'use strict';
// Claude 引擎：spawn `claude -p --output-format stream-json --verbose`，逐行解析事件。
// prompt 走 stdin（-p 沒有位置參數時讀 stdin），任意文字都安全。
// 沙盒對應：read-only → 禁用寫檔/執行工具；workspace-write → 自動接受檔案編輯（不執行指令）；
//           danger-full-access → 跳過所有權限確認。
const { spawn, execSync } = require('child_process');
const fs = require('fs');
const os = require('os');
const path = require('path');

const LOCAL_BIN = path.join(os.homedir(), '.local', 'bin');
let cachedCommand = null;

// 找 claude 執行檔實體：pm2 daemon 的 PATH 不一定帶到 ~/.local/bin（原生安裝位置），直接補找
function resolveClaudeCommand(config) {
  const custom = config && config.claudePath;
  if (custom) return { cmd: custom, shell: /\.cmd$/i.test(custom) };
  if (cachedCommand) return cachedCommand;
  const names = process.platform === 'win32' ? ['claude.exe', 'claude.cmd'] : ['claude'];
  const dirs = [...(process.env.PATH || '').split(path.delimiter), LOCAL_BIN];
  for (const dir of dirs) {
    if (!dir) continue;
    for (const n of names) {
      const p = path.join(dir, n);
      if (fs.existsSync(p)) {
        cachedCommand = { cmd: p, shell: /\.cmd$/i.test(p) };
        return cachedCommand;
      }
    }
  }
  cachedCommand = { cmd: 'claude', shell: process.platform === 'win32' };
  return cachedCommand;
}

// 只有退回 shell（.cmd shim）時才需要引號；參數裡不會有引號，包起來即可
function quoteForShell(s) {
  return /[\s"]/.test(s) ? `"${s.replace(/"/g, '\\"')}"` : s;
}

function killTree(proc) {
  if (process.platform === 'win32') {
    try { execSync(`taskkill /pid ${proc.pid} /T /F`, { windowsHide: true, stdio: 'ignore' }); } catch { /* ignore */ }
  } else {
    try { proc.kill('SIGKILL'); } catch { /* ignore */ }
  }
}

const TOOL_LABELS = {
  Bash: '⚙️ 執行指令',
  Read: '📖 讀取檔案',
  Write: '✏️ 寫入檔案',
  Edit: '✏️ 編輯檔案',
  MultiEdit: '✏️ 編輯檔案',
  NotebookEdit: '✏️ 編輯筆記本',
  Glob: '🔍 搜尋檔案',
  Grep: '🔍 搜尋內容',
  WebFetch: '🌐 擷取網頁',
  WebSearch: '🔎 搜尋網路',
  Agent: '🤖 派出子代理',
  Task: '🤖 派出子代理',
};

function permissionArgs(sandbox) {
  switch (sandbox) {
    case 'read-only':
      return ['--permission-mode', 'default', '--disallowedTools', 'Write,Edit,MultiEdit,NotebookEdit,Bash'];
    case 'danger-full-access':
      return ['--dangerously-skip-permissions'];
    default: // workspace-write
      return ['--permission-mode', 'acceptEdits'];
  }
}

/**
 * 執行一輪 Claude 對話。介面同 engines/codex.js 的 run。
 * @returns {Promise<{text: string, threadId: string|null, usage: object|null, model: string|null, denials: object[]}>}
 */
function run({ config, prompt, threadId, images = [], onProgress }) {
  return new Promise((resolve, reject) => {
    const { cmd, shell } = resolveClaudeCommand(config);

    const args = ['-p', '--output-format', 'stream-json', '--verbose'];
    if (config.model) args.push('--model', config.model);
    if (config.reasoningEffort) args.push('--effort', config.reasoningEffort);
    args.push(...permissionArgs(config.sandbox));
    // 附圖：claude -p 沒有圖片參數，改讓 Read 工具讀（要先把暫存目錄加進允許範圍）
    if (images.length > 0) args.push('--add-dir', path.dirname(images[0]));
    if (threadId) args.push('--resume', threadId);

    let fullPrompt = prompt;
    if (images.length > 0) {
      fullPrompt += '\n\n【附圖】請先用 Read 工具讀取下列圖片檔再處理：\n' + images.join('\n');
    }

    const env = { ...process.env };
    // 讓子程序也找得到 claude 與它可能呼叫的工具
    env.PATH = `${env.PATH || ''}${path.delimiter}${LOCAL_BIN}`;

