/**
 * GET /api/zabbix/wan-gap-analysis
 * Cross-references Datto RMM sites, Zabbix WAN hosts, and IT Glue WAN circuits
 * to surface monitoring gaps and event correlation.
 *
 * Returns:
 *   - summary: counts of covered/gap/no-itg sites
 *   - rmm_gaps: RMM sites with no Zabbix host
 *   - itg_gaps: IT Glue WAN circuits with no matched Zabbix host (and have a static IP)
 *   - multi_circuit_sites: companies with >1 IT Glue WAN circuit, showing Zabbix coverage per circuit
 *   - current_problems: Zabbix hosts with active problems + matching recent RMM alerts
 *   - last_synced: timestamps of the cache tables
 */
import { NextResponse } from 'next/server';
import { postgresClient } from '@/lib/services/postgres-client';

export async function GET() {
  try {
    // ── 1. RMM sites missing from Zabbix ─────────────────────────────────────
    const rmmGaps = await postgresClient.query(`
      SELECT
        s.uid            AS rmm_site_uid,
        s.name           AS rmm_site_name,
        s.autotask_company_name AS company_name,
        rsm.company_id,
        s.number_of_devices,
        s.number_of_online_devices
      FROM datto_rmm_sites s
      JOIN rmm_site_mappings rsm ON rsm.rmm_site_uid = s.uid
      LEFT JOIN zabbix_wan_hosts z ON z.rmm_site_uid = s.uid
      WHERE z.hostid IS NULL
        AND s.number_of_online_devices > 0
      ORDER BY s.autotask_company_name, s.name
    `);

    // ── 2. IT Glue WAN circuits missing from Zabbix (have IPs, not decommissioned) ──
    const itgGaps = await postgresClient.query(`
      SELECT
        ic.id            AS itg_asset_id,
        ic.org_name,
        ic.autotask_company_id,
        ic.provider,
        ic.link_type,
        ic.static_ips,
        ic.location_name,
        ic.location_city,
        ic.upload_mbps,
        ic.download_mbps
      FROM itg_wan_circuits ic
      WHERE ic.zabbix_hostid IS NULL
        AND ic.is_decommissioned = FALSE
        AND array_length(ic.static_ips, 1) > 0
      ORDER BY ic.org_name, ic.provider
    `);

    // ── 3. Multi-circuit companies (>1 IT Glue WAN circuit) ──────────────────
    const multiCircuit = await postgresClient.query(`
      SELECT
        ic.org_name,
        ic.autotask_company_id,
        COUNT(*)                                           AS total_circuits,
        COUNT(*) FILTER (WHERE ic.zabbix_hostid IS NOT NULL) AS monitored_circuits,
        COUNT(*) FILTER (WHERE ic.zabbix_hostid IS NULL
                           AND NOT ic.is_decommissioned
                           AND array_length(ic.static_ips,1) > 0) AS gap_circuits,
        json_agg(json_build_object(
          'id',            ic.id,
          'provider',      ic.provider,
          'link_type',     ic.link_type,
          'static_ips',    ic.static_ips,
          'location_name', ic.location_name,
          'zabbix_hostid', ic.zabbix_hostid,
          'is_decommissioned', ic.is_decommissioned
        ) ORDER BY ic.provider) AS circuits
      FROM itg_wan_circuits ic
      WHERE NOT ic.is_decommissioned
      GROUP BY ic.org_name, ic.autotask_company_id
      HAVING COUNT(*) > 1
      ORDER BY gap_circuits DESC, ic.org_name
    `);

    // ── 4. Current Zabbix problems + correlated RMM alerts ───────────────────
    const problems = await postgresClient.query(`
      SELECT
        z.hostid,
        z.display_name,
        z.wan_ip,
        z.isp_name,
        z.autotask_company_name,
        z.autotask_company_id,
        z.rmm_site_uid,
        z.last_problem_at,
        z.last_problem_name,
        -- Count open RMM alerts for the same company in the last 24h
        (
          SELECT COUNT(*) FROM datto_rmm_alerts a
          JOIN datto_rmm_sites ds ON ds.uid = a.site_uid
          WHERE ds.autotask_company_id = z.autotask_company_id
            AND a.resolved = FALSE
            AND a.timestamp > NOW() - INTERVAL '24 hours'
        ) AS open_rmm_alerts_24h,
        -- Most recent RMM network alert for this company
        (
          SELECT a.alert_message_en FROM datto_rmm_alerts a
          JOIN datto_rmm_sites ds ON ds.uid = a.site_uid
          WHERE ds.autotask_company_id = z.autotask_company_id
            AND (a.alert_category ILIKE '%network%' OR a.alert_category ILIKE '%wan%'
                 OR a.alert_type ILIKE '%ping%' OR a.alert_type ILIKE '%offline%')
            AND a.timestamp > NOW() - INTERVAL '24 hours'
          ORDER BY a.timestamp DESC LIMIT 1
        ) AS latest_rmm_network_alert,
        -- Open ticket count for this company today
        (
          SELECT COUNT(*) FROM tickets t
          WHERE t.company_id = z.autotask_company_id
            AND t.source = 8
            AND t.create_date > NOW() - INTERVAL '24 hours'
            AND t.is_deleted IS NOT TRUE
        ) AS monitor_tickets_24h
      FROM zabbix_wan_hosts z
      WHERE z.last_problem_at > NOW() - INTERVAL '24 hours'
         OR z.status = 1
      ORDER BY z.last_problem_at DESC NULLS LAST
    `);

    // ── 5. Summary counts ─────────────────────────────────────────────────────
    const summary = await postgresClient.query(`
      SELECT
        (SELECT COUNT(*) FROM datto_rmm_sites s JOIN rmm_site_mappings rsm ON rsm.rmm_site_uid = s.uid)
          AS total_rmm_sites,
        (SELECT COUNT(*) FROM zabbix_wan_hosts)
          AS total_zabbix_hosts,
        (SELECT COUNT(*) FROM zabbix_wan_hosts WHERE status = 0)
          AS zabbix_enabled,
        (SELECT COUNT(*) FROM datto_rmm_sites s
           JOIN rmm_site_mappings rsm ON rsm.rmm_site_uid = s.uid
           LEFT JOIN zabbix_wan_hosts z ON z.rmm_site_uid = s.uid
           WHERE z.hostid IS NULL AND s.number_of_online_devices > 0)
          AS rmm_sites_no_zabbix,
        (SELECT COUNT(*) FROM itg_wan_circuits WHERE NOT is_decommissioned)
          AS total_itg_circuits,
        (SELECT COUNT(*) FROM itg_wan_circuits
           WHERE zabbix_hostid IS NOT NULL AND NOT is_decommissioned)
          AS itg_circuits_monitored,
        (SELECT COUNT(*) FROM itg_wan_circuits
           WHERE zabbix_hostid IS NULL AND NOT is_decommissioned
             AND array_length(static_ips,1) > 0)
          AS itg_circuits_gap,
        (SELECT MAX(last_synced_at) FROM zabbix_wan_hosts)
          AS zabbix_last_synced,
        (SELECT MAX(last_synced_at) FROM itg_wan_circuits)
          AS itg_last_synced
    `);

    return NextResponse.json({
      summary: summary.rows[0],
      rmm_gaps: rmmGaps.rows,
      itg_gaps: itgGaps.rows,
      multi_circuit: multiCircuit.rows,
      problems: problems.rows,
    });
  } catch (err) {
    const msg = err instanceof Error ? err.message : String(err);
    return NextResponse.json({ error: msg }, { status: 500 });
  }
}