/**
 * 聊天 WebSocket 处理器
 *
 * 原始 Dart: lib/core/net/websocket_handler.dart
 *
 * 浏览器方案：使用原生 `WebSocket` API，封装连接管理 + 重连 + 事件回调。
 *
 * 事件：
 *   - onConnected(userId)
 *   - onTyping(isTyping)
 *   - onSentence(index, text, total, done)  ← AI 逐句推送
 *   - onVoiceReady(index, audioUrl)
 *   - onIntimacyUpdate(intimacyChange, newIntimacy, relationshipStage)
 *   - onMoodUpdate(mood)
 *   - onError(errorMessage)
 */
import { getApiConfig } from "@/core/net/config/api_config";

export interface SentencePayload {
  index: number;
  text: string;
  total: number;
  done: boolean;
}

export interface IntimacyPayload {
  intimacyChange?: number;
  newIntimacy?: number;
  relationshipStage?: string;
}

export class ChatWebSocket {
  private ws: WebSocket | null = null;
  private reconnectTimer: ReturnType<typeof setTimeout> | null = null;
  private disposed = false;

  onConnected: ((userId: string) => void) | null = null;
  onTyping: ((isTyping: boolean) => void) | null = null;
  onSentence: ((payload: SentencePayload) => void) | null = null;
  onVoiceReady: ((index: number, audioUrl: string) => void) | null = null;
  onIntimacyUpdate: ((payload: IntimacyPayload) => void) | null = null;
  onMoodUpdate: ((mood: string) => void) | null = null;
  onError: ((errorMessage: string) => void) | null = null;

  constructor(
    private readonly serverUrl: string,
    private readonly token: string,
  ) {}

  get isConnected(): boolean {
    return this.ws?.readyState === WebSocket.OPEN;
  }

  connect(): void {
    if (this.disposed) return;
    if (this.ws && this.ws.readyState !== WebSocket.CLOSED) return;
    try {
      const url = `${this.serverUrl}?token=${encodeURIComponent(this.token)}`;
      this.ws = new WebSocket(url);
      this.ws.onopen = () => {
        // 连接成功；userId 由后端在第一条消息中下发
      };
      this.ws.onmessage = (e) => this.handleMessage(e.data);
      this.ws.onerror = () => this.onError?.("WebSocket error");
      this.ws.onclose = () => {
        if (!this.disposed) {
          this.reconnectTimer = setTimeout(() => this.connect(), 3000);
        }
      };
    } catch (e) {
      this.onError?.(e instanceof Error ? e.message : String(e));
    }
  }

  sendMessage(content: string): boolean {
    if (!this.isConnected) return false;
    this.ws?.send(JSON.stringify({ type: "message", content }));
    return true;
  }

  disconnect(): void {
    this.disposed = true;
    if (this.reconnectTimer) {
      clearTimeout(this.reconnectTimer);
      this.reconnectTimer = null;
    }
    this.ws?.close();
    this.ws = null;
  }

  private handleMessage(data: unknown): void {
    if (typeof data !== "string") return;
    let payload: {
      type?: string;
      userId?: string;
      isTyping?: boolean;
      index?: number;
      text?: string;
      total?: number;
      done?: boolean;
      audioUrl?: string;
      intimacyChange?: number;
      newIntimacy?: number;
      relationshipStage?: string;
      mood?: string;
      error?: string;
    };
    try {
      payload = JSON.parse(data);
    } catch {
      return;
    }
    switch (payload.type) {
      case "connected":
        if (payload.userId) this.onConnected?.(payload.userId);
        break;
      case "typing":
        this.onTyping?.(payload.isTyping ?? false);
        break;
      case "sentence":
        this.onSentence?.({
          index: payload.index ?? 0,
          text: payload.text ?? "",
          total: payload.total ?? 0,
          done: payload.done ?? false,
        });
        break;
      case "voice_ready":
        this.onVoiceReady?.(payload.index ?? 0, payload.audioUrl ?? "");
        break;
      case "intimacy_update":
        this.onIntimacyUpdate?.({
          intimacyChange: payload.intimacyChange,
          newIntimacy: payload.newIntimacy,
          relationshipStage: payload.relationshipStage,
        });
        break;
      case "mood_update":
        if (payload.mood) this.onMoodUpdate?.(payload.mood);
        break;
      case "error":
        this.onError?.(payload.error ?? "Unknown error");
        break;
    }
  }
}

/** 默认创建实例：从 env 读取 WS URL。 */
export function createChatWebSocket(token: string): ChatWebSocket {
  const base = getApiConfig().wsUrl;
  return new ChatWebSocket(base, token);
}
