import { readdirSync, existsSync, createReadStream, statSync } from 'fs';
import { join, basename } from 'path';
import { homedir } from 'os';
import { createInterface } from 'readline';
import { BaseEngineAdapter } from './base.js';

const CLAUDE_HOME = process.env.CLAUDE_HOME || join(homedir(), '.claude');
const PROJECTS_DIR = join(CLAUDE_HOME, 'projects');

// Directories known to contain subagent spawn files, excluded from top-level sessions
const SUBAGENT_SUFFIXES = [
  '--claude',
  '-cliproxyapi',
];

export class ClaudeAdapter extends BaseEngineAdapter {
  constructor() {
    super('claude', 'Claude');
    this._sessionMessages = new Map();
  }

  async checkHealth() {
    const hasDir = existsSync(PROJECTS_DIR);
    this.available = hasDir;
    return this.getHealthInfo();
  }

  async refresh() {
    this.error = null;
    try {
      await this._scanSessions();
      this.available = true;
      this.lastRefresh = Date.now();
    } catch (err) {
      this.error = err.message;
      console.error(`[ClaudeAdapter] Refresh error:`, err.message);
    }
    return this.getHealthInfo();
  }

  _isSubagentDir(dirName) {
    return SUBAGENT_SUFFIXES.some(suffix => dirName.endsWith(suffix));
  }

  async _scanSessions() {
    this._sessions = [];
    this._sessionsMap.clear();
    this._sessionMessages.clear();

    if (!existsSync(PROJECTS_DIR)) return;

    const projectDirs = readdirSync(PROJECTS_DIR);

    for (const dir of projectDirs) {
      const dirPath = join(PROJECTS_DIR, dir);
      if (!statSync(dirPath).isDirectory()) continue;

      // Skip subagent directories
      if (this._isSubagentDir(dir)) continue;

      const files = readdirSync(dirPath).filter(f => f.endsWith('.jsonl'));
      for (const file of files) {
        const filePath = join(dirPath, file);
        const session = await this._parseSessionFile(filePath, dir);
        if (session) {
          this._sessions.push(session.session);
          this._sessionsMap.set(session.session.id, session.session);
          if (session.messages?.length) {
            this._sessionMessages.set(session.session.id, session.messages);
          }
        }
      }
    }
  }

  async _parseSessionFile(filePath, projectDir) {
    try {
      const sessionId = basename(filePath, '.jsonl');
      let firstUserMessage = '';
      let hasAssistant = false;
      let hasError = false;
      let hasInterrupt = false;
      const toolCalls = {};
      let toolCallCount = 0;
      let messageCount = 0;
      let userMessageCount = 0;
      let assistantMessageCount = 0;
      let earliestTime = null;
      let latestTime = null;
      let cwd = '';
      let model = '';
      let lastType = '';
      const assistantTypes = new Set();
      const messages = [];

      const rl = createInterface({
        input: createReadStream(filePath, { highWaterMark: 65536 }),
        crlfDelay: Infinity,
      });

      for await (const line of rl) {
        if (!line.trim()) continue;
        try {
          const entry = JSON.parse(line);
          messageCount++;
          const type = entry.type || '';

          // Get timestamp from any available field
          const entryTime = entry.timestamp || entry.ts || '';

