import { Job, Queue, QueueEvents, Worker } from "bullmq";
import dotenv from "dotenv";
import { fileTypeFromFile } from "file-type";
import { FileTypeResult } from "file-type/core";
import fs from "fs-extra";
import gm from "gm";
import path from "path";
import { fileURLToPath } from "url";
import { logger } from "../server.js";
import { generateUniqueHeicFilename } from "./generateUniqueFilename.js";
import { FolderPaths } from "./serverInit.js";

dotenv.config({
  path: path.resolve(process.cwd(), `.env.${process.env.NODE_ENV || "development"}`)
});

const QUEUE_NAME = "heicQueue";

const connectionOpts = {
  host: "localhost",
  port: 6379,
  enableReadyCheck: true,
  reconnectOnError: (err: Error) => err.message.includes("READONLY")
};

const heicQueue = new Queue(QUEUE_NAME, {
  connection: connectionOpts,
  defaultJobOptions: {
    removeOnComplete: true,
    removeOnFail: true,
    attempts: 3,
    backoff: { type: "exponential", delay: 1000 }
  }
});

// Re-added QueueEvents for waiting on job completion
const heicQueueEvents = new QueueEvents(QUEUE_NAME, {
  connection: connectionOpts
});

const CLEANUP_INTERVAL_MS = 10 * 60 * 1000; // 10 minutes
setInterval(cleanupQueue, CLEANUP_INTERVAL_MS);

async function cleanupQueue() {
  try {
    const ONE_HOUR = 60 * 60 * 1000;
    const SIX_HOURS = 6 * ONE_HOUR;

    await heicQueue.clean(ONE_HOUR, 500, "completed");
    await heicQueue.clean(SIX_HOURS, 500, "failed");

    const counts = await heicQueue.getJobCounts();
    logger.debug(`HEIC Queue status: ${JSON.stringify(counts)}`);
  } catch (error) {
    logger.error("HEIC Queue cleanup error:", error);
  }
}

/**
 * Filter files to include only valid HEIC images.
 */
async function filterHeicFiles(files: Express.Multer.File[]) {
  const valid: Express.Multer.File[] = [];
  for (const file of files) {
    const type: FileTypeResult | undefined = await fileTypeFromFile(file.path);
    if (type?.mime === "image/heic") valid.push(file);
  }
  return valid;
}

/**
 * Handle original file based on environment variable.
 */
async function handleOriginalFile(fileInfo: { path: string; destination: string; originalFilename: string }) {
  try {
    if (process.env.KEEP_CONVERTED_ORIGINALS) {
      const destDir = path.join(fileInfo.destination, FolderPaths.ConvertedOriginalSubDir);
      await fs.ensureDir(destDir);
      await fs.move(fileInfo.path, path.join(destDir, fileInfo.originalFilename), { overwrite: true });
    } else {
      await fs.unlink(fileInfo.path);
    }
  } catch (error) {
    logger.error("Error handling original file:", error);
    throw error;
  }
}

/**
 * Convert HEIC to JPEG using GraphicsMagick stream.
 */
async function convertToJpeg(inputPath: string, outputPath: string): Promise<string> {
  return new Promise((resolve, reject) => {
    const readStream = fs.createReadStream(inputPath);
    const writeStream = fs.createWriteStream(outputPath);

    gm(readStream)
      .setFormat("jpg")
      .stream()
      .pipe(writeStream)
      .on("finish", () => resolve(outputPath))
      .on("error", reject);
  });
}

/**
 * Add HEIC files to the conversion queue and wait for job completion.
 */
export async function convertHeicFiles(files: Express.Multer.File[]) {
  const heicFiles = await filterHeicFiles(files);

  if (heicFiles.length === 0) {
    logger.debug("No HEIC files found to convert.");
    return;
  }

  const jobs = heicFiles.map((file) => ({
    name: file.filename,
    data: {
      convertedFileName: generateUniqueHeicFilename(file),
      fileInfo: {
        path: file.path,
        destination: file.destination,
        originalFilename: file.filename
      }
    }
  }));

  // Add jobs and wait for completion of each before proceeding
  for (const jobData of jobs) {
    try {
      const job = await heicQueue.add(jobData.name, jobData.data);
      await job.waitUntilFinished(heicQueueEvents);
      logger.debug(`Job ${job.id} finished successfully.`);
    } catch (error) {
      logger.error(`Job for ${jobData.data.fileInfo.originalFilename} failed:`, error);
      // Depending on your error handling strategy you might rethrow or continue
    }
  }

  // Update original files list with new names, mimetype, and path
  const filenameToIndex = new Map(files.map((f, i) => [f.filename, i]));
  for (const { data } of jobs) {
    const idx = filenameToIndex.get(data.fileInfo.originalFilename);
    if (idx !== undefined) {
      const oldPath = files[idx].path;
      files[idx].filename = data.convertedFileName;
      files[idx].mimetype = "image/jpeg";
      files[idx].path = path.join(data.fileInfo.destination, data.convertedFileName);
      logger.debug(`Updated file entry: ${data.fileInfo.originalFilename} -> ${data.convertedFileName}`, {
        oldPath,
        newPath: files[idx].path,
        newMimetype: files[idx].mimetype
      });
    }
  }
}

// Worker processing HEIC conversion jobs
const heicWorker = new Worker(
  QUEUE_NAME,
  async (
    job: Job<{
      fileInfo: { path: string; destination: string; originalFilename: string };
      convertedFileName: string;
    }>
  ) => {
    const { fileInfo, convertedFileName } = job.data;
    try {
      logger.debug(`Converting ${fileInfo.originalFilename} from HEIC to JPEG.`);
      await job.updateProgress(10);

      const outputPath = path.join(fileInfo.destination, convertedFileName);
      await convertToJpeg(fileInfo.path, outputPath);

      await job.updateProgress(50);
      await handleOriginalFile(fileInfo);

      logger.debug(`Successfully converted ${fileInfo.originalFilename} to JPEG.`);
      await job.updateProgress(100);

      return true;
    } catch (error) {
      logger.error(`Error converting ${fileInfo.originalFilename}:`, error);
      throw error;
    }
  },
  {
    connection: connectionOpts,
    concurrency: 1
  }
);

// Event listeners for queue and worker
heicQueue.on("waiting", (job) => {
  logger.debug(`[heicQueue] Job waiting in queue: ${job.data.convertedFileName}`);
});
heicQueue.on("error", (error) => {
  logger.error(`[heicQueue] Queue error:`, error);
});

heicWorker.on("ready", () => {
  logger.debug("[heicWorker] Worker ready");
});
heicWorker.on("active", (job, prev) => {
  logger.debug(`[heicWorker] Job ${job.id} active (previous: ${prev})`);
});
heicWorker.on("completed", async (job) => {
  logger.debug(`[heicWorker] Job ${job.id} completed`);
  await job.remove();
  logger.debug(`Job ${job.id} removed from Redis`);
});
heicWorker.on("failed", (jobId, reason) => {
  logger.error(`[heicWorker] Job ${jobId} failed: ${reason}`);
});
heicWorker.on("error", (error) => {
  logger.error(`[heicWorker] Worker error:`, error);
});
heicWorker.on("stalled", (job) => {
  logger.error(`[heicWorker] Worker stalled: ${job}`);
});
heicWorker.on("ioredis:close", () => {
  logger.error("[heicWorker] Redis connection closed");
});