(await archives.read('data/global/palette/ACT1/pal.pl2'))
  const outDir = join(process.cwd(), 'public', 'ui')
  const fontsDir = join(outDir, 'fonts')
  mkdirSync(outDir, { recursive: true })
  mkdirSync(fontsDir, { recursive: true })

  let decodedCount = 0
  let decodeFailures = 0

  const decodeUiDc6 = async (path: string): Promise<SpriteSheet> => {
    try {
      const bytes = await archives.read(path)
      const sheet = decodeDc6(bytes)
      decodedCount++
      return sheet
    } catch (err) {
      decodeFailures++
      console.error(`Failed to decode DC6 ${path}:`, err)
      throw err
    }
  }

  const savePng = (relPath: string, width: number, height: number, pixels: Uint8Array, transparent = true): void => {
    const png = encodeIndexedPng({
      width,
      height,
      pixels,
      palette: pl2.rgb,
      transparentIndex: transparent ? 0 : undefined,
    })
    writeFileSync(join(outDir, relPath), png)
  }

  // --- STAGE 1: Base UI Panels, Globes, Borders, Fonts, Buttons ---
  console.log('Extracting base UI panels, globes, borders, and controls...')

  // 1. 800x600 Bottom Control Panel (`Panel/800CtrlPnl7.dc6`)
  const ctrl800 = await decodeUiDc6('data/global/ui/Panel/800CtrlPnl7.dc6')
  const cf = ctrl800.groups[0]!.frames
  const ctrlPixels = stitchFrames(800, 104, [
    { frame: cf[6]!, x: 64, y: 49 },
    { frame: cf[6]!, x: 600, y: 49 },
    { frame: cf[1]!, x: 165, y: 49 },
    { frame: cf[2]!, x: 293, y: 49 },
    { frame: cf[3]!, x: 421, y: 49 },
    { frame: cf[4]!, x: 549, y: 49 },
    { frame: cf[0]!, x: 0, y: 0 },
    { frame: cf[5]!, x: 683, y: 0 },
  ])
  savePng('ctrlpnl-800.png', 800, 104, ctrlPixels)

  // 2. Health & Mana Globes (`Panel/Hlthmana.dc6` & `Panel/overlap.dc6`)
  const hlthmana = await decodeUiDc6('data/global/ui/Panel/Hlthmana.dc6')
  const hf = hlthmana.groups[0]!.frames
  savePng('globe-life.png', hf[0]!.width, hf[0]!.height, hf[0]!.indices)
  savePng('globe-mana.png', hf[1]!.width, hf[1]!.height, hf[1]!.indices)
  if (hf[2]) savePng('globe-poison.png', hf[2].width, hf[2].height, hf[2].indices)

  const overlap = await decodeUiDc6('data/global/ui/Panel/overlap.dc6')
  const of = overlap.groups[0]!.frames
  savePng('overlap-left.png', of[0]!.width, of[0]!.height, of[0]!.indices)
  savePng('overlap-right.png', of[1]!.width, of[1]!.height, of[1]!.indices)

  // 3. 800x600 Gothic Stone Borders (`Panel/800BorderFrame.dc6`)
  const borderDc6 = await decodeUiDc6('data/global/ui/Panel/800BorderFrame.dc6')
  const bf = borderDc6.groups[0]!.frames
  const leftBorderPixels = stitchFrames(400, 553, [
    { frame: bf[0]!, x: 0, y: -3 },
    { frame: bf[1]!, x: 256, y: -3 },
    { frame: bf[2]!, x: 0, y: 253 },
    { frame: bf[3]!, x: 0, y: 482 },
    { frame: bf[4]!, x: 256, y: 482 },
  ])
  savePng('border-left.png', 400, 553, leftBorderPixels)

  const rightBorderPixels = stitchFrames(400, 553, [
    { frame: bf[5]!, x: 0, y: -3 },
    { frame: bf[6]!, x: 144, y: -3 },
    { frame: bf[7]!, x: 313, y: 253 },
    { frame: bf[8]!, x: 144, y: 482 },
    { frame: bf[9]!, x: 0, y: 482 },
  ])
  savePng('border-right.png', 400, 553, rightBorderPixels)

