import { randomUUID } from 'crypto'
import { existsSync } from 'fs'
import { mkdir, readFile, rm, writeFile } from 'fs/promises'
import { extname, join } from 'path'
import { compressWithBlender } from '@/lib/blender'
import { compressTextureBuffer } from '@/lib/texture-compression'
import { classifyAssetCategory } from '@/lib/asset-classification'
import { normalizeTextureFilename } from '@/lib/asset-naming'
import { TEXTURE_EXTENSIONS, TMP_DIR } from '@/lib/constants'
import { getErrorMessage, isRecord } from '@/lib/guards'
import { getModelAssetPath } from '@/lib/model-paths'
import type { GitModelMode, ParsedFile, PreparedAssetSummary, PreparedGitAssetsResult, PushFile } from '@/lib/types'

interface PrepareGitAssetsParams {
  folderName: string
  parsedFiles: ParsedFile[]
  gitModelMode: GitModelMode
}

type JsonValue = string | number | boolean | null | JsonValue[] | { [key: string]: JsonValue }

function isJsonValue(value: unknown): value is JsonValue {
  if (value === null) return true

  if (typeof value === 'string' || typeof value === 'number' || typeof value === 'boolean') {
    return true
  }

  if (Array.isArray(value)) {
    return value.every(isJsonValue)
  }

  return isRecord(value) && Object.values(value).every(isJsonValue)
}

function parseJsonValue(content: string) {
  const parsed: unknown = JSON.parse(content)

  if (!isJsonValue(parsed)) {
    throw new Error('model.gltf contient un JSON invalide')
  }

  return parsed
}

function getTextureFilenameMap(parsedFiles: ParsedFile[]) {
  const filenameMap = new Map<string, string>()
  const normalizedGroups = new Map<string, Array<{ original: string; normalized: string }>>()

  for (const file of parsedFiles) {
    const ext = extname(file.filename).toLowerCase()
    if (!TEXTURE_EXTENSIONS.has(ext)) continue

    const normalizedFilename = normalizeTextureFilename(file.filename)
    if (!normalizedFilename) continue

    const normalizedKey = normalizedFilename.toLowerCase()
    const group = normalizedGroups.get(normalizedKey) || []
    group.push({ original: file.filename, normalized: normalizedFilename })
    normalizedGroups.set(normalizedKey, group)
  }

  for (const group of normalizedGroups.values()) {
    if (group.length > 1) continue

    const [{ original, normalized }] = group
    filenameMap.set(original.toLowerCase(), normalized)
  }

  return filenameMap
}

function getReferencedFilename(uri: string) {
  const cleanUri = decodeURIComponent(uri.split(/[?#]/)[0] || '')
  return cleanUri.split(/[\\/]/).pop()?.toLowerCase()
}

function rewriteGltfUris(value: JsonValue, filenameMap: Map<string, string>): JsonValue {
  if (Array.isArray(value)) {
    return value.map((entry) => rewriteGltfUris(entry, filenameMap))
  }

  if (!value || typeof value !== 'object') return value

  const rewritten: Record<string, JsonValue> = {}

  for (const [key, entry] of Object.entries(value)) {
    if (key === 'uri' && typeof entry === 'string') {
      const filename = getReferencedFilename(entry)
      rewritten[key] = filename ? filenameMap.get(filename) || entry : entry
      continue
    }

    rewritten[key] = rewriteGltfUris(entry, filenameMap)
  }

  return rewritten
}

function prepareModelBuffer(buffer: Buffer, filenameMap: Map<string, string>) {
  if (filenameMap.size === 0) return buffer

  const parsed = parseJsonValue(buffer.toString('utf-8'))
  return Buffer.from(JSON.stringify(rewriteGltfUris(parsed, filenameMap), null, 2), 'utf-8')
}

async function prepareSeparateFiles(
  folderName: string,
  parsedFiles: ParsedFile[],
  textureFilenameMap: Map<string, string>,
) {
  const filesToPush: PushFile[] = []
  const assetSummaries: PreparedAssetSummary[] = []
  let modelFilename = ''
  let compressed = false
  let compressionError: string | undefined

