import { FastifyPluginAsync } from 'fastify'
import { db } from '../db'

type SlugParam = { Params: { slug: string } }
type RoomParam = { Params: { slug: string; roomId: string } }
type MsgParam  = { Params: { slug: string; roomId: string; msgId: string } }

const chatRoutes: FastifyPluginAsync = async (fastify) => {
  const getHotelId = async (slug: string) => {
    const { rows } = await db.query('SELECT id FROM hotels WHERE slug = $1', [slug])
    return rows[0]?.id as string | undefined
  }

  const canAccess = (userSlug: string | null, role: string, slug: string) =>
    role === 'super_admin' || userSlug === slug

  const ensureRoom = async (hotelId: string, type: string, name: string) => {
    const { rows: existing } = await db.query(
      `SELECT id FROM chat_rooms WHERE hotel_id = $1 AND type = $2 LIMIT 1`,
      [hotelId, type],
    )
    if (existing[0]) return existing[0].id as string
    const { rows } = await db.query(
      `INSERT INTO chat_rooms (hotel_id, type, name) VALUES ($1, $2, $3)
       ON CONFLICT DO NOTHING RETURNING id`,
      [hotelId, type, name],
    )
    if (rows[0]) return rows[0].id as string
    const { rows: r2 } = await db.query(
      `SELECT id FROM chat_rooms WHERE hotel_id = $1 AND type = $2 LIMIT 1`,
      [hotelId, type],
    )
    return r2[0]?.id as string
  }

  const ensureGeneralRoom      = (hotelId: string) => ensureRoom(hotelId, 'general',       'Общий чат')
  const ensureNotificationsRoom = (hotelId: string) => ensureRoom(hotelId, 'notifications', 'Уведомления')

  // Helper: fetch full message with reactions
  const fetchMessage = async (msgId: string, userId: string) => {
    const { rows } = await db.query(
      `SELECT m.id, m.room_id, m.sender_id, m.text, m.created_at,
              m.is_system, m.system_name, m.attachment_url, m.edited_at, m.deleted_at,
              COALESCE(m.system_name, u.name) AS sender_name,
              COALESCE(u.role, 'system') AS sender_role,
              COALESCE(
                (SELECT json_agg(r ORDER BY r.first_at)
                   FROM (SELECT emoji,
                                COUNT(*)::int        AS count,
                                bool_or(user_id = $2) AS has_own,
                                MIN(created_at)       AS first_at
                           FROM chat_reactions WHERE message_id = m.id
                          GROUP BY emoji) r
                ),
                '[]'::json
              ) AS reactions
         FROM chat_messages m
         LEFT JOIN users u ON u.id = m.sender_id
        WHERE m.id = $1`,
      [msgId, userId],
    )
    return rows[0]
  }

  // ── GET rooms ─────────────────────────────────────────────────────────────

  fastify.get<SlugParam>(
    '/api/hotels/:slug/chat/rooms',
    { onRequest: [fastify.authenticate] },
    async (request, reply) => {
      const { slug } = request.params
      if (!canAccess(request.user.hotelSlug, request.user.role, slug))
        return reply.code(403).send({ error: 'Forbidden' })
      const hotelId = await getHotelId(slug)
      if (!hotelId) return reply.code(404).send({ error: 'Hotel not found' })

      await ensureGeneralRoom(hotelId)
      await ensureNotificationsRoom(hotelId)
      const userId = request.user.sub