          if (type === 'user') {
            const msg = entry.message || {};
            const rawContent = msg.content || entry.content || '';
            const text = typeof rawContent === 'string' ? rawContent :
                         Array.isArray(rawContent) ? rawContent.map(c => c.text || c.content || '').join(' ') :
                         typeof rawContent === 'object' ? JSON.stringify(rawContent) : '';
            // Skip system-generated command wrapper messages
            const isSystemMsg = text.startsWith('<local-command') || text.startsWith('<command-');
            if (!firstUserMessage && text.trim() && !isSystemMsg) {
              firstUserMessage = text.slice(0, 500);
            }
            userMessageCount++;
            if (!isSystemMsg) {
              messages.push({ time: entryTime, type: 'user_message', message: text.slice(0, 2000) });
            }
          } else if (type === 'assistant') {
            hasAssistant = true;
            assistantMessageCount++;
            const msgContent = entry.message || {};
            const content = msgContent.content || [];
            const textParts = [];
            if (Array.isArray(content)) {
              for (const block of content) {
                if (block.type === 'text') {
                  textParts.push(block.text || '');
                } else if (block.type === 'tool_use') {
                  const name = block.name || 'unknown';
                  toolCalls[name] = (toolCalls[name] || 0) + 1;
                  toolCallCount++;
                  messages.push({
                    time: entryTime,
                    type: 'function_call',
                    name,
                    arguments: block.input ? JSON.stringify(block.input).slice(0, 500) : '',
                  });
                } else if (block.type === 'tool_result') {
                  const output = typeof block.content === 'string' ? block.content :
                                 Array.isArray(block.content) ? block.content.map(c => c.text || '').join(' ') : '';
                  messages.push({
                    time: entryTime,
                    type: 'function_call_output',
                    output_preview: (output || '').slice(0, 300),
                  });
                }
              }
            }
            const text = textParts.join(' ').trim();
            if (text) {
              messages.push({ time: entryTime, type: 'assistant_message', message: text.slice(0, 2000) });
            }
          } else if (type === 'ai-title') {
            // title info
          } else if (type === 'error' || type === 'fatal_error') {
            hasError = true;
          } else if (type === 'mode' || type === 'permission-mode') {
            // config entries
          }

          // Track time from message content
          const rawTs = entry.timestamp || entry.ts || '';
          if (rawTs) {
            const t = new Date(rawTs).getTime();
            if (!isNaN(t)) {
              if (earliestTime === null || t < earliestTime) earliestTime = t;
              if (latestTime === null || t > latestTime) latestTime = t;
            }
          }

          // Track last entry type for interrupt detection
          if (type === 'user' || type === 'assistant') {
            lastType = type;
          }
        } catch (e) {
          // skip malformed lines
        }
      }

      if (!hasAssistant && !firstUserMessage) return null;

      // Convert project dir name to a filesystem path
      // e.g. "-home-liumangmang-IdeaProjects-PR7050" → "/home/liumangmang/IdeaProjects/PR7050"
      if (!cwd) {
        let raw = projectDir;
        // Strip leading dash(es)
        raw = raw.replace(/^-+/, '');
        // Replace inter-segment dashes with /
        raw = raw.replace(/-/g, '/');
        // Ensure leading /
        cwd = '/' + raw;
        // Collapse any double slashes
        cwd = cwd.replace(/\/+/g, '/');
      }

      // Claude JSONL doesn't include interrupt/error signals reliably.
      // Only set status=error when an explicit error type is found.
      // Otherwise use "unknown" rather than guessing "success".

      return {
        session: {
          key: `claude:${sessionId}`,
          engine: 'claude',
          engine_label: 'Claude',
          id: sessionId,
          summary: firstUserMessage || '(无消息)',
          cwd: cwd,
          model: model || 'claude',
          cli_version: '',
          source: 'cli',
          created_at: earliestTime || 0,
          updated_at: latestTime || 0,
          duration_ms: earliestTime && latestTime ? latestTime - earliestTime : null,
          status: hasError ? 'error' : 'unknown',
          tool_call_count: toolCallCount,
          tool_calls: toolCalls,
          message_count: userMessageCount + assistantMessageCount,
          resume_command: this.buildResumeCommand(sessionId),
          can_resume: true,
        },
        messages: messages.slice(0, 300),
      };
    } catch (err) {
      console.warn(`[ClaudeAdapter] Parse error ${filePath}:`, err.message);
      return null;
    }
  }

  async getMessages(id) {
    if (this._sessionMessages.has(id)) {
      return this._sessionMessages.get(id);
    }
    return [];
  }

  buildResumeCommand(id) {
    return `claude --resume ${id}`;
  }
}