import { spawn } from 'child_process';

// --- Interfaces ---

interface ChatbotSession {
  sessionId: string;
  lastActivity: number;
  messageCount: number;
}

interface ClaudeJsonResponse {
  type: string;
  subtype: string;
  cost_usd: number;
  is_error: boolean;
  duration_ms: number;
  num_turns: number;
  result: string;
  session_id: string;
}

// --- Configuration ---

const CHATBOT_ENABLED = () => process.env.CHATBOT_ENABLED !== 'false';
const CHATBOT_CWD = () => process.env.CHATBOT_CWD || '/home/fitcrm';
const CHATBOT_MAX_TURNS = () => process.env.CHATBOT_MAX_TURNS || '3';
const CHATBOT_TIMEOUT = () => parseInt(process.env.CHATBOT_TIMEOUT || '120000');
const CHATBOT_SESSION_TIMEOUT = () => parseInt(process.env.CHATBOT_SESSION_TIMEOUT || '1800000');

// --- State ---

const chatbotSessions = new Map<string, ChatbotSession>();
const activeLocks = new Set<string>();
let cleanupTimer: NodeJS.Timeout | null = null;

// --- Public API ---

export function isChatbotEnabled(): boolean {
  return CHATBOT_ENABLED();
}

export function initChatbot(): void {
  if (cleanupTimer) clearInterval(cleanupTimer);

  cleanupTimer = setInterval(() => {
    const now = Date.now();
    const timeout = CHATBOT_SESSION_TIMEOUT();
    for (const [chatId, session] of chatbotSessions.entries()) {
      if (now - session.lastActivity > timeout) {
        chatbotSessions.delete(chatId);
        console.log(`[Chatbot] Expired session for chat ${chatId}`);
      }
    }
  }, 5 * 60 * 1000);

  console.log(`[Chatbot] Initialized (enabled: ${CHATBOT_ENABLED()}, cwd: ${CHATBOT_CWD()}, maxTurns: ${CHATBOT_MAX_TURNS()})`);
}

export async function handleChatbotMessage(
  chatId: string,
  message: string,
  sendTyping: () => Promise<void>,
  sendReply: (text: string, parseMode?: string) => Promise<void>
): Promise<void> {
  if (activeLocks.has(chatId)) {
    await sendReply('⏳ Подождите, обрабатываю предыдущее сообщение...');
    return;
  }

  activeLocks.add(chatId);

  const typingInterval = setInterval(async () => {
    try { await sendTyping(); } catch { /* ignore */ }
  }, 4000);

  try {
    await sendTyping();

    const session = chatbotSessions.get(chatId);
    const isExpired = session && (Date.now() - session.lastActivity > CHATBOT_SESSION_TIMEOUT());
    const resumeId = session && !isExpired ? session.sessionId : undefined;

    const response = await executeWithRetry(chatId, message, resumeId);

    chatbotSessions.set(chatId, {
      sessionId: response.session_id,
      lastActivity: Date.now(),
      messageCount: (session && !isExpired ? session.messageCount : 0) + 1,
    });

    const resultText = response.result || '(пустой ответ)';
    const chunks = splitMessage(resultText);

    for (const chunk of chunks) {
      await safeSendReply(sendReply, chunk);
    }
  } catch (error: any) {
    console.error('[Chatbot] Error:', error.message);
    await safeSendReply(sendReply, `❌ Ошибка: ${error.message}`);
  } finally {
    clearInterval(typingInterval);
    activeLocks.delete(chatId);
  }
}

export function resetChatbotSession(chatId: string): boolean {
  return chatbotSessions.delete(chatId);
}

export function getChatbotStatus(chatId: string): {
  enabled: boolean;
  hasSession: boolean;
  messageCount: number;
  sessionAge: number | null;
} {
  const session = chatbotSessions.get(chatId);
  return {
    enabled: CHATBOT_ENABLED(),
    hasSession: !!session,
    messageCount: session?.messageCount || 0,
    sessionAge: session ? Math.floor((Date.now() - session.lastActivity) / 60000) : null,
  };
}

// --- Internal ---

function executeClaudeCli(message: string, resumeSessionId?: string): Promise<ClaudeJsonResponse> {
  return new Promise((resolve, reject) => {
    const args: string[] = [
      '-p', message,
      '--output-format', 'json',
      '--max-turns', CHATBOT_MAX_TURNS(),
    ];

    if (resumeSessionId) {
      args.push('--resume', resumeSessionId);
    }

    // Clean env: remove all Claude Code session vars
    const env = { ...process.env };
    delete env.CLAUDECODE;
    delete env.CLAUDE_CODE_ENTRYPOINT;
    delete env.CLAUDE_SPAWNED;
    delete env.INNERVOICE_SPAWNED;

    console.log(`[Chatbot] Spawning: claude ${args.map((a, i) => i === 1 ? `"${a.substring(0, 40)}..."` : a).join(' ')}`);

    const child = spawn('claude', args, {
      cwd: CHATBOT_CWD(),
      env,
      stdio: ['ignore', 'pipe', 'pipe'],
    });

    let stdout = '';
    let stderr = '';

    child.stdout.on('data', (data: Buffer) => {
      stdout += data.toString();
    });

    child.stderr.on('data', (data: Buffer) => {
      stderr += data.toString();
    });

