/**
 * SSE 事件处理器
 * 处理与后端的流式通信
 * 使用 eventsource-parser + Node.js 原生 http 模块
 */
import * as http from 'http';
import * as https from 'https';
import { URL } from 'url';
import { createParser, type EventSourceParser } from 'eventsource-parser';
import { getApiUrl, getConfig } from '../config/settings';
import type {
  DialogRequest,
  SSEEventType,
  TextDeltaEvent,
  ToolCallRequest,
  ToolConfirmEvent,
  PlanConfirmEvent,
  AskUserEvent,
  CompleteEvent,
  ErrorEvent,
  ToolStartEvent,
  ToolCompleteEvent,
  ToolErrorEvent,
  WarningEvent,
  NotificationEvent,
  DepthUpdateEvent,
  AgentStartEvent,
  AgentProgressEvent,
  AgentCompleteEvent,
  AgentErrorEvent,
  ContextUsageEvent,
  CreditUpdateEvent
} from '../types/api';
import type { MemoryCompactedEvent } from '../types/memory';

/**
 * SSE 事件回调接口
 */
export interface SSECallbacks {
  /** 收到文本增量 */
  onTextDelta?: (data: TextDeltaEvent) => void;
  /** 收到工具调用请求 */
  onToolCall?: (data: ToolCallRequest) => void;
  /** 收到工具确认请求（Ask 模式） */
  onToolConfirm?: (data: ToolConfirmEvent) => void;
  /** 收到计划确认请求（Plan 模式） */
  onPlanConfirm?: (data: PlanConfirmEvent) => void;
  /** 阶段进度更新 */
  onPhaseProgress?: (data: import('../types/api').PhaseProgressEvent) => void;
  /** 添加计划步骤 */
  onPlanStepAdd?: (data: import('../types/api').PlanStepAddEvent) => void;
  /** 删除计划步骤 */
  onPlanStepRemove?: (data: import('../types/api').PlanStepRemoveEvent) => void;
  /** 更新计划步骤 */
  onPlanStepUpdate?: (data: import('../types/api').PlanStepUpdateEvent) => void;
  /** 更新计划摘要 */
  onPlanSummaryUpdate?: (data: import('../types/api').PlanSummaryUpdateEvent) => void;
  /** 工具开始执行 */
  onToolStart?: (data: ToolStartEvent) => void;
  /** 工具执行完成 */
  onToolComplete?: (data: ToolCompleteEvent) => void;
  /** 工具执行错误 */
  onToolError?: (data: ToolErrorEvent) => void;
  /** 收到用户提问 */
  onAskUser?: (data: AskUserEvent) => void;
  /** 对话完成 */
  onComplete?: (data: CompleteEvent) => void;
  /** 错误 */
  onError?: (data: ErrorEvent) => void;
  /** 警告 */
  onWarning?: (data: WarningEvent) => void;
  /** 通知 */
  onNotification?: (data: NotificationEvent) => void;
  /** 深度更新 */
  onDepthUpdate?: (data: DepthUpdateEvent) => void;
  /** 子智能体启动 */
  onAgentStart?: (data: AgentStartEvent) => void;
  /** 子智能体进度 */
  onAgentProgress?: (data: AgentProgressEvent) => void;
  /** 子智能体完成 */
  onAgentComplete?: (data: AgentCompleteEvent) => void;
  /** 子智能体错误 */
  onAgentError?: (data: AgentErrorEvent) => void;
  /** 记忆压缩完成 */
  onMemoryCompacted?: (data: MemoryCompactedEvent) => void;
  /** 上下文使用量更新 */
  onContextUsage?: (data: ContextUsageEvent) => void;
  /** 资源点余额更新 */
  onCreditUpdate?: (data: CreditUpdateEvent) => void;
  /** 连接打开 */
  onOpen?: () => void;
  /** 连接关闭 */
  onClose?: () => void;
}

/**
 * SSE 会话控制器
 */
export class SSEController {
  private request: http.ClientRequest | null = null;
  private isConnected = false;
  private isAborted = false;

  /**
   * 是否已连接
   */
  get connected(): boolean {
    return this.isConnected;
  }

  /**
   * 设置请求对象
   */
  setRequest(req: http.ClientRequest): void {
    this.request = req;
  }

  /**
   * 设置连接状态
   */
  setConnected(connected: boolean): void {
    this.isConnected = connected;
  }

