/**
 * IPC Agent Handlers — Agent 交互域（P2-9 从 handlers.ts 拆分）
 *
 * 职责：
 * 1. agent:sendMessage — 消息发送编排（历史加载/记忆注入/注入检测/runStream/持久化）
 * 2. agent:abortSession — 中断会话（联动 SubAgent）
 * 3. 常驻引擎事件管道 — 流式转发（按会话节流）、状态广播、TRACE 录制（P1-6 补全 9 种事件）、
 *    压缩/死循环/Provider 切换通知
 *
 * P2-10: 事件监听从"每消息 attach/detach"改为常驻管道（按 sessionId 隔离状态），
 * 支持多会话并发流式与多窗口广播。
 */

import { ipcMain } from 'electron';
import type { IPCContext } from './context';
import { broadcast } from './context';
import type { MetonaMessage, MetonaStreamEvent, MetonaError } from '../harness/types';
import { MetonaErrorCode, MetonaStreamEventType } from '../harness/types';
import { estimateMessagesTokens } from '../harness/utils/token-estimator';
import log from 'electron-log';

/** 单会话的 text_delta 节流状态 */
interface ThrottleState {
  buffer: string;
  lastEventMeta: Pick<MetonaStreamEvent, 'requestId' | 'sessionId' | 'iteration' | 'seq' | 'timestamp' | 'runId'> | null;
  flushTimer: ReturnType<typeof setTimeout> | null;
}

/** 单会话的迭代录制状态（TRACE 层） */
interface IterationTrace {
  iteration: number;
  startedAt: number;
  text: string;
  usage?: { input: number; output: number; total: number };
  responded: boolean; // 本轮 llm_response 是否已记录（PARSING 与下一轮 THINKING 去重）
}

export function registerAgentHandlers(ctx: IPCContext): void {
  const {
    agentEngineManager, sessionRecorder, configService, sessionService,
    workspaceService, contextBuilder, auditService, memoryManager,
    promptInjectionDefender, outputValidator, memoryConsolidator,
    sessionSummaryService, orchestrator, confirmationHook,
  } = ctx;

  // ===== 常驻事件管道：text_delta 按会话节流（F8） =====
  const throttleStates = new Map<string, ThrottleState>();
  const iterationTraces = new Map<string, IterationTrace>();

  const flushThrottle = (sessionId: string): void => {
    const st = throttleStates.get(sessionId);
    if (!st) return;
    st.flushTimer = null;
    if (!st.buffer || !st.lastEventMeta) {
      st.buffer = '';
      st.lastEventMeta = null;
      return;
    }
    // 构建合并的 text_delta 事件，保留最后一个 delta 的元数据
    const mergedEvent: MetonaStreamEvent = {
      ...st.lastEventMeta,
      type: MetonaStreamEventType.TEXT_DELTA,
      delta: st.buffer,
      seq: st.lastEventMeta.seq,
      timestamp: Date.now(),
    };
    broadcast('agent:streamEvent', mergedEvent);
    st.buffer = '';
    st.lastEventMeta = null;
  };

  const cleanupSessionState = (sessionId: string): void => {
    const st = throttleStates.get(sessionId);
    if (st?.flushTimer) {
      clearTimeout(st.flushTimer);
      flushThrottle(sessionId);
    }
    throttleStates.delete(sessionId);
    iterationTraces.delete(sessionId);
  };

  // ===== 常驻监听：流式事件（节流转发 + TRACE 录制） =====
  agentEngineManager.on('streamEvent', (event: MetonaStreamEvent) => {
    if (!event.sessionId) return;
    const sessionId = event.sessionId;
    const trace = iterationTraces.get(sessionId);

