/**
 * Agent Chat Route — 通用 Agent 对话 SSE 端点
 *
 * 存储架构：conversations/agents/{agentId}/{conversationId}/
 *    ├── meta.json                    ← 对话元数据
 *    ├── {messageId}/messages.log     ← 每轮对话日志
 *    └── history.json                 ← 有序的消息列表（供前端展示 + 上下文恢复）
 *
 * 多轮对话：
 *    - ClaudeCliProtocol 持久进程 → 天然多轮
 *    - 服务器重启后自动恢复：从 history.json 加载历史，注入 system prompt + 历史摘要
 *
 * 使用 @mas/acp-core 的 ClaudeCliProtocol。
 */
const express = require('express');
const path = require('path');
const fs = require('fs');
const { randomUUID } = require('crypto');
const { ClaudeCliProtocol } = require('@mas/acp-core');
const { Parser } = require('../src/core/parser');
const AgentManager = require('../src/core/agent-manager');
const systemConfig = require('../config');
const router = express.Router();

const DATA_DIR = path.resolve(__dirname, '../../data/agents');
// CONV_ROOT is now dynamically evaluated per-agent based on DATA_DIR.

function loadSystemConfig() {
    const configDir = path.resolve(__dirname, '../config');
    const backends = JSON.parse(fs.readFileSync(path.join(configDir, 'backends.json'), 'utf-8'));
    const { loadConfigFromSkills } = require('../src/core/skill-config-loader');
    const skillsDir = systemConfig.skillsCodeDir;
    return loadConfigFromSkills(skillsDir, backends);
}

const fullSystemConfig = loadSystemConfig();
// 初始化 AgentManager 用于 Sub-Agent 调用
const agentManager = new AgentManager(fullSystemConfig, path.resolve(__dirname, '../../'));

// ═══════════════════════════════════════
//  Bootstrap 工具
// ═══════════════════════════════════════

function loadFile(agentDir, filename) {
  try { return fs.readFileSync(path.join(agentDir, filename), 'utf-8'); }
  catch { return ''; }
}

function buildSystemPrompt(agentDir) {
  const files = ['agent.md', 'soul.md', 'identity.md', 'user.md', 'tools.md'];
  const parts = [];
  const agentListText = Object.entries(fullSystemConfig.agents || {})
    .filter(([name]) => name !== 'master' && name !== 'innovator')
    .map(([name, cfg]) => {
        const typeLabel = cfg.type === 'orchestrator' ? '子编排' : cfg.type;
        return `- ${name} (${typeLabel}): ${cfg.description || ''}`;
    })
    .join('\n');

  for (const f of files) {
    let c = loadFile(agentDir, f);
    if (c.trim()) {
      // 替换代理占位符模板
      if (c.includes('{{AVAILABLE_AGENTS}}')) {
        c = c.replace('{{AVAILABLE_AGENTS}}', agentListText);
      }
      parts.push(c.trim());
    }
  }
  const memory = loadFile(agentDir, 'memory/memory.md');
  if (memory.trim()) parts.push('---\n\n# 我的记忆\n\n' + memory.trim());
  let mainSkill = loadFile(agentDir, '.claude/skills/main_skill/SKILL.md');
  if (mainSkill.trim()) {
    if (mainSkill.includes('{{AVAILABLE_AGENTS}}')) {
      mainSkill = mainSkill.replace('{{AVAILABLE_AGENTS}}', agentListText);
    }
    parts.push('---\n\n# 我的核心主技能 (执行准则)\n\n' + mainSkill.trim());
  }
  const skills = loadFile(agentDir, '.claude/skills/skills.md');
  if (skills.trim()) parts.push('---\n\n' + skills.trim());
  return parts.join('\n\n---\n\n');
}

function loadAgentConfig(agentDir) {
  try { return JSON.parse(fs.readFileSync(path.join(agentDir, 'config.json'), 'utf-8')); }
  catch { return null; }
}

function loadIdentity(agentDir) {
  const content = loadFile(agentDir, 'identity.md');
  const r = { name: 'Agent', emoji: '🤖', greeting: '' };
  const nm = content.match(/名称:\s*(.+)/);   if (nm) r.name = nm[1].trim();
  const em = content.match(/Emoji:\s*(.+)/);   if (em) r.emoji = em[1].trim();
  const gm = content.match(/## 问候语\n"?([^"]*)"?/s);
  if (gm) r.greeting = gm[1].trim().replace(/^"|"$/g, '');
  return r;
}

function setupSSE(res) {
  res.writeHead(200, {
    'Content-Type': 'text/event-stream', 'Cache-Control': 'no-cache',
    'Connection': 'keep-alive', 'X-Accel-Buffering': 'no',
  });
  return (event, data) => res.write(`event: ${event}\ndata: ${JSON.stringify(data)}\n\n`);
}

