/**
 * 对话服务
 * 整合 SSE 通信、工具执行、用户交互
 */
import * as vscode from 'vscode';
import * as fs from 'fs';
import * as path from 'path';
import { startStreamDialog, generateTaskId, SSEController, SSECallbacks } from './sseHandler';
import { executeToolCall, createToolExecutorContext, ToolExecutorContext } from './toolExecutor';
import { userInteractionManager } from './userInteraction';
import { getConfig } from '../config/settings';
import type { DialogRequest, ToolCallRequest, AskUserEvent, RunMode, ToolConfirmEvent, PlanConfirmEvent } from '../types/api';
import { submitToolConfirm, submitAnswer, stopDialog } from './apiClient';
import { ChatHistoryManager } from '../utils/chatHistoryManager';

/**
 * 消息段落类型
 */
export interface MessageSegment {
  type: 'text' | 'tool' | 'question' | 'agent' | 'plan';
  content?: string;
  toolName?: string;
  toolStatus?: 'running' | 'success' | 'error';
  toolResult?: string;
  askId?: string;
  question?: string;
  options?: string[];
  // 智能体相关字段
  agentId?: string;
  agentName?: string;
  agentStatus?: 'running' | 'completed' | 'error';
  agentSteps?: AgentStep[];
  // 计划相关字段
  planTitle?: string;
  planSteps?: string[];
  planSummary?: string;
}

/**
 * 智能体执行步骤
 */
export interface AgentStep {
  step: number;
  toolName: string;
  toolInput?: unknown;
  toolResult?: string;
  status: 'running' | 'completed' | 'error';
}

/**
 * 对话回调接口
 */
export interface DialogCallbacks {
  /** 收到文本（可能多次调用，流式） */
  onText?: (text: string, isStreaming: boolean) => void;
  /** 工具开始执行 */
  onToolStart?: (toolName: string) => void;
  /** 工具执行完成 */
  onToolComplete?: (toolName: string, result: string) => void;
  /** 工具执行错误 */
  onToolError?: (toolName: string, error: string) => void;
  /** 工具确认请求（Ask 模式） */
  onToolConfirm?: (confirmId: number, toolName: string, toolInput: Record<string, unknown>) => void;
  /** 计划确认请求（Plan 模式） */
  onPlanConfirm?: (confirmId: number, title: string, steps: string[], summary: string) => void;
  /** 显示问题（ask_user） */
  onQuestion?: (askId: string, question: string, options: string[]) => void;
  /** 实时更新段落（流式过程中） */
  onSegmentUpdate?: (segments: MessageSegment[]) => void;
  /** 对话完成，返回所有段落 */
  onComplete?: (segments: MessageSegment[]) => void;
  /** 错误 */
  onError?: (message: string) => void;
  /** 通知消息 */
  onNotification?: (message: string) => void;
  /** 上下文使用量更新 */
  onContextUsage?: (data: { currentTokens: number; maxTokens: number; percentage: number }) => void;
}

/**
 * 对话会话
 */
export class DialogSession {
  private taskId: string;
  private sseController: SSEController | null = null;
  private toolContext: ToolExecutorContext;
  private accumulatedText = '';
  private isActive = false;
  private segments: MessageSegment[] = [];
  private currentTextSegment: MessageSegment | null = null;

  constructor(extensionPath: string, existingTaskId?: string) {
    // 支持复用现有 taskId（用于 Plan 模式确认后继续执行）
    this.taskId = existingTaskId || generateTaskId();
    this.toolContext = createToolExecutorContext(extensionPath);
  }

  /**
   * 添加文本到当前文本段落
   */
  private appendText(text: string): void {
    if (!this.currentTextSegment) {
      this.currentTextSegment = { type: 'text', content: '' };
      this.segments.push(this.currentTextSegment);
    }
    this.currentTextSegment.content = (this.currentTextSegment.content || '') + text;
  }

  /**
   * 结束当前文本段落
   */
  private finalizeTextSegment(): void {
    this.currentTextSegment = null;
  }

