import { spawn, SpawnOptions } from 'child_process';
import { promisify } from 'util';

const execAsync = promisify(require('child_process').exec);

export interface PcExecOptions {
  /** Current working directory */
  cwd?: string;
  /** Environment variables */
  env?: Record<string, string>;
  /** Timeout in milliseconds */
  timeout?: number;
  /** Maximum buffer size for stdout/stderr */
  maxBuffer?: number;
  /** Kill signal */
  killSignal?: NodeJS.Signals;
  /** Shell to use */
  shell?: string | boolean;
  /** UID to run as */
  uid?: number;
  /** GID to run as */
  gid?: number;
  /** Window style (Windows only) */
  windowsHide?: boolean;
}

export interface PcExecResult {
  /** Standard output */
  stdout: string;
  /** Standard error */
  stderr: string;
  /** Exit code */
  exitCode: number;
  /** Command that was executed */
  command: string;
}

export interface PcExecError extends Error {
  /** Exit code */
  code?: number;
  /** Signal that terminated the process */
  signal?: string;
  /** Standard output */
  stdout: string;
  /** Standard error */
  stderr: string;
  /** Killed by timeout */
  killed?: boolean;
}

/**
 * Extract pass_mgr get commands from a command string
 * Supports formats like:
 * - $(pass_mgr get key)
 * - `pass_mgr get key`
 * - pass_mgr get key (direct invocation)
 */
function extractPassMgrGets(command: string): Array<{ key: string; fullMatch: string }> {
  const results: Array<{ key: string; fullMatch: string }> = [];
  
  // Patterns for both old and new pass_mgr formats:
  //   Old: $(pass_mgr get key), `pass_mgr get key`, pass_mgr get key
  //   New: $(pass_mgr get-secret --key key), `pass_mgr get-secret --key key`
  const patterns = [
    // New format: pass_mgr get-secret --key <key>
    /\$\(\s*pass_mgr\s+get-secret\s+--key\s+(\S+)\s*\)/g,
    /`\s*pass_mgr\s+get-secret\s+--key\s+(\S+)\s*`/g,
    /pass_mgr\s+get-secret\s+--key\s+(\S+)/g,
    // Old format (backward compat): pass_mgr get <key>
    /\$\(\s*pass_mgr\s+get\s+(\S+)\s*\)/g,
    /`\s*pass_mgr\s+get\s+(\S+)\s*`/g,
    /pass_mgr\s+get\s+(\S+)/g,
  ];
  
  for (const pattern of patterns) {
    let match;
    while ((match = pattern.exec(command)) !== null) {
      results.push({
        key: match[1],
        fullMatch: match[0],
      });
    }
  }
  
  return results;
}

/**
 * Execute pass_mgr get and return the password
 */
async function getPassword(key: string): Promise<string> {
  return new Promise((resolve, reject) => {
    const passMgrPath = process.env.PASS_MGR_PATH || 'pass_mgr';
    const child = spawn(passMgrPath, ['get-secret', '--key', key], {
      stdio: ['ignore', 'pipe', 'pipe'],
      env: {
        ...process.env,
        AGENT_WORKSPACE: process.env.AGENT_WORKSPACE || '',
        AGENT_ID: process.env.AGENT_ID || '',
      },
    });
    
    let stdout = '';
    let stderr = '';
    
    child.stdout.on('data', (data) => {
      stdout += data.toString();
    });
    
    child.stderr.on('data', (data) => {
      stderr += data.toString();
    });
    
    child.on('close', (code) => {
      if (code !== 0) {
        reject(new Error(`pass_mgr get failed: ${stderr || stdout}`));
      } else {
        resolve(stdout.trim());
      }
    });
    
    child.on('error', (err) => {
      reject(err);
    });
  });
}

/**
 * Sanitize output by replacing passwords with ######
 */
function sanitizeOutput(output: string, passwords: string[]): string {
  let sanitized = output;
  for (const password of passwords) {
    if (password) {
      // Escape special regex characters
      const escaped = password.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
      const regex = new RegExp(escaped, 'g');
      sanitized = sanitized.replace(regex, '######');
    }
  }
  return sanitized;
}

/**
 * Replace pass_mgr get commands with actual passwords in command
 */
async function replacePassMgrGets(command: string): Promise<{ command: string; passwords: string[] }> {
  const passMgrGets = extractPassMgrGets(command);
  const passwords: string[] = [];
  let replacedCommand = command;
  
  for (const { key, fullMatch } of passMgrGets) {
    try {
      const password = await getPassword(key);
      passwords.push(password);
      replacedCommand = replacedCommand.replace(fullMatch, password);
    } catch (err) {
      throw new Error(`Failed to get password for key '${key}': ${err}`);
    }
  }
  
  return { command: replacedCommand, passwords };
}

/**
 * Safe exec wrapper that handles pass_mgr get commands and sanitizes output
 * 
 * @param command - Command to execute
 * @param options - Execution options
 * @returns Promise resolving to execution result
 */
export async function pcexec(command: string, options: PcExecOptions = {}): Promise<PcExecResult> {
  // Set up environment with workspace/agent info
  const env: Record<string, string> = {};
  
  // Copy process.env, filtering out undefined values
  for (const [key, value] of Object.entries(process.env)) {
    if (value !== undefined) {
      env[key] = value;
    }
  }
  
