/**
 * Offline UI / HUD / Font / Item Sprite Extraction & Stitching Script.
 *
 * Strictly follows Diablo II v1.13c (D2Client.dll 0x6fad70c0..0x6fad7f40 & D2WinFont.cpp)
 * to extract and stitch all authentic DC6 panels, borders, globes, buttons, cursors,
 * bitmap fonts, and inventory item graphics into `public/ui/`.
 */

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'

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

/**
 * 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
}

/**
 * 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: { x: number; y: number; w: number; h: number }[]
} {
  const height = Math.max(1, ...frames.map(f => f.height))
  let totalW = 0
  const rects: { x: number; y: number; w: number; h: number }[] = []
  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,
  }
}

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[]
}

/**
 * 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
  const decodeUiDc6 = async (path: string): Promise<SpriteSheet> => {
    const bytes = await archives.read(path)
    const sheet = decodeDc6(bytes)
    decodedCount++
    return sheet
  }

  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)
  }

  // 1. 800x600 Bottom Control Panel (`Panel\800CtrlPnl7.dc6`)
  // Per D2Client.dll 0x6fad7422..0x6fad7540:
  // Frame 0 (117x104) at x=0, y=0
  // Frame 6 (128x55) bridges left/right globe inner segments, Frames 1..4 at x=165, 293, 421, 549 (y=49), Frame 5 (117x104) at x=683, y=0
  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`)
  // Left Border (400x553) per D2Client.dll 0x6fad71ed..0x6fad7282:
  // Frame 0 (256x256) at (0, -3), Frame 1 (144x66) at (256, -3), Frame 2 (85x231) at (0, 253),
  // Frame 3 (256x71) at (0, 482), Frame 4 (145x71) at (256, 482)
  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)

  // Right Border (400x553, local x = screenX - 400) per D2Client.dll 0x6fad70f1..0x6fad71a8:
  // Frame 5 (145x66) at (0, -3), Frame 6 (256x256) at (144, -3), Frame 7 (87x231) at (313, 253),
  // Frame 8 (256x71) at (144, 482), Frame 9 (145x71) at (0, 482)
  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\\buysell.dc6')
  const vbf = vendorBg.groups[0]?.frames
  const expectedVendorBgFrames = [
    { w: 256, h: 256 },
    { w: 64, h: 256 },
    { w: 256, h: 176 },
    { w: 64, h: 176 },
  ]
  if (
    !vbf ||
    vbf.length < 4 ||
    expectedVendorBgFrames.some((exp, i) => vbf[i]?.width !== exp.w || vbf[i]?.height !== exp.h)
  ) {
    throw new Error('Invalid buysell.dc6 frame geometry: expected 4 frames (256x256, 64x256, 256x176, 64x176)')
  }
  savePng('vendor-bg.png', 320, 432, stitch320x432Panel(vendorBg, 0), false)

  // 6. Pop-up Belt, Mini-panel, Buttons, Cursors, and Equipment Silhouettes
  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 goldCoinBtn = await decodeUiDc6('data\\global\\ui\\Panel\\goldcoinbtn.dc6')
  const gcbFrames = goldCoinBtn.groups[0]?.frames
  if (!gcbFrames || gcbFrames.length !== 2 || gcbFrames.some(f => f.width !== 20 || f.height !== 18)) {
    throw new Error('Invalid goldcoinbtn.dc6 frame geometry: expected 2 frames of 20x18')
  }
  const gcbStrip = stitchHorizontalStrip(gcbFrames)
  savePng('goldcoinbtn.png', gcbStrip.width, gcbStrip.height, gcbStrip.pixels)

  const miniConvertDc6 = await decodeUiDc6('data\\global\\ui\\Panel\\miniconvert.dc6')
  const mcFrames = miniConvertDc6.groups[0]?.frames
  if (!mcFrames || mcFrames.length !== 2 || mcFrames.some(f => f.width !== 32 || f.height !== 32)) {
    throw new Error('Invalid miniconvert.dc6 frame geometry: expected 2 frames of 32x32')
  }
  const mcStrip = stitchHorizontalStrip(mcFrames)
  savePng('miniconvert.png', mcStrip.width, mcStrip.height, mcStrip.pixels)

  const buySellTabs = await decodeUiDc6('data\\global\\ui\\Panel\\buyselltabs.dc6')
  const bstFrames = buySellTabs.groups[0]?.frames
  if (!bstFrames || bstFrames.length !== 8 || bstFrames.some(f => f.width !== 79 || f.height !== 31)) {
    throw new Error('Invalid buyselltabs.dc6 frame geometry: expected 8 frames of 79x31')
  }
  const bstStrip = stitchHorizontalStrip(bstFrames)
  savePng('vendor-tabs.png', bstStrip.width, bstStrip.height, bstStrip.pixels)

  const boxPiecesDc6 = await decodeUiDc6('data\\global\\ui\\menu\\boxpieces.dc6')
  const bpFrames = boxPiecesDc6.groups[0]?.frames
  if (!bpFrames || bpFrames.length !== 22 || bpFrames.some(f => f.width !== 14 || f.height !== 15)) {
    throw new Error('Invalid boxpieces.dc6 frame geometry: expected 22 frames of 14x15')
  }
  const bpStrip = stitchHorizontalStrip(bpFrames)
  savePng('boxpieces.png', bpStrip.width, bpStrip.height, bpStrip.pixels)

  const focus16Dc6 = await decodeUiDc6('data\\global\\ui\\CURSOR\\focus16.dc6')
  const f16Frames = focus16Dc6.groups[0]?.frames
  if (!f16Frames || f16Frames.length !== 8 || f16Frames.some(f => f.width !== 20 || f.height !== 20)) {
    throw new Error('Invalid focus16.dc6 frame geometry: expected 8 frames of 20x20')
  }
  const f16Strip = stitchHorizontalStrip(f16Frames)
  savePng('focus16.png', f16Strip.width, f16Strip.height, f16Strip.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)

  // 7. Extract Bitmap Fonts (`data\local\font\latin\*.dc6 + *.tbl`)
  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))

  // 8. Extract Item Inventory Sprites (`data\global\items\inv*.dc6`)
  const codeToInvFile: Record<string, string> = {}
  const uniqueInvFiles = new Set<string>()

  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)
        }
      }
    }
  }

  // Pack all unique inv*.dc6 into a grid atlas (width 1024)
  const sortedInvNames = [...uniqueInvFiles].sort()
  const ATLAS_W = 1024
  let curX = 0
  let curY = 0
  let rowH = 0
  const itemRects: Record<string, { x: number; y: number; w: number; h: number }> = {}
  const itemPlacements: BlitPlacement[] = []

  for (const invName of sortedInvNames) {
    const dc6 = await decodeUiDc6(`data\\global\\items\\${invName}.dc6`)
    const frame = dc6.groups[0]?.frames[0]
    if (!frame) continue
    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
  }

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

  const manifest = {
    version: '1.13c',
    decodedDc6Count: decodedCount,
    dc6DecodeFailures: 0,
    atlasWidth: ATLAS_W,
    atlasHeight: atlasH,
    codeToInvFile,
    itemRects,
  }
  writeFileSync(join(outDir, 'manifest.json'), JSON.stringify(manifest, null, 2))
  console.log(`Successfully decoded ${decodedCount} DC6 sheets (0 failures) and generated public/ui/ assets!`)
}

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