/** Agency health checks → agency_alerts (sync stale, ecommerce volume drop). */

import { serviceHeaders, supabaseUrl } from '@/lib/agency';

const STALE_HOURS = 26;
const ECOM_DROP_RATIO = 0.4; // alert if this week < 40% of prior week
const ECOM_MIN_PRIOR = 3;

type AlertDraft = {
  tenant_id: string | null;
  severity: 'info' | 'warning' | 'critical';
  source: string;
  title: string;
  body: string;
  href?: string | null;
};

function hoursAgo(iso: string | null | undefined): number | null {
  if (!iso) return null;
  const t = new Date(iso).getTime();
  if (Number.isNaN(t)) return null;
  return (Date.now() - t) / 36e5;
}

function dayOffset(days: number): string {
  const d = new Date();
  d.setUTCDate(d.getUTCDate() + days);
  return d.toISOString().slice(0, 10);
}

async function existingUnreadTitle(
  headers: Record<string, string>,
  base: string,
  title: string,
  tenantId: string | null
): Promise<boolean> {
  const since = new Date(Date.now() - 36e5 * 36).toISOString();
  let q = `${base}/rest/v1/agency_alerts?select=id&title=eq.${encodeURIComponent(title)}&read_at=is.null&created_at=gte.${since}&limit=1`;
  if (tenantId) {
    q += `&tenant_id=eq.${encodeURIComponent(tenantId)}`;
  } else {
    q += `&tenant_id=is.null`;
  }
  const r = await fetch(q, { headers, cache: 'no-store' });
  if (!r.ok) return false;
  const rows = (await r.json()) as unknown[];
  return rows.length > 0;
}

async function insertAlert(
  headers: Record<string, string>,
  base: string,
  draft: AlertDraft
): Promise<boolean> {
  if (await existingUnreadTitle(headers, base, draft.title, draft.tenant_id)) {
    return false;
  }
  const r = await fetch(`${base}/rest/v1/agency_alerts`, {
    method: 'POST',
    headers: {
      ...headers,
      'Content-Type': 'application/json',
      Prefer: 'return=minimal',
    },
    body: JSON.stringify({
      tenant_id: draft.tenant_id,
      severity: draft.severity,
      source: draft.source,
      title: draft.title,
      body: draft.body,
      href: draft.href || null,
    }),
  });
  return r.ok;
}

const CRM_PROVIDERS = ['clientify', 'gohighlevel'] as const;
const DATA_PROVIDERS = [
  'clientify',
  'gohighlevel',
  'meta_ads',
  'google_ads',
  'ga4',
  'search_console',
  'shopify',
  'woocommerce',
] as const;

function isEcommerceDealName(name: string | null | undefined): boolean {
  return /^(order|pedido)\s+\d+/i.test(String(name || ''));
}

export type HealthAlertResult = {
  checked: number;
  created: number;
  skipped: number;
  details: string[];
};

/** Run health checks and write unread agency_alerts (deduped 36h). */
export async function runAgencyHealthAlerts(): Promise<HealthAlertResult> {
  const headers = serviceHeaders();
  const base = supabaseUrl();
  const out: HealthAlertResult = {
    checked: 0,
    created: 0,
    skipped: 0,
    details: [],
  };
  if (!headers || !base) {
    out.details.push('no service role');
    return out;
  }

  const [tRes, iRes] = await Promise.all([
    fetch(
      `${base}/rest/v1/tenants?select=id,slug,name&agency_followed=neq.false`,
      { headers, cache: 'no-store' }
    ),
    fetch(
      `${base}/rest/v1/integrations?select=tenant_id,provider,status,last_sync_at,enabled,error_message&enabled=neq.false`,
      { headers, cache: 'no-store' }
    ),
  ]);
  if (!tRes.ok || !iRes.ok) {
    out.details.push('fetch tenants/integrations failed');
    return out;
  }