  /**
   * 添加工具段落
   */
  private addToolSegment(toolName: string, status: 'running' | 'success' | 'error', result?: string): MessageSegment {
    this.finalizeTextSegment();
    const segment: MessageSegment = {
      type: 'tool',
      toolName,
      toolStatus: status,
      toolResult: result
    };
    this.segments.push(segment);
    return segment;
  }

  /**
   * 更新工具段落状态
   */
  private updateToolSegment(toolName: string, status: 'success' | 'error', result?: string): void {
    // 找到最后一个匹配的工具段落
    for (let i = this.segments.length - 1; i >= 0; i--) {
      const seg = this.segments[i];
      if (seg.type === 'tool' && seg.toolName === toolName && seg.toolStatus === 'running') {
        seg.toolStatus = status;
        seg.toolResult = result;
        break;
      }
    }
  }

  /**
   * 获取任务ID
   */
  getTaskId(): string {
    return this.taskId;
  }

  /**
   * 是否活跃
   */
  get active(): boolean {
    return this.isActive;
  }

  /**
   * 加载知识图谱数据
   * 从 .iccoder/knowledge.json 读取
   */
  private async loadKnowledgeData(): Promise<string | null> {
    console.log('[DialogSession] loadKnowledgeData 开始执行');

    // 等待 workspaceFolders 就绪（首次打开窗口/首次触发命令时可能为空）
    const workspaceFolders = await this.waitForWorkspaceFolders();
    if (!workspaceFolders || workspaceFolders.length === 0) {
      console.log('[DialogSession] 没有工作区文件夹');
      return null;
    }

    // 多根工作区场景：优先读取实际存在 knowledge.json 的根目录
    for (const folder of this.getWorkspaceFolderCandidates(workspaceFolders)) {
      const knowledgeUri = vscode.Uri.joinPath(folder.uri, '.iccoder', 'knowledge.json');
      console.log('[DialogSession] 知识图谱 URI:', knowledgeUri.toString());

      try {
        const content = await this.readTextFileWithRetry(knowledgeUri, 5);
        if (!content) {
          continue;
        }

        // 基础校验 + 清洗：避免偶发读取到半截内容导致后端反序列化失败
        try {
          const parsed = JSON.parse(content) as any;

          // 兼容：后端 KnowledgeGraph.isEmpty() 可能被序列化为 "empty"，老后端反序列化会失败
          if (parsed && typeof parsed === 'object' && 'empty' in parsed) {
            delete parsed.empty;
          }

          const sanitized = JSON.stringify(parsed);
          console.log('[DialogSession] 知识图谱已清洗, sanitizedLen:', sanitized.length);
          return sanitized;
        } catch (e) {
          console.warn('[DialogSession] 知识图谱 JSON 解析失败，跳过本次读取:', e);
          continue;
        }
      } catch (error) {
        console.warn('[DialogSession] 加载知识图谱失败:', error);
      }
    }

    return null;
  }

  private async waitForWorkspaceFolders(): Promise<readonly vscode.WorkspaceFolder[] | undefined> {
    for (let i = 0; i < 10; i++) {
      const folders = vscode.workspace.workspaceFolders;
      if (folders && folders.length > 0) {
        return folders;
      }
      await new Promise(resolve => setTimeout(resolve, 100));
    }
    return vscode.workspace.workspaceFolders;
  }

  private getWorkspaceFolderCandidates(
    workspaceFolders: readonly vscode.WorkspaceFolder[]
  ): vscode.WorkspaceFolder[] {
    const result: vscode.WorkspaceFolder[] = [];

    // 1) 当前激活文件所在的 workspace folder（如果有）
    const activeUri = vscode.window.activeTextEditor?.document?.uri;
    const activeFolder = activeUri ? vscode.workspace.getWorkspaceFolder(activeUri) : undefined;
    if (activeFolder) {
      result.push(activeFolder);
    }

