// src/observability/metrics.ts
import { Registry, Counter, Histogram, Gauge } from "prom-client";

export const registry = new Registry();

// API request counter (by operation and status)
export const apiRequests = new Counter({
  name: "webflow_api_requests_total",
  help: "Total Webflow API requests",
  labelNames: ["operation", "status_code", "method"] as const,
  registers: [registry],
});

// Request duration histogram
export const apiDuration = new Histogram({
  name: "webflow_api_request_duration_seconds",
  help: "Webflow API request duration in seconds",
  labelNames: ["operation"] as const,
  buckets: [0.05, 0.1, 0.25, 0.5, 1, 2, 5, 10],
  registers: [registry],
});

// Error counter by type
export const apiErrors = new Counter({
  name: "webflow_api_errors_total",
  help: "Webflow API errors by status code",
  labelNames: ["operation", "status_code", "error_type"] as const,
  registers: [registry],
});

// Rate limit remaining gauge
export const rateLimitRemaining = new Gauge({
  name: "webflow_rate_limit_remaining",
  help: "Remaining API calls before rate limit",
  registers: [registry],
});

// CMS items gauge (track total items across collections)
export const cmsItemCount = new Gauge({
  name: "webflow_cms_items_total",
  help: "Total CMS items by collection",
  labelNames: ["collection", "site"] as const,
  registers: [registry],
});

// Webhook event counter
export const webhookEvents = new Counter({
  name: "webflow_webhook_events_total",
  help: "Received webhook events by trigger type",
  labelNames: ["trigger_type", "status"] as const,
  registers: [registry],
});

// src/observability/instrumented-client.ts
import { WebflowClient } from "webflow-api";
import { apiRequests, apiDuration, apiErrors, rateLimitRemaining } from "./metrics.js";

export async function instrumentedCall<T>(
  operation: string,
  method: string,
  fn: () => Promise<T>
): Promise<T> {
  const timer = apiDuration.startTimer({ operation });

  try {
    const result = await fn();

    apiRequests.inc({ operation, status_code: "200", method });
    timer();
    return result;
  } catch (error: any) {
    const statusCode = String(error.statusCode || error.status || "unknown");

    apiRequests.inc({ operation, status_code: statusCode, method });
    apiErrors.inc({
      operation,
      status_code: statusCode,
      error_type: statusCode === "429" ? "rate_limit" : statusCode >= "500" ? "server" : "client",
    });

    timer();
    throw error;
  }
}

// Usage
const { sites } = await instrumentedCall("sites.list", "GET", () =>
  webflow.sites.list()
);

const { items } = await instrumentedCall("items.listLive", "GET", () =>
  webflow.collections.items.listItemsLive(collectionId)
);

const item = await instrumentedCall("items.create", "POST", () =>
  webflow.collections.items.createItem(collectionId, {
    fieldData: { name: "Test", slug: "test" },
  })
);

// api/metrics.ts
import express from "express";
import { registry } from "../observability/metrics.js";

const app = express();

app.get("/metrics", async (req, res) => {
  res.set("Content-Type", registry.contentType);
  res.send(await registry.metrics());
});

// src/observability/tracing.ts
import { trace, SpanStatusCode, context } from "@opentelemetry/api";

const tracer = trace.getTracer("webflow-integration", "1.0.0");

export async function tracedCall<T>(
  operationName: string,
  attributes: Record<string, string>,
  fn: () => Promise<T>
): Promise<T> {
  return tracer.startActiveSpan(`webflow.${operationName}`, async (span) => {
    span.setAttributes({
      "webflow.operation": operationName,
      ...attributes,
    });

    try {
      const result = await fn();
      span.setStatus({ code: SpanStatusCode.OK });
      return result;
    } catch (error: any) {
      span.setStatus({
        code: SpanStatusCode.ERROR,
        message: error.message,
      });
      span.recordException(error);
      span.setAttributes({
        "webflow.error.status_code": String(error.statusCode || "unknown"),
      });
      throw error;
    } finally {
      span.end();
    }
  });
}