    // Timeout handler
    const timer = setTimeout(() => {
      console.error(`[Chatbot] Timeout after ${CHATBOT_TIMEOUT()}ms, killing process`);
      child.kill('SIGTERM');
      setTimeout(() => child.kill('SIGKILL'), 5000);
    }, CHATBOT_TIMEOUT());

    child.on('error', (error) => {
      clearTimeout(timer);
      console.error(`[Chatbot] Spawn error: ${error.message}`);
      reject(new Error(`Failed to start claude: ${error.message}`));
    });

    child.on('close', (code) => {
      clearTimeout(timer);

      console.log(`[Chatbot] Process exited with code ${code}`);
      if (stderr.trim()) {
        console.error(`[Chatbot] stderr: ${stderr.substring(0, 500)}`);
      }
      if (stdout.trim()) {
        console.log(`[Chatbot] stdout (first 300): ${stdout.substring(0, 300)}`);
      } else {
        console.log(`[Chatbot] stdout: (empty)`);
      }

      // Try to parse response regardless of exit code
      if (stdout.trim()) {
        try {
          const parsed = parseClaudeResponse(stdout);
          if (parsed.is_error) {
            reject(new Error(parsed.result || 'Claude returned an error'));
          } else {
            resolve(parsed);
          }
          return;
        } catch (parseErr: any) {
          console.error(`[Chatbot] Parse error: ${parseErr.message}`);
        }
      }

      if (code !== 0) {
        const errDetail = stderr.trim() || stdout.trim() || `exit code ${code}`;
        reject(new Error(`Claude CLI failed: ${errDetail.substring(0, 200)}`));
      } else {
        reject(new Error('Empty response from Claude CLI'));
      }
    });
  });
}

async function executeWithRetry(
  chatId: string,
  message: string,
  resumeId?: string
): Promise<ClaudeJsonResponse> {
  try {
    return await executeClaudeCli(message, resumeId);
  } catch (error) {
    if (resumeId) {
      console.log(`[Chatbot] Resume failed for ${chatId}, retrying fresh`);
      chatbotSessions.delete(chatId);
      return await executeClaudeCli(message, undefined);
    }
    throw error;
  }
}

function parseClaudeResponse(stdout: string): ClaudeJsonResponse {
  const trimmed = stdout.trim();

  // Try the whole output as a single JSON
  try {
    return JSON.parse(trimmed);
  } catch { /* continue */ }

  // Try each line (may have streaming JSON lines)
  const lines = trimmed.split('\n');
  for (let i = lines.length - 1; i >= 0; i--) {
    const line = lines[i].trim();
    if (!line) continue;
    try {
      const parsed = JSON.parse(line);
      if (parsed.type === 'result') return parsed;
    } catch { continue; }
  }

  // Last resort: find result JSON anywhere in output
  const match = trimmed.match(/\{[^]*?"type"\s*:\s*"result"[^]*?\}/);
  if (match) {
    try {
      return JSON.parse(match[0]);
    } catch { /* continue */ }
  }

  throw new Error(`No valid JSON result in output (${trimmed.substring(0, 150)})`);
}

function splitMessage(text: string, maxLength: number = 4000): string[] {
  if (text.length <= maxLength) return [text];

  const chunks: string[] = [];
  let remaining = text;

  while (remaining.length > 0) {
    if (remaining.length <= maxLength) {
      chunks.push(remaining);
      break;
    }

    let splitIdx = remaining.lastIndexOf('\n\n', maxLength);
    if (splitIdx === -1 || splitIdx < maxLength * 0.3) {
      splitIdx = remaining.lastIndexOf('\n', maxLength);
    }
    if (splitIdx === -1 || splitIdx < maxLength * 0.3) {
      splitIdx = remaining.lastIndexOf(' ', maxLength);
    }
    if (splitIdx === -1 || splitIdx < maxLength * 0.3) {
      splitIdx = maxLength;
    }

    chunks.push(remaining.substring(0, splitIdx));
    remaining = remaining.substring(splitIdx).trimStart();
  }

  return chunks.slice(0, 5);
}

async function safeSendReply(
  sendReply: (text: string, parseMode?: string) => Promise<void>,
  text: string
): Promise<void> {
  try {
    await sendReply(text, 'Markdown');
  } catch {
    try {
      await sendReply(text);
    } catch (innerError) {
      console.error('[Chatbot] Failed to send reply:', innerError);
    }
  }
}