// ═══════════════════════════════════════
//  对话存储 — conversationId/messageId 两层
// ═══════════════════════════════════════

function getConvDir(agentId, convId) {
  const dir = path.join(DATA_DIR, agentId, 'conversations', convId);
  if (!fs.existsSync(dir)) fs.mkdirSync(dir, { recursive: true });
  return dir;
}

/** 读写 meta.json */
function loadMeta(agentId, convId) {
  try {
    return JSON.parse(fs.readFileSync(path.join(DATA_DIR, agentId, 'conversations', convId, 'meta.json'), 'utf-8'));
  } catch { return null; }
}

function saveMeta(agentId, convId, meta) {
  const dir = getConvDir(agentId, convId);
  meta.updatedAt = new Date().toISOString();
  fs.writeFileSync(path.join(dir, 'meta.json'), JSON.stringify(meta, null, 2));
}

/** 读写 history.json — 有序消息列表 */
function loadHistory(agentId, convId) {
  try {
    return JSON.parse(fs.readFileSync(path.join(DATA_DIR, agentId, 'conversations', convId, 'history.json'), 'utf-8'));
  } catch { return []; }
}

function appendHistory(agentId, convId, msg) {
  const history = loadHistory(agentId, convId);
  history.push(msg);
  const dir = getConvDir(agentId, convId);
  fs.writeFileSync(path.join(dir, 'history.json'), JSON.stringify(history, null, 2));
}

/** 写日志（流式或单次） */
function logMessageChunk(agentId, convId, content) {
  const dir = getConvDir(agentId, convId);
  fs.appendFileSync(path.join(dir, 'messages.log'), content, 'utf-8');
}

/** 传统单次写日志 (为了兼容) */
function logMessage(agentId, convId, role, content) {
  const ts = new Date().toISOString();
  const tag = role === 'user' ? 'USER' : 'AGENT';
  const line = `[${ts}] [${tag}]\n${content}\n\n`;
  logMessageChunk(agentId, convId, line);
}

function listConversations(agentId) {
  const agentConvDir = path.join(DATA_DIR, agentId, 'conversations');
  if (!fs.existsSync(agentConvDir)) return [];
  try {
    return fs.readdirSync(agentConvDir, { withFileTypes: true })
      .filter(d => d.isDirectory())
      .map(d => {
        const m = loadMeta(agentId, d.name);
        if (m) m.id = m.id || m.conversationId || d.name;
        return m;
      })
      .filter(Boolean)
      .sort((a, b) => new Date(b.updatedAt).getTime() - new Date(a.updatedAt).getTime());
  } catch { return []; }
}

// ═══════════════════════════════════════
//  ACP Session 池 — 支持多轮 + 上下文恢复
// ═══════════════════════════════════════

// key: `${agentId}:${conversationId}` → { protocol, messageCount }
const sessions = new Map();

async function getOrCreateProtocol(agentId, convId) {
  const key = `${agentId}:${convId}`;
  let entry = sessions.get(key);

  if (entry && entry.protocol.isConnected) {
    return entry;
  }

  // 关闭旧的
  if (entry) {
    try { entry.protocol.disconnect(); } catch {}
  }

  const agentDir = path.join(DATA_DIR, agentId);
  const identity = loadIdentity(agentDir);

  const protocol = new ClaudeCliProtocol({ name: identity.name });
  await protocol.connect(null, agentDir);
  await protocol.initialize();
  await protocol.newSession({ cwd: agentDir });

  const newEntry = { protocol, messageCount: 0, agentId, convId };
  sessions.set(key, newEntry);
  console.log(`[AgentChat] 🧬 ${identity.name} ACP 会话已创建 (conv: ${convId})`);

  return newEntry;
}

/**
 * 构建 prompt — 根据是否首次消息 & 是否有历史上下文
 *
 * 场景 A: 全新对话的第一条消息 → system prompt + 用户消息
 * 场景 B: 同一进程中的后续消息 → 直接发消息（ACP 自带上下文）
 * 场景 C: 服务重启后恢复对话 → system prompt + 历史摘要 + 用户消息
 */
function buildPrompt(agentDir, agentId, convId, userMessage, isNewSession) {
  if (!isNewSession) {
    // 场景 B: ACP 进程还在，多轮上下文自动保持
    return userMessage;
  }

  const systemPrompt = buildSystemPrompt(agentDir);
  const history = loadHistory(agentId, convId);

  if (history.length === 0) {
    // 场景 A: 全新对话
    return `${systemPrompt}\n\n---\n\n## 用户消息\n\n${userMessage}`;
  }