    // 2) 其它 workspace folders（去重）
    for (const folder of workspaceFolders) {
      if (!result.some(f => f.uri.toString() === folder.uri.toString())) {
        result.push(folder);
      }
    }

    return result;
  }

  private async readTextFileWithRetry(uri: vscode.Uri, maxAttempts: number): Promise<string | null> {
    for (let attempt = 1; attempt <= maxAttempts; attempt++) {
      try {
        const bytes = await vscode.workspace.fs.readFile(uri);
        const text = Buffer.from(bytes).toString('utf-8');
        if (!text || !text.trim()) {
          return null;
        }
        return text;
      } catch (error) {
        // 文件不存在：不是错误，直接返回 null
        if (error instanceof vscode.FileSystemError && error.code === 'FileNotFound') {
          return null;
        }

        const retryable =
          (error instanceof vscode.FileSystemError && error.code === 'Unavailable') ||
          (typeof (error as any)?.code === 'string' && ['EBUSY', 'EPERM', 'EACCES'].includes((error as any).code));

        if (!retryable || attempt >= maxAttempts) {
          throw error;
        }

        const delayMs = 50 * attempt;
        console.log(`[DialogSession] 读取知识图谱失败（可重试）: attempt=${attempt}/${maxAttempts}, delay=${delayMs}ms`);
        await new Promise(resolve => setTimeout(resolve, delayMs));
      }
    }

    return null;
  }

  /**
   * 获取工具操作描述（用于确认对话框）
   */
  private getToolDescription(toolName: string, toolInput: Record<string, unknown>): string {
    const lines: string[] = [];

    switch (toolName) {
      case 'file_write':
        lines.push(`文件路径: ${toolInput.path || '未知'}`);
        if (toolInput.content) {
          const content = String(toolInput.content);
          lines.push(`内容长度: ${content.length} 字符`);
          lines.push(`内容预览: ${content.substring(0, 100)}${content.length > 100 ? '...' : ''}`);
        }
        break;
      case 'file_delete':
        lines.push(`删除文件: ${toolInput.path || '未知'}`);
        break;
      case 'syntax_check':
        lines.push('执行语法检查');
        if (toolInput.code) {
          const code = String(toolInput.code);
          lines.push(`代码长度: ${code.length} 字符`);
        }
        break;
      case 'simulation':
        lines.push(`RTL文件: ${toolInput.rtlPath || '未知'}`);
        lines.push(`TB文件: ${toolInput.tbPath || '未知'}`);
        if (toolInput.duration) {
          lines.push(`仿真时长: ${toolInput.duration}`);
        }
        break;
      default:
        lines.push(`参数: ${JSON.stringify(toolInput, null, 2)}`);
    }

    return lines.join('\n');
  }

  /**
   * 发送消息并开始流式对话
   */
  async sendMessage(
    message: string,
    callbacks: DialogCallbacks,
    mode?: RunMode
  ): Promise<void> {
    if (this.isActive) {
      callbacks.onError?.('当前有对话正在进行中');
      return;
    }

    this.isActive = true;
    this.accumulatedText = '';
    this.segments = [];
    this.currentTextSegment = null;

    const config = getConfig();

    // 获取压缩数据和新消息（用于后端重启后恢复）
    const historyManager = ChatHistoryManager.getInstance();
    const compactedData = await historyManager.loadCompactedData(this.taskId);
    const newMessages = historyManager.getNewMessagesSinceCompaction();

    // 加载知识图谱数据
    const knowledgeData = await this.loadKnowledgeData();
    console.log('[DialogSession] knowledgeData 加载结果:', knowledgeData ? `${knowledgeData.length} 字符` : 'null');

    const request: DialogRequest = {
      taskId: this.taskId,
      message,
      userId: config.userId,
      mode: mode || 'agent',
      compactedData: compactedData || undefined,
      newMessages: newMessages.length > 0 ? newMessages : undefined,
      knowledgeData: knowledgeData || undefined
    };

    // 追踪用户消息
    historyManager.trackUserMessage(message);

    const sseCallbacks: SSECallbacks = {
      onTextDelta: (data) => {
        this.accumulatedText += data.text;
        this.appendText(data.text);
        console.log('[DialogSession] onTextDelta, 累积文本长度:', this.accumulatedText.length);
        callbacks.onText?.(this.accumulatedText, true);
        // 实时发送段落更新
        callbacks.onSegmentUpdate?.(this.segments);
      },

      onToolCall: async (data: ToolCallRequest) => {
        const toolName = data.params.name;
        console.log('[DialogSession] onToolCall:', toolName);

