const express = require('express');
const fs = require('fs').promises;

module.exports = function({ asyncHandler, ok, auditLogger, securityEventStore }) {
  const router = express.Router();

  // GET /api/v1/log-insights — Plain English summary of who's doing what
  router.get('/log-insights', asyncHandler(async (req, res) => {
    const hours = parseInt(req.query.hours) || 24;
    const since = new Date(Date.now() - hours * 60 * 60 * 1000).toISOString();

    // --- Collect data ---
    const auditEntries = await auditLogger.query({ limit: 10000 });
    const recentAudit = auditEntries.filter(e => e.timestamp >= since);

    let securityEvents = [];
    try { securityEvents = securityEventStore.query({ since, limit: 10000 }); } catch {}

    // --- Analyze IPs ---
    const ipMap = {};
    recentAudit.forEach(e => {
      const ip = e.ip || 'unknown';
      if (!ipMap[ip]) ipMap[ip] = { count: 0, actions: {}, resources: new Set(), first: e.timestamp, last: e.timestamp, failures: 0 };
      const s = ipMap[ip];
      s.count++;
      const cat = (e.action || 'unknown').split('.')[0];
      s.actions[cat] = (s.actions[cat] || 0) + 1;
      if (e.resource) s.resources.add(e.resource);
      if (e.timestamp < s.first) s.first = e.timestamp;
      if (e.timestamp > s.last) s.last = e.timestamp;
      if (e.outcome === 'failure' || e.outcome === 'denied') s.failures++;
    });

    // --- Build plain-English insights ---
    const insights = [];
    const ipArray = Object.entries(ipMap).sort((a, b) => b[1].count - a[1].count);

    // Heavy users
    ipArray.slice(0, 3).forEach(([ip, s]) => {
      const topAction = Object.entries(s.actions).sort((a, b) => b[1] - a[1])[0];
      insights.push({
        severity: s.count > 500 ? 'warning' : 'info',
        title: ip + ' — ' + s.count + ' requests in ' + hours + 'h',
        plain: ip + ' made ' + s.count + ' requests (mostly ' + (topAction ? topAction[0] : 'unknown') + ')' +
          (s.failures > 0 ? ', ' + s.failures + ' failed' : '') + '.'
      });
    });

    // Auth failures
    const totalFailures = recentAudit.filter(e => e.outcome === 'failure' || e.outcome === 'denied').length;
    if (totalFailures > 5) {
      insights.push({
        severity: totalFailures > 50 ? 'warning' : 'info',
        title: totalFailures + ' failed actions',
        plain: totalFailures + ' requests were denied or failed in the last ' + hours + ' hours.' +
          (totalFailures > 50 ? ' This could indicate someone trying to brute-force access.' : '')
      });
    }

    // Security events
    const secBySev = {};
    securityEvents.forEach(e => { secBySev[e.severity] = (secBySev[e.severity] || 0) + 1; });
    if (secBySev.critical || secBySev.error) {
      insights.push({
        severity: 'warning',
        title: ((secBySev.critical || 0) + (secBySev.error || 0)) + ' security alerts',
        plain: (secBySev.critical || 0) + ' critical and ' + (secBySev.error || 0) + ' error-level security events were logged.'
      });
    }

    // Quiet / nothing
    if (insights.length === 0) {
      insights.push({ severity: 'ok', title: 'All quiet', plain: 'No notable activity in the last ' + hours + ' hours.' });
    }

    // --- Storage info ---
    const auditPath = process.env.AUDIT_LOG_FILE || '/opt/dashcaddy/dashcaddy-api/data/audit-log.json';
    const secPath = process.env.SECURITY_EVENT_LOG_FILE || '/opt/dashcaddy/dashcaddy-api/data/security-events.jsonl';
    let storage = {};
    try {
      const a = await fs.stat(auditPath);
      storage.auditLog = { sizeMB: +(a.size / 1048576).toFixed(2), entries: auditEntries.length };
    } catch {}
    try {
      const s = await fs.stat(secPath);
      storage.securityEvents = { sizeMB: +(s.size / 1048576).toFixed(2), entries: securityEvents.length };
    } catch {}

    ok(res, {
      period: { hours, since, until: new Date().toISOString() },
      summary: {
        totalRequests: recentAudit.length,
        uniqueIPs: ipArray.length,
        securityEvents: securityEvents.length,
        failedActions: totalFailures
      },
      topIPs: ipArray.slice(0, 10).map(([ip, s]) => ({
        ip: ip,
        count: s.count,
        failures: s.failures,
        topActions: Object.entries(s.actions).sort((a, b) => b[1] - a[1]).slice(0, 3),
        activeFrom: s.first,
        lastSeen: s.last
      })),
      insights: insights,
      storage: storage
    });
  }));

  // POST /api/v1/log-insights/dispose — Preview then confirm cleanup
  router.post('/log-insights/dispose', asyncHandler(async (req, res) => {
    const keepDays = parseInt(req.body.keepDays) || 30;
    const confirm = req.body.confirm === true;
    const cutoff = new Date(Date.now() - keepDays * 86400000).toISOString();

    const auditPath = process.env.AUDIT_LOG_FILE || '/opt/dashcaddy/dashcaddy-api/data/audit-log.json';
    const secPath = process.env.SECURITY_EVENT_LOG_FILE || '/opt/dashcaddy/dashcaddy-api/data/security-events.jsonl';

    const auditRaw = await fs.readFile(auditPath, 'utf8').catch(function () { return '[]'; });
    const auditData = JSON.parse(auditRaw);
    const oldAudit = auditData.filter(function (e) { return e.timestamp < cutoff; });

    const secRaw = await fs.readFile(secPath, 'utf8').catch(function () { return ''; });
    const secLines = secRaw.split('\n').filter(Boolean);
    const oldSec = secLines.filter(function (l) { try { return JSON.parse(l).timestamp < cutoff; } catch (e) { return false; } });

    if (!confirm) {
      ok(res, {
        preview: true,
        message: 'This will delete ' + oldAudit.length + ' audit entries and ' + oldSec.length + ' security events older than ' + keepDays + ' days. Send {confirm: true} to proceed.',
        wouldDelete: { auditEntries: oldAudit.length, securityEvents: oldSec.length },
        cutoffDate: cutoff
      });
      return;
    }

    // Execute cleanup
    const keptAudit = auditData.filter(function (e) { return e.timestamp >= cutoff; });
    await fs.writeFile(auditPath, JSON.stringify(keptAudit, null, 2));

    const keptSec = secLines.filter(function (l) { try { return JSON.parse(l).timestamp >= cutoff; } catch (e) { return false; } });
    await fs.writeFile(secPath, keptSec.join('\n') + '\n');

    ok(res, {
      disposed: true,
      deleted: { auditEntries: oldAudit.length, securityEvents: oldSec.length },
      remaining: { auditEntries: keptAudit.length, securityEvents: keptSec.length },
      cutoffDate: cutoff
    });
  }));

  return router;
};