import { query } from '../db/pool.js';

/*
 * The audit service records every administrative mutation so the team can trace
 * when configuration changed and what the previous value was. Each row captures
 * the entity type (e.g. "image_rules"), the entity identifier, the action name,
 * and JSON snapshots of the old and new values.
 */

export async function logAuditEvent({ entityType, entityCode, action, oldValue = null, newValue = null }) {
  await query(
    `
      INSERT INTO audit_log (entity_type, entity_code, action, old_value_json, new_value_json)
      VALUES (?, ?, ?, ?, ?)
    `,
    [
      entityType,
      entityCode,
      action,
      oldValue ? JSON.stringify(oldValue) : null,
      newValue ? JSON.stringify(newValue) : null
    ]
  );
}

export async function getAuditLog({ entityType, entityCode, limit = 50 } = {}) {
  let sql = 'SELECT id, entity_type, entity_code, action, old_value_json, new_value_json, created_at FROM audit_log';
  const params = [];
  const clauses = [];

  if (entityType) {
    clauses.push('entity_type = ?');
    params.push(entityType);
  }

  if (entityCode) {
    clauses.push('entity_code = ?');
    params.push(entityCode);
  }

  if (clauses.length) {
    sql += ` WHERE ${clauses.join(' AND ')}`;
  }

  sql += ' ORDER BY id DESC LIMIT ?';
  params.push(limit);

  const rows = await query(sql, params);

  return rows.map((row) => ({
    id: row.id,
    entityType: row.entity_type,
    entityCode: row.entity_code,
    action: row.action,
    oldValue: safeParseJson(row.old_value_json),
    newValue: safeParseJson(row.new_value_json),
    createdAt: row.created_at
  }));
}

function safeParseJson(value) {
  if (value == null) {
    return null;
  }

  if (typeof value === 'object') {
    return value;
  }

  try {
    return JSON.parse(value);
  } catch {
    return null;
  }
}