import path from 'node:path';
import fs from 'node:fs';
import express from 'express';
import multer from 'multer';
import { rateLimit } from 'express-rate-limit';
import { v4 as uuidv4 } from 'uuid';
import { resolve as resolveConverter, listTargetFormats } from './converters/registry.js';
import { registerImageConverters } from './converters/image.js';
import { registerImageToPdfConverter } from './converters/imageToPdf.js';
import { registerDocumentConverters } from './converters/document.js';
import { registerIcoConverter } from './converters/ico.js';
import { registerHeicConverter } from './converters/heic.js';
import { registerFontConverter } from './converters/font.js';
import { registerDfontConverter } from './converters/dfont.js';
import { registerEbookConverter } from './converters/ebook.js';
import { resolveInputFormat } from './mime.js';
import { deleteIfExists } from './storage.js';
import { createJob, getJobByUuid } from './jobs/jobRepository.js';
import { outputPath } from './storage.js';

const VALID_ICON_SIZES = [16, 32, 48, 256, 512];

function isValidQuality(targetFormat, quality) {
  if (quality === null || quality === undefined) return true;
  if (!Number.isInteger(quality)) return false;
  if (targetFormat === 'gif' || targetFormat === 'ico') return false;
  if (targetFormat === 'png') return quality >= 0 && quality <= 9;
  return quality >= 1 && quality <= 100;
}

function isValidIconSize(targetFormat, iconSize) {
  if (iconSize === null || iconSize === undefined) return true;
  if (targetFormat !== 'ico') return false;
  return VALID_ICON_SIZES.includes(iconSize);
}

let convertersRegistered = false;

function registerAllConverters() {
  if (convertersRegistered) return;
  registerImageConverters();
  registerImageToPdfConverter();
  registerDocumentConverters();
  registerIcoConverter();
  registerHeicConverter();
  registerFontConverter();
  registerDfontConverter();
  registerEbookConverter();
  convertersRegistered = true;
}

export function createApp(config, prisma) {
  registerAllConverters();

  const app = express();
  app.set('trust proxy', '1');

  const storage = multer.diskStorage({
    destination: (req, file, cb) => cb(null, path.join(config.storageDir, 'uploads')),
    filename: (req, file, cb) => {
      const ext = path.extname(file.originalname).slice(1).toLowerCase();
      cb(null, `${uuidv4()}.${ext}`);
    },
  });

  const upload = multer({
    storage,
    limits: {
      fileSize: config.maxFileSizeMb * 1024 * 1024,
      files: 10,
    },
  });

  const jobsRateLimiter = rateLimit({
    windowMs: config.rateLimitWindowMinutes * 60 * 1000,
    limit: config.rateLimitMaxJobs,
    standardHeaders: 'draft-8',
    legacyHeaders: false,
  });

  app.get('/api/formats', (req, res) => {
    const source = String(req.query.source ?? '').toLowerCase();
    res.json({ targets: listTargetFormats(source) });
  });

  app.post('/api/jobs', jobsRateLimiter, upload.array('files', 10), async (req, res) => {
    if (!req.files || req.files.length === 0) {
      return res.status(400).json({ error: 'No files uploaded' });
    }

    let targetFormats;
    try {
      targetFormats = JSON.parse(req.body.targetFormats ?? '[]');
    } catch {
      return res.status(400).json({ error: 'targetFormats must be a JSON array' });
    }

    if (!Array.isArray(targetFormats) || targetFormats.length !== req.files.length) {
      return res.status(400).json({ error: 'targetFormats must have one entry per uploaded file' });
    }

    let qualities;
    try {
      qualities = JSON.parse(req.body.qualities ?? '[]');
    } catch {
      return res.status(400).json({ error: 'qualities must be a JSON array' });
    }

    if (!Array.isArray(qualities)) {
      return res.status(400).json({ error: 'qualities must be a JSON array' });
    }

    if (qualities.length > 0 && qualities.length !== req.files.length) {
      return res.status(400).json({ error: 'qualities must have one entry per uploaded file, or be omitted' });
    }

    let iconSizes;
    try {
      iconSizes = JSON.parse(req.body.iconSizes ?? '[]');
    } catch {
      return res.status(400).json({ error: 'iconSizes must be a JSON array' });
    }

