/**
 * Command executor for webhook events
 */
import { exec, execSync } from 'child_process';
import { promisify } from 'util';
import logger from './logger.js';

const execAsync = promisify(exec);

// Detect shell path at module load time
function detectShellPath() {
  try {
    // Try to find bash using 'which' command
    const bashPath = execSync('which bash', { encoding: 'utf8' }).trim();
    if (bashPath) {
      return bashPath;
    }
  } catch (error) {
    // Fallback to common bash locations
    const commonPaths = ['/bin/bash', '/usr/bin/bash', '/usr/local/bin/bash'];
    for (const path of commonPaths) {
      try {
        execSync(`test -x ${path}`, { encoding: 'utf8' });
        return path;
      } catch {
        continue;
      }
    }
  }
  // Ultimate fallback: use 'bash' without path (let PATH resolve it)
  return 'bash';
}

const SHELL_PATH = detectShellPath();
logger.info('Detected shell path', { shell: SHELL_PATH });

export class CommandExecutor {
  /**
   * Extract variables from webhook payload
   */
  extractVariables(eventType, payload, headers) {
    const variables = {
      event: eventType,
      repo: payload.repository?.name || '',
      full_repo: payload.repository?.full_name || payload.repository?.name || '',
      repo_owner: '',
      branch: '',
      pusher: '',
      commit: '',
      commit_msg: '',
      pr_number: '',
      pr_action: '',
      tag: '',
      ref_type: '',
      issue_number: '',
      issue_title: '',
      issue_action: '',
      issue_body: '',
      issue_assignee: '',
      issue_labels: '',
      comment_body: ''
    };

    // Extract repository owner
    if (payload.repository?.full_name) {
      const parts = payload.repository.full_name.split('/');
      variables.repo_owner = parts[0] || '';
    } else if (payload.repository?.owner) {
      variables.repo_owner = payload.repository.owner.username ||
                            payload.repository.owner.login ||
                            payload.repository.owner.name || '';
    }

    // Extract pusher/sender information
    variables.pusher = payload.pusher?.username ||
                       payload.pusher?.name ||
                       payload.sender?.username ||
                       payload.sender?.login ||
                       '';

    // Extract branch from ref (e.g., "refs/heads/main" -> "main")
    if (payload.ref) {
      const refMatch = payload.ref.match(/^refs\/(heads|tags)\/(.+)$/);
      if (refMatch) {
        variables.branch = refMatch[2];
        if (refMatch[1] === 'tags') {
          variables.tag = refMatch[2];
        }
      }
    }

    // Event-specific extractions
    switch (eventType) {
      case 'push':
        if (payload.commits && payload.commits.length > 0) {
          const lastCommit = payload.commits[payload.commits.length - 1];
          variables.commit = lastCommit.id || '';
          variables.commit_msg = lastCommit.message || '';
        }
        variables.commit = variables.commit.substring(0, 7); // Short hash
        break;

      case 'pull_request':
        variables.pr_number = payload.pull_request?.number || payload.number || '';
        variables.pr_action = payload.action || '';
        variables.branch = payload.pull_request?.head?.ref ||
                          payload.pull_request?.base?.ref || '';
        break;

      case 'create':
      case 'delete':
        variables.ref_type = payload.ref_type || '';
        variables.branch = payload.ref || '';
        if (payload.ref_type === 'tag') {
          variables.tag = payload.ref || '';
        }
        break;

      case 'release':
        variables.tag = payload.release?.tag_name || '';
        variables.pr_action = payload.action || '';
        break;

      case 'issues':
        variables.issue_number = payload.issue?.number || payload.number || '';
        variables.issue_title = payload.issue?.title || '';
        variables.issue_action = payload.action || '';
        variables.issue_body = payload.issue?.body || '';
        variables.issue_assignee = payload.issue?.assignee?.username ||
                                   payload.issue?.assignee?.login || '';
        // Extract issue labels as comma-separated string
        if (payload.issue?.labels && Array.isArray(payload.issue.labels)) {
          variables.issue_labels = payload.issue.labels.map(label => label.name).join(',');
        }
        break;

      case 'issue_comment':
        variables.issue_number = payload.issue?.number || '';
        variables.issue_title = payload.issue?.title || '';
        variables.issue_action = payload.action || '';
        variables.comment_body = payload.comment?.body || '';
        variables.issue_assignee = payload.issue?.assignee?.username ||
                                   payload.issue?.assignee?.login || '';
        // Extract issue labels as comma-separated string
        if (payload.issue?.labels && Array.isArray(payload.issue.labels)) {
          variables.issue_labels = payload.issue.labels.map(label => label.name).join(',');
        }
        break;
    }