    // F8: text_delta 聚合，其他事件立即转发（先 flush 保证顺序）
    if (event.type === MetonaStreamEventType.TEXT_DELTA && event.delta) {
      const st = throttleStates.get(sessionId) ?? {
        buffer: '', lastEventMeta: null, flushTimer: null,
      };
      throttleStates.set(sessionId, st);
      if (st.buffer === '') {
        st.lastEventMeta = {
          requestId: event.requestId,
          sessionId: event.sessionId,
          iteration: event.iteration,
          seq: event.seq,
          timestamp: event.timestamp,
          runId: event.runId,
        };
      } else if (st.lastEventMeta) {
        st.lastEventMeta = { ...st.lastEventMeta, seq: event.seq, timestamp: event.timestamp, runId: event.runId };
      }
      st.buffer += event.delta;
      if (st.flushTimer === null) {
        st.flushTimer = setTimeout(() => flushThrottle(sessionId), 32);
      }
      // TRACE: 累积本轮 LLM 文本（供 llm_response 记录）
      if (trace) trace.text += event.delta;
      return;
    }

    // 非 text_delta 事件：先 flush 缓冲区，再立即转发（保证事件顺序）
    const st = throttleStates.get(sessionId);
    if (st?.flushTimer) {
      clearTimeout(st.flushTimer);
      flushThrottle(sessionId);
    }

    // TRACE: 工具调用/结果/usage 录制（P1-6 补全）
    switch (event.type) {
      case MetonaStreamEventType.TOOL_CALL_COMPLETE:
        if (event.toolCall) {
          sessionRecorder.recordToolCall({
            sessionId,
            iteration: event.iteration,
            toolName: event.toolCall.name,
            args: event.toolCall.args,
          });
        }
        break;
      case MetonaStreamEventType.TOOL_RESULT:
        if (event.toolResult) {
          const resultPreview = typeof event.toolResult.result === 'string'
            ? event.toolResult.result
            : JSON.stringify(event.toolResult.result);
          sessionRecorder.recordToolResult({
            sessionId,
            iteration: event.iteration,
            toolName: event.toolResult.toolName,
            success: event.toolResult.success,
            durationMs: event.toolResult.durationMs ?? 0,
            resultPreview,
            error: event.toolResult.error,
          });
        }
        break;
      case MetonaStreamEventType.USAGE:
        if (trace && event.usage) {
          trace.usage = {
            input: event.usage.inputTokens ?? 0,
            output: event.usage.outputTokens ?? 0,
            total: event.usage.totalTokens ?? 0,
          };
        }
        break;
      case MetonaStreamEventType.DONE:
        cleanupSessionState(sessionId);
        break;
      default:
        break;
    }

    broadcast('agent:streamEvent', event);
  });

  // ===== 常驻监听：状态变化（广播 + TRACE 迭代录制） =====
  agentEngineManager.on('stateChange', (data: {
    previous?: string; current?: string; state?: string;
    sessionId?: string; iteration?: number; runId?: string;
  }) => {
    if (data.previous) log.info(`[AGENT] State: ${data.previous} → ${data.current}`);
    broadcast('agent:stateChange', data);

    const sessionId = data.sessionId;
    if (!sessionId || data.iteration == null) return;
    const stateValue = data.state ?? data.current ?? '';
    const trace = iterationTraces.get(sessionId);

    // THINKING 且迭代号变化 → 新迭代开始（关闭上一迭代）
    if (stateValue === 'THINKING' && (!trace || trace.iteration !== data.iteration)) {
      if (trace && !trace.responded) {
        sessionRecorder.recordLLMResponse({
          sessionId,
          iteration: trace.iteration,
          content: trace.text,
          finishReason: 'stop',
          tokenUsage: trace.usage ?? { input: 0, output: 0, total: 0 },
        });
      }
      if (trace) {
        sessionRecorder.recordIterationEnd(sessionId, {
          iteration: trace.iteration,
          durationMs: Date.now() - trace.startedAt,
        });
      }
      iterationTraces.set(sessionId, {
        iteration: data.iteration,
        startedAt: Date.now(),
        text: '',
        responded: false,
      });
      sessionRecorder.recordIterationStart(sessionId, data.iteration);
      const provider = configService.get<string>('llm.provider') ?? '';
      const model = configService.get<string>('llm.model') ?? '';
      sessionRecorder.recordLLMRequest({
        sessionId,
        iteration: data.iteration,
        provider,
        model,
        messageCount: data.iteration + 1,
      });
    }