    if (!Array.isArray(iconSizes)) {
      return res.status(400).json({ error: 'iconSizes must be a JSON array' });
    }

    if (iconSizes.length > 0 && iconSizes.length !== req.files.length) {
      return res.status(400).json({ error: 'iconSizes must have one entry per uploaded file, or be omitted' });
    }

    const results = [];
    for (let i = 0; i < req.files.length; i += 1) {
      const file = req.files[i];
      const targetFormat = targetFormats[i];
      const uuid = path.basename(file.filename, path.extname(file.filename));
      const sourceFormat = path.extname(file.filename).slice(1).toLowerCase();

      const { mime, valid } = await resolveInputFormat(file.path, sourceFormat);
      if (!valid) {
        await deleteIfExists(file.path);
        results.push({ file: file.originalname, error: 'File content does not match its extension' });
        continue;
      }

      const registryEntry = resolveConverter(sourceFormat, targetFormat);
      if (!registryEntry) {
        await deleteIfExists(file.path);
        results.push({
          file: file.originalname,
          error: `Unsupported conversion: ${sourceFormat} to ${targetFormat}`,
        });
        continue;
      }

      const requestedQuality = qualities[i] ?? null;
      if (!isValidQuality(targetFormat, requestedQuality)) {
        await deleteIfExists(file.path);
        results.push({
          file: file.originalname,
          error: `Invalid quality for target format ${targetFormat}`,
        });
        continue;
      }

      const requestedIconSize = iconSizes[i] ?? null;
      if (!isValidIconSize(targetFormat, requestedIconSize)) {
        await deleteIfExists(file.path);
        results.push({
          file: file.originalname,
          error: `Invalid iconSize for target format ${targetFormat}`,
        });
        continue;
      }

      const expiresAt = new Date(Date.now() + config.retentionHours * 3600 * 1000);
      await createJob(prisma, {
        uuid,
        family: registryEntry.family,
        sourceFormat,
        targetFormat,
        originalFilename: file.originalname,
        inputPath: file.filename,
        inputMimeType: mime,
        inputSizeBytes: file.size,
        expiresAt,
        quality: requestedQuality,
        iconSize: requestedIconSize,
      });

      results.push({ file: file.originalname, id: uuid, status: 'pending' });
    }

    res.status(201).json({ jobs: results });
  });

  app.get('/api/jobs/:id', async (req, res) => {
    const job = await getJobByUuid(prisma, req.params.id);
    if (!job) {
      return res.status(404).json({ error: 'Job not found' });
    }

    res.json({
      id: job.uuid,
      status: job.status,
      originalFilename: job.originalFilename,
      sourceFormat: job.sourceFormat,
      targetFormat: job.targetFormat,
      errorMessage: job.errorMessage,
    });
  });

  function contentDispositionHeader(filename) {
    const asciiFallback = filename.replace(/[^\x20-\x7E]/g, '_').replace(/"/g, "'");
    const encoded = encodeURIComponent(filename);
    return `attachment; filename="${asciiFallback}"; filename*=UTF-8''${encoded}`;
  }

  app.get('/api/jobs/:id/download', async (req, res) => {
    const job = await getJobByUuid(prisma, req.params.id);
    if (!job) {
      return res.status(404).json({ error: 'Job not found' });
    }
    if (job.status !== 'done') {
      return res.status(409).json({ error: `Job is not ready yet (status: ${job.status})` });
    }

    const filePath = outputPath(config, job.uuid, job.targetFormat);
    const downloadFilename = `${path.parse(job.originalFilename).name}.${job.targetFormat}`;
    res.set('Content-Type', job.outputMimeType);
    res.set('Content-Disposition', contentDispositionHeader(downloadFilename));
    fs.createReadStream(filePath).pipe(res);
  });

  const frontendDist = path.join(import.meta.dirname, '..', 'frontend', 'dist');
  app.use(express.static(frontendDist));
  app.get(/^\/(?!api\/).*/, (req, res) => {
    res.sendFile(path.join(frontendDist, 'index.html'));
  });

  app.use((err, req, res, next) => {
    console.error('Unhandled API error:', err);
    res.status(500).json({ error: 'Internal server error' });
  });

  return app;
}