    const proc = shell
      ? spawn(quoteForShell(cmd) + ' ' + args.map(quoteForShell).join(' '), { cwd: config.workDir, env, shell: true, windowsHide: true, stdio: ['pipe', 'pipe', 'pipe'] })
      : spawn(cmd, args, { cwd: config.workDir, env, windowsHide: true, stdio: ['pipe', 'pipe', 'pipe'] });

    proc.stdin.write(fullPrompt);
    proc.stdin.end();

    let buffer = '';
    let stderrTail = '';
    let sessionId = threadId || null;
    let model = null;
    let resultText = null;
    let resultError = null;
    let usage = null;
    let denials = [];
    let lastText = '';

    const timer = setTimeout(() => {
      killTree(proc);
      reject(new Error(`Claude 逾時（${config.timeoutMinutes} 分鐘）`));
    }, config.timeoutMinutes * 60 * 1000);

    const handleEvent = (obj) => {
      if (obj.type === 'system') {
        if (obj.session_id) sessionId = obj.session_id;
        if (obj.subtype === 'init' && obj.model) model = obj.model;
        return;
      }
      if (obj.type === 'assistant') {
        if (obj.message?.model) model = obj.message.model;
        if (!onProgress) return;
        let toolLabel = null;
        for (const block of obj.message?.content || []) {
          if (block.type === 'text' && block.text?.trim()) {
            const t = block.text.trim();
            lastText = t.length > 600 ? t.slice(0, 600) + '...' : t;
          } else if (block.type === 'tool_use') {
            let detail = '';
            if (block.name === 'Bash' && block.input?.command) {
              const c = String(block.input.command);
              detail = c.length > 300 ? c.slice(0, 300) + '...' : c;
            } else if (block.input?.file_path) {
              detail = String(block.input.file_path);
            }
            toolLabel = (TOOL_LABELS[block.name] || `🔧 ${block.name}`) + '...' + (detail ? '\n' + detail : '');
          }
        }
        if (toolLabel) onProgress(toolLabel);
        else if (lastText) onProgress('💬 ' + lastText);
        return;
      }
      if (obj.type === 'result') {
        if (obj.session_id) sessionId = obj.session_id;
        denials = Array.isArray(obj.permission_denials) ? obj.permission_denials : [];
        const u = obj.usage || null;
        if (u) {
          // iterations 有的話取最後一輪：那才是目前會話的實際上下文大小
          const iters = u.iterations;
          const ref = (Array.isArray(iters) && iters.length > 0) ? iters[iters.length - 1] : u;
          const mu = obj.modelUsage && (obj.modelUsage[model] || Object.values(obj.modelUsage)[0]);
          usage = {
            input_tokens: (ref.input_tokens || 0) + (ref.cache_creation_input_tokens || 0) + (ref.cache_read_input_tokens || 0),
            cached_input_tokens: ref.cache_read_input_tokens || 0,
            output_tokens: ref.output_tokens || 0,
            context_window: mu?.contextWindow || 200000,
          };
          if (mu?.canonicalModel) model = model || mu.canonicalModel;
        }
        if (obj.is_error) {
          const errs = Array.isArray(obj.errors) ? obj.errors.join('; ') : '';
          resultError = [obj.result, errs].filter(Boolean).join('\n') || obj.subtype || 'Claude 回報錯誤';
        } else {
          resultText = obj.result ?? '';
        }
      }
    };

    proc.stdout.on('data', (chunk) => {
      buffer += chunk.toString();
      const lines = buffer.split('\n');
      buffer = lines.pop();
      for (const line of lines) {
        if (!line.trim()) continue;
        try {
          handleEvent(JSON.parse(line));
        } catch { /* 非 JSON 行直接忽略 */ }
      }
    });

    proc.stderr.on('data', (chunk) => {
      stderrTail = (stderrTail + chunk.toString()).slice(-2000);
      if (process.env.DEBUG) console.error('[claude stderr]', chunk.toString());
    });

    proc.on('close', (code) => {
      clearTimeout(timer);
      if (resultText !== null) {
        return resolve({ text: resultText, threadId: sessionId, usage, model, denials });
      }
      const detail = resultError || stderrTail.split('\n').filter((l) => l.trim()).slice(-5).join('\n');
      const e = new Error(resultError ? `Claude 執行失敗：${resultError}` : `claude 結束（exit code ${code}）${detail ? '\n' + detail : ''}`);
      e.threadId = sessionId;
      e.transient = /ECONNRESET|socket hang up|timed out|stream|overloaded|529|rate limit|connection/i.test(detail || '');
      reject(e);
    });

    proc.on('error', (err) => {
      clearTimeout(timer);
      reject(new Error(`無法啟動 claude：${err.message}（請確認已安裝 Claude Code 並在 PATH 中）`));
    });
  });
}

module.exports = { run, resolveClaudeCommand };