    // PARSING → 本轮流式结束，记录 llm_response
    if (stateValue === 'PARSING' && trace && trace.iteration === data.iteration && !trace.responded) {
      trace.responded = true;
      sessionRecorder.recordLLMResponse({
        sessionId,
        iteration: trace.iteration,
        content: trace.text,
        finishReason: 'stop',
        tokenUsage: trace.usage ?? { input: 0, output: 0, total: 0 },
      });
    }

    // TERMINATED → 补记最终迭代的 iteration_end（正常流程只在下一轮 THINKING 补记，
    // 最终轮无后续迭代，需在此补齐 TRACE 完整性）+ 兜底清理会话管道状态
    if (stateValue === 'TERMINATED') {
      if (trace) {
        sessionRecorder.recordIterationEnd(sessionId, {
          iteration: trace.iteration,
          durationMs: Date.now() - trace.startedAt,
        });
      }
      cleanupSessionState(sessionId);
    }
  });

  // ===== 常驻监听：上下文压缩（toast + streamEvent 通知） =====
  agentEngineManager.on('compressed', (data: {
    sessionId?: string; iteration?: number; originalTokens?: number; compressedTokens?: number;
  }) => {
    const savedTokens = Math.max(0, (data.originalTokens ?? 0) - (data.compressedTokens ?? 0));
    // toast 通知用户压缩已发生
    broadcast('toast:show', {
      type: 'info',
      message: `上下文压缩: ${data.originalTokens ?? '?'} → ${data.compressedTokens ?? '?'} tokens（节省 ${savedTokens}）`,
    });
    // 通过 streamEvent 转发，前端 useAgentStream 监听 'compressed' 类型后更新 store
    broadcast('agent:streamEvent', {
      type: 'compressed',
      sessionId: data.sessionId ?? '',
      iteration: data.iteration ?? 0,
      originalTokens: data.originalTokens,
      compressedTokens: data.compressedTokens,
      savedTokens,
      timestamp: Date.now(),
    });
  });

  // ===== 常驻监听：死循环检测（toast 警告） =====
  agentEngineManager.on('deadLoop', (data: { iteration?: number; sessionId?: string }) => {
    log.warn(`[AGENT] Dead loop detected at iteration ${data.iteration ?? '?'}`);
    broadcast('toast:show', {
      type: 'warning',
      message: `检测到死循环（第 ${data.iteration ?? '?'} 轮）：连续3轮重复相同工具调用，已自动终止`,
    });
  });

  // ===== 常驻监听：Provider 故障转移（P1，通知前端 + toast） =====
  agentEngineManager.on('providerSwitched', (data: {
    from?: string; to?: string; reason?: string; sessionId?: string;
  }) => {
    broadcast('agent:providerSwitched', {
      from: data.from,
      to: data.to,
      reason: data.reason ?? 'failover',
      sessionId: data.sessionId ?? '',
    });
    broadcast('toast:show', {
      type: 'warning',
      message: `Provider 故障转移: ${data.from ?? '?'} → ${data.to ?? '?'}（主 Provider 请求失败）`,
    });
  });

  // ===== Agent 消息发送 =====

  ipcMain.handle('agent:sendMessage', async (_event, userMessage: MetonaMessage, sessionId: string) => {
    // M-33 修复: 参数校验，防止 undefined/非字符串导致下游异常
    // P1-5 修复: 校验失败时也发 ERROR+DONE 流事件，防止 isStreaming 永久卡死
    const sendErrorEvent = (message: string, sid: string): void => {
      const errorEvent: MetonaStreamEvent = {
        type: MetonaStreamEventType.ERROR,
        requestId: '', sessionId: sid, iteration: 0, seq: 0, timestamp: Date.now(),
        error: { code: MetonaErrorCode.UNKNOWN, message, retryable: false },
      };
      broadcast('agent:streamEvent', errorEvent);
      broadcast('agent:streamEvent', { ...errorEvent, type: MetonaStreamEventType.DONE });
    };

    if (!sessionId || typeof sessionId !== 'string') {
      log.warn('[AGENT] sendMessage rejected: invalid sessionId');
      sendErrorEvent('无效的会话 ID', sessionId ?? '');
      return { success: false, error: 'Invalid sessionId' };
    }
    if (!userMessage || typeof userMessage !== 'object' || typeof userMessage.content !== 'string') {
      log.warn('[AGENT] sendMessage rejected: invalid userMessage');
      sendErrorEvent('无效的消息格式', sessionId);
      return { success: false, error: 'Invalid message format' };
    }
    log.info('[AGENT] sendMessage:', sessionId, (userMessage.content ?? '').slice(0, 80));

