package apis

import (
	"reflect"
	"runtime"
	"strconv"
	"strings"
	"time"

	"github.com/prometheus/client_golang/prometheus"
)

var (
	requestCounter = prometheus.NewCounterVec(
		prometheus.CounterOpts{
			Name: "http_requests_total",
			Help: "Number of get requests.",
		},
		[]string{"handler", "method", "code"},
	)
	responseTimeDuration = prometheus.NewHistogramVec(
		prometheus.HistogramOpts{
			Name:    "http_request_duration_seconds",
			Help:    "Histogram of response time for HTTP requests.",
			Buckets: []float64{0.1, 0.2, 0.5, 1, 2, 5, 10, 30, 60},
		},
		[]string{"handler", "method", "code"},
	)
)

// getHandleName 获取FuncHandle/StreamHandle函数名
func getHandleName(fn any) string {
	fullName := runtime.FuncForPC(reflect.ValueOf(fn).Pointer()).Name()
	if fullName == "" {
		panic("get func name is empty")
	}

	parts := strings.Split(fullName, ".")
	lastPart := parts[len(parts)-1]
	name := strings.TrimSuffix(lastPart, "-fm")
	return name
}

// collectHandleMetrics api指标数据
func collectHandleMetrics(funcName, method string, st time.Time, err error) {
	code := 200
	if err != nil {
		code = APIError(err).(*APIResponse).HTTPStatusCode
	}

	codeStr := strconv.Itoa(code)
	requestCounter.WithLabelValues(funcName, method, codeStr).Inc()
	duration := time.Since(st).Seconds()
	responseTimeDuration.WithLabelValues(funcName, method, codeStr).Observe(duration)
}

func init() {
	prometheus.MustRegister(requestCounter)
	prometheus.MustRegister(responseTimeDuration)
}