package whisperx

import (
	"context"
	"encoding/json"
	"errors"
	"io"
	"mime/multipart"
	"net/http"
	"net/http/httptest"
	"os"
	"path/filepath"
	"strings"
	"sync/atomic"
	"testing"
	"time"
)

func TestHTTPClientTranscribeSuccess(t *testing.T) {
	var gotLanguage string
	var gotFileField string
	var gotFileSize int
	var gotFileData string

	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.Method != http.MethodPost {
			t.Fatalf("method = %s, want POST", r.Method)
		}
		if err := r.ParseMultipartForm(4 << 20); err != nil {
			t.Fatalf("ParseMultipartForm() error = %v", err)
		}

		gotLanguage = r.FormValue("language")
		file, fh, err := r.FormFile("file")
		if err != nil {
			t.Fatalf("FormFile(file) error = %v", err)
		}
		defer file.Close()
		gotFileField = fh.Filename
		data, err := io.ReadAll(file)
		if err != nil {
			t.Fatalf("ReadAll(file) error = %v", err)
		}
		gotFileSize = len(data)
		gotFileData = string(data)

		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(`{"schema":"speaker_transcript.v1","segments":[]}`))
	}))
	defer srv.Close()

	client, err := NewHTTPClientFromConfigValues(srv.URL, "en", "2s", "10ms", 0)
	if err != nil {
		t.Fatalf("NewHTTPClientFromConfigValues() error = %v", err)
	}

	audioPath := writeWhisperXTestFile(t, "audio.flac", "audio-data")
	outPath := filepath.Join(t.TempDir(), "raw.json")

	res, err := client.Transcribe(context.Background(), TranscribeRequest{
		SpeakerID:               "alice",
		AudioPath:               audioPath,
		OutputRawTranscriptPath: outPath,
	})
	if err != nil {
		t.Fatalf("Transcribe() error = %v", err)
	}
	if res.Attempts != 1 {
		t.Fatalf("Attempts = %d, want 1", res.Attempts)
	}
	if res.HTTPStatus != http.StatusOK {
		t.Fatalf("HTTPStatus = %d, want %d", res.HTTPStatus, http.StatusOK)
	}
	if gotLanguage != "en" {
		t.Fatalf("language = %q, want en", gotLanguage)
	}
	if gotFileField != "audio.flac" {
		t.Fatalf("file field filename = %q, want audio.flac", gotFileField)
	}
	if gotFileSize == 0 {
		t.Fatal("file size = 0, want >0")
	}
	if gotFileData != "audio-data" {
		t.Fatalf("file data = %q, want exact payload", gotFileData)
	}
	verifyJSONFile(t, outPath)
}

func TestHTTPClientRetriesOnTransientAndSucceeds(t *testing.T) {
	var calls atomic.Int32
	var payloads []string
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		n := calls.Add(1)
		file, _, err := r.FormFile("file")
		if err != nil {
			t.Fatalf("FormFile(file) error = %v", err)
		}
		data, err := io.ReadAll(file)
		_ = file.Close()
		if err != nil {
			t.Fatalf("ReadAll(file) error = %v", err)
		}
		payloads = append(payloads, string(data))
		if n == 1 {
			http.Error(w, "temporary", http.StatusInternalServerError)
			return
		}
		_, _ = w.Write([]byte(`{"ok":true}`))
	}))
	defer srv.Close()

	client, err := NewHTTPClientFromConfigValues(srv.URL, "en", "2s", "1ms", 2)
	if err != nil {
		t.Fatalf("NewHTTPClientFromConfigValues() error = %v", err)
	}

	audioPath := writeWhisperXTestFile(t, "audio.flac", "audio-data")
	outPath := filepath.Join(t.TempDir(), "raw.json")
	res, err := client.Transcribe(context.Background(), TranscribeRequest{
		AudioPath:               audioPath,
		OutputRawTranscriptPath: outPath,
	})
	if err != nil {
		t.Fatalf("Transcribe() error = %v", err)
	}
	if res.Attempts != 2 {
		t.Fatalf("Attempts = %d, want 2", res.Attempts)
	}
	if calls.Load() != 2 {
		t.Fatalf("calls = %d, want 2", calls.Load())
	}
	if len(payloads) != 2 || payloads[0] != "audio-data" || payloads[1] != "audio-data" {
		t.Fatalf("retry payloads = %#v, want two exact audio payloads", payloads)
	}
	verifyJSONFile(t, outPath)
}

func TestHTTPClientDoesNotRetryOnNonRetryableStatus(t *testing.T) {
	var calls atomic.Int32
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		calls.Add(1)
		http.Error(w, "bad request", http.StatusBadRequest)
	}))
	defer srv.Close()

