package app

import (
	"context"
	"errors"
	"strings"

	"gitea.nik4nao.com/nik/home-services/tts-gateway/internal/core/domain"
	"gitea.nik4nao.com/nik/home-services/tts-gateway/internal/core/ports/driven"
)

// ErrSpeakerNotFound is returned when the requested speaker name has no
// matching entry in domain.Speakers.
var ErrSpeakerNotFound = errors.New("speaker not found")

type TTSApp struct {
	normalizer driven.TextNormalizer
	engine     driven.TTSEngine
	encoder    driven.AudioEncoder
	nameToID   map[string]int
}

// NewTTSApp constructs the synthesis application service.
func NewTTSApp(normalizer driven.TextNormalizer, engine driven.TTSEngine, encoder driven.AudioEncoder) *TTSApp {
	nameToID := make(map[string]int, len(domain.Speakers))
	for _, s := range domain.Speakers {
		nameToID[s.Name] = s.ID
	}
	return &TTSApp{normalizer: normalizer, engine: engine, encoder: encoder, nameToID: nameToID}
}

// Synthesize normalizes text, runs the TTS engine, and encodes the result.
func (a *TTSApp) Synthesize(ctx context.Context, speakerName, text string, params domain.SynthesisParams) (*domain.AudioClip, error) {
	speakerID, ok := a.nameToID[speakerName]
	if !ok {
		return nil, ErrSpeakerNotFound
	}

	symbolIDs, err := a.normalizer.Normalize(ctx, text)
	if err != nil {
		return nil, err
	}

	pcm, sampleRate, err := a.engine.Synthesize(ctx, speakerID, symbolIDs, params)
	if err != nil {
		return nil, err
	}

	data, mimeType, err := a.encoder.Encode(ctx, pcm, sampleRate)
	if err != nil {
		return nil, err
	}

	return &domain.AudioClip{Data: data, MimeType: mimeType}, nil
}

// ListSpeakers returns speaker names filtered by a case-insensitive substring
// match, or the full roster when search is empty - matching uma-tts-api's
// /speakers endpoint.
func (a *TTSApp) ListSpeakers(_ context.Context, search string) []string {
	search = strings.ToLower(search)
	names := make([]string, 0, len(domain.Speakers))
	for _, s := range domain.Speakers {
		if search == "" || strings.Contains(strings.ToLower(s.Name), search) {
			names = append(names, s.Name)
		}
	}
	return names
}