const { query } = require('../config/database');

/**
 * Log audit trail for all important actions
 */
const logAudit = async ({ userId, action, entityType, entityId, oldValue = null, newValue = null, ipAddress = null, userAgent = null }) => {
  try {
    await query(
      `INSERT INTO audit_logs 
       (user_id, action, entity_type, entity_id, old_value, new_value, ip_address, user_agent)
       VALUES ($1, $2, $3, $4, $5, $6, $7, $8)`,
      [
        userId,
        action,
        entityType,
        entityId,
        oldValue ? JSON.stringify(oldValue) : null,
        newValue ? JSON.stringify(newValue) : null,
        ipAddress,
        userAgent
      ]
    );

    console.log(`Audit logged: ${action} by user ${userId}`);
  } catch (error) {
    console.error('Error logging audit:', error);
    // Don't throw error - audit logging should not break the main flow
  }
};

/**
 * Get audit logs for an entity
 */
const getAuditLogs = async (entityType, entityId) => {
  try {
    const result = await query(
      `SELECT al.*, u.full_name as user_name, u.email as user_email
       FROM audit_logs al
       LEFT JOIN users u ON al.user_id = u.id
       WHERE al.entity_type = $1 AND al.entity_id = $2
       ORDER BY al.created_at DESC`,
      [entityType, entityId]
    );

    return result.rows;
  } catch (error) {
    console.error('Error fetching audit logs:', error);
    return [];
  }
};

/**
 * Get all audit logs with filters
 */
const getAllAuditLogs = async ({ userId, action, entityType, startDate, endDate, limit = 100 }) => {
  try {
    let queryText = `
      SELECT al.*, u.full_name as user_name, u.email as user_email
      FROM audit_logs al
      LEFT JOIN users u ON al.user_id = u.id
      WHERE 1=1
    `;
    const params = [];
    let paramCount = 1;

    if (userId) {
      queryText += ` AND al.user_id = $${paramCount}`;
      params.push(userId);
      paramCount++;
    }

    if (action) {
      queryText += ` AND al.action = $${paramCount}`;
      params.push(action);
      paramCount++;
    }

    if (entityType) {
      queryText += ` AND al.entity_type = $${paramCount}`;
      params.push(entityType);
      paramCount++;
    }

    if (startDate) {
      queryText += ` AND al.created_at >= $${paramCount}`;
      params.push(startDate);
      paramCount++;
    }

    if (endDate) {
      queryText += ` AND al.created_at <= $${paramCount}`;
      params.push(endDate);
      paramCount++;
    }

    queryText += ` ORDER BY al.created_at DESC LIMIT $${paramCount}`;
    params.push(limit);

    const result = await query(queryText, params);
    return result.rows;
  } catch (error) {
    console.error('Error fetching all audit logs:', error);
    return [];
  }
};

module.exports = {
  logAudit,
  getAuditLogs,
  getAllAuditLogs
};