package playback

import (
	"errors"
	"sync"
	"testing"
)

func TestStatusStoreSnapshotUnknownUnit(t *testing.T) {
	store := NewStatusStore()

	status, ok := store.Snapshot(UnitVideo)
	if ok {
		t.Fatalf("Snapshot() = %#v, true; want false", status)
	}
}

func TestStatusStoreKeepsUnitsIndependent(t *testing.T) {
	store := NewStatusStore()
	wantVideo := Status{
		Unit:           UnitVideo,
		State:          StateReconnecting,
		Attempt:        3,
		FailedAttempts: 2,
		Err:            errors.New("video unavailable"),
	}
	wantAudio := Status{
		Unit:    UnitAudio,
		State:   StatePlaying,
		Attempt: 1,
	}

	store.Observe(wantVideo)
	store.Observe(wantAudio)

	if got, ok := store.Snapshot(UnitVideo); !ok || got != wantVideo {
		t.Fatalf("video Snapshot() = %#v, %t; want %#v, true", got, ok, wantVideo)
	}
	if got, ok := store.Snapshot(UnitAudio); !ok || got != wantAudio {
		t.Fatalf("audio Snapshot() = %#v, %t; want %#v, true", got, ok, wantAudio)
	}
}

func TestStatusStoreObserveReplacesLatestStatus(t *testing.T) {
	store := NewStatusStore()
	store.Observe(Status{Unit: UnitVideo, State: StateConnecting, Attempt: 1})
	want := Status{Unit: UnitVideo, State: StatePlaying, Attempt: 2}
	store.Observe(want)

	got, ok := store.Snapshot(UnitVideo)
	if !ok || got != want {
		t.Fatalf("Snapshot() = %#v, %t; want %#v, true", got, ok, want)
	}
}

func TestStatusStoreClearOnlySelectedUnit(t *testing.T) {
	store := NewStatusStore()
	wantAudio := Status{Unit: UnitAudio, State: StatePlaying}
	store.Observe(Status{Unit: UnitVideo, State: StatePlaying})
	store.Observe(wantAudio)

	store.Clear(UnitVideo)

	if status, ok := store.Snapshot(UnitVideo); ok {
		t.Fatalf("video Snapshot() = %#v, true after Clear", status)
	}
	if got, ok := store.Snapshot(UnitAudio); !ok || got != wantAudio {
		t.Fatalf("audio Snapshot() = %#v, %t; want %#v, true", got, ok, wantAudio)
	}
}

func TestStatusStoreConcurrentAccess(t *testing.T) {
	store := NewStatusStore()
	const iterations = 1000

	var writers sync.WaitGroup
	for _, unit := range []Unit{UnitVideo, UnitAudio, UnitSync} {
		unit := unit
		writers.Add(1)
		go func() {
			defer writers.Done()
			for attempt := 1; attempt <= iterations; attempt++ {
				store.Observe(Status{
					Unit:    unit,
					State:   StatePlaying,
					Attempt: attempt,
				})
				store.Snapshot(unit)
			}
		}()
	}
	writers.Wait()

	for _, unit := range []Unit{UnitVideo, UnitAudio, UnitSync} {
		status, ok := store.Snapshot(unit)
		if !ok {
			t.Fatalf("Snapshot(%v) not found", unit)
		}
		if status.Attempt != iterations {
			t.Fatalf(
				"Snapshot(%v) attempt = %d, want %d",
				unit,
				status.Attempt,
				iterations,
			)
		}
	}
}

func TestStatusStoreNewGenerationClearsPreviousUnits(t *testing.T) {
	store := NewStatusStore()
	store.Observe(Status{Unit: UnitVideo, State: StatePlaying, Generation: 1})
	store.Observe(Status{Unit: UnitAudio, State: StatePlaying, Generation: 1})
	want := Status{Unit: UnitSync, State: StateConnecting, Generation: 2}
	store.Observe(want)