	client, err := NewHTTPClientFromConfigValues(srv.URL, "en", "2s", "1ms", 3)
	if err != nil {
		t.Fatalf("NewHTTPClientFromConfigValues() error = %v", err)
	}

	audioPath := writeWhisperXTestFile(t, "audio.flac", "audio-data")
	outPath := filepath.Join(t.TempDir(), "raw.json")
	_, err = client.Transcribe(context.Background(), TranscribeRequest{
		AudioPath:               audioPath,
		OutputRawTranscriptPath: outPath,
	})
	if err == nil {
		t.Fatal("Transcribe() error = nil, want non-nil")
	}
	if calls.Load() != 1 {
		t.Fatalf("calls = %d, want 1", calls.Load())
	}
	if _, statErr := os.Stat(outPath); !errors.Is(statErr, os.ErrNotExist) {
		t.Fatalf("output should not exist, stat err = %v", statErr)
	}
}

func TestHTTPClientInvalidJSONFailsAndDoesNotInstallOutput(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		_, _ = w.Write([]byte(`not-json`))
	}))
	defer srv.Close()

	client, err := NewHTTPClientFromConfigValues(srv.URL, "en", "2s", "1ms", 0)
	if err != nil {
		t.Fatalf("NewHTTPClientFromConfigValues() error = %v", err)
	}

	audioPath := writeWhisperXTestFile(t, "audio.flac", "audio-data")
	outPath := filepath.Join(t.TempDir(), "raw.json")
	_, err = client.Transcribe(context.Background(), TranscribeRequest{
		AudioPath:               audioPath,
		OutputRawTranscriptPath: outPath,
	})
	if err == nil {
		t.Fatal("Transcribe() error = nil, want non-nil")
	}
	if !strings.Contains(strings.ToLower(err.Error()), "json") {
		t.Fatalf("error = %q, want json context", err.Error())
	}
	if _, statErr := os.Stat(outPath); !errors.Is(statErr, os.ErrNotExist) {
		t.Fatalf("output should not exist, stat err = %v", statErr)
	}
}

func TestHTTPClientTimeoutRetryDeterministic(t *testing.T) {
	var calls atomic.Int32
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		calls.Add(1)
		time.Sleep(150 * time.Millisecond)
		_, _ = w.Write([]byte(`{"ok":true}`))
	}))
	defer srv.Close()

	client, err := NewHTTPClientFromConfigValues(srv.URL, "en", "50ms", "1ms", 1)
	if err != nil {
		t.Fatalf("NewHTTPClientFromConfigValues() error = %v", err)
	}

	audioPath := writeWhisperXTestFile(t, "audio.flac", "audio-data")
	outPath := filepath.Join(t.TempDir(), "raw.json")
	res, err := client.Transcribe(context.Background(), TranscribeRequest{
		AudioPath:               audioPath,
		OutputRawTranscriptPath: outPath,
	})
	if err == nil {
		t.Fatal("Transcribe() error = nil, want timeout error")
	}
	if calls.Load() != 2 {
		t.Fatalf("calls = %d, want 2 attempts", calls.Load())
	}
	if res.Attempts != 2 {
		t.Fatalf("Attempts = %d, want 2", res.Attempts)
	}
}

func TestHTTPClientCancelDoesNotRetry(t *testing.T) {
	var calls atomic.Int32
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		calls.Add(1)
		time.Sleep(100 * time.Millisecond)
		_, _ = w.Write([]byte(`{"ok":true}`))
	}))
	defer srv.Close()

	client, err := NewHTTPClientFromConfigValues(srv.URL, "en", "2s", "1ms", 3)
	if err != nil {
		t.Fatalf("NewHTTPClientFromConfigValues() error = %v", err)
	}

	audioPath := writeWhisperXTestFile(t, "audio.flac", "audio-data")
	outPath := filepath.Join(t.TempDir(), "raw.json")
	ctx, cancel := context.WithCancel(context.Background())
	cancel()
	_, err = client.Transcribe(ctx, TranscribeRequest{
		AudioPath:               audioPath,
		OutputRawTranscriptPath: outPath,
	})
	if err == nil {
		t.Fatal("Transcribe() error = nil, want cancellation error")
	}
	if calls.Load() > 1 {
		t.Fatalf("calls = %d, want <= 1 when already canceled", calls.Load())
	}
}

