// Copyright (c) 2026 Storm Dragon
// SPDX-License-Identifier: GPL-3.0-or-later

package sound

import (
	"context"
	"errors"
	"math"
	"sync"
	"sync/atomic"
	"syscall"
	"testing"
	"time"

	"git.stormux.org/storm/fenrir/internal/presentation"
)

type fakeBackend struct {
	errors chan error
	closed chan struct{}
	once   sync.Once
	plays  atomic.Int32
	volume atomic.Uint64
}

func fake_backend() *fakeBackend {
	return &fakeBackend{errors: make(chan error, 1), closed: make(chan struct{})}
}
func (f *fakeBackend) Play(presentation.Cue) bool                        { f.plays.Add(1); return true }
func (f *fakeBackend) Play_wait(context.Context, presentation.Cue) error { f.plays.Add(1); return nil }
func (f *fakeBackend) Play_progress(float64) bool                        { return true }
func (f *fakeBackend) Play_indentation(int) bool                         { return true }
func (f *fakeBackend) Discard_progress()                                 {}
func (f *fakeBackend) Clear_progress()                                   {}
func (f *fakeBackend) Set_volume(volume float64)                         { f.volume.Store(math.Float64bits(volume)) }
func (f *fakeBackend) Errors() <-chan error                              { return f.errors }
func (f *fakeBackend) Finish(context.Context) error                      { return nil }
func (f *fakeBackend) Close()                                            { f.once.Do(func() { close(f.closed) }) }

func wait_player(t *testing.T, player *Player, backend *fakeBackend) {
	t.Helper()
	deadline := time.NewTimer(time.Second)
	defer deadline.Stop()
	tick := time.NewTicker(time.Millisecond)
	defer tick.Stop()
	for {
		if connection := player.connection.Load(); connection != nil && connection.backend == backend && math.Float64frombits(backend.volume.Load()) == math.Float64frombits(player.volume.Load()) {
			return
		}
		select {
		case <-deadline.C:
			t.Fatal("sound connection did not recover")
		case <-tick.C:
		}
	}
}

func TestSoundPlayerRecoversStartupAndDisconnectWithoutReplayingCues(t *testing.T) {
	first, second := fake_backend(), fake_backend()
	firstGate, secondGate := make(chan struct{}), make(chan struct{})
	attempts := make(chan int, 8)
	count := 0
	player := new_player(context.Background(), 0.7, func() (soundBackend, error) {
		count++
		attempts <- count
		switch count {
		case 1:
			// A completed library request timeout is safe to retry. It is
			// distinct from an opener that is still running after our deadline.
			return nil, context.DeadlineExceeded
		case 2:
			<-firstGate
			return first, nil
		default:
			<-secondGate
			return second, nil
		}
	})
	defer player.Close()
	<-attempts
	<-attempts
	if player.Play(presentation.Ready) || player.Play_progress(50) || player.Play_indentation(2) {
		t.Fatal("offline sound suppressed speech fallback")
	}
	player.Set_volume(0.4)
	close(firstGate)
	wait_player(t, player, first)
	if !player.Play(presentation.Ready) {
		t.Fatal("recovered sound rejected cue")
	}
	first.errors <- errors.New("server disconnected")
	<-attempts
	if player.Play(presentation.Error) {
		t.Fatal("disconnected sound accepted stale cue")
	}
	player.Set_volume(0.2)
	close(secondGate)
	wait_player(t, player, second)
	if second.plays.Load() != 0 || first.plays.Load() != 1 {
		t.Fatal("recovery replayed old cues", first.plays.Load(), second.plays.Load())
	}
	select {
	case <-first.closed:
	default:
		t.Fatal("old sound connection leaked")
	}
}

func TestUnresponsiveSoundAttemptIsCancelledAndLateResultClosed(t *testing.T) {
	gate := make(chan struct{})
	backend := fake_backend()
	ctx, cancel := context.WithTimeout(context.Background(), 20*time.Millisecond)
	defer cancel()
	started := time.Now()
	got, err := sound_attempt(ctx, func() (soundBackend, error) { <-gate; return backend, nil })
	if got != nil || !errors.Is(err, context.DeadlineExceeded) || time.Since(started) > time.Second {
		t.Fatal("sound attempt blocked caller", got, err)
	}
	close(gate)
	select {
	case <-backend.closed:
	case <-time.After(time.Second):
		t.Fatal("late sound result leaked")
	}
	attempts := 0
	player := new_player(context.Background(), 0.7, func() (soundBackend, error) {
		attempts++
		return nil, errors.Join(errSoundAttemptStalled, context.DeadlineExceeded)
	})
	defer player.Close()
	select {
	case <-player.Errors():
	case <-time.After(time.Second):
		t.Fatal("unresponsive attempt was retried")
	}
	if attempts != 1 {
		t.Fatal("overlapping sound opener calls", attempts)
	}
}

func TestSoundPlayerCloseDoesNotWaitForHungReconnect(t *testing.T) {
	backend := fake_backend()
	gate, entered := make(chan struct{}), make(chan struct{})
	attempts := 0
	player := new_player(context.Background(), 0.7, func() (soundBackend, error) {
		attempts++
		if attempts == 1 {
			return nil, syscall.ENOENT
		}
		close(entered)
		<-gate
		return backend, nil
	})
	<-entered
	closed := make(chan struct{})
	go func() { player.Close(); close(closed) }()
	select {
	case <-closed:
	case <-time.After(time.Second):
		t.Fatal("shutdown waited for hung sound server")
	}
	close(gate)
	select {
	case <-backend.closed:
	case <-time.After(time.Second):
		t.Fatal("late sound connection leaked")
	}
}