      const { rows } = await db.query(
        `SELECT r.id, r.type, r.name,
                (SELECT COUNT(*) FROM chat_messages m
                  WHERE m.room_id = r.id AND m.deleted_at IS NULL
                    AND m.created_at > COALESCE(
                      (SELECT rs.last_read FROM chat_read_status rs WHERE rs.room_id = r.id AND rs.user_id = $2),
                      '1970-01-01'
                    )
                    AND (m.sender_id != $2 OR m.sender_id IS NULL)
                ) AS unread_count,
                (SELECT CASE WHEN m.deleted_at IS NOT NULL THEN 'Сообщение удалено'
                             WHEN m.attachment_url IS NOT NULL AND m.text = '' THEN '📷 Фото'
                             ELSE m.text END
                   FROM chat_messages m WHERE m.room_id = r.id ORDER BY m.created_at DESC LIMIT 1) AS last_message,
                (SELECT m.created_at FROM chat_messages m WHERE m.room_id = r.id ORDER BY m.created_at DESC LIMIT 1) AS last_message_at,
                (SELECT COALESCE(m.system_name, u.name) FROM chat_messages m LEFT JOIN users u ON u.id = m.sender_id WHERE m.room_id = r.id ORDER BY m.created_at DESC LIMIT 1) AS last_sender,
                (SELECT u.name FROM chat_room_members crm JOIN users u ON u.id = crm.user_id WHERE crm.room_id = r.id AND crm.user_id != $2 LIMIT 1) AS other_user_name,
                (SELECT u.role FROM chat_room_members crm JOIN users u ON u.id = crm.user_id WHERE crm.room_id = r.id AND crm.user_id != $2 LIMIT 1) AS other_user_role,
                (SELECT crm.user_id FROM chat_room_members crm WHERE crm.room_id = r.id AND crm.user_id != $2 LIMIT 1) AS other_user_id,
                (SELECT rs.last_read FROM chat_read_status rs WHERE rs.room_id = r.id AND rs.user_id != $2 LIMIT 1) AS other_user_last_read
           FROM chat_rooms r
          WHERE r.hotel_id = $1
            AND (r.type IN ('general', 'notifications') OR EXISTS (
              SELECT 1 FROM chat_room_members crm WHERE crm.room_id = r.id AND crm.user_id = $2
            ))
          ORDER BY last_message_at DESC NULLS LAST, r.type = 'general' DESC`,
        [hotelId, userId],
      )
      return rows
    },
  )

  // ── GET messages ──────────────────────────────────────────────────────────

  fastify.get<RoomParam & { Querystring: { limit?: string; before?: string } }>(
    '/api/hotels/:slug/chat/rooms/:roomId/messages',
    { onRequest: [fastify.authenticate] },
    async (request, reply) => {
      const { slug, roomId } = request.params
      if (!canAccess(request.user.hotelSlug, request.user.role, slug))
        return reply.code(403).send({ error: 'Forbidden' })
      const hotelId = await getHotelId(slug)
      if (!hotelId) return reply.code(404).send({ error: 'Hotel not found' })

      const limit = Math.min(Number(request.query.limit ?? 50), 100)
      const before = request.query.before  // ISO timestamp cursor
      const userId = request.user.sub

      const params: unknown[] = [roomId, hotelId, userId, limit]
      const beforeClause = before ? `AND m.created_at < $5` : ''
      if (before) params.push(before)

      const { rows } = await db.query(
        `SELECT m.id, m.room_id, m.sender_id, m.text, m.created_at,
                m.is_system, m.system_name, m.attachment_url, m.edited_at, m.deleted_at,
                COALESCE(m.system_name, u.name) AS sender_name,
                COALESCE(u.role, 'system') AS sender_role,
                COALESCE(
                  (SELECT json_agg(r ORDER BY r.first_at)
                     FROM (SELECT emoji,
                                  COUNT(*)::int         AS count,
                                  bool_or(user_id = $3) AS has_own,
                                  MIN(created_at)        AS first_at
                             FROM chat_reactions WHERE message_id = m.id
                            GROUP BY emoji) r
                  ),
                  '[]'::json
                ) AS reactions
           FROM chat_messages m
           LEFT JOIN users u ON u.id = m.sender_id
          WHERE m.room_id = $1 AND m.hotel_id = $2 ${beforeClause}
          ORDER BY m.created_at DESC
          LIMIT $4`,
        params,
      )

      // Only mark read on initial load (no before cursor)
      if (!before) {
        await db.query(
          `INSERT INTO chat_read_status (room_id, user_id, last_read) VALUES ($1, $2, NOW())
           ON CONFLICT (room_id, user_id) DO UPDATE SET last_read = NOW()`,
          [roomId, userId],
        )
      }
      return rows.reverse()
    },
  )