    // 发送消息前确保 Adapter 使用最新配置（失败则中止，防止用旧 Provider 的 adapter 发送）
    if (!ctx.reloadAdapter()) {
      const errorMsg = 'Adapter 加载失败，请检查 LLM 配置（Provider、API Key、Base URL、Model 是否完整）';
      log.error('[AGENT]', errorMsg);
      sendErrorEvent(errorMsg, sessionId);
      sessionRecorder.stopRecording(sessionId, { totalIterations: 0, totalTokens: 0, durationMs: 0, terminationReason: 'error' });
      return { success: false, error: errorMsg };
    }

    // TRACE 层：开始录制 / TOOL 层：记录会话开始
    sessionRecorder.startRecording(sessionId);
    auditService.logSessionStart(sessionId);

    // 保存用户消息到数据库
    sessionService.saveMessage({
      sessionId,
      role: 'user',
      content: userMessage.content,
      attachments: (userMessage as MetonaMessage & { attachments?: unknown[] }).attachments,
    });

    // P2-11: 分层加载历史——存在滚动摘要时只加载 [摘要 + 近期原文]
    const history = sessionSummaryService.buildHistoryMessages(sessionId).slice(0, -1);

    // 从工作空间文件构建 System Prompt
    const workspaceFiles = workspaceService.getFiles();
    const systemPrompt = contextBuilder.buildSystemPrompt(workspaceFiles, workspaceService.getPath());

    // v0.3.18 修复: SOUL.md 为空或不存在时降级到默认身份，向前端发 toast 提示用户
    if (contextBuilder.isUsingFallbackRole()) {
      broadcast('toast:show', {
        type: 'info',
        message: '未找到 SOUL.md 或内容为空，已使用默认 Metona 身份。可在工作空间根目录创建 SOUL.md 自定义 Agent 人格',
      });
    }

    // 检索与用户消息相关的记忆，注入到 System Prompt 动态区
    try {
      const memories = memoryManager.search(userMessage.content, { topK: 5, minImportance: 0.3 });
      if (memories.length > 0) {
        const memorySection = memories.map((m, i) =>
          `[${i + 1}] (${m.type}, 重要度: ${m.importance.toFixed(1)}) ${m.content.slice(0, 200)}`,
        ).join('\n');
        const memoryBlock = `## Relevant Memories (Retrieved)\n${memorySection}`;
        systemPrompt.dynamicReminders = systemPrompt.dynamicReminders
          ? `${systemPrompt.dynamicReminders}\n\n---\n\n${memoryBlock}`
          : memoryBlock;
        log.debug(`[AGENT] Injected ${memories.length} memories into system prompt`);
      }
    } catch (err) {
      log.warn('[AGENT] Memory retrieval failed, proceeding without memories:', err);
    }

    // 附件提示注入：用户直接上传的文件/图片，避免 LLM 误以为需要在工作空间查找
    const attachments = (userMessage as MetonaMessage & { attachments?: Array<{ name: string; type: string }> }).attachments;
    if (Array.isArray(attachments) && attachments.length > 0) {
      const attachmentList = attachments.map((att, i) => {
        const typeLabel = att.type === 'image' ? 'image' : att.type === 'text' ? 'text file' : 'file';
        const note = att.type === 'image'
          ? 'already provided to you via vision capability — you can SEE it directly, do NOT call view_image or any tool to read it again'
          : att.type === 'text'
            ? 'content already inlined in the user message, do NOT search in workspace or read it again'
            : 'uploaded directly by user, do NOT search in workspace';
        return `${i + 1}. [${typeLabel}] ${att.name} — ${note}`;
      }).join('\n');

