/**
 * WFDASH — Purchase Order Outbound Send (Cron / Scheduled Trigger)
 *
 * Companion to `wf-po-send` (webhook). Same execution chain, different
 * trigger: every 15 minutes, scans for POs in `status="draft"` older
 * than 15min and queues them for send.
 *
 * Why a cron pass when the manual trigger is synchronous:
 *   - Catches POs where the operator started the send modal and walked
 *     away (status got flipped but webhook never reached n8n).
 *   - Catches a webhook fire that hit a transient network blip.
 *   - Catches operators working from a different page where the
 *     modal-driven send isn't available.
 *
 * Filtering: only `status="draft"` rows are processed. Status flips to
 * `sending`/`sent` by the in-flight path; cron doesn't re-send those.
 *
 * Cron still reads from PocketBase (only on the scan tick — every
 * 15min — and only for the list + per-row fetch). The DNS-resolution
 * flake we hit on the webhook path matters less here because a
 * transient miss just rolls to the next tick. After fetch, the cron
 * calls back into the same dashboard endpoints:
 *   1. Dashboard route returns the same push-payload the manual path
 *      sends (recipient + subject + body + PDF attachment URL).
 *   2. SMTP send happens.
 *   3. Outcome callback posts to /send-email/outcome with the result.
 *
 * Auth: n8n carries AGENT_API_KEY (Bearer) + DASHBOARD_URL (env).
 * n8n never holds the PocketBase admin token — that stays in the
 * dashboard's process env.
 *
 * Reply tracking is OUT OF SCOPE for this version.
 */
import { workflow, trigger, node } from '@n8n/workflow-sdk';

const cron = trigger({
  type: 'n8n-nodes-base.scheduleTrigger',
  version: 1.2,
  config: {
    name: 'PO Send Cron (every 15min)',
    parameters: {
      rule: {
        interval: [{ field: 'cronExpression', expression: '*/15 * * * *' }],
      },
    },
  },
});

/**
 * Scan PB for draft POs older than 15min, return IDs only. We use
 * PB env (PB_URL + PB_ADMIN_TOKEN) for the scan because that's the
 * bulk query that's too expensive to push from the dashboard. DNS
 * issues here are self-healing: a missed scan rolls to the next tick.
 */
const scanDrafts = node({
  type: 'n8n-nodes-base.code',
  version: 2,
  config: {
    name: 'Scan for draft POs older than 15min',
    parameters: {
      jsCode: `// Scan PB for draft POs older than 15min. Emit one item per
// candidate. Per-PO payload is fetched downstream via the dashboard
// /api/v1/purchase-orders/[id]/dispatch endpoint (so we don't carry
// the admin token here).
//
// n8n Code node sandbox has no global 'fetch' — use
// this.helpers.httpRequest().
const pbUrl = ($env.PB_URL || '').replace(/\\/$/, '');
const pbToken = $env.PB_ADMIN_TOKEN || '';
const agentKey = $env.AGENT_API_KEY || '';
const dashboardBase = ($env.DASHBOARD_URL || '').replace(/\\/$/, '');

if (!dashboardBase || !agentKey) {
  return [{ json: { skip: true, reason: 'DASHBOARD_URL or AGENT_API_KEY missing in env' } }];
}

if (!pbUrl || !pbToken) {
  return [{ json: { skip: true, reason: 'PB_URL or PB_ADMIN_TOKEN missing in env (cold-start probe)' } }];
}

const cutoff = new Date(Date.now() - 15 * 60 * 1000).toISOString();
const filter = encodeURIComponent('status="draft" && created<"' + cutoff + '"');

let list;
try {
  list = await this.helpers.httpRequest({
    method: 'GET',
    url: pbUrl + '/api/collections/purchase_orders/records?perPage=50&filter=' + filter,
    headers: { 'Authorization': pbToken, 'Content-Type': 'application/json' },
    json: true,
    timeout: 8000,
  });
} catch (err) {
  return [{ json: { skip: true, reason: 'PB scan failed (DNS or auth): ' + (err.message || String(err)) } }];
}

const candidates = (list.items || []).map((p) => p.id);
if (candidates.length === 0) {
  return [{ json: { skip: true, reason: 'No draft POs older than 15min' } }];
}

return candidates.map((poId) => ({
  json: {
    trigger: 'cron',
    poId,
    dashboardBase,
  },
}));
`,
    },
  },
});

/**
 * Per-PO dispatch: calls /api/v1/purchase-orders/[id]/dispatch which
 * (a) runs the same pre-send validation + status flip as the manual
 * path, (b) resolves the current PDF, (c) returns the push-payload.
 * Returns `skip: { reason }` if the row is no longer in draft.
 */
const resolvePerPo = node({
  type: 'n8n-nodes-base.code',
  version: 2,
  config: {
    name: 'Resolve per-PO payload (cron path)',
    parameters: {
      jsCode: `// For each candidate poId, ask the dashboard to flip status
// "draft" → "sending" + return the same push-payload the manual path
// uses. If the row is no longer draft (race with manual flow), the
// dashboard returns { skip: { reason } } and we silently drop this
// item.
//
// n8n Code nodes don't expose fetch — use this.helpers.httpRequest().
const cur = ($('Scan for draft POs older than 15min').first().json || {});
const dashboardBase = (cur.dashboardBase || $env.DASHBOARD_URL || '').replace(/\\/$/, '');
const agentKey = $env.AGENT_API_KEY || '';
const poId = cur.poId;

