import express, { type Request, type Response } from 'express'
import fs from 'fs/promises'
import path from 'path'
import { asyncHandler } from '../../utils/asyncHandler.js'
import { successResponse } from '../../utils/response.js'
import { resolveNotebookPath } from '../../utils/pathSafety.js'
import { getUniqueFilename, mimeToExt, validateImageBuffer, detectImageMimeType } from '../../utils/file.js'
import { NOTEBOOK_ROOT } from '../../config/paths.js'
import { toPosixPath } from '../../../shared/utils/path.js'
import { pad2, formatTimestamp } from '../../../shared/utils/date.js'
import { ValidationError, UnsupportedMediaTypeError } from '../../../shared/errors/index.js'

const router = express.Router()

const parseImageDataUrl = (dataUrl: string): { mimeType: string; base64Data: string } | null => {
  const match = dataUrl.match(/^data:(image\/[a-zA-Z0-9.+-]+);base64,([A-Za-z0-9+/=\s]+)$/)
  if (!match) return null
  const [, mimeType, base64Data] = match
  return { mimeType, base64Data: base64Data.replace(/\s/g, '') }
}

router.post(
  '/image',
  asyncHandler(async (req: Request, res: Response) => {
    const { image } = req.body as { image?: string }
    if (!image) throw new ValidationError('需要图片数据')

    const parsed = parseImageDataUrl(image)
    if (!parsed) {
      throw new ValidationError('无效的图片数据URL')
    }

    const ext = mimeToExt[parsed.mimeType]
    if (!ext) {
      throw new UnsupportedMediaTypeError('不支持的图片类型')
    }

    const buffer = Buffer.from(parsed.base64Data, 'base64')

    validateImageBuffer(buffer, parsed.mimeType)

    const detectedMimeType = detectImageMimeType(buffer)
    if (!detectedMimeType || detectedMimeType !== parsed.mimeType) {
      throw new ValidationError('图片内容类型不匹配或图片已损坏')
    }

    const now = new Date()
    const year = now.getFullYear()
    const month = pad2(now.getMonth() + 1)
    const day = pad2(now.getDate())

    const imagesSubDir = `images/${year}/${month}/${day}`
    const { fullPath: imagesDirFullPath } = resolveNotebookPath(imagesSubDir)
    await fs.mkdir(imagesDirFullPath, { recursive: true })

    const baseName = formatTimestamp(now)
    const filename = await getUniqueFilename(imagesDirFullPath, baseName, ext)
    const relPath = `${imagesSubDir}/${filename}`
    const { fullPath } = resolveNotebookPath(relPath)

    await fs.writeFile(fullPath, buffer)
    successResponse(res, { name: toPosixPath(relPath), path: toPosixPath(relPath) })
  }),
)

router.post(
  '/wallpaper',
  asyncHandler(async (req: Request, res: Response) => {
    const { image } = req.body as { image?: string }
    if (!image) throw new ValidationError('需要图片数据')

    const parsed = parseImageDataUrl(image)
    if (!parsed) {
      throw new ValidationError('无效的图片数据URL')
    }

    const allowedWallpaperTypes = ['image/png', 'image/jpeg', 'image/webp']
    if (!allowedWallpaperTypes.includes(parsed.mimeType)) {
      throw new UnsupportedMediaTypeError('壁纸只支持PNG、JPEG和WebP格式')
    }

    const buffer = Buffer.from(parsed.base64Data, 'base64')

    validateImageBuffer(buffer, parsed.mimeType)

    const detectedMimeType = detectImageMimeType(buffer)
    if (!detectedMimeType || detectedMimeType !== parsed.mimeType) {
      throw new ValidationError('图片内容类型不匹配或图片已损坏')
    }

    const configDir = path.join(NOTEBOOK_ROOT, '.config')
    const backgroundPath = path.join(configDir, 'background.png')

    await fs.mkdir(configDir, { recursive: true })
    await fs.writeFile(backgroundPath, buffer)
    successResponse(res, { message: '壁纸已更新' })
  }),
)

export default router