  // 场景 C: 恢复上下文 — 注入历史摘要
  const recentHistory = history.slice(-20); // 最近 20 条
  const historyText = recentHistory.map(m => {
    const role = m.role === 'user' ? 'Human' : 'Assistant';
    const content = m.content.length > 500 ? m.content.slice(0, 500) + '...(截断)' : m.content;
    return `${role}: ${content}`;
  }).join('\n\n');

  return `${systemPrompt}\n\n---\n\n## 之前的对话历史（供你参考以保持上下文连贯）\n\n${historyText}\n\n---\n\n## 用户新消息\n\n${userMessage}`;
}

// ═══════════════════════════════════════
//  路由
// ═══════════════════════════════════════

router.get('/list', (req, res) => {
  try {
    if (!fs.existsSync(DATA_DIR)) return res.json([]);
    const entries = fs.readdirSync(DATA_DIR, { withFileTypes: true });
    const agents = entries.filter(e => e.isDirectory()).map(e => {
      const agentDir = path.join(DATA_DIR, e.name);
      const config = loadAgentConfig(agentDir);
      if (!config) return null;
      const identity = loadIdentity(agentDir);
      return { id: config.id || e.name, name: identity.name, emoji: identity.emoji, type: config.type, status: config.status, greeting: identity.greeting };
    }).filter(Boolean);
    res.json(agents);
  } catch (err) { res.status(500).json({ error: err.message }); }
});

router.get('/:agentId/info', (req, res) => {
  const agentDir = path.join(DATA_DIR, req.params.agentId);
  if (!fs.existsSync(agentDir)) return res.status(404).json({ error: 'Agent not found' });
  const config = loadAgentConfig(agentDir); const identity = loadIdentity(agentDir);
  res.json({ id: config?.id || req.params.agentId, ...identity, type: config?.type, status: config?.status,
    bootstrapFiles: ['agent.md','soul.md','identity.md','user.md','tools.md','heartbeat.md'].filter(f => loadFile(agentDir, f).trim().length > 0),
  });
});

/** 列出对话 */
router.get('/:agentId/conversations', (req, res) => {
  res.json(listConversations(req.params.agentId));
});

/** 获取对话详情 (meta + history) */
router.get('/:agentId/conversations/:convId', (req, res) => {
  const { agentId, convId } = req.params;
  const meta = loadMeta(agentId, convId);
  if (!meta) return res.status(404).json({ error: 'Not found' });
  const messages = loadHistory(agentId, convId);
  res.json({ ...meta, messages });
});

/** 删除对话 */
router.delete('/:agentId/conversations/:convId', (req, res) => {
  const { agentId, convId } = req.params;
  try {
    const dir = path.join(DATA_DIR, agentId, 'conversations', convId);
    if (fs.existsSync(dir)) fs.rmSync(dir, { recursive: true, force: true });
    const key = `${agentId}:${convId}`;
    const entry = sessions.get(key);
    if (entry && entry.protocol) entry.protocol.disconnect();
    sessions.delete(key);
    res.json({ success: true });
  } catch (err) { res.status(500).json({ error: err.message }); }
});

/** 停止当前正在生成的任务 */
router.post('/:agentId/chat/:convId/stop', (req, res) => {
  const { agentId, convId } = req.params;
  const key = `${agentId}:${convId}`;
  const entry = sessions.get(key);
  if (entry && entry.protocol) {
    entry.protocol.disconnect(); // 关闭底层 claude cli 进程
    sessions.delete(key); // 下次从冷启动重新加载
    return res.json({ success: true, message: 'Agent 已中断' });
  }
  res.json({ success: false, message: '未找到运行中的 Agent 进程' });
});

/** 读取 bootstrap file */
router.get('/:agentId/bootstrap/:filename', (req, res) => {
  const allowed = ['agent.md','soul.md','identity.md','user.md','tools.md','heartbeat.md'];
  if (!allowed.includes(req.params.filename)) return res.status(400).json({ error: 'Invalid' });
  res.json({ filename: req.params.filename, content: loadFile(path.join(DATA_DIR, req.params.agentId), req.params.filename) });
});

