package runner_test

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

	"github.com/libnovel/backend/internal/domain"
	"github.com/libnovel/backend/internal/runner"
)

// ── Stub types ────────────────────────────────────────────────────────────────

// stubConsumer is a test double for taskqueue.Consumer.
type stubConsumer struct {
	scrapeQueue []domain.ScrapeTask
	audioQueue  []domain.AudioTask
	scrapeIdx   int
	audioIdx    int
	finished    []string
	failCalled  []string
	claimErr    error
}

func (s *stubConsumer) ClaimNextScrapeTask(_ context.Context, _ string) (domain.ScrapeTask, bool, error) {
	if s.claimErr != nil {
		return domain.ScrapeTask{}, false, s.claimErr
	}
	if s.scrapeIdx >= len(s.scrapeQueue) {
		return domain.ScrapeTask{}, false, nil
	}
	t := s.scrapeQueue[s.scrapeIdx]
	s.scrapeIdx++
	return t, true, nil
}

func (s *stubConsumer) ClaimNextAudioTask(_ context.Context, _ string) (domain.AudioTask, bool, error) {
	if s.claimErr != nil {
		return domain.AudioTask{}, false, s.claimErr
	}
	if s.audioIdx >= len(s.audioQueue) {
		return domain.AudioTask{}, false, nil
	}
	t := s.audioQueue[s.audioIdx]
	s.audioIdx++
	return t, true, nil
}

func (s *stubConsumer) FinishScrapeTask(_ context.Context, id string, _ domain.ScrapeResult) error {
	s.finished = append(s.finished, id)
	return nil
}

func (s *stubConsumer) FinishAudioTask(_ context.Context, id string, _ domain.AudioResult) error {
	s.finished = append(s.finished, id)
	return nil
}

func (s *stubConsumer) FailTask(_ context.Context, id, _ string) error {
	s.failCalled = append(s.failCalled, id)
	return nil
}

func (s *stubConsumer) HeartbeatTask(_ context.Context, _ string) error { return nil }

func (s *stubConsumer) ReapStaleTasks(_ context.Context, _ time.Duration) (int, error) {
	return 0, nil
}

// stubBookWriter satisfies bookstore.BookWriter (no-op).
type stubBookWriter struct{}

func (s *stubBookWriter) WriteMetadata(_ context.Context, _ domain.BookMeta) error { return nil }
func (s *stubBookWriter) WriteChapter(_ context.Context, _ string, _ domain.Chapter) error {
	return nil
}
func (s *stubBookWriter) WriteChapterRefs(_ context.Context, _ string, _ []domain.ChapterRef) error {
	return nil
}
func (s *stubBookWriter) ChapterExists(_ context.Context, _ string, _ domain.ChapterRef) bool {
	return false
}

// stubBookReader satisfies bookstore.BookReader — returns a single chapter.
type stubBookReader struct {
	text    string
	readErr error
}

func (s *stubBookReader) ReadChapter(_ context.Context, _ string, _ int) (string, error) {
	return s.text, s.readErr
}
func (s *stubBookReader) ReadMetadata(_ context.Context, _ string) (domain.BookMeta, bool, error) {
	return domain.BookMeta{}, false, nil
}
func (s *stubBookReader) ListBooks(_ context.Context) ([]domain.BookMeta, error) { return nil, nil }
func (s *stubBookReader) LocalSlugs(_ context.Context) (map[string]bool, error)  { return nil, nil }
func (s *stubBookReader) MetadataMtime(_ context.Context, _ string) int64        { return 0 }
func (s *stubBookReader) ListChapters(_ context.Context, _ string) ([]domain.ChapterInfo, error) {
	return nil, nil
}
func (s *stubBookReader) CountChapters(_ context.Context, _ string) int { return 0 }
func (s *stubBookReader) ReindexChapters(_ context.Context, _ string) (int, error) {
	return 0, nil
}

// stubAudioStore satisfies bookstore.AudioStore.
type stubAudioStore struct {
	putCalled atomic.Int32
	putErr    error
}

func (s *stubAudioStore) AudioObjectKey(slug string, n int, voice string) string {
	return slug + "/" + string(rune('0'+n)) + "/" + voice + ".mp3"
}
func (s *stubAudioStore) AudioExists(_ context.Context, _ string) bool { return false }
func (s *stubAudioStore) PutAudio(_ context.Context, _ string, _ []byte) error {
	s.putCalled.Add(1)
	return s.putErr
}

