import { Router } from "@oak/oak";
import { verifyJWT } from "../lib/jwt.ts";
import {
  APIErrorCode,
  APIException,
  isCreatePlaylistRequest,
  isReorderPlaylistRequest,
  isUpdatePlaylistRequest,
} from "../model/interfaces.ts";
import { authMiddleware, type AuthState } from "../middleware/auth.ts";
import {
  addDumpToPlaylist,
  createPlaylist,
  deletePlaylist,
  getPlaylist,
  getPlaylistImageMime,
  getPlaylistMembershipsForDump,
  removeDumpFromPlaylist,
  reorderPlaylist,
  setPlaylistImage,
  updatePlaylist,
} from "../services/playlist-service.ts";

const PLAYLIST_IMAGES_DIR = "api/uploads/playlist-images";
const MAX_IMAGE_SIZE = 5 * 1024 * 1024;
const ALLOWED_IMAGE_MIMES = new Set([
  "image/jpeg",
  "image/png",
  "image/gif",
  "image/webp",
]);

function checkImageMagicBytes(data: Uint8Array, mime: string): boolean {
  if (mime === "image/webp") {
    return data[0] === 0x52 && data[1] === 0x49 && data[2] === 0x46 &&
      data[3] === 0x46 && data[8] === 0x57 && data[9] === 0x45 &&
      data[10] === 0x42 && data[11] === 0x50;
  }
  const magic: Record<string, number[]> = {
    "image/jpeg": [0xFF, 0xD8, 0xFF],
    "image/png": [0x89, 0x50, 0x4E, 0x47],
    "image/gif": [0x47, 0x49, 0x46, 0x38],
  };
  return (magic[mime] ?? []).every((b, i) => data[i] === b);
}

const router = new Router<AuthState>({ prefix: "/api/playlists" });

// GET /api/playlists/by-dump/:dumpId/memberships — must be before /:playlistId
router.get("/by-dump/:dumpId/memberships", authMiddleware, (ctx) => {
  const { dumpId } = ctx.params;
  const userId = ctx.state.user.userId;
  const memberships = getPlaylistMembershipsForDump(dumpId, userId);
  ctx.response.body = { success: true, data: memberships };
});

// POST /api/playlists — create
router.post("/", authMiddleware, async (ctx) => {
  const body = await ctx.request.body.json();
  if (!isCreatePlaylistRequest(body)) {
    throw new APIException(
      APIErrorCode.VALIDATION_ERROR,
      400,
      "Invalid request",
    );
  }
  const playlist = createPlaylist(body, ctx.state.user.userId);
  ctx.response.status = 201;
  ctx.response.body = { success: true, data: playlist };
});

// GET /api/playlists/:playlistId — optional auth
router.get("/:playlistId", async (ctx) => {
  let requestingUserId: string | null = null;
  const authHeader = ctx.request.headers.get("Authorization");
  if (authHeader?.startsWith("Bearer ")) {
    const payload = await verifyJWT(authHeader.substring(7));
    if (payload) requestingUserId = payload.userId;
  }
  const playlist = getPlaylist(ctx.params.playlistId, requestingUserId);
  ctx.response.body = { success: true, data: playlist };
});

// PUT /api/playlists/:playlistId — update metadata
router.put("/:playlistId", authMiddleware, async (ctx) => {
  const body = await ctx.request.body.json();
  if (!isUpdatePlaylistRequest(body)) {
    throw new APIException(
      APIErrorCode.VALIDATION_ERROR,
      400,
      "Invalid request",
    );
  }
  const playlist = updatePlaylist(
    ctx.params.playlistId,
    body,
    ctx.state.user.userId,
  );
  ctx.response.body = { success: true, data: playlist };
});

// DELETE /api/playlists/:playlistId
router.delete("/:playlistId", authMiddleware, (ctx) => {
  deletePlaylist(ctx.params.playlistId, ctx.state.user.userId);
  ctx.response.status = 204;
});

// POST /api/playlists/:playlistId/dumps/:dumpId — add dump
router.post("/:playlistId/dumps/:dumpId", authMiddleware, (ctx) => {
  addDumpToPlaylist(
    ctx.params.playlistId,
    ctx.params.dumpId,
    ctx.state.user.userId,
  );
  ctx.response.status = 204;
});

// DELETE /api/playlists/:playlistId/dumps/:dumpId — remove dump
router.delete("/:playlistId/dumps/:dumpId", authMiddleware, (ctx) => {
  removeDumpFromPlaylist(
    ctx.params.playlistId,
    ctx.params.dumpId,
    ctx.state.user.userId,
  );
  ctx.response.status = 204;
});

// POST /api/playlists/:playlistId/image — upload playlist image
router.post("/:playlistId/image", authMiddleware, async (ctx) => {
  const contentType = ctx.request.headers.get("content-type") ?? "";
  if (!contentType.includes("multipart/form-data")) {
    throw new APIException(
      APIErrorCode.BAD_REQUEST,
      400,
      "Expected multipart/form-data",
    );
  }

  const body = await ctx.request.body.formData();
  const file = body.get("file");

  if (!(file instanceof File)) {
    throw new APIException(APIErrorCode.BAD_REQUEST, 400, "Missing file field");
  }

  if (!ALLOWED_IMAGE_MIMES.has(file.type)) {
    throw new APIException(
      APIErrorCode.BAD_REQUEST,
      400,
      "Only JPEG, PNG, GIF, WebP images are allowed",
    );
  }

  if (file.size > MAX_IMAGE_SIZE) {
    throw new APIException(
      APIErrorCode.BAD_REQUEST,
      400,
      "File too large (max 5 MB)",
    );
  }

  const data = new Uint8Array(await file.arrayBuffer());
  if (!checkImageMagicBytes(data, file.type)) {
    throw new APIException(
      APIErrorCode.BAD_REQUEST,
      400,
      "File content does not match declared type",
    );
  }

  await Deno.mkdir(PLAYLIST_IMAGES_DIR, { recursive: true });
  await Deno.writeFile(`${PLAYLIST_IMAGES_DIR}/${ctx.params.playlistId}`, data);
  const playlist = setPlaylistImage(
    ctx.params.playlistId,
    file.type,
    ctx.state.user.userId,
  );
  ctx.response.body = { success: true, data: playlist };
});

// GET /api/playlists/:playlistId/image — serve playlist image
router.get("/:playlistId/image", async (ctx) => {
  const imageMime = getPlaylistImageMime(ctx.params.playlistId);
  if (!imageMime) {
    ctx.response.status = 404;
    return;
  }

  let data: Uint8Array;
  try {
    data = await Deno.readFile(
      `${PLAYLIST_IMAGES_DIR}/${ctx.params.playlistId}`,
    );
  } catch {
    ctx.response.status = 404;
    return;
  }

  ctx.response.headers.set("Content-Type", imageMime);
  ctx.response.headers.set("Content-Disposition", "inline");
  ctx.response.headers.set("Cache-Control", "public, max-age=3600");
  ctx.response.body = data;
});

// PUT /api/playlists/:playlistId/order — reorder
router.put("/:playlistId/order", authMiddleware, async (ctx) => {
  const body = await ctx.request.body.json();
  if (!isReorderPlaylistRequest(body)) {
    throw new APIException(
      APIErrorCode.VALIDATION_ERROR,
      400,
      "Invalid request",
    );
  }
  reorderPlaylist(ctx.params.playlistId, body.dumpIds, ctx.state.user.userId);
  ctx.response.body = { success: true, data: null };
});

export default router;