  for (const pf of parsedFiles) {
    let content = pf.buffer
    let filename = pf.filename

    if (pf.isModel) {
      content = prepareModelBuffer(pf.buffer, textureFilenameMap)
      modelFilename = pf.filename

      assetSummaries.push({
        filename,
        kind: 'model',
        compressed: false,
      })
    } else {
      filename = textureFilenameMap.get(pf.filename.toLowerCase()) || pf.filename
      const categoryFilename = textureFilenameMap.get(pf.filename.toLowerCase()) || normalizeTextureFilename(pf.filename) || pf.filename
      const category = classifyAssetCategory(categoryFilename)

      const textureResult = await compressTextureBuffer(filename, pf.buffer)
      content = textureResult.buffer
      compressed ||= textureResult.compressed

      if (textureResult.error && !compressionError) {
        compressionError = textureResult.error
      }

      assetSummaries.push({
        filename,
        kind: category === 'assets' ? 'asset' : 'texture',
        category,
        compressed: textureResult.compressed,
      })
    }

    filesToPush.push({
      path: getModelAssetPath(folderName, filename),
      contentBase64: content.toString('base64'),
    })
  }

  return {
    filesToPush,
    modelFilename,
    assetSummaries,
    compressed,
    compressionError,
    deliveryMode: 'keep-gltf' as const,
  }
}

async function prepareDracoGlb(
  folderName: string,
  parsedFiles: ParsedFile[],
  textureFilenameMap: Map<string, string>,
): Promise<PreparedGitAssetsResult> {
  const tmpFolder = join(TMP_DIR, 'blender', `${folderName}-${randomUUID()}`)
  const inputModelPath = join(tmpFolder, 'model.gltf')
  const outputModelPath = join(tmpFolder, 'model.glb')

  await mkdir(tmpFolder, { recursive: true })

  try {
    for (const pf of parsedFiles) {
      if (pf.isModel) {
        await writeFile(inputModelPath, prepareModelBuffer(pf.buffer, textureFilenameMap))
        continue
      }

      const filename = textureFilenameMap.get(pf.filename.toLowerCase()) || pf.filename
      const ext = extname(filename).toLowerCase()
      const content = TEXTURE_EXTENSIONS.has(ext)
        ? (await compressTextureBuffer(filename, pf.buffer)).buffer
        : pf.buffer

      await writeFile(join(tmpFolder, filename), content)
    }

    try {
      const result = await compressWithBlender(inputModelPath, outputModelPath)
      if (!result.success || !existsSync(outputModelPath)) {
        throw new Error(result.error || 'Compression Blender echouee')
      }

      const content = await readFile(outputModelPath)
      const modelFilename = 'model.glb'

      return {
        filesToPush: [{
          path: getModelAssetPath(folderName, modelFilename),
          contentBase64: content.toString('base64'),
        }],
        modelFilename,
        assetSummaries: [{ filename: modelFilename, kind: 'model', compressed: true }],
        compressed: true,
        deliveryMode: 'draco-glb',
      }
    } catch (err) {
      const fallback = await prepareSeparateFiles(folderName, parsedFiles, textureFilenameMap)
      const message = getErrorMessage(err, 'Compression Blender echouee')

      return {
        ...fallback,
        compressionError: fallback.compressionError
          ? `${message}. ${fallback.compressionError}`
          : message,
      }
    }
  } finally {
    await rm(tmpFolder, { recursive: true, force: true }).catch(() => {})
  }
}

export async function prepareGitAssets({
  folderName,
  parsedFiles,
  gitModelMode,
}: PrepareGitAssetsParams): Promise<PreparedGitAssetsResult> {
  const textureFilenameMap = getTextureFilenameMap(parsedFiles)

  if (gitModelMode === 'keep-gltf') {
    return prepareSeparateFiles(folderName, parsedFiles, textureFilenameMap)
  }

  return prepareDracoGlb(folderName, parsedFiles, textureFilenameMap)
}