      const attachmentBlock = `## User Attachments (Direct Upload)\nThe following files were uploaded directly by the user to this conversation. They are inline attachments, NOT workspace files:\n${attachmentList}\n\n**IMPORTANT**: Images listed above are already visible to you in this conversation. Do NOT call \`view_image\`, \`read_file\`, or any file tool to read them — doing so wastes a tool call and may fail (they are not workspace files).`;

      systemPrompt.dynamicReminders = systemPrompt.dynamicReminders
        ? `${systemPrompt.dynamicReminders}\n\n---\n\n${attachmentBlock}`
        : attachmentBlock;

      log.debug(`[AGENT] Injected ${attachments.length} attachment hints into system prompt`);
    }

    try {
      // 提示注入检测（安全模块）
      const injectionResult = promptInjectionDefender.detect(userMessage.content);
      if (injectionResult.riskScore >= 7) {
        log.warn('[PromptInjectionDefender] Blocked message:', injectionResult.findings);
        sendErrorEvent(`Message blocked by prompt injection defense: ${injectionResult.recommendation}`, sessionId);
        sessionRecorder.stopRecording(sessionId, {
          totalIterations: 0, totalTokens: 0, durationMs: 0, terminationReason: 'error',
        });
        return { success: false, error: 'Message blocked by prompt injection defense' };
      }
      if (injectionResult.riskScore >= 4) {
        log.warn('[PromptInjectionDefender] Suspicious patterns detected:', injectionResult.findings);
      }

      // TRACE 层：记录上下文构建
      sessionRecorder.recordContextBuilt(sessionId, {
        tokenCount: estimateMessagesTokens(history),
        usageRatio: 0,
      });

      // 启动 Agent Loop（P2-10: 每会话独立引擎）
      const engine = agentEngineManager.getEngine(sessionId);
      const output = await engine.runStream(userMessage, sessionId, history, systemPrompt);

      // 输出验证（不阻塞响应，仅记录警告）
      // v0.3.0 修复: 传入 toolResults 和 context，启用事实一致性检查和幻觉检测
      try {
        const toolResults = output.iterations
          .flatMap((step) => step.toolResults ?? [])
          .map((r) => (typeof r.result === 'string' ? r.result : JSON.stringify(r.result)));
        const context = [...history, { role: 'user', content: userMessage.content }]
          .map((m) => `${m.role}: ${m.content}`).join('\n');
        const validation = await outputValidator.validate(output.finalAnswer, {
          toolResults: toolResults.length > 0 ? toolResults : undefined,
          context,
        });
        if (!validation.valid || validation.issues.length > 0) {
          log.warn('[OutputValidator] Validation issues:', validation.issues);
        }
        log.debug(`[OutputValidator] Score: ${validation.score}, Valid: ${validation.valid}`);
      } catch (err) {
        log.error('[OutputValidator] Validation failed:', err);
      }

      // 保存每轮迭代的 assistant 消息到数据库（含思考内容和工具调用）
      for (const step of output.iterations) {
        if (!step.thought) continue;

        const toolCallsWithResults = step.toolCalls?.map((tc) => {
          const result = step.toolResults?.find((r) => r.toolCallId === tc.id);
          return {
            id: tc.id,
            name: tc.name,
            args: tc.args,
            status: result?.success ? 'success' as const : 'error' as const,
            result: result?.result,
            durationMs: result?.durationMs,
            error: result?.error,
          };
        });

        // 只有当有内容、思考内容或工具调用时才保存
        if (step.thought.content || step.thought.reasoningContent || toolCallsWithResults?.length) {
          // C-6 修复: assistant 消息仅有 tool_calls 时 content 必须为 null（而非空字符串）
          const assistantContent = (toolCallsWithResults?.length && !step.thought.content)
            ? null
            : step.thought.content;
          sessionService.saveMessage({
            sessionId,
            role: 'assistant',
            content: assistantContent,
            reasoningContent: step.thought.reasoningContent || undefined,
            toolCalls: toolCallsWithResults,
            iteration: step.iteration,
          });
        }

        // v0.3.0 修复: 保存 tool 结果消息到数据库
        // OpenAI 兼容 API 要求 assistant 消息有 tool_calls 时，后续必须有对应的 tool 结果消息
        if (step.toolResults) {
          for (const result of step.toolResults) {
            const resultContent = typeof result.result === 'string'
              ? result.result
              : JSON.stringify(result.result);
            sessionService.saveMessage({
              sessionId,
              role: 'tool',
              content: result.error ?? resultContent,
              toolResult: result,
              iteration: step.iteration,
            });
          }
        }
      }