func TestHTTPClientConstructorValidation(t *testing.T) {
	_, err := NewHTTPClientFromConfigValues("", "en", "30m", "2s", 1)
	if err == nil {
		t.Fatal("expected missing URL error")
	}
	_, err = NewHTTPClientFromConfigValues("https://example.com", "en", "bad", "2s", 1)
	if err == nil {
		t.Fatal("expected bad timeout error")
	}
	_, err = NewHTTPClientFromConfigValues("https://example.com", "en", "30m", "bad", 1)
	if err == nil {
		t.Fatal("expected bad retry_delay error")
	}
	for _, endpoint := range []string{"ftp://example.com/transcribe", "file:///tmp/transcribe", "//example.com/transcribe", "https:/missing-host"} {
		if _, err := NewHTTPClientFromConfigValues(endpoint, "en", "30m", "2s", 1); err == nil {
			t.Errorf("NewHTTPClientFromConfigValues(%q) error = nil, want endpoint validation error", endpoint)
		}
	}
	for _, endpoint := range []string{"http://example.com/transcribe", "https://example.com/transcribe"} {
		if _, err := NewHTTPClientFromConfigValues(endpoint, "en", "30m", "2s", 1); err != nil {
			t.Errorf("NewHTTPClientFromConfigValues(%q) error = %v", endpoint, err)
		}
	}
}

func TestHTTPClientStreamsUploadBeforeSourceCompletes(t *testing.T) {
	release := make(chan struct{})
	source := newGatedReadCloser([]byte("audio-data"), release)
	firstByteReceived := make(chan struct{})

	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		part := firstMultipartFilePart(t, r)
		buf := make([]byte, 1)
		if _, err := part.Read(buf); err != nil {
			t.Errorf("Read(file) error = %v", err)
			return
		}
		close(firstByteReceived)
		if _, err := io.Copy(io.Discard, part); err != nil {
			t.Errorf("discard remaining file data: %v", err)
			return
		}
		_, _ = w.Write([]byte(`{"ok":true}`))
	}))
	defer srv.Close()

	client := newTestHTTPClient(t, srv.URL)
	client.openAudio = func(string) (io.ReadCloser, error) { return source, nil }

	done := make(chan error, 1)
	go func() {
		_, err := client.Transcribe(context.Background(), TranscribeRequest{AudioPath: "audio.flac", OutputRawTranscriptPath: filepath.Join(t.TempDir(), "raw.json")})
		done <- err
	}()

	select {
	case <-firstByteReceived:
		close(release)
	case <-time.After(time.Second):
		t.Fatal("server did not receive streamed audio before source completed")
	}
	if err := <-done; err != nil {
		t.Fatalf("Transcribe() error = %v", err)
	}
}

func TestHTTPClientSourceReadFailureReachesCaller(t *testing.T) {
	sourceErr := errors.New("source read failed")
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		_, _ = io.Copy(io.Discard, r.Body)
	}))
	defer srv.Close()

	client := newTestHTTPClient(t, srv.URL)
	client.openAudio = func(string) (io.ReadCloser, error) {
		return &failingReadCloser{first: []byte("partial"), err: sourceErr}, nil
	}

	_, err := client.Transcribe(context.Background(), TranscribeRequest{AudioPath: "audio.flac", OutputRawTranscriptPath: filepath.Join(t.TempDir(), "raw.json")})
	if !errors.Is(err, sourceErr) {
		t.Fatalf("Transcribe() error = %v, want source read failure", err)
	}
}

func TestHTTPClientEarlyServerResponseReleasesBlockedProducer(t *testing.T) {
	release := make(chan struct{})
	source := newGatedReadCloser([]byte("audio-data"), release)
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		http.Error(w, "bad request", http.StatusBadRequest)
	}))
	defer srv.Close()

	client := newTestHTTPClient(t, srv.URL)
	client.openAudio = func(string) (io.ReadCloser, error) { return source, nil }

	done := make(chan error, 1)
	go func() {
		_, err := client.Transcribe(context.Background(), TranscribeRequest{AudioPath: "audio.flac", OutputRawTranscriptPath: filepath.Join(t.TempDir(), "raw.json")})
		done <- err
	}()

	select {
	case err := <-done:
		if err == nil {
			t.Fatal("Transcribe() error = nil, want HTTP status error")
		}
	case <-time.After(time.Second):
		t.Fatal("Transcribe() did not finish after server closed the request early")
	}
	select {
	case <-source.closed:
	case <-time.After(time.Second):
		t.Fatal("blocked audio source was not closed")
	}
}

func TestHTTPClientCancellationReleasesBlockedProducer(t *testing.T) {
	release := make(chan struct{})
	source := newGatedReadCloser([]byte("audio-data"), release)
	firstByteReceived := make(chan struct{})
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		part := firstMultipartFilePart(t, r)
		buf := make([]byte, 1)
		if _, err := part.Read(buf); err != nil {
			t.Errorf("Read(file) error = %v", err)
			return
		}
		close(firstByteReceived)
		<-r.Context().Done()
	}))
	defer srv.Close()

