package stt

import (
	"context"
	"errors"
	"io"
	"net/http"
	"net/http/httptest"
	"strconv"
	"strings"
	"testing"
	"time"

	"github.com/kami/maven/internal/audio"
)

func TestHTTPTranscriberSendsRawPCM(t *testing.T) {
	t.Parallel()
	var gotBody []byte
	var gotHeader http.Header
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		gotBody, _ = io.ReadAll(r.Body)
		gotHeader = r.Header.Clone()
		w.Header().Set("Content-Type", "application/json")
		_, _ = io.WriteString(w, `{"text":"привет","confidence":0.82}`)
	}))
	defer srv.Close()

	a := audio.Audio{Format: audio.PCM16kMono, Bytes: []byte("pcm-bytes")}
	tr := NewHTTPTranscriber(srv.URL, "s3cret", "ru", 2*time.Second)
	text, conf, err := tr.Transcribe(context.Background(), a)
	if err != nil {
		t.Fatalf("Transcribe: %v", err)
	}
	if text != "привет" || conf != 0.82 {
		t.Fatalf("got %q %v", text, conf)
	}
	if string(gotBody) != "pcm-bytes" {
		t.Fatalf("body should be the PCM itself, got %q", gotBody)
	}
	if got := gotHeader.Get("X-Sample-Rate"); got != strconv.Itoa(audio.PCM16kMono.SampleRate) {
		t.Fatalf("X-Sample-Rate = %q", got)
	}
	if got := gotHeader.Get("X-Language"); got != "ru" {
		t.Fatalf("X-Language = %q", got)
	}
	// Audio is the most sensitive thing crossing this seam.
	if got := gotHeader.Get("Authorization"); got != "Bearer s3cret" {
		t.Fatalf("Authorization = %q", got)
	}
}

func TestHTTPTranscriberOmitsEmptyToken(t *testing.T) {
	t.Parallel()
	var auth string
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		auth = r.Header.Get("Authorization")
		_, _ = io.WriteString(w, `{"text":"x","confidence":0}`)
	}))
	defer srv.Close()
	a := audio.Audio{Format: audio.PCM16kMono, Bytes: []byte("x")}
	if _, _, err := NewHTTPTranscriber(srv.URL, "", "ru", time.Second).Transcribe(context.Background(), a); err != nil {
		t.Fatalf("Transcribe: %v", err)
	}
	if auth != "" {
		t.Fatalf("Authorization should be absent, got %q", auth)
	}
}

func TestHTTPTranscriberRejectsInvalidSuccessResponse(t *testing.T) {
	t.Parallel()
	tests := []struct {
		name string
		body string
	}{
		{name: "empty object", body: `{}`},
		{name: "blank text", body: `{"text":"  ","confidence":0.5}`},
		{name: "missing confidence", body: `{"text":"hello"}`},
		{name: "negative confidence", body: `{"text":"hello","confidence":-0.1}`},
		{name: "confidence above one", body: `{"text":"hello","confidence":1.1}`},
	}
	for _, tc := range tests {
		t.Run(tc.name, func(t *testing.T) {
			srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
				_, _ = io.WriteString(w, tc.body)
			}))
			defer srv.Close()
			_, _, err := NewHTTPTranscriber(srv.URL, "", "ru", time.Second).
				Transcribe(context.Background(), audio.Audio{Format: audio.PCM16kMono, Bytes: []byte("x")})
			if !errors.Is(err, ErrInvalidTranscript) {
				t.Fatalf("error = %v, want ErrInvalidTranscript", err)
			}
		})
	}
}

func TestHTTPTranscriberRejectsOversizeResponse(t *testing.T) {
	t.Parallel()
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
		_, _ = io.WriteString(w, strings.Repeat("x", int(MaxTranscriptResponseBytes+1)))
	}))
	defer srv.Close()
	_, _, err := NewHTTPTranscriber(srv.URL, "", "ru", time.Second).
		Transcribe(context.Background(), audio.Audio{Format: audio.PCM16kMono, Bytes: []byte("x")})
	if !errors.Is(err, ErrInvalidTranscript) {
		t.Fatalf("error = %v, want ErrInvalidTranscript", err)
	}
}

func TestHTTPTranscriberRefusesWrongFormat(t *testing.T) {
	t.Parallel()
	a := audio.Audio{Format: audio.Format{SampleRate: 44100, Channels: 2, SampleBits: 16, Encoding: "pcm_s16le"}}
	_, _, err := NewHTTPTranscriber("http://example.invalid", "", "ru", time.Second).Transcribe(context.Background(), a)
	if !errors.Is(err, ErrFormat) {
		t.Fatalf("want ErrFormat, got %v", err)
	}
}

func TestHTTPTranscriberErrorsOnBadStatus(t *testing.T) {
	t.Parallel()
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
		w.WriteHeader(http.StatusUnauthorized)
	}))
	defer srv.Close()
	a := audio.Audio{Format: audio.PCM16kMono, Bytes: []byte("x")}
	_, _, err := NewHTTPTranscriber(srv.URL, "", "ru", time.Second).Transcribe(context.Background(), a)
	if err == nil {
		t.Fatal("a 401 must be an error, so the Pair falls back")
	}
}