  // 4. Character Sheet & Inventory Sheet (`Panel/invchar6.dc6` & `Panel/invchar6Tab.dc6`)
  const invchar6 = await decodeUiDc6('data/global/ui/Panel/invchar6.dc6')
  savePng('char-sheet.png', 320, 432, stitch320x432Panel(invchar6, 0), false)
  savePng('inv-sheet.png', 320, 432, stitch320x432Panel(invchar6, 4), false)

  const invTab = await decodeUiDc6('data/global/ui/Panel/invchar6Tab.dc6')
  const itf = invTab.groups[0]!.frames
  savePng('inv-tab-0.png', itf[0]!.width, itf[0]!.height, itf[0]!.indices)
  savePng('inv-tab-1.png', itf[1]!.width, itf[1]!.height, itf[1]!.indices)

  // 5. Quest Log, Waypoint Menu, Stash, Horadric Cube, Vendor (`320x432` panels)
  const questBg = await decodeUiDc6('data/global/ui/Menu/questbackground.dc6')
  savePng('quest-bg.png', 320, 432, stitch320x432Panel(questBg, 0), false)

  const wpBg = await decodeUiDc6('data/global/ui/Menu/waygatebackground.dc6')
  savePng('waypoint-bg.png', 320, 432, stitch320x432Panel(wpBg, 0), false)

  const stashBg = await decodeUiDc6('data/global/ui/Panel/TradeStash.dc6')
  savePng('stash-bg.png', 320, 432, stitch320x432Panel(stashBg, 0), false)

  const cubeBg = await decodeUiDc6('data/global/ui/Panel/supertransmogrifier.dc6')
  savePng('cube-bg.png', 320, 432, stitch320x432Panel(cubeBg, 0), false)

  const vendorBg = await decodeUiDc6('data/global/ui/Panel/NPCInv.dc6')
  savePng('vendor-bg.png', 320, 432, stitch320x432Panel(vendorBg, 0), false)

  // 6. Pop-up Belt, Mini-panel, Buttons, Cursors
  const popbelt = await decodeUiDc6('data/global/ui/Panel/ctrlpnl_popbelt.dc6')
  savePng('popbelt.png', popbelt.groups[0]!.frames[0]!.width, popbelt.groups[0]!.frames[0]!.height, popbelt.groups[0]!.frames[0]!.indices, false)

  const minipanel = await decodeUiDc6('data/global/ui/Panel/minipanel.dc6')
  savePng('minipanel.png', minipanel.groups[0]!.frames[0]!.width, minipanel.groups[0]!.frames[0]!.height, minipanel.groups[0]!.frames[0]!.indices)

  const minipanelBtns = await decodeUiDc6('data/global/ui/Panel/minipanelbtn.dc6')
  const mpStrip = stitchHorizontalStrip(minipanelBtns.groups[0]!.frames)
  savePng('minipanel-btns.png', mpStrip.width, mpStrip.height, mpStrip.pixels)

  const runBtn = await decodeUiDc6('data/global/ui/Panel/runbutton.dc6')
  const runStrip = stitchHorizontalStrip(runBtn.groups[0]!.frames)
  savePng('runbutton.png', runStrip.width, runStrip.height, runStrip.pixels)

  const menuBtn = await decodeUiDc6('data/global/ui/Panel/menubutton.dc6')
  const menuStrip = stitchHorizontalStrip(menuBtn.groups[0]!.frames)
  savePng('menubutton.png', menuStrip.width, menuStrip.height, menuStrip.pixels)

  const buySellBtn = await decodeUiDc6('data/global/ui/Panel/buysellbtn.dc6')
  const bsStrip = stitchHorizontalStrip(buySellBtn.groups[0]!.frames)
  savePng('buysellbtn.png', bsStrip.width, bsStrip.height, bsStrip.pixels)

  const levelBtn = await decodeUiDc6('data/global/ui/Panel/Level.dc6')
  const lvlStrip = stitchHorizontalStrip(levelBtn.groups[0]!.frames)
  savePng('level-btn.png', lvlStrip.width, lvlStrip.height, lvlStrip.pixels)

  const levelSocket = await decodeUiDc6('data/global/ui/Panel/Levelsocket.dc6')
  savePng('level-socket.png', levelSocket.groups[0]!.frames[0]!.width, levelSocket.groups[0]!.frames[0]!.height, levelSocket.groups[0]!.frames[0]!.indices)

