import { extname } from 'path'
import { compressTextureBuffer } from '@/lib/texture-compression'
import { classifyAssetCategory } from '@/lib/asset-classification'
import { normalizeTextureFilename } from '@/lib/asset-naming'
import { TEXTURE_EXTENSIONS } from '@/lib/constants'
import { getModelAssetPath } from '@/lib/model-paths'
import type { ParsedFile, PreparedAssetSummary, PushFile } from '@/lib/types'

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

interface PrepareGitAssetsResult {
  filesToPush: PushFile[]
  modelFilename: string
  assetSummaries: PreparedAssetSummary[]
  compressed: boolean
  compressionError?: string
}

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

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

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

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

export async function prepareGitAssets({
  folderName,
  parsedFiles,
}: PrepareGitAssetsParams): Promise<PrepareGitAssetsResult> {
  const filesToPush: PushFile[] = []
  const assetSummaries: PreparedAssetSummary[] = []
  let modelFilename = ''
  let compressed = false
  let compressionError: string | undefined
  const textureFilenameMap = getTextureFilenameMap(parsedFiles)

  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,
  }
}