// ═══════════════════════════════════════
//  POST /api/agent/:agentId/chat — SSE 流式对话
// ═══════════════════════════════════════

router.post('/:agentId/chat', async (req, res) => {
  const { message, conversationId: reqConvId } = req.body;
  if (!message) return res.status(400).json({ error: 'message is required' });

  const agentId = req.params.agentId;
  const agentDir = path.join(DATA_DIR, agentId);
  if (!fs.existsSync(agentDir)) return res.status(404).json({ error: 'Agent not found' });

  const convId = reqConvId || `conv-${Date.now().toString(36)}`;
  const msgId = `msg-${Date.now()}-${randomUUID().substring(0, 8)}`;
  const sendSSE = setupSSE(res);
  const identity = loadIdentity(agentDir);

  // 确保 meta.json 存在
  let meta = loadMeta(agentId, convId);
  if (!meta) {
    meta = {
      conversationId: convId,
      agentId,
      title: message.slice(0, 50),
      createdAt: new Date().toISOString(),
      updatedAt: new Date().toISOString(),
      status: 'running',
      stats: { messageCount: 0, toolCallCount: 0 },
    };
  }
  if (!meta.stats) meta.stats = { messageCount: 0, toolCallCount: 0 };
  meta.stats.messageCount = (meta.stats.messageCount || 0) + 1;
  meta.status = 'running';
  saveMeta(agentId, convId, meta);

  // 写用户消息到两层存储
  logMessage(agentId, convId, 'user', message);
  appendHistory(agentId, convId, { role: 'user', content: message, messageId: msgId, timestamp: new Date().toISOString() });

  sendSSE('session', { conversationId: convId, agentId, messageId: msgId });
  sendSSE('thinking', { message: `${identity.emoji} ${identity.name} 思考中...` });

  let fullOutput = '';
  // 记录 Agent 开始回复的标识头
  logMessageChunk(agentId, convId, `[${new Date().toISOString()}] [AGENT]\n`);

  try {
    // 获取或创建 ACP 会话（per conversation）
    const entry = await getOrCreateProtocol(agentId, convId);
    const isNewSession = entry.messageCount === 0;

    // 构建 prompt（自动处理首次/后续/恢复三种场景）
    let prompt = buildPrompt(agentDir, agentId, convId, message, isNewSession);
    entry.messageCount++;

    let loopCount = 0;
    while (loopCount < 10) {
      loopCount++;
      fullOutput = ''; // Reset fullOutput for this turn

      // 监听流式事件
      const onUpdate = (payload) => {
        const update = payload.update;
        if (update?.sessionUpdate === 'agent_message_chunk' && update.content?.text) {
          fullOutput += update.content.text;
          logMessageChunk(agentId, convId, update.content.text);
          sendSSE('agent_output', { agent: agentId, message: update.content.text });
        } else if (update?.sessionUpdate === 'agent_thought_chunk' && update.content?.text) {
          logMessageChunk(agentId, convId, update.content.text);
          sendSSE('thinking', { message: update.content.text });
        }
      };

      const onAcpEvent = (event) => {
        if (event.method === 'claude/tool_use_start') {
          const toolMsg = `\n🔧 [TOOL_CALL] ${event.params.name} (ID: ${event.params.toolUseId || 'unknown'})\n`;
          logMessageChunk(agentId, convId, toolMsg);
          sendSSE('tool_call', { tool: event.params.name, message: `🔧 调用工具: ${event.params.name}` });
          meta.stats.toolCallCount = (meta.stats.toolCallCount || 0) + 1;
        } else if (event.method === 'claude/tool_use_success') {
          logMessageChunk(agentId, convId, `✅ [TOOL_SUCCESS] ${event.params.name}\n`);
        } else if (event.method === 'claude/tool_use_failure') {
          logMessageChunk(agentId, convId, `❌ [TOOL_ERROR] ${event.params.error}\n`);
        } else if (event.method === 'session/result') {
          if (!fullOutput && event.params?.result) {
            fullOutput = event.params.result;
            sendSSE('agent_output', { agent: agentId, message: event.params.result });
          }
        }
      };

      entry.protocol.on('session_update', onUpdate);
      entry.protocol.on('acp_event', onAcpEvent);

      // 发送 prompt 并等待完成
      await entry.protocol.sendPrompt(prompt);