// stubNovelScraper satisfies scraper.NovelScraper minimally.
type stubNovelScraper struct {
	entries  []domain.CatalogueEntry
	metaErr  error
	chapters []domain.ChapterRef
}

func (s *stubNovelScraper) ScrapeCatalogue(_ context.Context) (<-chan domain.CatalogueEntry, <-chan error) {
	ch := make(chan domain.CatalogueEntry, len(s.entries))
	errCh := make(chan error, 1)
	for _, e := range s.entries {
		ch <- e
	}
	close(ch)
	close(errCh)
	return ch, errCh
}

func (s *stubNovelScraper) ScrapeMetadata(_ context.Context, _ string) (domain.BookMeta, error) {
	if s.metaErr != nil {
		return domain.BookMeta{}, s.metaErr
	}
	return domain.BookMeta{Slug: "test-book", Title: "Test Book", SourceURL: "https://example.com/book/test-book"}, nil
}

func (s *stubNovelScraper) ScrapeChapterList(_ context.Context, _ string) ([]domain.ChapterRef, error) {
	return s.chapters, nil
}

func (s *stubNovelScraper) ScrapeChapterText(_ context.Context, ref domain.ChapterRef) (domain.Chapter, error) {
	return domain.Chapter{Ref: ref, Text: "# Chapter\n\nSome text."}, nil
}

func (s *stubNovelScraper) ScrapeRanking(_ context.Context, _ int) (<-chan domain.BookMeta, <-chan error) {
	ch := make(chan domain.BookMeta)
	errCh := make(chan error, 1)
	close(ch)
	close(errCh)
	return ch, errCh
}

func (s *stubNovelScraper) SourceName() string { return "stub" }

// stubKokoro satisfies kokoro.Client.
type stubKokoro struct {
	data   []byte
	genErr error
	called atomic.Int32
}

func (s *stubKokoro) GenerateAudio(_ context.Context, _, _ string) ([]byte, error) {
	s.called.Add(1)
	return s.data, s.genErr
}

func (s *stubKokoro) ListVoices(_ context.Context) ([]string, error) {
	return []string{"af_bella"}, nil
}

// ── stripMarkdown helper ──────────────────────────────────────────────────────

func TestStripMarkdownViaAudioTask(t *testing.T) {
	// Verify markdown is stripped before sending to Kokoro.
	// We inject chapter text with markdown; the kokoro stub verifies data flows.
	consumer := &stubConsumer{
		audioQueue: []domain.AudioTask{
			{ID: "a1", Slug: "book", Chapter: 1, Voice: "af_bella", Status: domain.TaskStatusRunning},
		},
	}
	bookReader := &stubBookReader{text: "## Chapter 1\n\nPlain **text** here."}
	audioStore := &stubAudioStore{}
	kokoroStub := &stubKokoro{data: []byte("mp3")}

	cfg := runner.Config{
		WorkerID:     "test",
		PollInterval: time.Hour, // long poll — we'll cancel manually
	}
	deps := runner.Dependencies{
		Consumer:   consumer,
		BookWriter: &stubBookWriter{},
		BookReader: bookReader,
		AudioStore: audioStore,
		Novel:      &stubNovelScraper{},
		Kokoro:     kokoroStub,
	}

	r := runner.New(cfg, deps)
	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
	defer cancel()
	_ = r.Run(ctx)

	if kokoroStub.called.Load() != 1 {
		t.Errorf("expected Kokoro.GenerateAudio called once, got %d", kokoroStub.called.Load())
	}
	if audioStore.putCalled.Load() != 1 {
		t.Errorf("expected PutAudio called once, got %d", audioStore.putCalled.Load())
	}
}

func TestAudioTask_ReadChapterError(t *testing.T) {
	consumer := &stubConsumer{
		audioQueue: []domain.AudioTask{
			{ID: "a2", Slug: "book", Chapter: 2, Voice: "af_bella", Status: domain.TaskStatusRunning},
		},
	}
	bookReader := &stubBookReader{readErr: errors.New("chapter not found")}
	audioStore := &stubAudioStore{}
	kokoroStub := &stubKokoro{data: []byte("mp3")}

	cfg := runner.Config{WorkerID: "test", PollInterval: time.Hour}
	deps := runner.Dependencies{
		Consumer:   consumer,
		BookWriter: &stubBookWriter{},
		BookReader: bookReader,
		AudioStore: audioStore,
		Novel:      &stubNovelScraper{},
		Kokoro:     kokoroStub,
	}

	r := runner.New(cfg, deps)
	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
	defer cancel()
	_ = r.Run(ctx)