// Usage
const { collections } = await tracedCall(
  "collections.list",
  { "webflow.site_id": siteId },
  () => webflow.collections.list(siteId)
);

// src/observability/logger.ts
import pino from "pino";

export const logger = pino({
  name: "webflow-integration",
  level: process.env.LOG_LEVEL || "info",
  serializers: {
    err: pino.stdSerializers.err,
  },
  // Redact sensitive fields
  redact: {
    paths: ["accessToken", "apiToken", "*.authorization", "req.headers.authorization"],
    censor: "[REDACTED]",
  },
});

// Log API calls with consistent structure
export function logApiCall(
  operation: string,
  durationMs: number,
  status: "success" | "error",
  metadata?: Record<string, any>
) {
  const logFn = status === "error" ? logger.error.bind(logger) : logger.info.bind(logger);

  logFn({
    service: "webflow",
    operation,
    durationMs,
    status,
    ...metadata,
  }, `webflow.${operation} ${status} (${durationMs}ms)`);
}

// Log webhook events
export function logWebhook(triggerType: string, status: "processed" | "failed" | "skipped") {
  logger.info({
    service: "webflow",
    event: "webhook",
    triggerType,
    status,
  }, `webhook.${triggerType} ${status}`);
}

# prometheus/webflow-alerts.yml
groups:
  - name: webflow
    rules:
      - alert: WebflowHighErrorRate
        expr: |
          (
            rate(webflow_api_errors_total[5m]) /
            rate(webflow_api_requests_total[5m])
          ) > 0.05
        for: 5m
        labels:
          severity: warning
        annotations:
          summary: "Webflow API error rate > 5%"
          description: "{{ $value | humanizePercentage }} errors in last 5m"

      - alert: WebflowRateLimited
        expr: |
          rate(webflow_api_errors_total{status_code="429"}[5m]) > 0
        for: 2m
        labels:
          severity: warning
        annotations:
          summary: "Webflow API rate limited"

      - alert: WebflowHighLatency
        expr: |
          histogram_quantile(0.95,
            rate(webflow_api_request_duration_seconds_bucket[5m])
          ) > 3
        for: 5m
        labels:
          severity: warning
        annotations:
          summary: "Webflow P95 latency > 3s"

      - alert: WebflowDown
        expr: |
          sum(rate(webflow_api_requests_total{status_code=~"5.."}[5m])) /
          sum(rate(webflow_api_requests_total[5m])) > 0.5
        for: 2m
        labels:
          severity: critical
        annotations:
          summary: "Webflow API > 50% server errors"

      - alert: WebflowRateLimitLow
        expr: webflow_rate_limit_remaining < 10
        for: 1m
        labels:
          severity: warning
        annotations:
          summary: "Webflow rate limit nearly exhausted"

{
  "panels": [
    {
      "title": "Request Rate by Operation",
      "targets": [{ "expr": "sum by (operation) (rate(webflow_api_requests_total[5m]))" }]
    },
    {
      "title": "Error Rate",
      "targets": [{ "expr": "sum(rate(webflow_api_errors_total[5m])) / sum(rate(webflow_api_requests_total[5m]))" }]
    },
    {
      "title": "Latency P50 / P95 / P99",
      "targets": [
        { "expr": "histogram_quantile(0.5, rate(webflow_api_request_duration_seconds_bucket[5m]))", "legendFormat": "p50" },
        { "expr": "histogram_quantile(0.95, rate(webflow_api_request_duration_seconds_bucket[5m]))", "legendFormat": "p95" },
        { "expr": "histogram_quantile(0.99, rate(webflow_api_request_duration_seconds_bucket[5m]))", "legendFormat": "p99" }
      ]
    },
    {
      "title": "Rate Limit Remaining",
      "targets": [{ "expr": "webflow_rate_limit_remaining" }]
    },
    {
      "title": "Webhook Events by Type",
      "targets": [{ "expr": "sum by (trigger_type) (rate(webflow_webhook_events_total[5m]))" }]
    }
  ]
}