if (!poId) {
  return [{ json: { skip: true, reason: 'No poId in scan row' } }];
}

try {
  const res = await this.helpers.httpRequest({
    method: 'POST',
    url: dashboardBase + '/api/v1/purchase-orders/' + poId + '/dispatch',
    headers: {
      'Content-Type': 'application/json',
      'Authorization': 'Bearer ' + agentKey,
    },
    json: true,
    body: { trigger: 'cron' },
    timeout: 10000,
  });

  if (res && res.skip) {
    return [{ json: { skip: true, reason: res.skip.reason || 'dismissed by route', poId } }];
  }
  if (!res || !res.poId) {
    return [{ json: { skip: true, reason: 'dispatch returned no payload', poId } }];
  }

  return [{ json: {
    trigger: 'cron',
    poId: res.poId,
    body: res, // so the SMTP node reads $json.body.{recipient,subject,body,...}
  } }];
} catch (err) {
  return [{ json: { skip: true, reason: 'dispatch failed: ' + (err.message || String(err)), poId } }];
}
`,
    },
  },
});

const sendEmail = node({
  type: 'n8n-nodes-base.emailSend',
  version: 2.1,
  config: {
    name: 'Send PO email (SMTP)',
    parameters: {
      fromEmail: '={{ $env.PO_FROM_EMAIL || "orders@wfdash.local" }}',
      toEmail: '={{ $json.body.recipient }}',
      ccEmail: '={{ $json.body.cc }}',
      bccEmail: '={{ $json.body.bcc }}',
      subject: '={{ $json.body.subject }}',
      text: '={{ $json.body.body }}',
      html: '={{ $json.body.body }}',
      options: {
        attachments: [
          // Filled in by the Fetch PDF bytes step below.
        ],
      },
    },
  },
});

const fetchAttachments = node({
  type: 'n8n-nodes-base.code',
  version: 2,
  config: {
    name: 'Fetch PDF attachment bytes',
    parameters: {
      jsCode: `// Resolve attachment URLs into { name, content (base64), type }.
// Same shape as the webhook-path attachment node.
//
// n8n Code nodes don't expose fetch — use this.helpers.httpRequest().
const first = ($input.first() || {}).json || {};
const body = first.body || first;
const attachments = (body && body.attachments) || [];

if (!Array.isArray(attachments) || attachments.length === 0) {
  return [{ json: { ...first, attachmentsResolved: [] } }];
}

const agentKey = $env.AGENT_API_KEY || '';
const resolved = [];
for (const att of attachments) {
  try {
    const res = await this.helpers.httpRequest({
      method: 'GET',
      url: att.url,
      headers: agentKey ? { 'Authorization': 'Bearer ' + agentKey } : {},
      encoding: 'base64',
      timeout: 15000,
    });
    resolved.push({
      name: att.filename || 'attachment.pdf',
      content: typeof res === 'string' ? res : (res && res.data) || '',
      type: att.contentType || 'application/pdf',
    });
  } catch (err) {
    return [{ json: { ...first, attachmentsResolved: [], _attachmentFetchError: 'PDF fetch failed: ' + (err.message || String(err)) } }];
  }
}

return [{ json: { ...first, attachmentsResolved: resolved } }];
`,
    },
  },
});

/**
 * Same callback semantics as the webhook path: POST the SMTP outcome
 * back to /api/v1/purchase-orders/[id]/send-email/outcome on the
 * dashboard.
 */
const recordOutcome = node({
  type: 'n8n-nodes-base.code',
  version: 2,
  config: {
    name: 'Record outcome to PB',
    parameters: {
      jsCode: `// POST the SMTP outcome back to the dashboard's outcome route.
// The dashboard owns the canonical write using its own admin PB auth.
//
// n8n Code nodes don't expose fetch — use this.helpers.httpRequest().
const first = ($input.first() || {}).json || {};
const body = first.body || first;
const agentKey = $env.AGENT_API_KEY || '';
const dashboardBase = ($env.DASHBOARD_URL || '').replace(/\\/$/, '');
const poId = body.poId;

if (!agentKey || !dashboardBase) {
  return [{ json: {
    poId,
    ok: false,
    error: 'AGENT_API_KEY or DASHBOARD_URL missing in n8n env',
  } }];
}

const sendResult = ($('Send PO email (SMTP)').first().json) || {};
const ok = !sendResult.error && sendResult.ok !== false;
const messageId = sendResult.messageId || sendResult.message_id || '';
const errorMessage = ok ? '' : (sendResult.error || sendResult.response || 'Unknown SMTP error').toString().slice(0, 990);

try {
  const out = await this.helpers.httpRequest({
    method: 'POST',
    url: dashboardBase + '/api/v1/purchase-orders/' + poId + '/send-email/outcome',
    headers: {
      'Content-Type': 'application/json',
      'Authorization': 'Bearer ' + agentKey,
    },
    json: true,
    body: {
      outcome: ok ? 'success' : 'failure',
      messageId,
      errorMessage,
    },
  });
  return [{ json: { poId, ok, messageId, error: errorMessage, outcome: out } }];
} catch (err) {
  return [{ json: {
    poId,
    ok,
    messageId,
    error: 'Outcome callback failed: ' + (err.message || String(err)),
  } }];
}
`,
    },
  },
});

export default workflow(
  'wf-po-send-cron',
  'WFDASH — Purchase Order Send (Cron)'
)
  .add(cron)
  .to(scanDrafts)
  .to(resolvePerPo)
  .to(fetchAttachments)
  .to(sendEmail)
  .to(recordOutcome);