  const skillPts = await decodeUiDc6('data/global/ui/Panel/skillpoints.dc6')
  savePng('skillpoints.png', skillPts.groups[0]!.frames[0]!.width, skillPts.groups[0]!.frames[0]!.height, skillPts.groups[0]!.frames[0]!.indices)

  const expQuestTabs = await decodeUiDc6('data/global/ui/Menu/expquesttabs.dc6')
  const eqtStrip = stitchHorizontalStrip(expQuestTabs.groups[0]!.frames)
  savePng('quest-tabs.png', eqtStrip.width, eqtStrip.height, eqtStrip.pixels)

  const expWpTabs = await decodeUiDc6('data/global/ui/Menu/expwaygatetabs.dc6')
  const ewtStrip = stitchHorizontalStrip(expWpTabs.groups[0]!.frames)
  savePng('waypoint-tabs.png', ewtStrip.width, ewtStrip.height, ewtStrip.pixels)

  const wpIcons = await decodeUiDc6('data/global/ui/Menu/waygateicons.dc6')
  const wpiStrip = stitchHorizontalStrip(wpIcons.groups[0]!.frames)
  savePng('waypoint-icons.png', wpiStrip.width, wpiStrip.height, wpiStrip.pixels)

  const genericSkills = await decodeUiDc6('data/global/ui/SPELLS/Skillicon.DC6')
  const gsStrip = stitchHorizontalStrip(genericSkills.groups[0]!.frames)
  savePng('generic-skills.png', gsStrip.width, gsStrip.height, gsStrip.pixels)

  const ohand = await decodeUiDc6('data/global/ui/CURSOR/ohand.dc6')
  savePng('cursor-hand.png', ohand.groups[0]!.frames[0]!.width, ohand.groups[0]!.frames[0]!.height, ohand.groups[0]!.frames[0]!.indices)

  // Extract authentic dynamic cursor atlas (Issue #148: protate, ohand, orotate)
  console.log('Extracting authentic dynamic cursor atlas (Issue #148)...')
  await packCursorAssets(process.cwd())

  // 7. Extract Bitmap Fonts (`data/local/font/latin/*.dc6 + *.tbl`)
  console.log('Extracting bitmap fonts...')
  const fontNames = ['font6', 'font8', 'font16', 'font30', 'fontexocet10', 'fontformal12'] as const
  const fontMetas: Record<string, FontAtlasMeta> = {}
  for (const fn of fontNames) {
    const fDc6 = await decodeUiDc6(`data/local/font/latin/${fn}.dc6`)
    const fTbl = await archives.read(`data/local/font/latin/${fn}.tbl`)
    const built = buildFontAtlas(fn, fDc6, fTbl)
    fontMetas[fn] = built.meta
    savePng(`fonts/${fn}.png`, built.meta.atlasWidth, built.meta.atlasHeight, built.pixels)
  }
  writeFileSync(join(fontsDir, 'metrics.json'), JSON.stringify(fontMetas, null, 2))

  // --- STAGE 2: Comprehensive Items & Unique Items Packing ---
  console.log('Extracting item sprites (including uniqueitems.txt & setitems.txt)...')
  const codeToInvFile: Record<string, string> = {}
  const uniqueInvFiles = new Set<string>()

  // A. Base Items from weapons.txt, armor.txt, misc.txt
  for (const t of ['weapons.txt', 'armor.txt', 'misc.txt']) {
    const tbl = parseTable(new TextDecoder().decode(await archives.read(`data/global/excel/${t}`)))
    for (const r of tbl.rows) {
      const code = r['code']?.trim()
      const inv = r['invfile']?.trim().toLowerCase()
      if (code && inv && archives.has(`data/global/items/${inv}.dc6`)) {
        codeToInvFile[code] = inv
        uniqueInvFiles.add(inv)
      }
      for (const extraCol of ['uniqueinvfile', 'setinvfile']) {
        const extra = r[extraCol]?.trim().toLowerCase()
        if (extra && archives.has(`data/global/items/${extra}.dc6`)) {
          uniqueInvFiles.add(extra)
        }
      }
    }
  }

  // B. Unique Items from uniqueitems.txt (includes invmss, invtrch, invamu2, etc.)
  if (archives.has('data/global/excel/uniqueitems.txt')) {
    const uTbl = parseTable(new TextDecoder().decode(await archives.read('data/global/excel/uniqueitems.txt')))
    for (const r of uTbl.rows) {
      const inv = r['invfile']?.trim().toLowerCase()
      if (inv && archives.has(`data/global/items/${inv}.dc6`)) {
        uniqueInvFiles.add(inv)
      }
      const idx = r['index']?.trim()
      if (idx && inv && archives.has(`data/global/items/${inv}.dc6`)) {
        codeToInvFile[idx] = inv
      }
    }
  }

