// src/metrics.ts

import { IMetricsComponent } from "@well-known-components/interfaces"
import { validateMetricsDeclaration } from "@well-known-components/metrics"

export const metricDeclarations = {
  // register all http-server metrics
  ...getDefaultHttpMetrics(),
  // IMetricsComponent.SummaryType
  // IMetricsComponent.HistogramType
  // IMetricsComponent.GaugeType
  // IMetricsComponent.CounterType
  user_counter: {
    type: IMetricsComponent.CounterType,
    help: "Count calls to /user/:userId",
    labelNames: ["userId"],
  },
}

// type assertions
validateMetricsDeclaration(metricDeclarations)

// src/components.ts

import { metricDeclarations } from "./metrics"

export async function initComponents(): Promise<AppComponents> {
  ...
  // const config
  // const server
  const metrics = await createMetricsComponent(metricDeclarations, {config})
  await instrumentHttpServerWithMetrics({ metrics, config, server })

  return { ...components, metrics }
}

export async function userIdHandler(context: { components: Pick<AppComponents, "metrics"> }) {
  const {
    components: { metrics },
  } = context

  metrics.increment("user_counter", { userId: Math.random() })
  // metrics.decrement("user_counter", { userId: Math.random() })
  // metrics.observe("user_counter", { userId: Math.random() }, 1)
  // metrics.reset("user_counter")

  return {}
}