        // 检查是否有活跃的智能体（如果有，工具执行会显示在智能体卡片内，不需要单独显示）
        const hasActiveAgent = this.segments.some(
          s => s.type === 'agent' && s.agentStatus === 'running'
        );

        if (hasActiveAgent) {
          console.log('[DialogSession] onToolCall: 智能体执行中，跳过工具段落:', toolName);
        } else {
          // 检查是否已经有相同的工具段落（可能由 onToolStart 添加）
          const lastToolSegment = this.segments.filter(s => s.type === 'tool').pop();
          if (lastToolSegment && lastToolSegment.toolName === toolName && lastToolSegment.toolStatus === 'running') {
            console.log('[DialogSession] onToolCall: 跳过重复的工具段落:', toolName);
          } else {
            this.addToolSegment(toolName, 'running');
            // 实时发送段落更新
            callbacks.onSegmentUpdate?.(this.segments);
          }
        }

        // 注意：不在这里调用 callbacks.onToolStart，避免与 onToolStart 事件重复
        try {
          await executeToolCall(data, this.toolContext);
          if (!hasActiveAgent) {
            this.updateToolSegment(toolName, 'success', '执行完成');
            // 实时发送段落更新
            callbacks.onSegmentUpdate?.(this.segments);
          }
          // 也不调用 callbacks.onToolComplete，避免重复
        } catch (error) {
          const errorMsg = error instanceof Error ? error.message : '未知错误';
          if (!hasActiveAgent) {
            this.updateToolSegment(toolName, 'error', errorMsg);
            callbacks.onSegmentUpdate?.(this.segments);
          }
          callbacks.onToolError?.(toolName, errorMsg);
        }
      },

      onToolStart: (data) => {
        console.log('[DialogSession] onToolStart:', data.tool_name);
        // 检查是否已经有相同的工具段落（可能由 onToolCall 添加）
        const lastToolSegment = this.segments.filter(s => s.type === 'tool').pop();
        if (lastToolSegment && lastToolSegment.toolName === data.tool_name && lastToolSegment.toolStatus === 'running') {
          console.log('[DialogSession] 跳过重复的工具段落:', data.tool_name);
        } else {
          this.addToolSegment(data.tool_name, 'running');
          // 实时发送段落更新
          callbacks.onSegmentUpdate?.(this.segments);
        }
        console.log('[DialogSession] segments 数量:', this.segments.length);
        callbacks.onToolStart?.(data.tool_name);
      },

      onToolComplete: (data) => {
        this.updateToolSegment(data.tool_name, 'success', data.result);
        callbacks.onToolComplete?.(data.tool_name, data.result);
        // 实时发送段落更新
        callbacks.onSegmentUpdate?.(this.segments);
      },

      onToolError: (data) => {
        this.updateToolSegment(data.tool_name, 'error', data.error);
        callbacks.onToolError?.(data.tool_name, data.error);
        // 实时发送段落更新
        callbacks.onSegmentUpdate?.(this.segments);
      },

      onToolConfirm: async (data: ToolConfirmEvent) => {
        console.log('[DialogSession] onToolConfirm:', data.toolName, data.confirmId);

        // 结束当前文本段落
        this.finalizeTextSegment();

        // 生成工具描述
        const toolDescription = this.getToolDescription(data.toolName, data.toolInput);

        // 构建问题文本
        const toolNameMap: Record<string, string> = {
          'file_write': '写入文件',
          'file_delete': '删除文件',
          'syntax_check': '语法检查',
          'simulation': '运行仿真'
        };
        const toolDisplayName = toolNameMap[data.toolName] || data.toolName;
        const question = `确认执行操作：${toolDisplayName}\n\n${toolDescription}`;

        // 生成唯一的 askId
        const askId = `tool_confirm_${data.confirmId}`;