	// Kokoro should not be called; FinishAudioTask should be called with error.
	if kokoroStub.called.Load() != 0 {
		t.Errorf("expected Kokoro not called, got %d", kokoroStub.called.Load())
	}
	if len(consumer.finished) != 1 {
		t.Errorf("expected FinishAudioTask called once, got %d", len(consumer.finished))
	}
}

func TestAudioTask_KokoroError(t *testing.T) {
	consumer := &stubConsumer{
		audioQueue: []domain.AudioTask{
			{ID: "a3", Slug: "book", Chapter: 3, Voice: "af_bella", Status: domain.TaskStatusRunning},
		},
	}
	bookReader := &stubBookReader{text: "Chapter text."}
	audioStore := &stubAudioStore{}
	kokoroStub := &stubKokoro{genErr: errors.New("tts failed")}

	cfg := runner.Config{WorkerID: "test", PollInterval: time.Hour}
	deps := runner.Dependencies{
		Consumer:   consumer,
		BookWriter: &stubBookWriter{},
		BookReader: bookReader,
		AudioStore: audioStore,
		Novel:      &stubNovelScraper{},
		Kokoro:     kokoroStub,
	}

	r := runner.New(cfg, deps)
	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
	defer cancel()
	_ = r.Run(ctx)

	if audioStore.putCalled.Load() != 0 {
		t.Errorf("expected PutAudio not called, got %d", audioStore.putCalled.Load())
	}
	if len(consumer.finished) != 1 {
		t.Errorf("expected FinishAudioTask called once, got %d", len(consumer.finished))
	}
}

func TestScrapeTask_BookKind(t *testing.T) {
	consumer := &stubConsumer{
		scrapeQueue: []domain.ScrapeTask{
			{ID: "s1", Kind: "book", TargetURL: "https://example.com/book/test-book", Status: domain.TaskStatusRunning},
		},
	}

	cfg := runner.Config{WorkerID: "test", PollInterval: time.Hour}
	deps := runner.Dependencies{
		Consumer:   consumer,
		BookWriter: &stubBookWriter{},
		BookReader: &stubBookReader{},
		AudioStore: &stubAudioStore{},
		Novel:      &stubNovelScraper{},
		Kokoro:     &stubKokoro{},
	}

	r := runner.New(cfg, deps)
	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
	defer cancel()
	_ = r.Run(ctx)

	if len(consumer.finished) != 1 || consumer.finished[0] != "s1" {
		t.Errorf("expected task s1 finished, got %v", consumer.finished)
	}
}

func TestScrapeTask_UnknownKind(t *testing.T) {
	consumer := &stubConsumer{
		scrapeQueue: []domain.ScrapeTask{
			{ID: "s2", Kind: "unknown_kind", Status: domain.TaskStatusRunning},
		},
	}

	cfg := runner.Config{WorkerID: "test", PollInterval: time.Hour}
	deps := runner.Dependencies{
		Consumer:   consumer,
		BookWriter: &stubBookWriter{},
		BookReader: &stubBookReader{},
		AudioStore: &stubAudioStore{},
		Novel:      &stubNovelScraper{},
		Kokoro:     &stubKokoro{},
	}

	r := runner.New(cfg, deps)
	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
	defer cancel()
	_ = r.Run(ctx)

	// Unknown kind still finishes the task (with error message in result).
	if len(consumer.finished) != 1 || consumer.finished[0] != "s2" {
		t.Errorf("expected task s2 finished, got %v", consumer.finished)
	}
}

func TestRun_CancelImmediately(t *testing.T) {
	consumer := &stubConsumer{}
	cfg := runner.Config{WorkerID: "test", PollInterval: 10 * time.Millisecond}
	deps := runner.Dependencies{
		Consumer:   consumer,
		BookWriter: &stubBookWriter{},
		BookReader: &stubBookReader{},
		AudioStore: &stubAudioStore{},
		Novel:      &stubNovelScraper{},
		Kokoro:     &stubKokoro{},
	}

	r := runner.New(cfg, deps)
	ctx, cancel := context.WithCancel(context.Background())
	cancel() // cancel before Run

	err := r.Run(ctx)
	if err != nil {
		t.Errorf("expected nil on graceful shutdown, got %v", err)
	}
}