package metrics

import (
	"strconv"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/prometheus/client_golang/prometheus"
	"github.com/prometheus/client_golang/prometheus/promauto"
)

var (
	HTTPRequestsTotal = promauto.NewCounterVec(
		prometheus.CounterOpts{Name: "http_requests_total", Help: "Total HTTP requests."},
		[]string{"method", "path", "status"},
	)
	HTTPRequestDuration = promauto.NewHistogramVec(
		prometheus.HistogramOpts{Name: "http_request_duration_seconds", Help: "HTTP request latency.", Buckets: prometheus.DefBuckets},
		[]string{"method", "path", "status"},
	)

	ReminderSendTotal = promauto.NewCounterVec(
		prometheus.CounterOpts{Name: "reminder_send_total", Help: "Reminder delivery results."},
		[]string{"status"},
	)
	ReminderRetryTotal = promauto.NewCounter(
		prometheus.CounterOpts{Name: "reminder_retry_total", Help: "Reminder retry count."},
	)

	DBQueryDuration = promauto.NewHistogramVec(
		prometheus.HistogramOpts{Name: "db_query_duration_seconds", Help: "DB query duration.", Buckets: prometheus.DefBuckets},
		[]string{"op", "table", "success"},
	)
)

func init() {
	ReminderSendTotal.WithLabelValues("sent").Add(0)
	ReminderSendTotal.WithLabelValues("failed").Add(0)
	ReminderRetryTotal.Add(0)
	DBQueryDuration.WithLabelValues("scan_pending", "reminders", "true").Observe(0)
}

func ObserveHTTP(c *gin.Context, start time.Time) {
	path := c.FullPath()
	if path == "" {
		path = c.Request.URL.Path
	}
	status := strconv.Itoa(c.Writer.Status())
	labels := []string{c.Request.Method, path, status}
	HTTPRequestsTotal.WithLabelValues(labels...).Inc()
	HTTPRequestDuration.WithLabelValues(labels...).Observe(time.Since(start).Seconds())
}

func ObserveDB(op, table string, success bool, dur time.Duration) {
	if table == "" {
		table = "unknown"
	}
	s := "false"
	if success {
		s = "true"
	}
	DBQueryDuration.WithLabelValues(op, table, s).Observe(dur.Seconds())
}