        // 添加问题段落到聊天界面
        this.segments.push({
          type: 'question',
          askId: askId,
          question: question,
          options: ['确认执行', '取消']
        });

        // 实时发送段落更新
        callbacks.onSegmentUpdate?.(this.segments);

        // 调用回调通知 UI
        callbacks.onToolConfirm?.(data.confirmId, data.toolName, data.toolInput);

        // 使用 userInteractionManager 等待用户回答
        try {
          await userInteractionManager.handleAskUser(
            {
              askId: askId,
              question: question,
              options: ['确认执行', '取消']
            } as AskUserEvent,
            this.taskId
          );

          // 注意：用户回答后，需要在 receiveAnswer 中处理 tool_confirm 类型的 askId
          // 这里不直接调用 submitToolConfirm，而是在 userInteractionManager 中统一处理
        } catch (error) {
          console.error('[DialogSession] 处理工具确认失败:', error);
          // 如果出错，默认取消执行
          try {
            await submitToolConfirm({
              confirmId: data.confirmId,
              taskId: this.taskId,
              approved: false
            });
          } catch (submitError) {
            console.error('[DialogSession] 发送取消响应失败:', submitError);
          }
        }
      },

      onPlanConfirm: async (data: PlanConfirmEvent) => {
        console.log('[DialogSession] onPlanConfirm:', data.title);

        // 结束当前文本段落
        this.finalizeTextSegment();

        const askId = `ask_${data.confirmId}`;

        // 添加计划段落到聊天界面（包含 askId 用于响应）
        this.segments.push({
          type: 'plan',
          askId: askId,
          planTitle: data.title,
          planSteps: data.steps,
          planSummary: data.summary
        });

        // 实时发送段落更新
        callbacks.onSegmentUpdate?.(this.segments);

        // 注册问题到前端（类似 askUser），以便用户回答时能找到
        const planEvent = {
          askId: askId,
          question: `请确认执行计划：${data.title}`,
          options: ['确认执行', '修改计划', '取消']
        };
        try {
          await userInteractionManager.handleAskUser(planEvent as AskUserEvent, this.taskId);
        } catch (error) {
          console.error('[DialogSession] 处理计划确认失败:', error);
        }

        // 调用回调通知 UI
        callbacks.onPlanConfirm?.(data.confirmId, data.title, data.steps, data.summary);
      },

      onAskUser: async (data: AskUserEvent) => {
        this.finalizeTextSegment();
        this.segments.push({
          type: 'question',
          askId: data.askId,
          question: data.question,
          options: data.options
        });
        // 实时发送段落更新（包含问题）
        callbacks.onSegmentUpdate?.(this.segments);
        // 同时调用 onQuestion 用于更新状态栏等
        callbacks.onQuestion?.(data.askId, data.question, data.options);
        try {
          await userInteractionManager.handleAskUser(data, this.taskId);
        } catch (error) {
          console.error('[DialogSession] 处理用户问题失败:', error);
        }
      },

      onComplete: (data) => {
        this.isActive = false;
        this.finalizeTextSegment();

        // 追踪 AI 消息（用于后端重启后恢复）
        if (this.accumulatedText) {
          historyManager.trackAiMessage(this.accumulatedText);
        }

        // 发送所有段落
        callbacks.onComplete?.(this.segments);
      },

      onError: (data) => {
        this.isActive = false;
        callbacks.onError?.(data.message);
      },

      onWarning: (data) => {
        callbacks.onNotification?.(`⚠️ ${data.message}`);
      },

      onNotification: (data) => {
        callbacks.onNotification?.(data.message);
      },