  // ── POST message ──────────────────────────────────────────────────────────

  fastify.post<RoomParam & { Body: { text?: string; attachment_url?: string } }>(
    '/api/hotels/:slug/chat/rooms/:roomId/messages',
    { onRequest: [fastify.authenticate] },
    async (request, reply) => {
      const { slug, roomId } = request.params
      if (!canAccess(request.user.hotelSlug, request.user.role, slug))
        return reply.code(403).send({ error: 'Forbidden' })
      const hotelId = await getHotelId(slug)
      if (!hotelId) return reply.code(404).send({ error: 'Hotel not found' })

      const { rows: roomRows } = await db.query('SELECT type FROM chat_rooms WHERE id = $1', [roomId])
      if (roomRows[0]?.type === 'notifications')
        return reply.code(403).send({ error: 'Cannot post to notifications room' })

      const { text, attachment_url } = request.body
      if (!text?.trim() && !attachment_url) return reply.code(400).send({ error: 'Text or attachment required' })

      const { rows } = await db.query(
        `INSERT INTO chat_messages (room_id, hotel_id, sender_id, text, attachment_url)
         VALUES ($1, $2, $3, $4, $5) RETURNING id`,
        [roomId, hotelId, request.user.sub, text?.trim() ?? '', attachment_url ?? null],
      )
      const msg = await fetchMessage(rows[0].id, request.user.sub)
      return reply.code(201).send(msg)
    },
  )

  // ── PATCH message (edit) ──────────────────────────────────────────────────

  fastify.patch<MsgParam & { Body: { text: string } }>(
    '/api/hotels/:slug/chat/rooms/:roomId/messages/:msgId',
    { onRequest: [fastify.authenticate] },
    async (request, reply) => {
      const { slug, msgId } = request.params
      if (!canAccess(request.user.hotelSlug, request.user.role, slug))
        return reply.code(403).send({ error: 'Forbidden' })

      const { rows } = await db.query(
        `SELECT sender_id, is_system, deleted_at FROM chat_messages WHERE id = $1`, [msgId],
      )
      const msg = rows[0]
      if (!msg) return reply.code(404).send({ error: 'Message not found' })
      if (msg.is_system) return reply.code(403).send({ error: 'Cannot edit system message' })
      if (msg.deleted_at) return reply.code(400).send({ error: 'Message is deleted' })
      if (msg.sender_id !== request.user.sub)
        return reply.code(403).send({ error: 'Can only edit own messages' })

      const { text } = request.body
      if (!text?.trim()) return reply.code(400).send({ error: 'Text required' })

      await db.query(
        `UPDATE chat_messages SET text = $1, edited_at = NOW() WHERE id = $2`,
        [text.trim(), msgId],
      )
      const updated = await fetchMessage(msgId, request.user.sub)
      return updated
    },
  )

  // ── DELETE message (soft) ─────────────────────────────────────────────────

  fastify.delete<MsgParam>(
    '/api/hotels/:slug/chat/rooms/:roomId/messages/:msgId',
    { onRequest: [fastify.authenticate] },
    async (request, reply) => {
      const { slug, msgId } = request.params
      if (!canAccess(request.user.hotelSlug, request.user.role, slug))
        return reply.code(403).send({ error: 'Forbidden' })

      const { rows } = await db.query(
        `SELECT sender_id, is_system FROM chat_messages WHERE id = $1`, [msgId],
      )
      const msg = rows[0]
      if (!msg) return reply.code(404).send({ error: 'Message not found' })
      if (msg.is_system) return reply.code(403).send({ error: 'Cannot delete system message' })

      const isAdmin = ['super_admin', 'hotel_admin', 'manager'].includes(request.user.role)
      if (msg.sender_id !== request.user.sub && !isAdmin)
        return reply.code(403).send({ error: 'Can only delete own messages' })

      await db.query(
        `UPDATE chat_messages SET deleted_at = NOW(), text = '', attachment_url = NULL WHERE id = $1`,
        [msgId],
      )
      return { ok: true, id: msgId }
    },
  )

  // ── POST reaction (toggle) ────────────────────────────────────────────────

  fastify.post<MsgParam & { Body: { emoji: string } }>(
    '/api/hotels/:slug/chat/rooms/:roomId/messages/:msgId/reactions',
    { onRequest: [fastify.authenticate] },
    async (request, reply) => {
      const { slug, msgId } = request.params
      if (!canAccess(request.user.hotelSlug, request.user.role, slug))
        return reply.code(403).send({ error: 'Forbidden' })

      const { emoji } = request.body
      if (!emoji) return reply.code(400).send({ error: 'Emoji required' })

      const userId = request.user.sub
      // Toggle: if exists — remove, else — add
      const { rows } = await db.query(
        `SELECT 1 FROM chat_reactions WHERE message_id = $1 AND user_id = $2 AND emoji = $3`,
        [msgId, userId, emoji],
      )
      if (rows[0]) {
        await db.query(
          `DELETE FROM chat_reactions WHERE message_id = $1 AND user_id = $2 AND emoji = $3`,
          [msgId, userId, emoji],
        )
      } else {
        await db.query(
          `INSERT INTO chat_reactions (message_id, user_id, emoji) VALUES ($1, $2, $3)`,
          [msgId, userId, emoji],
        )
      }
      const updated = await fetchMessage(msgId, userId)
      return updated
    },
  )