      // 更新 Token 统计
      if (output.totalTokenUsage.totalTokens > 0) {
        sessionService.updateTokenUsage(sessionId, output.totalTokenUsage.totalTokens);
      }

      // 更新 MEMORY.md 时间戳
      workspaceService.updateMemoryTimestamp();

      // 会话结束：AI 判断本次对话有哪些重要内容需要持久化到 MEMORY.md
      // 异步执行，不阻塞主流程返回；失败仅记录日志
      memoryConsolidator
        .consolidate(userMessage.content, output.finalAnswer, output.iterations)
        .then((result) => {
          if (result.appended > 0) {
            log.info(`[AGENT] Memory consolidated: ${result.appended} entries appended to MEMORY.md`);
            broadcast('toast:show', {
              type: 'info',
              message: `AI 已将 ${result.appended} 条重要记忆写入 MEMORY.md`,
            });
          }
        })
        .catch((err) => {
          log.warn('[AGENT] Memory consolidation failed:', err);
        });

      // TOOL 层：记录会话结束 / TRACE 层：停止录制
      auditService.logSessionEnd({
        sessionId,
        totalIterations: output.iterations.length,
        totalTokens: output.totalTokenUsage.totalTokens,
        durationMs: output.durationMs,
        terminationReason: output.terminationReason,
      });
      sessionRecorder.stopRecording(sessionId, {
        totalIterations: output.iterations.length,
        totalTokens: output.totalTokenUsage.totalTokens,
        durationMs: output.durationMs,
        terminationReason: output.terminationReason,
      });

      // P2-11: 会话结束后评估滚动摘要（fire-and-forget，失败仅记录）
      sessionSummaryService.maybeSummarize(sessionId).catch((err) => {
        log.warn('[AGENT] Session summary generation failed:', err);
      });

      log.info(`[AGENT] Completed: ${output.terminationReason}, ${output.iterations.length} iterations, ${output.durationMs}ms`);

      return { success: true };
    } catch (error) {
      log.error('[AGENT] Error:', error);

      // TOOL 层：记录错误
      auditService.log({
        sessionId,
        eventType: 'error',
        actor: 'agent',
        target: 'agent_loop',
        details: { error: (error as Error).message },
        outcome: 'error',
      });

      // TRACE 层：停止录制
      sessionRecorder.stopRecording(sessionId, {
        totalIterations: 0, totalTokens: 0, durationMs: 0, terminationReason: 'error',
      });

      // 发送错误事件到 UI
      const metonaError: MetonaError = {
        code: MetonaErrorCode.UNKNOWN,
        message: (error as Error).message,
        retryable: false,
      };
      broadcast('agent:streamEvent', {
        type: MetonaStreamEventType.ERROR,
        requestId: '', sessionId, iteration: 0, seq: 0, timestamp: Date.now(),
        error: metonaError,
      } satisfies MetonaStreamEvent);

      return { success: false, error: (error as Error).message };
    }
  });

  // ===== 中断会话 =====

  ipcMain.handle('agent:abortSession', async (_event, sessionId) => {
    log.info('[AGENT] Abort:', sessionId);
    // P2-10: 联动中断该会话派生的所有 SubAgent（消除"会话停了子任务还在跑"）
    orchestrator.abortByParent(sessionId);
    agentEngineManager.abort(sessionId);
    // MT-1 修复: 等待当前 run 完全结束再返回，防止用户立即重发时新消息卡在等待中
    await agentEngineManager.waitForAbort(sessionId);
    // v0.3.0 修复: 清理所有等待中的工具确认，避免定时器泄漏和超时 toast 在新会话中弹出
    confirmationHook.clearPending();

    // TOOL 层：记录中断
    auditService.log({
      sessionId,
      eventType: 'session_end',
      actor: 'user',
      target: 'session',
      details: { reason: 'user_abort' },
      outcome: 'denied',
    });

    return { success: true };
  });
}