  // C. Set Items from setitems.txt
  if (archives.has('data/global/excel/setitems.txt')) {
    const sTbl = parseTable(new TextDecoder().decode(await archives.read('data/global/excel/setitems.txt')))
    for (const r of sTbl.rows) {
      const inv = r['invfile']?.trim().toLowerCase()
      if (inv && archives.has(`data/global/items/${inv}.dc6`)) {
        uniqueInvFiles.add(inv)
      }
      const idx = r['index']?.trim()
      if (idx && inv && archives.has(`data/global/items/${inv}.dc6`)) {
        codeToInvFile[idx] = inv
      }
    }
  }

  // Identity mapping for every invfile: codeToInvFile[inv] = inv
  for (const inv of uniqueInvFiles) {
    codeToInvFile[inv] = inv
  }
  // Explicitly guarantee Annihilus and Torch mappings
  if (archives.has('data/global/items/invmss.dc6')) {
    uniqueInvFiles.add('invmss')
    codeToInvFile['mss'] = 'invmss'
    codeToInvFile['invmss'] = 'invmss'
  }
  if (archives.has('data/global/items/invtrch.dc6')) {
    uniqueInvFiles.add('invtrch')
    codeToInvFile['trch'] = 'invtrch'
    codeToInvFile['invtrch'] = 'invtrch'
  }

  // Register transformed item lookups in codeToInvFile
  codeToInvFile['Harlequin Crest'] = 'invcap_cgrn'
  codeToInvFile["Tal Rasha's Guardianship"] = 'invgth_dpur'
  codeToInvFile["Tal Rasha's Howling Wind"] = 'invgth_dpur'
  codeToInvFile['Magefist'] = 'invtgl_lgry'
  codeToInvFile['Arachnid Mesh'] = 'invvbl_blac'

  // Identity mappings for transformed items
  codeToInvFile['invcap_cgrn'] = 'invcap_cgrn'
  codeToInvFile['invgth_dpur'] = 'invgth_dpur'
  codeToInvFile['invtgl_lgry'] = 'invtgl_lgry'
  codeToInvFile['invvbl_blac'] = 'invvbl_blac'
  codeToInvFile['invlbl_blac'] = 'invlbl_blac'

  // Pack items-atlas.png (ATLAS_W = 1024)
  const sortedInvNames = [...uniqueInvFiles].sort()
  const ATLAS_W = 1024
  let curX = 0
  let curY = 0
  let rowH = 0
  const itemRects: Record<string, SpriteRect> = {}
  const itemPlacements: BlitPlacement[] = []
  const decodedBaseFrames = new Map<string, SpriteFrame>()

  for (const invName of sortedInvNames) {
    const dc6 = await decodeUiDc6(`data/global/items/${invName}.dc6`)
    const frame = dc6.groups[0]?.frames[0]
    if (!frame) continue
    decodedBaseFrames.set(invName, frame)
    if (curX + frame.width > ATLAS_W) {
      curX = 0
      curY += rowH + 2
      rowH = 0
    }
    itemRects[invName] = { x: curX, y: curY, w: frame.width, h: frame.height }
    itemPlacements.push({ frame, x: curX, y: curY })
    curX += frame.width + 2
    if (frame.height > rowH) rowH = frame.height
  }

  // Pre-bake and stitch transformed item frames (cgrn, dpur, lgry, blac)
  const COLOR_TABLE_MAP: Record<string, number> = {
    cgrn: 104, // emerald green RGB [51, 135, 75]
    dpur: 108, // royal dark purple RGB [92, 35, 154]
    lgry: 73,  // silver grey RGB [117, 117, 117]
    blac: 98,  // jet black RGB [0, 0, 0]
  }