  // ── POST direct room ──────────────────────────────────────────────────────

  fastify.post<{ Params: { slug: string; otherUserId: string } }>(
    '/api/hotels/:slug/chat/direct/:otherUserId',
    { onRequest: [fastify.authenticate] },
    async (request, reply) => {
      const { slug, otherUserId } = request.params
      if (!canAccess(request.user.hotelSlug, request.user.role, slug))
        return reply.code(403).send({ error: 'Forbidden' })
      const hotelId = await getHotelId(slug)
      if (!hotelId) return reply.code(404).send({ error: 'Hotel not found' })

      const userId = request.user.sub
      const { rows: existing } = await db.query(
        `SELECT r.id FROM chat_rooms r
          JOIN chat_room_members m1 ON m1.room_id = r.id AND m1.user_id = $1
          JOIN chat_room_members m2 ON m2.room_id = r.id AND m2.user_id = $2
         WHERE r.hotel_id = $3 AND r.type = 'direct' LIMIT 1`,
        [userId, otherUserId, hotelId],
      )
      if (existing[0]) return { room_id: existing[0].id }

      const { rows: [room] } = await db.query(
        `INSERT INTO chat_rooms (hotel_id, type) VALUES ($1, 'direct') RETURNING id`, [hotelId],
      )
      await db.query(
        `INSERT INTO chat_room_members (room_id, user_id) VALUES ($1, $2), ($1, $3)`,
        [room.id, userId, otherUserId],
      )
      return reply.code(201).send({ room_id: room.id })
    },
  )

  // ── PATCH mark read ───────────────────────────────────────────────────────

  fastify.patch<RoomParam>(
    '/api/hotels/:slug/chat/rooms/:roomId/read',
    { onRequest: [fastify.authenticate] },
    async (request, reply) => {
      const { roomId } = request.params
      await db.query(
        `INSERT INTO chat_read_status (room_id, user_id, last_read) VALUES ($1, $2, NOW())
         ON CONFLICT (room_id, user_id) DO UPDATE SET last_read = NOW()`,
        [roomId, request.user.sub],
      )
      return { ok: true }
    },
  )

  // ── GET search ────────────────────────────────────────────────────────────

  fastify.get<SlugParam & { Querystring: { q?: string } }>(
    '/api/hotels/:slug/chat/search',
    { onRequest: [fastify.authenticate] },
    async (request, reply) => {
      const { slug } = request.params
      if (!canAccess(request.user.hotelSlug, request.user.role, slug))
        return reply.code(403).send({ error: 'Forbidden' })
      const hotelId = await getHotelId(slug)
      if (!hotelId) return reply.code(404).send({ error: 'Hotel not found' })

      const q = (request.query.q ?? '').trim()
      if (!q) return []
      const userId = request.user.sub

      const { rows } = await db.query(
        `SELECT m.id, m.room_id, m.text, m.created_at,
                COALESCE(m.system_name, u.name) AS sender_name,
                r.type AS room_type, r.name AS room_name,
                (SELECT u2.name FROM chat_room_members crm2 JOIN users u2 ON u2.id = crm2.user_id
                  WHERE crm2.room_id = r.id AND crm2.user_id != $2 LIMIT 1) AS other_user_name
           FROM chat_messages m
           JOIN chat_rooms r ON r.id = m.room_id
           LEFT JOIN users u ON u.id = m.sender_id
          WHERE m.hotel_id = $1 AND m.deleted_at IS NULL AND m.text ILIKE $3
            AND (r.type IN ('general', 'notifications') OR EXISTS (
              SELECT 1 FROM chat_room_members crm WHERE crm.room_id = r.id AND crm.user_id = $2
            ))
          ORDER BY m.created_at DESC LIMIT 30`,
        [hotelId, userId, `%${q}%`],
      )
      return rows
    },
  )

