package metrics

import (
	"github.com/prometheus/client_golang/prometheus"
	"github.com/prometheus/client_golang/prometheus/promauto"
)

// MusicServer's own metrics. Labels only take values from small fixed sets: never song
// names, IDs, tokens or IPs, since every value creates a new time series.
var (
	// SongsRequested counts random songs handed out, by how they were picked.
	SongsRequested = promauto.NewCounterVec(prometheus.CounterOpts{
		Name: "musicserver_songs_requested_total",
		Help: "Random songs handed out, by how they were picked (random, low, classic).",
	}, []string{"mode"})

	// SongsPlayed counts songs marked as played, by how they were picked.
	SongsPlayed = promauto.NewCounterVec(prometheus.CounterOpts{
		Name: "musicserver_songs_played_total",
		Help: "Songs marked as played, by how they were picked (random, low, classic).",
	}, []string{"mode"})

	// LibrarySoundtracks is the number of soundtracks in the library.
	LibrarySoundtracks = promauto.NewGauge(prometheus.GaugeOpts{
		Name: "musicserver_library_soundtracks",
		Help: "Soundtracks in the library, counted at startup and after each sync.",
	})

	// LibrarySongs is the number of songs in the library.
	LibrarySongs = promauto.NewGauge(prometheus.GaugeOpts{
		Name: "musicserver_library_songs",
		Help: "Songs in the library, counted at startup and after each sync.",
	})

	// SyncDuration is how long syncs take, by type.
	SyncDuration = promauto.NewHistogramVec(prometheus.HistogramOpts{
		Name:    "musicserver_sync_duration_seconds",
		Help:    "How long a sync took, by type (full, changes).",
		Buckets: []float64{1, 5, 10, 30, 60, 120, 300, 600, 1200, 1800, 3600},
	}, []string{"type"})

	// SyncLastSuccess is when the last sync without errors finished.
	SyncLastSuccess = promauto.NewGauge(prometheus.GaugeOpts{
		Name: "musicserver_sync_last_success_timestamp_seconds",
		Help: "Unix time when the last sync without errors finished.",
	})

	// BrokenSongs is the number of songs the last full sync found missing and removed.
	BrokenSongs = promauto.NewGauge(prometheus.GaugeOpts{
		Name: "musicserver_broken_songs",
		Help: "Songs whose file was missing in the last full sync. They are removed from the library.",
	})
)