import express from 'express';
import multer from 'multer';
import { Queue } from 'bullmq';
import { v4 as uuidv4 } from 'uuid';
import pool from '../db/pool.js';
import { s3Client, uploadStream, deleteObject, getS3Bucket } from '../s3/client.js';
import {
  CreateMultipartUploadCommand,
  UploadPartCommand,
  CompleteMultipartUploadCommand,
  AbortMultipartUploadCommand,
} from '@aws-sdk/client-s3';
import { getAmppConfig, ensureFolderPath } from '../ampp/client.js';

const router = express.Router();

const memoryStorage = multer.memoryStorage();
const upload = multer({ storage: memoryStorage });

const parseRedisUrl = (url) => {
  const parsed = new URL(url);
  return { host: parsed.hostname, port: parseInt(parsed.port, 10) };
};

// Only proxy queue needed here — proxy worker dispatches thumbnail once done
const proxyQueue = new Queue('proxy', {
  connection: parseRedisUrl(process.env.REDIS_URL || 'redis://queue:6379'),
});

// ---------------------------------------------------------------
// AMPP Sync Helpers
// ---------------------------------------------------------------

async function resolveBinPath(binId) {
  const segments = [];
  let currentId = binId;
  while (currentId) {
    const result = await pool.query(
      'SELECT id, name, parent_id FROM bins WHERE id = $1',
      [currentId]
    );
    if (result.rows.length === 0) break;
    const bin = result.rows[0];
    segments.unshift(bin.name);
    currentId = bin.parent_id;
  }
  return segments;
}

/**
 * Fire-and-forget: mirror asset's project/bin path into AMPP folder hierarchy.
 * Never throws — failures are logged but never surface to the caller.
 */
async function syncToAmpp(assetId, projectId, binId) {
  try {
    const config = await getAmppConfig();
    if (!config) return;

    const projResult = await pool.query(
      'SELECT name FROM projects WHERE id = $1',
      [projectId]
    );
    if (projResult.rows.length === 0) return;
    const projectName = projResult.rows[0].name;

    const segments = [projectName];
    if (binId) {
      const binSegments = await resolveBinPath(binId);
      segments.push(...binSegments);
    }

    const folderId = await ensureFolderPath(config, segments);
    if (!folderId) return;

    await pool.query(
      'UPDATE assets SET ampp_folder_id = $1, ampp_synced_at = NOW() WHERE id = $2',
      [folderId, assetId]
    );

    console.log(`[AMPP] asset ${assetId} → folder ${folderId} (${segments.join(' / ')})`);
  } catch (err) {
    console.error(`[AMPP] sync failed for asset ${assetId}:`, err.message);
  }
}

// Derive a media_type string from a MIME type
function mediaTypeFromMime(mime = '') {
  if (mime.startsWith('video')) return 'video';
  if (mime.startsWith('audio')) return 'audio';
  if (mime.startsWith('image')) return 'image';
  return 'document';
}

// POST /api/v1/upload/init - Initialize a multipart upload
router.post('/init', async (req, res, next) => {
  try {
    const { filename, fileSize, contentType, projectId, binId, tags } = req.body;

    if (!filename || !fileSize || !contentType || !projectId) {
      return res.status(400).json({
        error: 'Missing required fields: filename, fileSize, contentType, projectId',
      });
    }

    const assetId = uuidv4();
    const s3Key   = `originals/${assetId}/${filename}`;
    const tagsArray = tags ? (Array.isArray(tags) ? tags : [tags]) : [];

    await pool.query(
      `INSERT INTO assets (
        id, project_id, bin_id, filename, display_name, status,
        media_type, original_s3_key, file_size, tags, created_at, updated_at
      )
      VALUES ($1,$2,$3,$4,$4,'ingesting',$5,$6,$7,$8,NOW(),NOW())`,
      [
        assetId, projectId, binId || null, filename,
        mediaTypeFromMime(contentType),
        s3Key, fileSize,
        tagsArray.length > 0 ? tagsArray : null,
      ]
    );

    const multipartUpload = await s3Client.send(
      new CreateMultipartUploadCommand({
        Bucket: getS3Bucket(),
        Key: s3Key,
        ContentType: contentType,
      })
    );

    res.json({
      assetId,
      uploadId: multipartUpload.UploadId,
      key: s3Key,
    });
  } catch (err) {
    next(err);
  }
});