  const tenants = (await tRes.json()) as {
    id: string;
    slug: string;
    name: string;
  }[];
  const integrations = (await iRes.json()) as {
    tenant_id: string;
    provider: string;
    status?: string;
    last_sync_at?: string | null;
    error_message?: string | null;
  }[];

  const byTenant = new Map<string, typeof integrations>();
  for (const row of integrations) {
    const list = byTenant.get(row.tenant_id) || [];
    list.push(row);
    byTenant.set(row.tenant_id, list);
  }

  const thisWeekStart = dayOffset(-7);
  const thisWeekEnd = dayOffset(0);
  const priorStart = dayOffset(-14);
  const priorEnd = dayOffset(-7);

  for (const t of tenants) {
    out.checked += 1;
    const rows = byTenant.get(t.id) || [];

    for (const row of rows) {
      if (!DATA_PROVIDERS.includes(row.provider as (typeof DATA_PROVIDERS)[number])) {
        continue;
      }
      if (row.status === 'error') {
        const title = `Integración en error: ${row.provider} · ${t.name}`;
        const ok = await insertAlert(headers, base, {
          tenant_id: t.id,
          severity: 'critical',
          source: 'health',
          title,
          body: row.error_message || 'Revisa credenciales / sync en ficha cliente.',
          href: `/dashboard/agencia/cliente/${t.id}`,
        });
        if (ok) {
          out.created += 1;
          out.details.push(title);
        } else out.skipped += 1;
        continue;
      }
      if (row.status !== 'connected') continue;
      const age = hoursAgo(row.last_sync_at);
      if (age == null || age > STALE_HOURS) {
        const title = `Sync atrasado: ${row.provider} · ${t.name}`;
        const ok = await insertAlert(headers, base, {
          tenant_id: t.id,
          severity: CRM_PROVIDERS.includes(
            row.provider as (typeof CRM_PROVIDERS)[number]
          )
            ? 'critical'
            : 'warning',
          source: 'health',
          title,
          body:
            age == null
              ? 'Conectado pero sin last_sync_at. Lanza sync o revisa el cron.'
              : `Último sync hace ${Math.round(age)}h (umbral ${STALE_HOURS}h).`,
          href: `/dashboard/agencia/cliente/${t.id}`,
        });
        if (ok) {
          out.created += 1;
          out.details.push(title);
        } else out.skipped += 1;
      }
    }

    // Ecommerce volume: Order/Pedido won deals this week vs prior
    const dealsRes = await fetch(
      `${base}/rest/v1/deals?tenant_id=eq.${encodeURIComponent(t.id)}&stage=eq.won&won_at=gte.${priorStart}&won_at=lt.${thisWeekEnd}&select=name,won_at,amount&limit=2000`,
      { headers, cache: 'no-store' }
    );
    if (!dealsRes.ok) continue;
    const deals = (await dealsRes.json()) as {
      name?: string | null;
      won_at?: string | null;
      amount?: number | null;
    }[];
    const ecom = deals.filter(
      (d) => isEcommerceDealName(d.name) && Number(d.amount || 0) > 0
    );
    const thisW = ecom.filter((d) => {
      const day = (d.won_at || '').slice(0, 10);
      return day >= thisWeekStart && day < thisWeekEnd;
    }).length;
    const priorW = ecom.filter((d) => {
      const day = (d.won_at || '').slice(0, 10);
      return day >= priorStart && day < priorEnd;
    }).length;
    if (priorW >= ECOM_MIN_PRIOR && thisW < priorW * ECOM_DROP_RATIO) {
      const title = `Caída ventas ecommerce · ${t.name}`;
      const ok = await insertAlert(headers, base, {
        tenant_id: t.id,
        severity: 'warning',
        source: 'ecommerce-health',
        title,
        body: `Pedidos CRM (Order/Pedido) esta semana: ${thisW} vs ${priorW} la anterior. Posible fallo Woo→Clientify/Shopify.`,
        href: `/dashboard/crm`,
      });
      if (ok) {
        out.created += 1;
        out.details.push(title);
      } else out.skipped += 1;
    }
  }

  return out;
}