/**
 * /api/admin/audit-logs
 * Accessible admin uniquement (requireAuth + requireAdmin appliqués dans server.js).
 */

import { Router } from 'express';
import db from '../db/index.js';

const router = Router();

// ── Nettoyage automatique des logs > 30 jours ─────────────────────────────
function purgeOldLogs() {
  db.prepare("DELETE FROM audit_logs WHERE created_at < datetime('now', '-30 days')").run();
}

// ── Classification succès / avertissement / échec par action ──────────────
// IMPORTANT : garder cette liste synchronisée avec ACTION_STATUS dans
// frontend/src/pages/admin/AuditLogsSection.jsx (icônes + libellés).
const STATUS_ACTIONS = {
  success: ['login_success', 'login_2fa_success', 'user_registered', 'user_created', 'email_verified_admin', 'invitation_accepted', 'invitation_sent', '2fa_enabled'],
  warning: ['role_changed', 'status_changed', '2fa_disabled', 'user_deleted', 'account_self_deleted'],
  failure: ['login_failed'],
};
const STATUS_CASE_SQL = `
  CASE
    WHEN al.action IN (${STATUS_ACTIONS.success.map(() => '?').join(',')}) THEN 'success'
    WHEN al.action IN (${STATUS_ACTIONS.warning.map(() => '?').join(',')}) THEN 'warning'
    WHEN al.action IN (${STATUS_ACTIONS.failure.map(() => '?').join(',')}) THEN 'failure'
    ELSE NULL
  END
`;
const STATUS_CASE_PARAMS = [...STATUS_ACTIONS.success, ...STATUS_ACTIONS.warning, ...STATUS_ACTIONS.failure];

// ── GET / — liste paginée avec filtres ────────────────────────────────────
router.get('/', (req, res, next) => {
  try {
    purgeOldLogs();

    const page     = Math.max(1, Number(req.query.page) || 1);
    const limit    = Math.min(Number(req.query.limit) || 50, 200);
    const offset   = (page - 1) * limit;
    const category = req.query.category   || null;
    const status   = req.query.status     || null;   // 'success' | 'warning' | 'failure'
    const search   = req.query.search     || null;   // filtre sur email acteur ou cible
    const dateFrom = req.query.dateFrom   || null;
    const dateTo   = req.query.dateTo     || null;
    const userId   = req.query.userId     ? Number(req.query.userId) : null;

    // Conditions communes (hors statut) — réutilisées pour les compteurs par statut,
    // qui doivent rester visibles/à jour même quand un statut est déjà sélectionné.
    const baseConditions = [];
    const baseParams     = [];

    if (category) {
      baseConditions.push('al.category = ?');
      baseParams.push(category);
    }
    if (userId) {
      baseConditions.push('(al.actor_id = ? OR al.target_user_id = ?)');
      baseParams.push(userId, userId);
    }
    if (search) {
      baseConditions.push('(actor.email LIKE ? OR target.email LIKE ? OR actor.display_name LIKE ? OR target.display_name LIKE ?)');
      const like = `%${search}%`;
      baseParams.push(like, like, like, like);
    }
    if (dateFrom) {
      baseConditions.push('al.created_at >= ?');
      baseParams.push(dateFrom);
    }
    if (dateTo) {
      baseConditions.push('al.created_at <= ?');
      baseParams.push(dateTo + ' 23:59:59');
    }

    const conditions = [...baseConditions];
    const params     = [...baseParams];
    if (status) {
      conditions.push(`(${STATUS_CASE_SQL}) = ?`);
      params.push(...STATUS_CASE_PARAMS, status);
    }

    const where     = conditions.length     ? `WHERE ${conditions.join(' AND ')}`         : '';
    const baseWhere = baseConditions.length ? `WHERE ${baseConditions.join(' AND ')}` : '';

    const rows = db.prepare(`
      SELECT
        al.id,
        al.action,
        al.category,
        al.details,
        al.ip_address,
        al.user_agent,
        al.created_at,
        actor.id           AS actor_id,
        actor.email        AS actor_email,
        actor.display_name AS actor_name,
        target.id          AS target_id,
        target.email       AS target_email,
        target.display_name AS target_name
      FROM audit_logs al
      LEFT JOIN users actor  ON actor.id  = al.actor_id
      LEFT JOIN users target ON target.id = al.target_user_id
      ${where}
      ORDER BY al.created_at DESC
      LIMIT ? OFFSET ?
    `).all(...params, limit, offset);

    const total = db.prepare(`
      SELECT COUNT(*) AS n
      FROM audit_logs al
      LEFT JOIN users actor  ON actor.id  = al.actor_id
      LEFT JOIN users target ON target.id = al.target_user_id
      ${where}
    `).get(...params).n;

    // Compteurs par statut, calculés avec les mêmes filtres (catégorie/recherche/dates)
    // mais SANS le filtre statut lui-même, pour permettre de basculer entre statuts.
    const statusRows = db.prepare(`
      SELECT (${STATUS_CASE_SQL}) AS ev_status, COUNT(*) AS n
      FROM audit_logs al
      LEFT JOIN users actor  ON actor.id  = al.actor_id
      LEFT JOIN users target ON target.id = al.target_user_id
      ${baseWhere}
      GROUP BY ev_status
    `).all(...STATUS_CASE_PARAMS, ...baseParams);

    const statusCounts = { success: 0, warning: 0, failure: 0 };
    for (const r of statusRows) {
      if (r.ev_status && statusCounts[r.ev_status] !== undefined) statusCounts[r.ev_status] = r.n;
    }

    // Parser les details JSON
    const parsed = rows.map(r => {
      const details = r.details ? (() => { try { return JSON.parse(r.details); } catch { return r.details; } })() : null;
      // Repli sur les infos figées dans "details" quand l'utilisateur (acteur et/ou cible)
      // a depuis été supprimé — son FK passe à NULL (ON DELETE SET NULL) mais l'email/nom
      // saisis au moment de l'action restent lisibles pour les admins.
      const fallbackName  = details && typeof details === 'object' ? (details.display_name || null) : null;
      const fallbackEmail = details && typeof details === 'object' ? (details.email || null) : null;
      return {
        ...r,
        details,
        actor_name:  r.actor_name  ?? (r.actor_id  == null ? fallbackName  : null),
        actor_email: r.actor_email ?? (r.actor_id  == null ? fallbackEmail : null),
        target_name: r.target_name ?? (r.target_id == null ? fallbackName  : null),
        target_email:r.target_email?? (r.target_id == null ? fallbackEmail: null),
      };
    });

    res.json({ total, page, limit, rows: parsed, statusCounts });
  } catch (e) { next(e); }
});

// ── GET /categories — liste des catégories présentes ──────────────────────
router.get('/categories', (_req, res, next) => {
  try {
    const rows = db.prepare(
      "SELECT DISTINCT category FROM audit_logs WHERE created_at >= datetime('now', '-30 days') ORDER BY category"
    ).all();
    res.json(rows.map(r => r.category));
  } catch (e) { next(e); }
});

export default router;