// POST /api/v1/upload/part - Upload a single part
router.post('/part', upload.single('file'), async (req, res, next) => {
  try {
    const { uploadId, key, partNumber } = req.body;

    if (!uploadId || !key || !partNumber || !req.file) {
      return res.status(400).json({
        error: 'Missing required fields: uploadId, key, partNumber, and file',
      });
    }

    const partUpload = await s3Client.send(
      new UploadPartCommand({
        Bucket: getS3Bucket(),
        Key: key,
        PartNumber: parseInt(partNumber, 10),
        UploadId: uploadId,
        Body: req.file.buffer,
      })
    );

    res.json({
      partNumber: parseInt(partNumber, 10),
      etag: partUpload.ETag,
    });
  } catch (err) {
    next(err);
  }
});

// POST /api/v1/upload/complete - Complete the multipart upload
router.post('/complete', async (req, res, next) => {
  try {
    const { uploadId, key, assetId, parts } = req.body;

    if (!uploadId || !key || !assetId || !parts || !Array.isArray(parts)) {
      return res.status(400).json({
        error: 'Missing required fields: uploadId, key, assetId, and parts array',
      });
    }

    await s3Client.send(
      new CompleteMultipartUploadCommand({
        Bucket: getS3Bucket(),
        Key: key,
        UploadId: uploadId,
        MultipartUpload: {
          Parts: parts.map(p => ({
            ETag: p.ETag || p.etag,
            PartNumber: p.partNumber || p.PartNumber,
          })),
        },
      })
    );

    const result = await pool.query(
      `UPDATE assets
       SET status = 'processing', updated_at = NOW()
       WHERE id = $1 RETURNING *`,
      [assetId]
    );

    if (result.rows.length === 0) {
      return res.status(404).json({ error: 'Asset not found' });
    }

    const asset = result.rows[0];

    await proxyQueue.add('generate', {
      assetId,
      inputKey:  key,
      outputKey: `proxies/${assetId}.mp4`,
    });

    syncToAmpp(asset.id, asset.project_id, asset.bin_id);

    res.json(asset);
  } catch (err) {
    next(err);
  }
});

// POST /api/v1/upload/abort - Abort upload
router.post('/abort', async (req, res, next) => {
  try {
    const { uploadId, key, assetId } = req.body;

    if (!uploadId || !key || !assetId) {
      return res.status(400).json({
        error: 'Missing required fields: uploadId, key, assetId',
      });
    }

    await s3Client.send(
      new AbortMultipartUploadCommand({ Bucket: getS3Bucket(), Key: key, UploadId: uploadId })
    );

    await pool.query('DELETE FROM assets WHERE id = $1', [assetId]);

    res.json({ message: 'Upload aborted and asset deleted' });
  } catch (err) {
    next(err);
  }
});

// POST /api/v1/upload/simple - Single-file upload for smaller files (<50 MB)
router.post('/simple', upload.single('file'), async (req, res, next) => {
  try {
    const { filename, projectId, binId, tags, contentType } = req.body;

    if (!filename || !projectId || !req.file) {
      return res.status(400).json({
        error: 'Missing required fields: filename, projectId, and file',
      });
    }

    const assetId   = uuidv4();
    const s3Key     = `originals/${assetId}/${filename}`;
    const mimeType  = contentType || req.file.mimetype;
    const tagsArray = tags ? (Array.isArray(tags) ? tags : [tags]) : [];

    await pool.query(
      `INSERT INTO assets (
        id, project_id, bin_id, filename, display_name, status,
        media_type, original_s3_key, file_size, tags, created_at, updated_at
      )
      VALUES ($1,$2,$3,$4,$4,'ingesting',$5,$6,$7,$8,NOW(),NOW())`,
      [
        assetId, projectId, binId || null, filename,
        mediaTypeFromMime(mimeType),
        s3Key, req.file.size,
        tagsArray.length > 0 ? tagsArray : null,
      ]
    );

    await uploadStream(s3Key, req.file.buffer, mimeType);

    const result = await pool.query(
      `UPDATE assets SET status = 'processing', updated_at = NOW()
       WHERE id = $1 RETURNING *`,
      [assetId]
    );

    const asset = result.rows[0];

    await proxyQueue.add('generate', {
      assetId,
      inputKey:  s3Key,
      outputKey: `proxies/${assetId}.mp4`,
    });

    syncToAmpp(assetId, projectId, binId || null);

    res.json(asset);
  } catch (err) {
    next(err);
  }
});

export default router;