  const TRANSFORMED_ITEMS: ReadonlyArray<{
    baseInv: string
    transformedName: string
    colorCode: 'cgrn' | 'dpur' | 'lgry' | 'blac'
  }> = [
    { baseInv: 'invcap', transformedName: 'invcap_cgrn', colorCode: 'cgrn' },
    { baseInv: 'invgth', transformedName: 'invgth_dpur', colorCode: 'dpur' },
    { baseInv: 'invtgl', transformedName: 'invtgl_lgry', colorCode: 'lgry' },
    { baseInv: 'invvbl', transformedName: 'invvbl_blac', colorCode: 'blac' },
    { baseInv: 'invlbl', transformedName: 'invlbl_blac', colorCode: 'blac' },
  ]

  for (const t of TRANSFORMED_ITEMS) {
    let baseFrame = decodedBaseFrames.get(t.baseInv)
    if (!baseFrame) {
      const dc6 = await decodeUiDc6(`data/global/items/${t.baseInv}.dc6`)
      baseFrame = dc6.groups[0]?.frames[0]
      if (!baseFrame) {
        throw new Error(`Base DC6 frame missing for transformed item ${t.transformedName}`)
      }
    }
    const tableIdx = COLOR_TABLE_MAP[t.colorCode]
    if (tableIdx === undefined) {
      throw new Error(`Color table code ${t.colorCode} not defined in COLOR_TABLE_MAP`)
    }
    const table = pl2.hueVariations[tableIdx]
    if (!table) {
      throw new Error(`PL2 hue variation table ${tableIdx} not found in pal.pl2`)
    }
    const transformedFrame = transformSpriteFrame(baseFrame, table)
    if (curX + transformedFrame.width > ATLAS_W) {
      curX = 0
      curY += rowH + 2
      rowH = 0
    }
    itemRects[t.transformedName] = { x: curX, y: curY, w: transformedFrame.width, h: transformedFrame.height }
    itemPlacements.push({ frame: transformedFrame, x: curX, y: curY })
    curX += transformedFrame.width + 2
    if (transformedFrame.height > rowH) rowH = transformedFrame.height
  }

  const atlasH = Math.max(1, curY + rowH)
  savePng('items-atlas.png', ATLAS_W, atlasH, stitchFrames(ATLAS_W, atlasH, itemPlacements))

  // --- STAGE 3: 27 Active Quest Icons + Completed Quest Icons Atlas ---
  console.log('Extracting quest icons (27 active + 27 completed)...')
  const canonicalQuests = [
    // Act 1 (0..5)
    'a1q1', 'a1q2', 'a1q3', 'a1q4', 'a1q5', 'a1q6',
    // Act 2 (6..11)
    'a2q1', 'a2q2', 'a2q3', 'a2q4', 'a2q5', 'a2q6',
    // Act 3 (12..17)
    'a3q1', 'a3q2', 'a3q3', 'a3q4', 'a3q5', 'a3q6',
    // Act 4 (18..20)
    'a4q1', 'a4q2', 'a4q3',
    // Act 5 (21..26)
    'a5q1', 'a5q2', 'a5q3', 'a5q4', 'a5q5', 'a5q6',
  ]

  const questRects: Record<string, SpriteRect> = {}
  const questPlacements: BlitPlacement[] = []

  // Pack in a 6-column grid (each tile 72x86):
  // Width: 6 * 72 = 432
  // Height: 9 rows * 86 = 774
  const QUEST_ATLAS_W = 432
  const QUEST_ATLAS_H = 774

  // 1. 27 Active quest icons (frame 0)
  for (let i = 0; i < canonicalQuests.length; i++) {
    const qSlug = canonicalQuests[i]!
    const qDc6 = await decodeUiDc6(`data/global/ui/MENU/${qSlug}.dc6`)
    const frame = qDc6.groups[0]!.frames[0]!
    const col = i % 6
    const row = Math.floor(i / 6) // rows 0..4
    const qx = col * 72
    const qy = row * 86
    questRects[qSlug] = { x: qx, y: qy, w: 72, h: 86 }
    questPlacements.push({ frame, x: qx, y: qy })
  }

  // 2. 27 Completed quest icons from questdone.dc6
  const qDoneDc6 = await decodeUiDc6('data/global/ui/MENU/questdone.dc6')
  const doneFrames = qDoneDc6.groups[0]!.frames
  for (let i = 0; i < doneFrames.length; i++) {
    const frame = doneFrames[i]!
    const idx = 27 + i
    const col = idx % 6
    const row = Math.floor(idx / 6) // rows 4..8
    const qx = col * 72
    const qy = row * 86
    const qSlug = canonicalQuests[i]!
    questRects[`questdone_${i}`] = { x: qx, y: qy, w: 72, h: 86 }
    questRects[`questdone_${qSlug}`] = { x: qx, y: qy, w: 72, h: 86 }
    questPlacements.push({ frame, x: qx, y: qy })
  }

  savePng('quests-atlas.png', QUEST_ATLAS_W, QUEST_ATLAS_H, stitchFrames(QUEST_ATLAS_W, QUEST_ATLAS_H, questPlacements))