    // Log extracted variables at debug level
    logger.variablesExtracted(eventType, variables);

    return variables;
  }

  /**
   * Substitute variables in command string
   */
  substituteVariables(command, variables) {
    let result = command;

    for (const [key, value] of Object.entries(variables)) {
      const regex = new RegExp(`{{${key}}}`, 'g');
      result = result.replace(regex, value || '');
    }

    return result;
  }

  /**
   * Build command string from command and args
   */
  buildCommandString(command, args = []) {
    // Escape arguments for shell execution
    const escapeArg = (arg) => {
      // Always wrap empty strings in quotes to preserve them as arguments
      if (arg === '') {
        return "''";
      }
      // If arg contains spaces or special chars, wrap in single quotes
      if (arg.includes(' ') || arg.includes('$') || arg.includes('`') || arg.includes('"')) {
        return `'${arg.replace(/'/g, "'\\''")}'`;
      }
      return arg;
    };

    const escapedArgs = args.map(escapeArg);
    return [command, ...escapedArgs].join(' ');
  }

  /**
   * Execute a command with timeout
   */
  async executeCommand(command, options = {}) {
    const {
      timeout = 300000,
      cwd = process.cwd(),
      type = 'shell',
      args = []
    } = options;

    let fullCommand;

    if (type === 'node') {
      // For Node.js execution, use 'node' as the shell command
      fullCommand = this.buildCommandString('node', [command, ...args]);
    } else {
      // For shell execution, build command from command and args
      fullCommand = this.buildCommandString(command, args);
    }

    logger.info('Executing command', { type, command, args, fullCommand, cwd, timeout });

    try {
      // Use default shell if SHELL_PATH is just 'bash' (more compatible with restricted environments)
      const execOptions = {
        timeout,
        cwd: cwd || process.cwd(),
        maxBuffer: 10 * 1024 * 1024 // 10MB
      };

      // Only set custom shell if we have a full path
      if (SHELL_PATH.startsWith('/')) {
        execOptions.shell = SHELL_PATH;
      } else {
        // Let Node.js use default shell resolution
        execOptions.shell = true;
      }

      const { stdout, stderr } = await execAsync(fullCommand, execOptions);

      if (stdout) {
        logger.info('Command output (stdout)');
        console.log(stdout);
      }

      if (stderr) {
        logger.info('Command output (stderr)');
        console.error(stderr);
      }

      logger.info('Command completed successfully');
      return { success: true, stdout, stderr };
    } catch (error) {
      logger.error('Command execution failed', error);

      if (error.stdout) {
        logger.info('Command output (stdout) before error');
        console.log(error.stdout);
      }

      if (error.stderr) {
        logger.info('Command output (stderr)');
        console.error(error.stderr);
      }

      return {
        success: false,
        error: error.message,
        stdout: error.stdout,
        stderr: error.stderr,
        code: error.code
      };
    }
  }

  /**
   * Execute configured command for webhook event
   */
  async executeWebhookCommand(eventType, payload, headers, config) {
    // Support both old format (single command string) and new format (command + args)
    const isNewFormat = config.command && config.args !== undefined;

    if (!config.command) {
      return null;
    }

    // Extract variables from payload
    const variables = this.extractVariables(eventType, payload, headers);

    // Apply branch filter if configured
    if (config.filterBranch && variables.branch !== config.filterBranch) {
      const commandName = config.name || config.command || 'unknown';
      logger.branchFiltered(variables.branch, config.filterBranch, commandName);
      logger.info(`Skipping command execution - branch '${variables.branch}' does not match filter '${config.filterBranch}'`);
      return null;
    }

    // Apply action filter if configured
    if (config.filterActions && Array.isArray(config.filterActions) && config.filterActions.length > 0) {
      const action = variables.issue_action || variables.pr_action || payload.action || '';
      if (!config.filterActions.includes(action)) {
        const commandName = config.name || config.command || 'unknown';
        logger.info(`Skipping command '${commandName}' - action '${action}' not in filterActions [${config.filterActions.join(', ')}]`);
        return null;
      }
    }

    // Apply assignee filter if configured
    if (config.filterAssignee) {
      const assignee = variables.issue_assignee || '';
      if (assignee !== config.filterAssignee) {
        const commandName = config.name || config.command || 'unknown';
        logger.info(`Skipping command '${commandName}' - assignee '${assignee}' does not match filter '${config.filterAssignee}'`);
        return null;
      }
    }

    // Skip execution if issue is closed (for issue and issue_comment events)
    if (eventType === 'issues' || eventType === 'issue_comment') {
      const issueState = payload.issue?.state || '';
      if (issueState === 'closed') {
        const commandName = config.name || config.command || 'unknown';
        logger.info(`Skipping command '${commandName}' - issue state is 'closed'`);
        return null;
      }
    }

    let command, args, type;

    if (isNewFormat) {
      // New format: separate command and args
      command = this.substituteVariables(config.command, variables);
      args = (config.args || []).map(arg => this.substituteVariables(arg, variables));
      type = config.type || 'shell';
    } else {
      // Old format: single command string (for backward compatibility)
      const fullCommand = this.substituteVariables(config.command, variables);
      // Parse command string into command and args
      const parts = fullCommand.split(' ');
      command = parts[0];
      args = parts.slice(1);
      type = 'shell';
    }

    logger.info('Webhook command prepared', {
      eventType,
      type,
      command,
      args,
      variables
    });

    // Execute command
    const result = await this.executeCommand(command, {
      type,
      args,
      timeout: config.timeout || 300000,
      cwd: config.cwd || config.workingDir || process.cwd()
    });

    return result;
  }
}

export default new CommandExecutor();