      // 智能体事件处理
      onAgentStart: (data) => {
        console.log('[DialogSession] onAgentStart:', data.agentId);
        this.finalizeTextSegment();
        this.segments.push({
          type: 'agent',
          agentId: data.agentId,
          agentName: data.agentName,
          content: data.instruction,
          agentStatus: 'running',
          agentSteps: []
        });
        callbacks.onSegmentUpdate?.(this.segments);
      },

      onAgentProgress: (data) => {
        console.log('[DialogSession] onAgentProgress:', data.agentId, data.step, data.status);
        const agentSegment = this.segments.find(
          s => s.type === 'agent' && s.agentId === data.agentId
        );
        if (agentSegment && agentSegment.agentSteps) {
          if (data.status === 'running') {
            agentSegment.agentSteps.push({
              step: data.step,
              toolName: data.toolName,
              toolInput: data.toolInput,
              status: 'running'
            });
          } else {
            const step = agentSegment.agentSteps.find(s => s.step === data.step);
            if (step) {
              step.status = data.status;
              step.toolResult = data.toolResult;
            }
          }
          callbacks.onSegmentUpdate?.(this.segments);
        }
      },

      onAgentComplete: (data) => {
        console.log('[DialogSession] onAgentComplete:', data.agentId);
        const agentSegment = this.segments.find(
          s => s.type === 'agent' && s.agentId === data.agentId
        );
        if (agentSegment) {
          agentSegment.agentStatus = 'completed';
          agentSegment.content = data.summary;
          callbacks.onSegmentUpdate?.(this.segments);
        }
      },

      onAgentError: (data) => {
        console.log('[DialogSession] onAgentError:', data.agentId, data.error);
        const agentSegment = this.segments.find(
          s => s.type === 'agent' && s.agentId === data.agentId
        );
        if (agentSegment) {
          agentSegment.agentStatus = 'error';
          agentSegment.content = data.error;
          callbacks.onSegmentUpdate?.(this.segments);
        }
      },

      onMemoryCompacted: async (data) => {
        console.log('[DialogSession] onMemoryCompacted:', data.taskId);
        // 保存压缩数据到本地
        await historyManager.saveCompactedData(data.compactedData);
      },

      onContextUsage: (data) => {
        console.log('[DialogSession] onContextUsage:', data.currentTokens, '/', data.maxTokens);
        callbacks.onContextUsage?.(data);
      },

      onOpen: () => {
        console.log('[DialogSession] SSE 连接已建立');
      },

      onClose: () => {
        console.log('[DialogSession] SSE 连接已关闭');
        this.isActive = false;
      }
    };

    try {
      this.sseController = await startStreamDialog(request, sseCallbacks);
    } catch (error) {
      this.isActive = false;
      const errorMsg = error instanceof Error ? error.message : '连接失败';
      callbacks.onError?.(errorMsg);
      throw error;
    }
  }

  /**
   * 中止当前对话
   */
  abort(): void {
    if (this.sseController) {
      this.sseController.abort();
      this.sseController = null;
    }
    this.isActive = false;
    userInteractionManager.cancelAll();

    // 通知后端停止处理
    stopDialog(this.taskId).catch(err => {
      console.warn('[DialogSession] 停止对话请求失败:', err);
    });
  }

  /**
   * 获取当前的消息段落（用于中止时保存）
   */
  getSegments(): MessageSegment[] {
    return this.segments;
  }

  /**
   * 获取累积的文本内容
   */
  getAccumulatedText(): string {
    return this.accumulatedText;
  }

  /**
   * 提交用户回答
   */
  async submitAnswer(
    askId: string,
    selected?: string[],
    customInput?: string
  ): Promise<void> {
    await userInteractionManager.receiveAnswer(askId, selected, customInput);
  }
}

/**
 * 全局对话会话管理
 */
class DialogManager {
  private currentSession: DialogSession | null = null;

  /**
   * 创建新会话
   * @param extensionPath 扩展路径
   * @param existingTaskId 可选，复用现有的 taskId（用于 Plan 模式确认后继续执行）
   */
  createSession(extensionPath: string, existingTaskId?: string): DialogSession {
    // 如果有活跃会话，先中止
    if (this.currentSession?.active) {
      this.currentSession.abort();
    }
    this.currentSession = new DialogSession(extensionPath, existingTaskId);
    return this.currentSession;
  }

  /**
   * 获取当前会话
   */
  getCurrentSession(): DialogSession | null {
    return this.currentSession;
  }

  /**
   * 中止当前会话
   */
  abortCurrentSession(): void {
    this.currentSession?.abort();
  }
}

export const dialogManager = new DialogManager();