  /**
   * 是否已中止
   */
  get aborted(): boolean {
    return this.isAborted;
  }

  /**
   * 中止当前连接
   */
  abort(): void {
    if (this.request && !this.isAborted) {
      this.isAborted = true;
      this.request.destroy();
      this.request = null;
      this.isConnected = false;
    }
  }
}

/**
 * 发起流式对话
 * @param request 对话请求
 * @param callbacks 事件回调
 * @returns SSE 控制器（用于中止连接）
 */
export async function startStreamDialog(
  request: DialogRequest,
  callbacks: SSECallbacks
): Promise<SSEController> {
  const controller = new SSEController();

  const urlString = getApiUrl('/api/dialog/stream');
  const url = new URL(urlString);
  const isHttps = url.protocol === 'https:';
  const httpModule = isHttps ? https : http;

  const body = JSON.stringify(request);

  console.log(`[SSE] 开始流式对话: taskId=${request.taskId}, mode=${request.mode}, url=${urlString}`);

  return new Promise((resolve, reject) => {
    const options: http.RequestOptions = {
      hostname: url.hostname,
      port: url.port || (isHttps ? 443 : 80),
      path: url.pathname + url.search,
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        'Accept': 'text/event-stream',
        'Cache-Control': 'no-cache',
        'Content-Length': Buffer.byteLength(body),
        ...(request.token ? { 'Authorization': `Bearer ${request.token}` } : {})
      }
    };

    const req = httpModule.request(options, (res) => {
      // 检查响应状态
      if (res.statusCode !== 200) {
        let errorBody = '';
        res.on('data', chunk => errorBody += chunk);
        res.on('end', () => {
          // 检测是否是登录状态过期
          const isLoginExpired = errorBody.includes('登录状态已过期') ||
                                 errorBody.includes('token') && errorBody.includes('过期') ||
                                 res.statusCode === 401;

          if (isLoginExpired) {
            const error = new Error('LOGIN_EXPIRED:登录状态已过期，请重新登录');
            callbacks.onError?.({ message: error.message });
            reject(error);
          } else {
            const error = new Error(`SSE 连接失败: ${res.statusCode} ${errorBody}`);
            callbacks.onError?.({ message: error.message });
            reject(error);
          }
        });
        return;
      }

      // 连接成功
      console.log('[SSE] 连接已建立');
      controller.setConnected(true);
      callbacks.onOpen?.();
      resolve(controller);

      // 创建 SSE 解析器
      const parser = createParser({
        onEvent: (event) => {
          const eventType = event.event as SSEEventType;
          const eventData = event.data;

          if (!eventData) {
            console.log(`[SSE] 收到空事件: ${eventType}`);
            return;
          }

          try {
            const data = JSON.parse(eventData);
            console.log(`[SSE] 收到事件: ${eventType}`, data);

            // 分发事件到对应回调
            dispatchEvent(eventType, data, callbacks);
          } catch (e) {
            console.error(`[SSE] 解析事件数据失败: ${eventData}`, e);
          }
        }
      });

      // 设置编码
      res.setEncoding('utf8');

      // 处理数据流
      res.on('data', (chunk: string) => {
        if (!controller.aborted) {
          console.log('[SSE] 收到原始数据块:', chunk.substring(0, 200));

          // 检查是否是业务错误码（Gateway 返回 HTTP 200 但响应体是错误 JSON）
          try {
            const trimmed = chunk.trim();
            if (trimmed.startsWith('{') && trimmed.includes('"code"')) {
              const json = JSON.parse(trimmed);
              if (json.code === 401 || json.msg?.includes('登录状态已过期')) {
                console.log('[SSE] 检测到登录过期业务错误');
                const error = new Error('LOGIN_EXPIRED:登录状态已过期，请重新登录');
                callbacks.onError?.({ message: error.message });
                controller.abort();
                reject(error);
                return;
              }
            }
          } catch {
            // 不是 JSON 格式，继续正常处理
          }

          parser.feed(chunk);
        }
      });

      // 处理连接关闭
      res.on('end', () => {
        console.log('[SSE] 连接已关闭');
        controller.setConnected(false);
        callbacks.onClose?.();
      });

