package main

import (
	"context"
	"encoding/json"
	"fmt"
	"strings"
	"sync"
	"time"

	"github.com/gorilla/websocket"
)

type ttsCfg struct {
	Model       string  `json:"model"`
	Voice       string  `json:"voice"`
	Instruction string  `json:"instruction"`
	Rate        float64 `json:"rate"`
	Pitch       float64 `json:"pitch"`
	Volume      int     `json:"volume"`
}

func defaultTTS(cfg agentCfg) ttsCfg {
	return ttsCfg{Model: cfg.TTSModel, Voice: cfg.TTSVoice, Instruction: cfg.TTSInstruction, Rate: 1, Pitch: 1, Volume: 50}
}

func normalizeTTS(in *ttsCfg, cfg agentCfg) (ttsCfg, error) {
	if in == nil {
		return defaultTTS(cfg), nil
	}
	t := *in
	t.Model, t.Voice, t.Instruction = strings.TrimSpace(t.Model), strings.TrimSpace(t.Voice), strings.TrimSpace(t.Instruction)
	if t.Model == "" {
		t.Model = cfg.TTSModel
	}
	if t.Voice == "" {
		t.Voice = cfg.TTSVoice
	}
	if t.Voice == "" {
		return t, fmt.Errorf("请填写音色或复刻音色 ID")
	}
	if len(t.Model) > 100 || len(t.Voice) > 200 || len([]rune(t.Instruction)) > 100 {
		return t, fmt.Errorf("TTS 配置文本过长")
	}
	if t.Rate < 0.5 || t.Rate > 2 || t.Pitch < 0.5 || t.Pitch > 2 || t.Volume < 0 || t.Volume > 100 {
		return t, fmt.Errorf("TTS 参数超出范围：语速/语调 0.5~2.0，音量 0~100")
	}
	return t, nil
}

// ttsSpeak: 百炼 CosyVoice 流式合成，音频块实时回调 onAudio。
func ttsSpeak(ctx context.Context, cfg agentCfg, tts ttsCfg, text string, onAudio func([]byte)) error {
	cctx, cancel := context.WithTimeout(ctx, 60*time.Second)
	defer cancel()
	conn, _, err := websocket.DefaultDialer.DialContext(cctx, cfg.BailianWssBaseURL,
		map[string][]string{"Authorization": {"Bearer " + cfg.BailianKey}})
	if err != nil {
		return fmt.Errorf("连接 TTS: %w", err)
	}
	defer conn.Close()

	taskID := uuid()
	parameters := map[string]any{
		"text_type": "PlainText", "voice": tts.Voice,
		"format": "pcm", "sample_rate": 16000,
		"volume": tts.Volume, "rate": tts.Rate, "pitch": tts.Pitch,
	}
	if tts.Instruction != "" {
		parameters["instruction"] = tts.Instruction
	}
	err = conn.WriteJSON(map[string]any{
		"header": map[string]string{"action": "run-task", "task_id": taskID, "streaming": "duplex"},
		"payload": map[string]any{
			"task_group": "audio", "task": "tts", "function": "SpeechSynthesizer",
			"model":      tts.Model,
			"parameters": parameters,
			"input":      map[string]any{},
		},
	})
	if err != nil {
		return fmt.Errorf("TTS run-task: %w", err)
	}

	var once sync.Once
	done := make(chan error, 1)
	go func() {
		for {
			mt, data, err := conn.ReadMessage()
			if err != nil {
				select {
				case done <- err:
				default:
				}
				return
			}
			if mt == websocket.BinaryMessage {
				onAudio(data)
				continue
			}
			var ev struct {
				Header struct {
					Event        string `json:"event"`
					ErrorMessage string `json:"error_message"`
				} `json:"header"`
			}
			if json.Unmarshal(data, &ev) != nil {
				continue
			}
			switch ev.Header.Event {
			case "task-started":
				once.Do(func() {
					// task-started 到达后才允许发文本
					if err := conn.WriteJSON(map[string]any{
						"header":  map[string]string{"action": "continue-task", "task_id": taskID, "streaming": "duplex"},
						"payload": map[string]any{"input": map[string]string{"text": text}},
					}); err != nil {
						select {
						case done <- err:
						default:
						}
					}
					conn.WriteJSON(map[string]any{
						"header":  map[string]string{"action": "finish-task", "task_id": taskID, "streaming": "duplex"},
						"payload": map[string]any{"input": map[string]any{}},
					})
				})
			case "task-finished":
				select {
				case done <- nil:
				default:
				}
				return
			case "task-failed":
				select {
				case done <- fmt.Errorf("TTS 失败: %s", ev.Header.ErrorMessage):
				default:
				}
				return
			}
		}
	}()
	select {
	case err := <-done:
		return err
	case <-cctx.Done():
		conn.Close()
		return cctx.Err()
	}
}