package whisperx

import (
	"context"
	"encoding/json"
	"errors"
	"io"
	"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

	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)

		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")
	}
	verifyJSONFile(t, outPath)
}

func TestHTTPClientRetriesOnTransientAndSucceeds(t *testing.T) {
	var calls atomic.Int32
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		n := calls.Add(1)
		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())
	}
	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")
	}
}

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)
	}
}