package transcribe_test

import (
	"context"
	"errors"
	"testing"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"

	"git.d-ma.be/mathias/tapir/internal/adapters/transcribe"
	"git.d-ma.be/mathias/tapir/internal/domain"
)

type fakeBackend struct {
	name  string
	text  string
	err   error
	calls int
}

func (f *fakeBackend) Name() string { return f.name }
func (f *fakeBackend) Transcribe(_ context.Context, _ string) (domain.Transcription, error) {
	f.calls++
	if f.err != nil {
		return domain.Transcription{}, f.err
	}
	return domain.Transcription{Text: f.text, Endpoint: f.name}, nil
}

func TestChain_PrimarySuccessNeverTouchesTheFallback(t *testing.T) {
	primary := &fakeBackend{name: "iguana/kb-whisper", text: "primary text"}
	fallback := &fakeBackend{name: "berget/kb-whisper", text: "fallback text"}

	got, err := transcribe.NewChain(primary, fallback).Transcribe(context.Background(), "/a.wav")

	require.NoError(t, err)
	assert.Equal(t, "primary text", got.Text)
	assert.Equal(t, "iguana/kb-whisper", got.Endpoint)
	assert.Zero(t, fallback.calls, "audio must not leave the homelab when the local endpoint worked")
}

func TestChain_AnyPrimaryFailureFallsBackAndRecordsTheFallbackEndpoint(t *testing.T) {
	tests := []struct {
		name string
		err  error
	}{
		{"server error", &transcribe.StatusError{Code: 500}},
		{"gateway timeout", &transcribe.StatusError{Code: 504}},
		{"client error", &transcribe.StatusError{Code: 400}},
		{"transport failure", errors.New("dial tcp: connection refused")},
		{"empty transcript", transcribe.ErrEmptyTranscript},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			primary := &fakeBackend{name: "iguana/kb-whisper", err: tt.err}
			fallback := &fakeBackend{name: "berget/kb-whisper", text: "fallback text"}

			got, err := transcribe.NewChain(primary, fallback).Transcribe(context.Background(), "/a.wav")

			require.NoError(t, err)
			assert.Equal(t, "fallback text", got.Text)
			assert.Equal(t, "berget/kb-whisper", got.Endpoint,
				"the row must say berget served it: that means the audio left the homelab")
		})
	}
}

func TestChain_BothFailingReportsBothErrors(t *testing.T) {
	primary := &fakeBackend{name: "iguana/kb-whisper", err: errors.New("iguana down")}
	fallback := &fakeBackend{name: "berget/kb-whisper", err: errors.New("berget down")}

	_, err := transcribe.NewChain(primary, fallback).Transcribe(context.Background(), "/a.wav")

	require.Error(t, err)
	assert.Contains(t, err.Error(), "iguana down")
	assert.Contains(t, err.Error(), "berget down")
}

func TestChain_WithoutAFallbackAPrimaryFailureIsTheResult(t *testing.T) {
	primary := &fakeBackend{name: "iguana/kb-whisper", err: errors.New("iguana down")}

	_, err := transcribe.NewChain(primary, nil).Transcribe(context.Background(), "/a.wav")

	require.Error(t, err)
	assert.Contains(t, err.Error(), "iguana down")
}

func TestChain_ACancelledJobDoesNotFallBack(t *testing.T) {
	ctx, cancel := context.WithCancel(context.Background())
	cancel()
	primary := &fakeBackend{name: "iguana/kb-whisper", err: context.Canceled}
	fallback := &fakeBackend{name: "berget/kb-whisper", text: "x"}

	_, err := transcribe.NewChain(primary, fallback).Transcribe(ctx, "/a.wav")

	assert.ErrorIs(t, err, context.Canceled)
	assert.Zero(t, fallback.calls, "a cancelled job must not ship the audio to a cloud endpoint")
}