const Announcement = require('../models/Announcement');
const { saveOptimizedImage, removeStoredFile } = require('../services/mediaService');
const { sanitizeText, isValidDateInput } = require('../validation/commonValidation');
const { isValidAnnouncementCategory, normalizeAnnouncementInput, parseBooleanInput } = require('../validation/announcementValidation');
const { ensureValidIdOrRespond, findByIdOrRespondNotFound } = require('../utils/controllerResponses');
const { asyncController } = require('../utils/asyncController');
const { emitAnnouncementUpdated } = require('../socket/socketServer');

const MAX_TITLE_LENGTH = 180;
const MAX_DESCRIPTION_LENGTH = 2200;

const ALLOWED_MIME = new Set(['image/jpeg', 'image/jpg', 'image/png', 'image/webp', 'image/x-png']);
const stripHtml = (value) => String(value || '').replace(/<[^>]*>/g, '');

const publishedOrLegacyFilter = {
  $or: [{ isPublished: true }, { isPublished: { $exists: false } }],
};

const getAnnouncements = asyncController(async (req, res) => {
  const category = sanitizeText(req.query.category);
  const parsedLimit = Number.parseInt(String(req.query.limit ?? ''), 10);
  const includeUnpublished = req.user
    ? parseBooleanInput(req.query.includeUnpublished) === true
    : false;
  const published = parseBooleanInput(req.query.published);

  if (category && !isValidAnnouncementCategory(category)) return res.status(400).json({ message: 'Invalid category filter' });

  let filter = category ? { category } : {};
  if (published === true) {
    filter = { ...filter, ...publishedOrLegacyFilter };
  } else if (published === false) {
    filter = { ...filter, isPublished: false };
  } else if (!includeUnpublished) {
    filter = { ...filter, ...publishedOrLegacyFilter };
  }

  const query = Announcement.find(filter).sort({ createdAt: -1 }).lean();
  if (Number.isInteger(parsedLimit) && parsedLimit > 0) query.limit(Math.min(parsedLimit, 100));
  res.json(await query);
});

const getAnnouncementById = asyncController(async (req, res) => {
  if (!ensureValidIdOrRespond(res, req.params.id, 'announcement')) return;
  const announcement = await findByIdOrRespondNotFound({
    Model: Announcement,
    id: req.params.id,
    res,
    notFoundMessage: 'Announcement not found',
    lean: true,
  });
  if (!announcement) return;
  res.json(announcement);
});

const createAnnouncement = asyncController(async (req, res) => {
  const payload = normalizeAnnouncementInput(req.body);

  // Strip HTML from free-text fields
  payload.title = stripHtml(payload.title);
  payload.description = stripHtml(payload.description);

  const errors = {};
  if (!payload.title) errors.title = 'Title is required';
  if (!payload.date) errors.date = 'Date is required';
  else if (!isValidDateInput(payload.date)) errors.date = 'Date must use a valid YYYY-MM-DD format';
  if (payload.title && payload.title.length > MAX_TITLE_LENGTH) errors.title = `Title must be ${MAX_TITLE_LENGTH} characters or less`;
  if (payload.description && payload.description.length > MAX_DESCRIPTION_LENGTH) errors.description = `Description must be ${MAX_DESCRIPTION_LENGTH} characters or less`;
  if (payload.category && !isValidAnnouncementCategory(payload.category)) errors.category = 'Invalid category';
  if (Object.keys(errors).length > 0) {
    return res.status(400).json({ error: 'Validation failed', fields: errors });
  }

  if (req.file && !ALLOWED_MIME.has(req.file.mimetype)) {
    return res.status(415).json({ message: 'Unsupported file type. Use JPG, PNG, or WEBP.' });
  }

  if (req.file) {
    payload.photo = await saveOptimizedImage({
      file: req.file,
      subdir: 'announcements',
      width: 1200,
      height: 900,
      quality: 80,
    });
  }
  const announcement = await Announcement.create(payload);
  emitAnnouncementUpdated({ action: 'created', id: String(announcement._id) });
  res.status(201).json(announcement);
}, { defaultStatus: 400 });

const updateAnnouncement = asyncController(async (req, res) => {
  if (!ensureValidIdOrRespond(res, req.params.id, 'announcement')) return;
  const announcement = await findByIdOrRespondNotFound({
    Model: Announcement,
    id: req.params.id,
    res,
    notFoundMessage: 'Announcement not found',
  });
  if (!announcement) return;

  const payload = normalizeAnnouncementInput(req.body, { partial: true });

  if (!Object.keys(payload).length && !req.file) return res.status(400).json({ message: 'No fields provided to update' });

  // Strip HTML from free-text fields when present
  if (payload.title !== undefined) payload.title = stripHtml(payload.title);
  if (payload.description !== undefined) payload.description = stripHtml(payload.description);

  const errors = {};
  if (payload.title !== undefined && !payload.title) errors.title = 'Title is required';
  if (payload.date !== undefined && !payload.date) errors.date = 'Date is required';
  else if (payload.date !== undefined && !isValidDateInput(payload.date)) errors.date = 'Date must use a valid YYYY-MM-DD format';
  if (payload.title !== undefined && payload.title && payload.title.length > MAX_TITLE_LENGTH) errors.title = `Title must be ${MAX_TITLE_LENGTH} characters or less`;
  if (payload.description !== undefined && payload.description.length > MAX_DESCRIPTION_LENGTH) errors.description = `Description must be ${MAX_DESCRIPTION_LENGTH} characters or less`;
  if (payload.category !== undefined && !isValidAnnouncementCategory(payload.category)) errors.category = 'Invalid category';
  if (Object.keys(errors).length > 0) {
    return res.status(400).json({ error: 'Validation failed', fields: errors });
  }

  if (req.file && !ALLOWED_MIME.has(req.file.mimetype)) {
    return res.status(415).json({ message: 'Unsupported file type. Use JPG, PNG, or WEBP.' });
  }

  Object.assign(announcement, payload);

  if (req.file) {
    await removeStoredFile(announcement.photo);
    announcement.photo = await saveOptimizedImage({
      file: req.file,
      subdir: 'announcements',
      width: 1200,
      height: 900,
      quality: 80,
    });
  }

  const updated = await announcement.save();
  emitAnnouncementUpdated({ action: 'updated', id: String(updated._id) });
  res.json(updated);
}, { defaultStatus: 400 });

const deleteAnnouncement = asyncController(async (req, res) => {
  if (!ensureValidIdOrRespond(res, req.params.id, 'announcement')) return;
  const announcement = await findByIdOrRespondNotFound({
    Model: Announcement,
    id: req.params.id,
    res,
    notFoundMessage: 'Announcement not found',
  });
  if (!announcement) return;
  const deletedId = String(announcement._id);
  await removeStoredFile(announcement.photo);
  await announcement.deleteOne();
  emitAnnouncementUpdated({ action: 'deleted', id: deletedId });
  res.json({ message: 'Announcement deleted' });
});

module.exports = { getAnnouncements, getAnnouncementById, createAnnouncement, updateAnnouncement, deleteAnnouncement };