	if _, ok := store.Snapshot(UnitVideo); ok {
		t.Fatal("video status survived generation change")
	}
	if _, ok := store.Snapshot(UnitAudio); ok {
		t.Fatal("audio status survived generation change")
	}
	if got, ok := store.Snapshot(UnitSync); !ok || got != want {
		t.Fatalf("sync Snapshot() = %#v, %t; want %#v, true", got, ok, want)
	}
}

func TestStatusStoreIgnoresOlderGeneration(t *testing.T) {
	store := NewStatusStore()
	want := Status{Unit: UnitSync, State: StatePlaying, Generation: 3}
	store.Observe(want)
	store.Observe(Status{Unit: UnitVideo, State: StateIdle, Generation: 2})

	if _, ok := store.Snapshot(UnitVideo); ok {
		t.Fatal("older video status was stored")
	}
	if got, ok := store.Snapshot(UnitSync); !ok || got != want {
		t.Fatalf("sync Snapshot() = %#v, %t; want %#v, true", got, ok, want)
	}
}

func TestStatusStoreKeepsEqualGenerationUnitsIndependent(t *testing.T) {
	store := NewStatusStore()
	wantVideo := Status{Unit: UnitVideo, State: StatePlaying, Generation: 4}
	wantAudio := Status{Unit: UnitAudio, State: StateReconnecting, Generation: 4}
	store.Observe(wantVideo)
	store.Observe(wantAudio)

	if got, ok := store.Snapshot(UnitVideo); !ok || got != wantVideo {
		t.Fatalf("video Snapshot() = %#v, %t", got, ok)
	}
	if got, ok := store.Snapshot(UnitAudio); !ok || got != wantAudio {
		t.Fatalf("audio Snapshot() = %#v, %t", got, ok)
	}
}

func TestStatusStoreSnapshotAll(t *testing.T) {
	store := NewStatusStore()
	wantVideo := Status{Unit: UnitVideo, State: StatePlaying, Generation: 5}
	wantAudio := Status{Unit: UnitAudio, State: StateReconnecting, Generation: 5}
	store.Observe(wantVideo)
	store.Observe(wantAudio)

	got := store.SnapshotAll()
	if got.Generation != 5 {
		t.Fatalf("SnapshotAll() generation = %d, want 5", got.Generation)
	}
	if !got.HasVideo || got.Video != wantVideo {
		t.Fatalf("SnapshotAll() video = %#v, %v; want %#v, true", got.Video, got.HasVideo, wantVideo)
	}
	if !got.HasAudio || got.Audio != wantAudio {
		t.Fatalf("SnapshotAll() audio = %#v, %v; want %#v, true", got.Audio, got.HasAudio, wantAudio)
	}
	if got.HasSync {
		t.Fatalf("SnapshotAll() HasSync = true, want false")
	}
}

func TestStatusStoreSnapshotAllClearsOldGenerationUnits(t *testing.T) {
	store := NewStatusStore()
	store.Observe(Status{Unit: UnitVideo, State: StatePlaying, Generation: 2})
	store.Observe(Status{Unit: UnitAudio, State: StatePlaying, Generation: 2})
	wantSync := Status{Unit: UnitSync, State: StateConnecting, Generation: 3}
	store.Observe(wantSync)

	got := store.SnapshotAll()
	if got.Generation != 3 {
		t.Fatalf("SnapshotAll() generation = %d, want 3", got.Generation)
	}
	if got.HasVideo || got.HasAudio {
		t.Fatalf("SnapshotAll() retained old units: %#v", got)
	}
	if !got.HasSync || got.Sync != wantSync {
		t.Fatalf("SnapshotAll() sync = %#v, %v; want %#v, true", got.Sync, got.HasSync, wantSync)
	}
}

func TestStatusStoreSnapshotAllConcurrentObserve(t *testing.T) {
	store := NewStatusStore()
	done := make(chan struct{})
	go func() {
		defer close(done)
		for generation := uint64(1); generation <= 1000; generation++ {
			store.Observe(Status{
				Unit:       Unit(generation % 3),
				State:      StatePlaying,
				Generation: generation,
			})
		}
	}()

	for {
		select {
		case <-done:
			_ = store.SnapshotAll()
			return
		default:
			_ = store.SnapshotAll()
		}
	}
}