      // 处理错误
      res.on('error', (err) => {
        if (!controller.aborted) {
          console.error('[SSE] 响应错误:', err);
          controller.setConnected(false);
          callbacks.onError?.({ message: err.message });
        }
      });
    });

    // 保存请求引用用于中止
    controller.setRequest(req);

    // 处理请求错误
    req.on('error', (err) => {
      if (!controller.aborted) {
        console.error('[SSE] 请求错误:', err);
        controller.setConnected(false);
        callbacks.onError?.({ message: err.message });
        reject(err);
      }
    });

    // 处理超时
    const { timeout } = getConfig();
    req.setTimeout(timeout, () => {
      if (!controller.aborted) {
        console.error('[SSE] 请求超时');
        controller.abort();
        const error = new Error('请求超时');
        callbacks.onError?.({ message: error.message });
        reject(error);
      }
    });

    // 发送请求体
    req.write(body);
    req.end();
  });
}

/**
 * 分发 SSE 事件到对应回调
 */
function dispatchEvent(
  eventType: SSEEventType,
  data: unknown,
  callbacks: SSECallbacks
): void {
  switch (eventType) {
    case 'text_delta':
      callbacks.onTextDelta?.(data as TextDeltaEvent);
      break;
    case 'tool_call':
      callbacks.onToolCall?.(data as ToolCallRequest);
      break;
    case 'tool_confirm':
      callbacks.onToolConfirm?.(data as ToolConfirmEvent);
      break;
    case 'plan_confirm':
      callbacks.onPlanConfirm?.(data as PlanConfirmEvent);
      break;
    case 'phase_progress':
      callbacks.onPhaseProgress?.(data as import('../types/api').PhaseProgressEvent);
      break;
    case 'plan_step_add':
      callbacks.onPlanStepAdd?.(data as import('../types/api').PlanStepAddEvent);
      break;
    case 'plan_step_remove':
      callbacks.onPlanStepRemove?.(data as import('../types/api').PlanStepRemoveEvent);
      break;
    case 'plan_step_update':
      callbacks.onPlanStepUpdate?.(data as import('../types/api').PlanStepUpdateEvent);
      break;
    case 'plan_summary_update':
      callbacks.onPlanSummaryUpdate?.(data as import('../types/api').PlanSummaryUpdateEvent);
      break;
    case 'tool_start':
      callbacks.onToolStart?.(data as ToolStartEvent);
      break;
    case 'tool_complete':
      callbacks.onToolComplete?.(data as ToolCompleteEvent);
      break;
    case 'tool_error':
      callbacks.onToolError?.(data as ToolErrorEvent);
      break;
    case 'ask_user':
      callbacks.onAskUser?.(data as AskUserEvent);
      break;
    case 'complete':
      callbacks.onComplete?.(data as CompleteEvent);
      break;
    case 'error':
      callbacks.onError?.(data as ErrorEvent);
      break;
    case 'warning':
      callbacks.onWarning?.(data as WarningEvent);
      break;
    case 'notification':
      callbacks.onNotification?.(data as NotificationEvent);
      break;
    case 'depth_update':
      callbacks.onDepthUpdate?.(data as DepthUpdateEvent);
      break;
    case 'agent_start':
      callbacks.onAgentStart?.(data as AgentStartEvent);
      break;
    case 'agent_progress':
      callbacks.onAgentProgress?.(data as AgentProgressEvent);
      break;
    case 'agent_complete':
      callbacks.onAgentComplete?.(data as AgentCompleteEvent);
      break;
    case 'agent_error':
      callbacks.onAgentError?.(data as AgentErrorEvent);
      break;
    case 'memory_compacted':
      callbacks.onMemoryCompacted?.(data as MemoryCompactedEvent);
      break;
    case 'context_usage':
      callbacks.onContextUsage?.(data as ContextUsageEvent);
      break;
    case 'credit_update':
      callbacks.onCreditUpdate?.(data as CreditUpdateEvent);
      break;
    case 'heartbeat':
      // 心跳事件：仅用于保持连接，不需要特殊处理
      // Node.js req.setTimeout 会在收到数据时自动重置计时器
      console.log('[SSE] 收到心跳');
      break;
    default:
      console.log(`[SSE] 未知事件类型: ${eventType}`, data);
  }
}

/**
 * 生成任务ID
 */
export function generateTaskId(): string {
  return `task-${Date.now()}-${Math.random().toString(36).substring(2, 8)}`;
}