	client := newTestHTTPClient(t, srv.URL)
	client.openAudio = func(string) (io.ReadCloser, error) { return source, nil }
	ctx, cancel := context.WithCancel(context.Background())
	done := make(chan error, 1)
	go func() {
		_, err := client.Transcribe(ctx, TranscribeRequest{AudioPath: "audio.flac", OutputRawTranscriptPath: filepath.Join(t.TempDir(), "raw.json")})
		done <- err
	}()

	select {
	case <-firstByteReceived:
		cancel()
	case <-time.After(time.Second):
		cancel()
		t.Fatal("server did not receive initial streamed audio")
	}
	select {
	case err := <-done:
		if !errors.Is(err, context.Canceled) {
			t.Fatalf("Transcribe() error = %v, want context cancellation", err)
		}
	case <-time.After(time.Second):
		t.Fatal("Transcribe() did not finish after cancellation")
	}
	select {
	case <-source.closed:
	case <-time.After(time.Second):
		t.Fatal("blocked audio source was not closed on cancellation")
	}
}

func TestHTTPClientBoundsWhisperXResponse(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		_, _ = io.Copy(io.Discard, r.Body)
		_, _ = w.Write([]byte(`{"ok":true}`))
	}))
	defer srv.Close()

	client, err := NewHTTPClient(HTTPClientConfig{TranscribeURL: srv.URL, Language: "en", Timeout: time.Second, MaxResponseBytes: 4})
	if err != nil {
		t.Fatalf("NewHTTPClient() error = %v", err)
	}
	audioPath := writeWhisperXTestFile(t, "audio.flac", "audio-data")
	_, err = client.Transcribe(context.Background(), TranscribeRequest{AudioPath: audioPath, OutputRawTranscriptPath: filepath.Join(t.TempDir(), "raw.json")})
	if err == nil || !strings.Contains(err.Error(), "whisperx response exceeds configured limit") {
		t.Fatalf("Transcribe() error = %v, want bounded WhisperX response error", err)
	}
}

func newTestHTTPClient(t *testing.T, endpoint string) *HTTPClient {
	t.Helper()
	client, err := NewHTTPClientFromConfigValues(endpoint, "en", "2s", "1ms", 0)
	if err != nil {
		t.Fatalf("NewHTTPClientFromConfigValues() error = %v", err)
	}
	return client
}

func firstMultipartFilePart(t *testing.T, r *http.Request) *multipart.Part {
	t.Helper()
	reader, err := r.MultipartReader()
	if err != nil {
		t.Fatalf("MultipartReader() error = %v", err)
	}
	part, err := reader.NextPart()
	if err != nil {
		t.Fatalf("NextPart() error = %v", err)
	}
	if part.FormName() != "file" {
		t.Fatalf("first form field = %q, want file", part.FormName())
	}
	return part
}

type gatedReadCloser struct {
	first   []byte
	release <-chan struct{}
	closed  chan struct{}
	sent    bool
	once    atomic.Bool
}

func newGatedReadCloser(first []byte, release <-chan struct{}) *gatedReadCloser {
	return &gatedReadCloser{first: first, release: release, closed: make(chan struct{})}
}

func (r *gatedReadCloser) Read(p []byte) (int, error) {
	if !r.sent {
		r.sent = true
		return copy(p, r.first), nil
	}
	select {
	case <-r.release:
		return 0, io.EOF
	case <-r.closed:
		return 0, errors.New("audio source closed")
	}
}

func (r *gatedReadCloser) Close() error {
	if r.once.CompareAndSwap(false, true) {
		close(r.closed)
	}
	return nil
}

type failingReadCloser struct {
	first []byte
	err   error
	sent  bool
}

func (r *failingReadCloser) Read(p []byte) (int, error) {
	if !r.sent {
		r.sent = true
		return copy(p, r.first), nil
	}
	return 0, r.err
}

func (r *failingReadCloser) Close() error { return nil }

func writeWhisperXTestFile(t *testing.T, name, contents string) string {
	t.Helper()
	path := filepath.Join(t.TempDir(), name)
	if err := os.WriteFile(path, []byte(contents), 0o644); err != nil {
		t.Fatalf("WriteFile(%q) error = %v", path, err)
	}
	return path
}

func verifyJSONFile(t *testing.T, path string) {
	t.Helper()
	data, err := os.ReadFile(path)
	if err != nil {
		t.Fatalf("ReadFile(%q) error = %v", path, err)
	}
	var v any
	if err := json.Unmarshal(data, &v); err != nil {
		t.Fatalf("json unmarshal output %q: %v", path, err)
	}
}