package api

import (
	"fmt"
	"runtime"

	"github.com/aptly-dev/aptly/aptly"
	"github.com/aptly-dev/aptly/deb"
	"github.com/gin-gonic/gin"
	"github.com/prometheus/client_golang/prometheus"
	"github.com/prometheus/client_golang/prometheus/promauto"
	"github.com/rs/zerolog/log"
)

var (
	apiRequestsInFlightGauge = promauto.NewGaugeVec(
		prometheus.GaugeOpts{
			Name: "aptly_api_http_requests_in_flight",
			Help: "Number of concurrent HTTP api requests currently handled.",
		},
		[]string{"method", "path"},
	)
	apiRequestsTotalCounter = promauto.NewCounterVec(
		prometheus.CounterOpts{
			Name: "aptly_api_http_requests_total",
			Help: "Total number of api requests.",
		},
		[]string{"code", "method", "path"},
	)
	apiRequestSizeSummary = promauto.NewSummaryVec(
		prometheus.SummaryOpts{
			Name: "aptly_api_http_request_size_bytes",
			Help: "Api HTTP request size in bytes.",
		},
		[]string{"code", "method", "path"},
	)
	apiResponseSizeSummary = promauto.NewSummaryVec(
		prometheus.SummaryOpts{
			Name: "aptly_api_http_response_size_bytes",
			Help: "Api HTTP response size in bytes.",
		},
		[]string{"code", "method", "path"},
	)
	apiRequestsDurationSummary = promauto.NewSummaryVec(
		prometheus.SummaryOpts{
			Name: "aptly_api_http_request_duration_seconds",
			Help: "Duration of api requests in seconds.",
		},
		[]string{"code", "method", "path"},
	)
	apiVersionGauge = promauto.NewGaugeVec(
		prometheus.GaugeOpts{
			Name: "aptly_build_info",
			Help: "Metric with a constant '1' value labeled by version and goversion from which aptly was built.",
		},
		[]string{"version", "goversion"},
	)
	apiFilesUploadedCounter = promauto.NewCounterVec(
		prometheus.CounterOpts{
			Name: "aptly_api_files_uploaded_total",
			Help: "Total number of uploaded files labeled by upload directory.",
		},
		[]string{"directory"},
	)
	apiReposPackageCountGauge = promauto.NewGaugeVec(
		prometheus.GaugeOpts{
			Name: "aptly_repos_package_count",
			Help: "Current number of published packages labeled by source, distribution and component.",
		},
		[]string{"source", "distribution", "component"},
	)
)

type metricsCollectorRegistrar struct {
	hasRegistered bool
}

func (r *metricsCollectorRegistrar) Register(router *gin.Engine) {
	if !r.hasRegistered {
		apiVersionGauge.WithLabelValues(aptly.Version, runtime.Version()).Set(1)
		router.Use(instrumentHandlerInFlight(apiRequestsInFlightGauge, getBasePath))
		router.Use(instrumentHandlerCounter(apiRequestsTotalCounter, getBasePath))
		router.Use(instrumentHandlerRequestSize(apiRequestSizeSummary, getBasePath))
		router.Use(instrumentHandlerResponseSize(apiResponseSizeSummary, getBasePath))
		router.Use(instrumentHandlerDuration(apiRequestsDurationSummary, getBasePath))
		r.hasRegistered = true
	}
}

var MetricsCollectorRegistrar = metricsCollectorRegistrar{hasRegistered: false}

func countPackagesByRepos() {
	err := context.NewCollectionFactory().PublishedRepoCollection().ForEach(func(repo *deb.PublishedRepo) error {
		err := context.NewCollectionFactory().PublishedRepoCollection().LoadComplete(repo, context.NewCollectionFactory())
		if err != nil {
			msg := fmt.Sprintf(
				"Error %s found while determining package count for metrics endpoint (prefix:%s / distribution:%s / component:%s\n).",
				err, repo.StoragePrefix(), repo.Distribution, repo.Components())
			log.Warn().Msg(msg)
			return err
		}

		components := repo.Components()
		for _, c := range components {
			count := float64(len(repo.RefList(c).Refs))
			apiReposPackageCountGauge.WithLabelValues(fmt.Sprintf("%s", (repo.SourceNames())), repo.Distribution, c).Set(count)
		}

		return nil
	})

	if err != nil {
		msg := fmt.Sprintf("Error %s found while listing published repos for metrics endpoint", err)
		log.Warn().Msg(msg)
	}
}