import path from 'path'
import fs from 'fs'
import sharp from 'sharp'
import { NextRequest, NextResponse } from 'next/server'
import { getLibrary, resolveLibraryRoot, resolveAndJail } from '@/lib/libraries'
import { requireAdmin, requireLibraryAccess } from '@/lib/auth'
import { fileApiUrl, thumbnailApiUrl } from '@/lib/media-utils'

const SCREENSHOT_EXTENSIONS = new Set(['.jpg', '.jpeg', '.png', '.webp', '.gif'])
const MAX_SCREENSHOT_BYTES = 20 * 1024 * 1024 // 20 MB

type GameDirResult =
  | { gameDir: string; screenshotsDir: string; folderPath: string }
  | { error: string; status: number }

function getGameDir(libraryId: string, gameId: string): GameDirResult {
  const library = getLibrary(libraryId)
  if (!library) return { error: 'Library not found', status: 404 }
  if (library.type !== 'games') return { error: 'Library is not a games library', status: 400 }

  const libraryRoot = resolveLibraryRoot(library)
  const folderPath = decodeURIComponent(gameId)

  let gameDir: string
  try {
    gameDir = resolveAndJail(libraryRoot, folderPath)
  } catch {
    return { error: 'Invalid game path', status: 400 }
  }

  if (!fs.existsSync(gameDir)) return { error: 'Game folder not found', status: 404 }

  return { gameDir, screenshotsDir: path.join(gameDir, 'screenshots'), folderPath }
}

// ─── GET: list screenshots ────────────────────────────────────────────────────

export async function GET(request: NextRequest) {
  const { searchParams } = request.nextUrl
  const libraryId = searchParams.get('libraryId')
  const gameId = searchParams.get('gameId')

  if (!libraryId || !gameId) {
    return NextResponse.json({ error: 'Missing libraryId or gameId' }, { status: 400 })
  }

  const auth = await requireLibraryAccess(request, libraryId)
  if (auth instanceof NextResponse) return auth

  const resolved = getGameDir(libraryId, gameId)
  if ('error' in resolved) return NextResponse.json({ error: resolved.error }, { status: resolved.status })
  const { screenshotsDir, folderPath } = resolved

  if (!fs.existsSync(screenshotsDir)) {
    return NextResponse.json({ screenshots: [] })
  }

  let files: string[]
  try {
    files = fs.readdirSync(screenshotsDir)
  } catch {
    return NextResponse.json({ screenshots: [] })
  }

  const screenshots = files
    .filter((f) => SCREENSHOT_EXTENSIONS.has(path.extname(f).toLowerCase()))
    .sort()
    .map((filename) => {
      const relPath = path.join(folderPath, 'screenshots', filename)
      return {
        filename,
        url: fileApiUrl(libraryId, relPath),
        thumbnailUrl: thumbnailApiUrl(libraryId, relPath),
      }
    })

  return NextResponse.json({ screenshots })
}

// ─── POST: upload screenshot ──────────────────────────────────────────────────

export async function POST(request: NextRequest) {
  const auth = await requireAdmin(request)
  if (auth instanceof NextResponse) return auth

  const { searchParams } = request.nextUrl
  const libraryId = searchParams.get('libraryId')
  const gameId = searchParams.get('gameId')

  if (!libraryId || !gameId) {
    return NextResponse.json({ error: 'Missing libraryId or gameId' }, { status: 400 })
  }

  const resolved = getGameDir(libraryId, gameId)
  if ('error' in resolved) return NextResponse.json({ error: resolved.error }, { status: resolved.status })
  const { screenshotsDir, folderPath } = resolved

  let formData: FormData
  try {
    formData = await request.formData()
  } catch {
    return NextResponse.json({ error: 'Invalid form data' }, { status: 400 })
  }

  const file = formData.get('screenshot')
  if (!(file instanceof File)) {
    return NextResponse.json({ error: 'screenshot field is required' }, { status: 400 })
  }

  if (file.size > MAX_SCREENSHOT_BYTES) {
    return NextResponse.json({ error: 'File too large. Maximum size is 20 MB.' }, { status: 400 })
  }

  const rawBuffer = Buffer.from(await file.arrayBuffer())

  let processedBuffer: Buffer
  try {
    processedBuffer = await sharp(rawBuffer).jpeg({ quality: 90 }).toBuffer()
  } catch {
    return NextResponse.json({ error: 'Invalid or corrupt image file.' }, { status: 400 })
  }

  fs.mkdirSync(screenshotsDir, { recursive: true })

  const filename = `shot-${Date.now()}.jpg`
  fs.writeFileSync(path.join(screenshotsDir, filename), processedBuffer)

  const relPath = path.join(folderPath, 'screenshots', filename)
  return NextResponse.json(
    {
      filename,
      url: fileApiUrl(libraryId, relPath),
      thumbnailUrl: thumbnailApiUrl(libraryId, relPath),
    },
    { status: 201 }
  )
}

// ─── DELETE: remove screenshot ────────────────────────────────────────────────

export async function DELETE(request: NextRequest) {
  const auth = await requireAdmin(request)
  if (auth instanceof NextResponse) return auth

  const { searchParams } = request.nextUrl
  const libraryId = searchParams.get('libraryId')
  const gameId = searchParams.get('gameId')
  const filename = searchParams.get('filename')

  if (!libraryId || !gameId || !filename) {
    return NextResponse.json({ error: 'Missing libraryId, gameId, or filename' }, { status: 400 })
  }

  // Filename must be a plain basename — no path separators, no traversal
  if (filename !== path.basename(filename) || filename.includes('..')) {
    return NextResponse.json({ error: 'Invalid filename' }, { status: 400 })
  }

  const resolved = getGameDir(libraryId, gameId)
  if ('error' in resolved) return NextResponse.json({ error: resolved.error }, { status: resolved.status })
  const { screenshotsDir } = resolved

  let filePath: string
  try {
    filePath = resolveAndJail(screenshotsDir, filename)
  } catch {
    return NextResponse.json({ error: 'Invalid filename' }, { status: 400 })
  }

  try {
    fs.unlinkSync(filePath)
  } catch {
    return NextResponse.json({ error: 'File not found or could not be deleted' }, { status: 404 })
  }

  return new NextResponse(null, { status: 204 })
}