package eino

import (
	"context"
	"encoding/base64"

	"github.com/cloudwego/eino/compose"

	"github.com/hhs/camtalk/internal/ai/tts"
	"github.com/hhs/camtalk/internal/logger"
	"github.com/hhs/camtalk/internal/models"
)

// NewTTSLambda 创建 TTS Lambda 节点。
// 输入: []string（句子数组，框架自动从 StreamReader concat）→ 输出: struct{}
//
// 将句子数组转为 channel，调用 ttsService.SynthesizeStream() 流式合成，
// 逐 chunk 推送 tts_audio 到客户端。TTS 失败静默跳过。
func NewTTSLambda(ttsService tts.Service, ttsVoice string, ttsSpeed float64, ttsOutputFmt string, ttsSampleRate int) *compose.Lambda {
	return compose.InvokableLambda(func(ctx context.Context, sentences []string) (struct{}, error) {
		log := logger.Log
		sender := senderFromCtx(ctx)
		requestID := requestIDFromCtx(ctx)
		state := stateFromCtx(ctx)

		// 检查 TTS 是否启用（从 State 或 context 获取）
		// TTSEnabled 信息在 PipelineInput 中，通过 State 传递
		if state != nil {
			state.mu.Lock()
			ttsEnabled := true // 默认启用，由适配器通过 State 设置
			state.mu.Unlock()
			if !ttsEnabled {
				return struct{}{}, nil
			}
		}

		if len(sentences) == 0 {
			return struct{}{}, nil
		}

		if sender == nil || requestID == "" {
			return struct{}{}, nil
		}

		log.Infow("开始 TTS 合成", "request_id", requestID, "sentence_count", len(sentences))

		// 将句子数组转为 channel（ttsService.SynthesizeStream 需要 <-chan string）
		sentenceCh := make(chan string, len(sentences))
		for _, s := range sentences {
			sentenceCh <- s
		}
		close(sentenceCh)

		// 调用 TTS 服务
		ttsStream, err := ttsService.SynthesizeStream(ctx, sentenceCh, tts.Options{
			Voice:      ttsVoice,
			Speed:      ttsSpeed,
			OutputFmt:  ttsOutputFmt,
			SampleRate: ttsSampleRate,
		})
		if err != nil {
			log.Errorw("TTS 合成启动失败（已跳过）", "error", err, "request_id", requestID)
			return struct{}{}, nil // TTS 失败不中断流程
		}

		// 消费 TTS 音频流，推送到客户端
		for chunk := range ttsStream {
			select {
			case <-ctx.Done():
				log.Infow("TTS 流被中断", "request_id", requestID)
				return struct{}{}, ctx.Err()
			default:
			}

			audioBase64 := base64.StdEncoding.EncodeToString(chunk.Audio)

			if err := sender.SendTTSAudio(models.WsTTSAudio{
				Type:      "tts_audio",
				RequestID: requestID,
				Audio:     audioBase64,
				MimeType:  "audio/mp3",
				IsLast:    chunk.IsLast,
				Final:     chunk.Final,
			}); err != nil {
				log.Errorw("发送 tts_audio 失败", "error", err)
			}
		}

		log.Infow("TTS 合成完成", "request_id", requestID)
		return struct{}{}, nil
	})
}