package grpc

import (
	"context"
	"errors"

	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"

	ttsv1 "gitea.nik4nao.com/nik/home-services/gen/tts/v1"
	"gitea.nik4nao.com/nik/home-services/tts-gateway/internal/app"
	"gitea.nik4nao.com/nik/home-services/tts-gateway/internal/core/domain"
	"gitea.nik4nao.com/nik/home-services/tts-gateway/internal/core/ports/driving"
)

type TTSGRPC struct {
	ttsv1.UnimplementedTTSServiceServer
	svc driving.TTSService
}

// NewTTSGRPC constructs the gRPC adapter for TTSService.
func NewTTSGRPC(svc driving.TTSService) *TTSGRPC {
	return &TTSGRPC{svc: svc}
}

// Synthesize translates a protobuf request into a domain call, applying
// uma-tts-api's sampling defaults for any knob the client omits.
func (h *TTSGRPC) Synthesize(ctx context.Context, req *ttsv1.SynthesizeRequest) (*ttsv1.SynthesizeResponse, error) {
	params := domain.SynthesisParams{
		NoiseScale:  domain.DefaultNoiseScale,
		NoiseScaleW: domain.DefaultNoiseScaleW,
		LengthScale: domain.DefaultLengthScale,
	}
	if req.NoiseScale != nil {
		params.NoiseScale = *req.NoiseScale
	}
	if req.NoiseScaleW != nil {
		params.NoiseScaleW = *req.NoiseScaleW
	}
	if req.LengthScale != nil {
		params.LengthScale = *req.LengthScale
	}

	clip, err := h.svc.Synthesize(ctx, req.SpeakerName, req.Text, params)
	if err != nil {
		return nil, grpcError(err)
	}
	return &ttsv1.SynthesizeResponse{Audio: clip.Data, MimeType: clip.MimeType}, nil
}

// ListSpeakers returns the (optionally filtered) speaker roster.
func (h *TTSGRPC) ListSpeakers(ctx context.Context, req *ttsv1.ListSpeakersRequest) (*ttsv1.ListSpeakersResponse, error) {
	names := h.svc.ListSpeakers(ctx, req.Search)
	return &ttsv1.ListSpeakersResponse{SpeakerNames: names}, nil
}

// grpcError maps domain errors to appropriate gRPC status codes, mirroring
// uma-tts-api's /synthesize 400 response for an unknown speaker name.
func grpcError(err error) error {
	if errors.Is(err, app.ErrSpeakerNotFound) {
		return status.Errorf(codes.InvalidArgument, "%v", err)
	}
	return status.Errorf(codes.Internal, "%v", err)
}