const { query } = require('../config/db');
const axios = require('axios');
const settings = require('../services/settings');

/**
 * Сохранить пост в базу (как черновик или сразу запланированный).
 */
async function savePost({ userId, channelId, content, imageUrl = null, imageCredit = null, topic = null, status = 'draft', scheduledAt = null }) {
  const { rows } = await query(
    `INSERT INTO user_posts (user_id, channel_id, content, image_url, image_credit, topic, status, scheduled_at)
     VALUES ($1,$2,$3,$4,$5,$6,$7,$8) RETURNING *`,
    [userId, channelId, content, imageUrl, imageCredit, topic, status, scheduledAt]
  );
  return rows[0];
}

async function listUserPosts({ userId, channelId = null, status = null, limit = 50 }) {
  let sql = `SELECT * FROM user_posts WHERE user_id=$1`;
  const params = [userId];
  if (channelId) { sql += ` AND channel_id=$${params.length + 1}`; params.push(channelId); }
  if (status) { sql += ` AND status=$${params.length + 1}`; params.push(status); }
  sql += ` ORDER BY created_at DESC LIMIT $${params.length + 1}`;
  params.push(limit);
  const { rows } = await query(sql, params);
  return rows;
}

async function getPost(userId, postId) {
  const { rows } = await query(`SELECT * FROM user_posts WHERE id=$1 AND user_id=$2`, [postId, userId]);
  return rows[0] || null;
}

async function updatePost(userId, postId, data) {
  const allowed = ['content','image_url','image_credit','status','scheduled_at','topic'];
  const fields = []; const vals = []; let i = 1;
  for (const key of allowed) {
    if (data[key] !== undefined) { fields.push(`${key}=$${i++}`); vals.push(data[key]); }
  }
  if (!fields.length) return null;
  fields.push(`updated_at=NOW()`);
  vals.push(postId, userId);
  const { rows } = await query(
    `UPDATE user_posts SET ${fields.join(',')} WHERE id=$${i++} AND user_id=$${i} RETURNING *`,
    vals
  );
  return rows[0];
}

async function deletePost(userId, postId) {
  const { rowCount } = await query(`DELETE FROM user_posts WHERE id=$1 AND user_id=$2`, [postId, userId]);
  return rowCount > 0;
}

/**
 * Опубликовать пост в Telegram.
 */
async function publishToTelegram(post, channel) {
  if (!channel.bot_token || !channel.tg_channel_id) {
    throw new Error('Telegram не настроен (нужны bot_token и tg_channel_id)');
  }
  // Если есть картинка — отправляем как фото с подписью, иначе текст
  if (post.image_url) {
    const photoUrl = post.image_url.startsWith('http')
      ? post.image_url
      : `https://app.zeropost.ru${post.image_url}`;
    const res = await axios.post(
      `${await settings.get('TELEGRAM_API_BASE', 'https://api.telegram.org')}/bot${channel.bot_token}/sendPhoto`,
      {
        chat_id: channel.tg_channel_id,
        photo: photoUrl,
        caption: post.content.slice(0, 1024),
        parse_mode: 'Markdown',
      },
      { timeout: 30000 }
    );
    return { ok: true, message_id: res.data?.result?.message_id };
  } else {
    const res = await axios.post(
      `${await settings.get('TELEGRAM_API_BASE', 'https://api.telegram.org')}/bot${channel.bot_token}/sendMessage`,
      {
        chat_id: channel.tg_channel_id,
        text: post.content,
        parse_mode: 'Markdown',
        disable_web_page_preview: false,
      },
      { timeout: 15000 }
    );
    return { ok: true, message_id: res.data?.result?.message_id };
  }
}

/**
 * Опубликовать пост (выбирает платформу по channel.platform).
 */
async function publishPost(userId, postId) {
  const post = await getPost(userId, postId);
  if (!post) throw new Error('Post not found');

  const { rows: chRows } = await query(`SELECT * FROM channels WHERE id=$1`, [post.channel_id]);
  if (!chRows.length) throw new Error('Channel not found');
  const channel = chRows[0];

  let result;
  try {
    if (channel.platform === 'telegram' || !channel.platform) {
      result = await publishToTelegram(post, channel);
    } else {
      throw new Error(`Платформа ${channel.platform} пока не поддерживается`);
    }
    await query(
      `UPDATE user_posts SET status='published', published_at=NOW(), tg_message_id=$1, error=NULL WHERE id=$2`,
      [result.message_id || null, postId]
    );
    return { ok: true, message_id: result.message_id };
  } catch (err) {
    const msg = err.response?.data?.description || err.message;
    await query(
      `UPDATE user_posts SET status='failed', error=$1 WHERE id=$2`,
      [msg, postId]
    );
    throw new Error(msg);
  }
}

/**
 * Запустить публикацию запланированных постов (вызывается cron-ом).
 */
async function runScheduledPublications() {
  const { rows } = await query(
    `SELECT * FROM user_posts
     WHERE status='scheduled' AND scheduled_at <= NOW()
     ORDER BY scheduled_at LIMIT 50`
  );
  const results = [];
  for (const post of rows) {
    try {
      const res = await publishPost(post.user_id, post.id);
      results.push({ id: post.id, ok: true, message_id: res.message_id });
    } catch (err) {
      results.push({ id: post.id, ok: false, error: err.message });
    }
  }
  return { processed: rows.length, results };
}

module.exports = { savePost, listUserPosts, getPost, updatePost, deletePost, publishPost, runScheduledPublications };