  // --- STAGE 4: Emit public/ui/manifest.json ---
  const imagesMap: Record<string, string> = {
    ctrlPnl: '/ui/ctrlpnl-800.png',
    globeLife: '/ui/globe-life.png',
    globeMana: '/ui/globe-mana.png',
    globePoison: '/ui/globe-poison.png',
    overlapLeft: '/ui/overlap-left.png',
    overlapRight: '/ui/overlap-right.png',
    borderLeft: '/ui/border-left.png',
    borderRight: '/ui/border-right.png',
    charSheet: '/ui/char-sheet.png',
    invSheet: '/ui/inv-sheet.png',
    invTab0: '/ui/inv-tab-0.png',
    invTab1: '/ui/inv-tab-1.png',
    questBg: '/ui/quest-bg.png',
    waypointBg: '/ui/waypoint-bg.png',
    stashBg: '/ui/stash-bg.png',
    cubeBg: '/ui/cube-bg.png',
    vendorBg: '/ui/vendor-bg.png',
    popbelt: '/ui/popbelt.png',
    minipanel: '/ui/minipanel.png',
    minipanelBtns: '/ui/minipanel-btns.png',
    runBtn: '/ui/runbutton.png',
    menuBtn: '/ui/menubutton.png',
    buySellBtn: '/ui/buysellbtn.png',
    levelBtn: '/ui/level-btn.png',
    levelSocket: '/ui/level-socket.png',
    skillPoints: '/ui/skillpoints.png',
    genericSkills: '/ui/generic-skills.png',
    cursorHand: '/ui/cursor-hand.png',
    cursorAtlas: '/ui/cursor.png',
    questTabs: '/ui/quest-tabs.png',
    waypointTabs: '/ui/waypoint-tabs.png',
    waypointIcons: '/ui/waypoint-icons.png',
    itemsAtlas: '/ui/items-atlas.png',
    questsAtlas: '/ui/quests-atlas.png',
  }

  const manifest = {
    version: '1.13c',
    decodedDc6Count: decodedCount,
    dc6DecodeFailures: decodeFailures,
    atlasWidth: ATLAS_W,
    atlasHeight: atlasH,
    questsAtlasWidth: QUEST_ATLAS_W,
    questsAtlasHeight: QUEST_ATLAS_H,
    codeToInvFile,
    itemRects,
    questRects,
    images: imagesMap,
  }
  writeFileSync(join(outDir, 'manifest.json'), JSON.stringify(manifest, null, 2))

  // --- STAGE 5: Emit src/ui/baked-ui-meta.ts ---
  const bakedMetaCode = `/**
 * Auto-generated baked UI metadata for Diablo II Web client.
 * Generated by \`scripts/pack-ui.ts\`.
 * Enforces the Zero Runtime MPQ/DLL Architectural Invariant.
 */

export interface SpriteRect {
  readonly x: number
  readonly y: number
  readonly w: number
  readonly h: number
}

export interface QuestAssetInfo {
  readonly activeIcon: string
  readonly doneIcon: string
  readonly doneFrame: number
}

export interface BakedUiManifest {
  readonly version: string
  readonly decodedDc6Count: number
  readonly dc6DecodeFailures: number
  readonly atlasWidth: number
  readonly atlasHeight: number
  readonly questsAtlasWidth: number
  readonly questsAtlasHeight: number
  readonly codeToInvFile: Record<string, string>
  readonly itemRects: Record<string, SpriteRect>
  readonly questRects: Record<string, SpriteRect>
  readonly images: Record<string, string>
}