      // 清理监听
      entry.protocol.off('session_update', onUpdate);
      entry.protocol.off('acp_event', onAcpEvent);

      // 持久化当前轮次的回复
      if (fullOutput) {
        logMessageChunk(agentId, convId, '\n\n'); 
        appendHistory(agentId, convId, { role: 'assistant', content: fullOutput, messageId: `msg-${Date.now()}-${loopCount}`, timestamp: new Date().toISOString() });
      }

      // 解析是否带有 [CALL: sub_agent] 标记
      const calls = Parser.parseCalls(fullOutput, { allowParallel: true, agents: fullSystemConfig.agents });
      if (calls.length === 0) {
        break; // 没有后续调用，当前回合结束
      }

      // 存在 Sub-Agent 嵌套调用
      logMessageChunk(agentId, convId, `\n\n[System] 执行子 Agent 编排调度（并行）...\n`);
      sendSSE('thinking', { message: `🔄 分析到系统编排指令，正在并行启动 ${calls.length} 个子代理...` });

      const resultsText = [];
      
      // 并行执行所有的 calls
      await Promise.all(calls.map(async (call) => {
        const callId = `sub-${randomUUID().substring(0, 6)}`;
        sendSSE('sub_agent', { event: 'start', callId, agent: call.agent, message: `🚀 开始执行: ${call.agent}...` });
        logMessageChunk(agentId, convId, `\n--- 调度 [${callId}]: ${call.agent} ---\n任务: ${call.task}\n\n`);
        try {
          // 调用 Sub Agent (l1/l2/l3 或其他)
          const res = await agentManager.callAgent(call.agent, call.task, {
             metadata: { parentConvId: convId, layer: 'sub' },
             onData: (chunk) => {
                 sendSSE('sub_agent', { event: 'chunk', callId, agent: call.agent, chunk });
             }
          });
          resultsText.push(`[Sub Agent ${call.agent} (${callId}) 返回结果]\n${res.output}\n[/Sub Agent ${call.agent} (${callId}) 返回结果]`);
          logMessageChunk(agentId, convId, `✅ 子 Agent ${call.agent} [${callId}] 执行成功。\n`);
          sendSSE('sub_agent', { event: 'done', callId, agent: call.agent, status: 'success', message: `✅ [${call.agent}] 执行完毕.` });
        } catch (subErr) {
          resultsText.push(`[Sub Agent ${call.agent} (${callId}) 执行失败]\n${subErr.message}\n[/Sub Agent ${call.agent} (${callId}) 执行失败]`);
          logMessageChunk(agentId, convId, `❌ 子 Agent ${call.agent} [${callId}] 失败: ${subErr.message}\n`);
          sendSSE('sub_agent', { event: 'done', callId, agent: call.agent, status: 'error', message: `❌ [${call.agent}] 抛出异常: ${subErr.message}` });
        }
      }));

      // 构造下一次反思与后续动作的 Prompt
      prompt = `
## Sub Agent 执行结果反馈

${resultsText.join('\n\n')}

---
请对本次执行结果进行 Reflection 反思，并在确定所有步骤完成时，记得在对话结尾加上 [RESULT: DONE]。
`;
      
      // 更新消息计数和记录 User 视角的 system 反馈消息
      entry.messageCount++;
      logMessageChunk(agentId, convId, `\n[${new Date().toISOString()}] [SYSTEM FEEDBACK]\n${prompt}\n\n`);
      appendHistory(agentId, convId, { role: 'user', content: prompt, messageId: `sys-${Date.now()}`, timestamp: new Date().toISOString() });
      
      // 循环继续，下一次将会把这个反馈 prompt 发给 Innovator
      logMessageChunk(agentId, convId, `[${new Date().toISOString()}] [AGENT]\n`);
    }

    meta.status = 'completed';
    saveMeta(agentId, convId, meta);

    sendSSE('result', { conversationId: convId, agentId, messageId: msgId, output: fullOutput });

  } catch (err) {
    console.error('[AgentChat] Error:', err.message);
    logMessageChunk(agentId, convId, `\n\n[ERROR]\n${err.message}\n\n`);
    meta.status = 'failed';
    meta.error = err.message;
    saveMeta(agentId, convId, meta);

    // 清理断开的 session
    const key = `${agentId}:${convId}`;
    sessions.delete(key);

    sendSSE('error', { message: err.message });
  } finally {
    res.end();
  }
});

module.exports = router;