import { spawn } from 'child_process';
import * as fs from 'fs';
import { promisify } from 'util';
import { StatusManager } from './status-manager';

const sleep = promisify(setTimeout);

export interface SafeRestartOptions {
  /** Agent ID performing the restart */
  agentId: string;
  /** Session key for notifications */
  sessionKey: string;
  /** API endpoint for query-restart */
  apiEndpoint?: string;
  /** Rollback script path */
  rollback?: string;
  /** Log file path */
  log?: string;
  /** Polling interval in ms (default: 5000) */
  pollInterval?: number;
  /** Maximum wait time in ms (default: 300000 = 5min) */
  maxWaitTime?: number;
  /** Restart script/command */
  restartScript?: string;
  /** Callback for notifications */
  onNotify?: (sessionKey: string, message: string) => Promise<void>;
}

export interface SafeRestartResult {
  success: boolean;
  message: string;
  log?: string;
}

/**
 * Performs a safe restart with polling and rollback support
 */
export async function safeRestart(options: SafeRestartOptions): Promise<SafeRestartResult> {
  const {
    agentId,
    sessionKey,
    apiEndpoint = 'http://localhost:8765',
    rollback,
    log: logPath,
    pollInterval = 5000,
    maxWaitTime = 300000,
    restartScript = 'openclaw gateway restart',
    onNotify,
  } = options;

  const logs: string[] = [];
  const log = (msg: string) => {
    const entry = `[${new Date().toISOString()}] ${msg}`;
    logs.push(entry);
    console.log(entry);
  };

  try {
    log(`Starting safe restart. Agent: ${agentId}, Session: ${sessionKey}`);

    // Step 1: Poll query-restart until OK or timeout
    const startTime = Date.now();
    let restartApproved = false;

    while (Date.now() - startTime < maxWaitTime) {
      try {
        const response = await fetch(`${apiEndpoint}/query-restart`, {
          method: 'POST',
          headers: { 'Content-Type': 'application/json' },
          body: JSON.stringify({
            requesterAgentId: agentId,
            requesterSessionKey: sessionKey,
          }),
        });

        const data = await response.json() as { status: string };

        if (data.status === 'OK') {
          log('All agents ready for restart');
          restartApproved = true;
          break;
        } else if (data.status === 'ALREADY_SCHEDULED') {
          log('Restart already scheduled by another agent');
          return {
            success: false,
            message: 'ALREADY_SCHEDULED',
          };
        } else {
          log(`Waiting for agents to be ready... (${data.status})`);
        }
      } catch (err) {
        log(`Error polling query-restart: ${err}`);
      }

      await sleep(pollInterval);
    }

    if (!restartApproved) {
      const msg = 'Timeout waiting for agents to be ready';
      log(msg);
      return {
        success: false,
        message: msg,
        log: logs.join('\n'),
      };
    }

    // Step 2: Report restart starting
    log('Executing restart...');

    // Step 3: Start restart in background process
    const restartProcess = startBackgroundRestart(restartScript, logPath);

    // Wait a moment for restart to initiate
    await sleep(2000);

    // Step 4: Check if gateway comes back
    log('Waiting for gateway to restart...');
    await sleep(60000); // Wait 60s as specified

    // Check gateway status
    const gatewayOk = await checkGatewayStatus();
    
    if (gatewayOk) {
      log('Gateway restarted successfully');

      // Report success
      await fetch(`${apiEndpoint}/restart-result`, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({
          status: 'ok',
          log: logPath || logs.join('\n'),
        }),
      });

      // Notify resumption
      if (onNotify) {
        await onNotify(sessionKey, 'restart 结束了，我们继续');
      }

      return {
        success: true,
        message: 'Restart completed successfully',
      };
    } else {
      log('Gateway restart failed');

      // Execute rollback if provided
      if (rollback) {
        log(`Executing rollback: ${rollback}`);
        try {
          await executeRollback(rollback);
          log('Rollback completed');
        } catch (err) {
          log(`Rollback failed: ${err}`);
        }
      }

      // Report failure
      await fetch(`${apiEndpoint}/restart-result`, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({
          status: 'failed',
          log: logPath || logs.join('\n'),
        }),
      });

      // Notify failure
      if (onNotify) {
        await onNotify(sessionKey, 'restart 失败，已经 rollback，请参考 log 调查。');
      }

      return {
        success: false,
        message: 'Restart failed',
        log: logs.join('\n'),
      };
    }
  } catch (err) {
    const errorMsg = `Unexpected error: ${err}`;
    log(errorMsg);
    return {
      success: false,
      message: errorMsg,
      log: logs.join('\n'),
    };
  }
}

function startBackgroundRestart(restartScript: string, logPath?: string): void {
  const script = `
#!/bin/bash
set -e
sleep 60
${restartScript}
openclaw gateway status
`;

  const child = spawn('bash', ['-c', script], {
    detached: true,
    stdio: logPath ? ['ignore', fs.openSync(logPath, 'w'), fs.openSync(logPath, 'w+')] : 'ignore',
  });

  child.unref();
}

async function checkGatewayStatus(): Promise<boolean> {
  return new Promise((resolve) => {
    const child = spawn('openclaw', ['gateway', 'status'], {
      timeout: 10000,
    });

    let output = '';
    child.stdout?.on('data', (data) => {
      output += data.toString();
    });

    child.on('close', (code) => {
      resolve(code === 0 && output.includes('running'));
    });

    child.on('error', () => {
      resolve(false);
    });
  });
}

async function executeRollback(rollbackScript: string): Promise<void> {
  return new Promise((resolve, reject) => {
    const child = spawn('bash', ['-c', rollbackScript], {
      timeout: 120000,
    });

    child.on('close', (code) => {
      if (code === 0) {
        resolve();
      } else {
        reject(new Error(`Rollback script exited with code ${code}`));
      }
    });

    child.on('error', (err) => {
      reject(err);
    });
  });
}

/**
 * Safe restart tool that can be registered with OpenClaw
 */
export function createSafeRestartTool(statusManager: StatusManager) {
  return {
    name: 'safe_restart',
    description: 'Perform a safe restart of OpenClaw gateway with agent coordination',
    parameters: {
      type: 'object',
      properties: {
        rollback: {
          type: 'string',
          description: 'Path to rollback script',
        },
        log: {
          type: 'string',
          description: 'Path to log file',
        },
      },
    },
    handler: async (params: { rollback?: string; log?: string }, context: { agentId: string; sessionKey: string }) => {
      const result = await safeRestart({
        agentId: context.agentId,
        sessionKey: context.sessionKey,
        rollback: params.rollback,
        log: params.log,
        async onNotify(sessionKey, message) {
          // This would be connected to the messaging system
          console.log(`[${sessionKey}] ${message}`);
        },
      });

      return {
        success: result.success,
        message: result.message,
      };
    },
  };
}