  // Merge options.env
  if (options.env) {
    Object.assign(env, options.env);
  }
  
  if (process.env.AGENT_WORKSPACE) {
    env.AGENT_WORKSPACE = process.env.AGENT_WORKSPACE;
  }
  if (process.env.AGENT_ID) {
    env.AGENT_ID = process.env.AGENT_ID;
  }
  
  // Extract and replace pass_mgr get commands
  let finalCommand = command;
  let passwords: string[] = [];
  
  try {
    const result = await replacePassMgrGets(command);
    finalCommand = result.command;
    passwords = result.passwords;
  } catch (err) {
    throw err;
  }
  
  return new Promise((resolve, reject) => {
    const spawnOptions: SpawnOptions = {
      cwd: options.cwd,
      env,
      // Don't use shell by default - we're already using bash -c explicitly
      shell: options.shell,
      windowsHide: options.windowsHide,
      uid: options.uid,
      gid: options.gid,
    };
    
    // Use bash for better compatibility
    const child = spawn('bash', ['-c', finalCommand], spawnOptions);
    
    let stdout = '';
    let stderr = '';
    let killed = false;
    let timeoutId: NodeJS.Timeout | null = null;
    
    // Set up timeout
    if (options.timeout && options.timeout > 0) {
      timeoutId = setTimeout(() => {
        killed = true;
        child.kill(options.killSignal || 'SIGTERM');
      }, options.timeout);
    }
    
    // Handle stdout
    child.stdout?.on('data', (data) => {
      stdout += data.toString();
      
      // Check maxBuffer
      if (options.maxBuffer && stdout.length > options.maxBuffer) {
        child.kill(options.killSignal || 'SIGTERM');
      }
    });
    
    // Handle stderr
    child.stderr?.on('data', (data) => {
      stderr += data.toString();
      
      // Check maxBuffer
      if (options.maxBuffer && stderr.length > options.maxBuffer) {
        child.kill(options.killSignal || 'SIGTERM');
      }
    });
    
    // Handle process close
    child.on('close', (code, signal) => {
      if (timeoutId) {
        clearTimeout(timeoutId);
      }
      
      // Sanitize output
      const sanitizedStdout = sanitizeOutput(stdout, passwords);
      const sanitizedStderr = sanitizeOutput(stderr, passwords);
      
      if (code === 0) {
        resolve({
          stdout: sanitizedStdout,
          stderr: sanitizedStderr,
          exitCode: 0,
          command: finalCommand,
        });
      } else {
        const error = new Error(`Command failed: ${command}`) as PcExecError;
        error.code = code ?? undefined;
        error.signal = signal ?? undefined;
        error.stdout = sanitizedStdout;
        error.stderr = sanitizedStderr;
        error.killed = killed;
        reject(error);
      }
    });
    
    // Handle process error
    child.on('error', (err) => {
      if (timeoutId) {
        clearTimeout(timeoutId);
      }
      
      const error = new Error(`Failed to execute command: ${err.message}`) as PcExecError;
      error.stdout = sanitizeOutput(stdout, passwords);
      error.stderr = sanitizeOutput(stderr, passwords);
      reject(error);
    });
  });
}

/**
 * Synchronous version of pcexec
 * Note: Password sanitization is still applied
 */
export function pcexecSync(command: string, options: PcExecOptions = {}): PcExecResult {
  const { execSync } = require('child_process');
  
  // Set up environment
  const env: Record<string, string> = {};
  
  // Copy process.env, filtering out undefined values
  for (const [key, value] of Object.entries(process.env)) {
    if (value !== undefined) {
      env[key] = value;
    }
  }
  
  // Merge options.env
  if (options.env) {
    Object.assign(env, options.env);
  }
  
  if (process.env.AGENT_WORKSPACE) {
    env.AGENT_WORKSPACE = process.env.AGENT_WORKSPACE;
  }
  if (process.env.AGENT_ID) {
    env.AGENT_ID = process.env.AGENT_ID;
  }
  
  // For sync version, we need to pre-resolve passwords
  // This is a limitation - passwords will be in command
  const passMgrGets = extractPassMgrGets(command);
  let finalCommand = command;
  const passwords: string[] = [];
  
  // Note: In sync version, we can't async fetch passwords
  // So we use the original command and rely on the user to not use pass_mgr gets in sync mode
  // Or they need to resolve passwords beforehand
  
  const execOptions: any = {
    cwd: options.cwd,
    env,
    // Don't use shell by default
    shell: options.shell,
    encoding: 'utf8',
    windowsHide: options.windowsHide,
    uid: options.uid,
    gid: options.gid,
    maxBuffer: options.maxBuffer,
    timeout: options.timeout,
    killSignal: options.killSignal,
  };
  
  try {
    const stdout = execSync(finalCommand, execOptions);
    const sanitizedStdout = sanitizeOutput(stdout.toString(), passwords);
    
    return {
      stdout: sanitizedStdout,
      stderr: '',
      exitCode: 0,
      command: finalCommand,
    };
  } catch (err: any) {
    const sanitizedStdout = sanitizeOutput(err.stdout?.toString() || '', passwords);
    const sanitizedStderr = sanitizeOutput(err.stderr?.toString() || '', passwords);
    
    const error = new Error(`Command failed: ${command}`) as PcExecError;
    error.code = err.status;
    error.signal = err.signal;
    error.stdout = sanitizedStdout;
    error.stderr = sanitizedStderr;
    throw error;
  }
}

// Default export
export default pcexec;