  // ── POST presence (heartbeat) ─────────────────────────────────────────────

  fastify.post<SlugParam>(
    '/api/hotels/:slug/chat/presence',
    { onRequest: [fastify.authenticate] },
    async (request, reply) => {
      const { slug } = request.params
      if (!canAccess(request.user.hotelSlug, request.user.role, slug)) return reply.code(403).send({ error: 'Forbidden' })
      const hotelId = await getHotelId(slug)
      if (!hotelId) return reply.code(404).send({ error: 'Hotel not found' })
      await db.query(
        `INSERT INTO chat_presence (user_id, hotel_id, last_seen) VALUES ($1, $2, NOW())
         ON CONFLICT (user_id, hotel_id) DO UPDATE SET last_seen = NOW()`,
        [request.user.sub, hotelId],
      )
      return { ok: true }
    },
  )

  // ── GET online users ──────────────────────────────────────────────────────

  fastify.get<SlugParam>(
    '/api/hotels/:slug/chat/presence',
    { onRequest: [fastify.authenticate] },
    async (request, reply) => {
      const { slug } = request.params
      if (!canAccess(request.user.hotelSlug, request.user.role, slug)) return reply.code(403).send({ error: 'Forbidden' })
      const hotelId = await getHotelId(slug)
      if (!hotelId) return reply.code(404).send({ error: 'Hotel not found' })
      const { rows } = await db.query(
        `SELECT user_id FROM chat_presence WHERE hotel_id = $1 AND last_seen > NOW() - INTERVAL '90 seconds'`,
        [hotelId],
      )
      return rows.map((r: { user_id: string }) => r.user_id)
    },
  )

  // ── POST typing ───────────────────────────────────────────────────────────

  fastify.post<MsgParam & { Body: { typing: boolean } }>(
    '/api/hotels/:slug/chat/rooms/:roomId/typing',
    { onRequest: [fastify.authenticate] },
    async (request, reply) => {
      const { roomId } = request.params
      const { typing } = request.body
      const { rows: uRows } = await db.query('SELECT name FROM users WHERE id = $1', [request.user.sub])
      const name = uRows[0]?.name ?? 'Кто-то'
      if (typing) {
        await db.query(
          `INSERT INTO chat_typing (user_id, room_id, name, typing_at) VALUES ($1, $2, $3, NOW())
           ON CONFLICT (user_id, room_id) DO UPDATE SET typing_at = NOW(), name = $3`,
          [request.user.sub, roomId, name],
        )
      } else {
        await db.query('DELETE FROM chat_typing WHERE user_id = $1 AND room_id = $2', [request.user.sub, roomId])
      }
      return { ok: true }
    },
  )

  // ── GET typing ────────────────────────────────────────────────────────────

  fastify.get<RoomParam>(
    '/api/hotels/:slug/chat/rooms/:roomId/typing',
    { onRequest: [fastify.authenticate] },
    async (request, reply) => {
      const { roomId } = request.params
      const userId = request.user.sub
      const { rows } = await db.query(
        `SELECT name FROM chat_typing WHERE room_id = $1 AND user_id != $2 AND typing_at > NOW() - INTERVAL '5 seconds'`,
        [roomId, userId],
      )
      return rows.map((r: { name: string }) => r.name)
    },
  )

  // ── POST notify ───────────────────────────────────────────────────────────

  fastify.post<SlugParam & { Body: { text: string; system_name?: string } }>(
    '/api/hotels/:slug/chat/notify',
    { onRequest: [fastify.authenticate] },
    async (request, reply) => {
      const { slug } = request.params
      if (!canAccess(request.user.hotelSlug, request.user.role, slug))
        return reply.code(403).send({ error: 'Forbidden' })
      if (!['super_admin', 'hotel_admin', 'manager'].includes(request.user.role))
        return reply.code(403).send({ error: 'Insufficient permissions' })

      const hotelId = await getHotelId(slug)
      if (!hotelId) return reply.code(404).send({ error: 'Hotel not found' })

      const { text, system_name = 'Система' } = request.body
      if (!text?.trim()) return reply.code(400).send({ error: 'Text required' })

      const notifRoomId = await ensureNotificationsRoom(hotelId)
      const { rows } = await db.query(
        `INSERT INTO chat_messages (room_id, hotel_id, sender_id, text, is_system, system_name)
         VALUES ($1, $2, NULL, $3, true, $4) RETURNING id`,
        [notifRoomId, hotelId, text.trim(), system_name],
      )
      const msg = await fetchMessage(rows[0].id, request.user.sub)
      return reply.code(201).send(msg)
    },
  )
}

export default chatRoutes