/**
 * Authoritative 1.13c Quest Asset Mapping: [act: number] -> QuestAssetInfo[]
 * Act 1: 6 quests (a1q1..a1q6, done frames 0..5)
 * Act 2: 6 quests (a2q1..a2q6, done frames 6..11)
 * Act 3: 6 quests (a3q1..a3q6, done frames 12..17)
 * Act 4: 3 quests (a4q1..a4q3, done frames 18..20)
 * Act 5: 6 quests (a5q1..a5q6, done frames 21..26)
 */
export const ACT_QUEST_ASSET_MAP: Readonly<Record<number, readonly QuestAssetInfo[]>> = {
  1: [
    { activeIcon: 'a1q1', doneIcon: 'questdone_0', doneFrame: 0 },
    { activeIcon: 'a1q2', doneIcon: 'questdone_1', doneFrame: 1 },
    { activeIcon: 'a1q3', doneIcon: 'questdone_2', doneFrame: 2 },
    { activeIcon: 'a1q4', doneIcon: 'questdone_3', doneFrame: 3 },
    { activeIcon: 'a1q5', doneIcon: 'questdone_4', doneFrame: 4 },
    { activeIcon: 'a1q6', doneIcon: 'questdone_5', doneFrame: 5 },
  ],
  2: [
    { activeIcon: 'a2q1', doneIcon: 'questdone_6', doneFrame: 6 },
    { activeIcon: 'a2q2', doneIcon: 'questdone_7', doneFrame: 7 },
    { activeIcon: 'a2q3', doneIcon: 'questdone_8', doneFrame: 8 },
    { activeIcon: 'a2q4', doneIcon: 'questdone_9', doneFrame: 9 },
    { activeIcon: 'a2q5', doneIcon: 'questdone_10', doneFrame: 10 },
    { activeIcon: 'a2q6', doneIcon: 'questdone_11', doneFrame: 11 },
  ],
  3: [
    { activeIcon: 'a3q1', doneIcon: 'questdone_12', doneFrame: 12 },
    { activeIcon: 'a3q2', doneIcon: 'questdone_13', doneFrame: 13 },
    { activeIcon: 'a3q3', doneIcon: 'questdone_14', doneFrame: 14 },
    { activeIcon: 'a3q4', doneIcon: 'questdone_15', doneFrame: 15 },
    { activeIcon: 'a3q5', doneIcon: 'questdone_16', doneFrame: 16 },
    { activeIcon: 'a3q6', doneIcon: 'questdone_17', doneFrame: 17 },
  ],
  4: [
    { activeIcon: 'a4q1', doneIcon: 'questdone_18', doneFrame: 18 },
    { activeIcon: 'a4q2', doneIcon: 'questdone_19', doneFrame: 19 },
    { activeIcon: 'a4q3', doneIcon: 'questdone_20', doneFrame: 20 },
  ],
  5: [
    { activeIcon: 'a5q1', doneIcon: 'questdone_21', doneFrame: 21 },
    { activeIcon: 'a5q2', doneIcon: 'questdone_22', doneFrame: 22 },
    { activeIcon: 'a5q3', doneIcon: 'questdone_23', doneFrame: 23 },
    { activeIcon: 'a5q4', doneIcon: 'questdone_24', doneFrame: 24 },
    { activeIcon: 'a5q5', doneIcon: 'questdone_25', doneFrame: 25 },
    { activeIcon: 'a5q6', doneIcon: 'questdone_26', doneFrame: 26 },
  ],
}

export const BAKED_UI_MANIFEST: BakedUiManifest = {
  version: '1.13c',
  decodedDc6Count: ${decodedCount},
  dc6DecodeFailures: ${decodeFailures},
  atlasWidth: ${ATLAS_W},
  atlasHeight: ${atlasH},
  questsAtlasWidth: ${QUEST_ATLAS_W},
  questsAtlasHeight: ${QUEST_ATLAS_H},
  codeToInvFile: ${JSON.stringify(codeToInvFile, null, 2)},
  itemRects: ${JSON.stringify(itemRects, null, 2)},
  questRects: ${JSON.stringify(questRects, null, 2)},
  images: ${JSON.stringify(imagesMap, null, 2)},
}

export { CURSOR_METADATA, type CursorFrameMeta, type CursorAtlasMetadata } from './cursor-meta.ts'
`
  writeFileSync(join(process.cwd(), 'src', 'ui', 'baked-ui-meta.ts'), bakedMetaCode, 'utf8')
  console.log(`Successfully decoded ${decodedCount} DC6 sheets (${decodeFailures} failures)!`)
  console.log('Emitted public/ui/manifest.json and src/ui/baked-ui-meta.ts.')
}

main().catch((err) => {
  console.error('pack-ui failed:', err)
  process.exit(1)
})