'use strict'

const { query, queryOne } = require('../database/postgres')

class DirectMessage {
  /**
   * Enviar DM para um colaborador
   */
  static async send(tenantId, fromAccountId, toAccountId, content) {
    if (!fromAccountId || !toAccountId || !content?.trim()) {
      throw new Error('fromAccountId, toAccountId e content obrigatórios')
    }
    const row = await queryOne(
      `INSERT INTO direct_messages (tenant_id, from_account, to_account, content, created_at)
       VALUES ($1, $2, $3, $4, NOW())
       RETURNING id, from_account, to_account, content, created_at`,
      [tenantId, fromAccountId, toAccountId, content]
    )
    return row
  }

  /**
   * Listar histórico de DMs entre dois colaboradores (conversação)
   */
  static async getConversation(tenantId, accountId1, accountId2, limit = 50) {
    const msgs = await query(
      `SELECT
        id, from_account, to_account, content, read_at, created_at
       FROM direct_messages
       WHERE tenant_id = $1
         AND ((from_account = $2 AND to_account = $3)
              OR (from_account = $3 AND to_account = $2))
       ORDER BY created_at DESC
       LIMIT $4`,
      [tenantId, accountId1, accountId2, limit]
    )
    return msgs.reverse() // mais antigos primeiro
  }

  /**
   * Listar últimas DMs por colaborador (preview de conversas)
   * Retorna a última mensagem em cada conversação
   */
  static async getLastMessagesByAccount(tenantId, accountId) {
    const msgs = await query(
      `SELECT DISTINCT ON (other_account)
        id, from_account, to_account, content, read_at, created_at,
        CASE
          WHEN from_account = $2 THEN to_account
          ELSE from_account
        END AS other_account
       FROM direct_messages
       WHERE tenant_id = $1
         AND (from_account = $2 OR to_account = $2)
       ORDER BY other_account, created_at DESC`,
      [tenantId, accountId]
    )
    return msgs
  }

  /**
   * Contar DMs não lidas para um colaborador
   */
  static async getUnreadCount(tenantId, accountId) {
    const row = await queryOne(
      `SELECT COUNT(*) as count
       FROM direct_messages
       WHERE tenant_id = $1
         AND to_account = $2
         AND read_at IS NULL`,
      [tenantId, accountId]
    )
    return Number(row?.count ?? 0)
  }

  /**
   * Marcar DMs como lidas
   */
  static async markAsRead(tenantId, accountId, fromAccountId) {
    await query(
      `UPDATE direct_messages
       SET read_at = NOW()
       WHERE tenant_id = $1
         AND to_account = $2
         AND from_account = $3
         AND read_at IS NULL`,
      [tenantId, accountId, fromAccountId]
    )
  }

  /**
   * Contar DMs não lidas por remetente
   * Útil para badges de quantas DMs cada pessoa tem
   */
  static async getUnreadCountByContact(tenantId, accountId) {
    const rows = await query(
      `SELECT from_account, COUNT(*) as unread_count
       FROM direct_messages
       WHERE tenant_id = $1
         AND to_account = $2
         AND read_at IS NULL
       GROUP BY from_account`,
      [tenantId, accountId]
    )
    const map = {}
    rows.forEach(r => {
      map[r.from_account] = Number(r.unread_count)
    })
    return map
  }
}

module.exports = DirectMessage