"""Security validation script for the Team Tryouts application.

This script performs pre-deployment security checks to validate:
- HTTP security headers
- Cookie security attributes
- Debug mode status
- HTTPS configuration
- Dependency vulnerabilities
- Database connectivity

Usage:
    python security_scan.py [--url http://localhost:5000]
"""

import os
import sys
import json
import subprocess
import urllib.request
import ssl
from datetime import datetime


def check_environment():
    """Check required environment variables are set.
    
    Returns:
        bool: True if all critical variables are set.
    """
    print('=' * 60)
    print('1. ENVIRONMENT VARIABLES CHECK')
    print('=' * 60)
    
    critical_vars = ['SECRET_KEY']
    recommended_vars = ['DATABASE_URL', 'CORS_ALLOWED_ORIGINS']
    all_ok = True
    
    for var in critical_vars:
        value = os.getenv(var)
        if value:
            # Check SECRET_KEY is not a default/weak value
            if var == 'SECRET_KEY' and len(value) < 32:
                print(f'[WARN] {var} is set but too short (less than 32 chars)')
                all_ok = False
            else:
                print(f'[OK] {var} is set')
        else:
            print(f'[FAIL] {var} is not set!')
            all_ok = False
    
    for var in recommended_vars:
        value = os.getenv(var)
        if value:
            print(f'[OK] {var} is set')
        else:
            print(f'[INFO] {var} is not set (using default)')
    
    # Check FLASK_DEBUG
    debug = os.getenv('FLASK_DEBUG', 'false').lower()
    if debug == 'true':
        print('[WARN] FLASK_DEBUG is enabled! Should be disabled in production.')
    else:
        print('[OK] FLASK_DEBUG is disabled')
    
    return all_ok


def check_https_headers(url):
    """Check HTTP security headers from a running application.
    
    Args:
        url: The base URL of the application to check.
        
    Returns:
        bool: True if all critical headers are present.
    """
    print('\n' + '=' * 60)
    print('2. HTTP SECURITY HEADERS CHECK')
    print('=' * 60)
    
    required_headers = {
        'Strict-Transport-Security': 'HSTS enabled',
        'X-Content-Type-Options': 'Prevents MIME sniffing',
        'X-Frame-Options': 'Prevents clickjacking',
        'Content-Security-Policy': 'CSP configured',
        'Referrer-Policy': 'Referrer control',
        'Permissions-Policy': 'Permissions control',
        'Cross-Origin-Opener-Policy': 'Cross-origin isolation',
    }
    
    all_ok = True
    
    try:
        # Create a context that doesn't verify SSL (for local testing)
        ctx = ssl.create_default_context()
        ctx.check_hostname = False
        ctx.verify_mode = ssl.CERT_NONE
        
        req = urllib.request.Request(url, method='HEAD')
        
        try:
            with urllib.request.urlopen(req, context=ctx, timeout=10) as response:
                headers = response.headers
                status = response.status
                
                print(f'[INFO] Response status: {status}')
                
                for header, description in required_headers.items():
                    if header in headers:
                        print(f'[OK] {header}: {description}')
                    else:
                        print(f'[FAIL] {header} is missing: {description}')
                        all_ok = False
                
                # Check cookie attributes if any set-cookie headers exist
                if 'Set-Cookie' in headers:
                    cookie = headers['Set-Cookie']
                    if 'Secure' in cookie:
                        print('[OK] Cookies have Secure flag')
                    else:
                        print('[WARN] Cookies missing Secure flag')
                        all_ok = False
                    
                    if 'HttpOnly' in cookie:
                        print('[OK] Cookies have HttpOnly flag')
                    else:
                        print('[WARN] Cookies missing HttpOnly flag')
                        all_ok = False
                    
                    if 'SameSite' in cookie:
                        print(f'[OK] Cookies have SameSite={cookie.split("SameSite=")[1].split(";")[0] if "SameSite=" in cookie else "?"}')
                    else:
                        print('[WARN] Cookies missing SameSite attribute')
                        all_ok = False
                else:
                    print('[INFO] No Set-Cookie headers in response')
                    
        except urllib.error.HTTPError as e:
            print(f'[INFO] Got HTTP {e.code} (may need authentication)')
            # Still check headers even on error responses
            for header, description in required_headers.items():
                if header in e.headers:
                    print(f'[OK] {header}: {description}')
                else:
                    print(f'[FAIL] {header} is missing: {description}')
                    all_ok = False
                    
    except urllib.error.URLError as e:
        print(f'[SKIP] Cannot connect to {url}: {e.reason}')
        print('[SKIP] Run with --url <application_url> to check headers')
        return True  # Not a failure, just can't check
    
    return all_ok


def check_dependencies():
    """Run pip-audit to check for known vulnerabilities.
    
    Returns:
        bool: True if no critical vulnerabilities found.
    """
    print('\n' + '=' * 60)
    print('3. DEPENDENCY VULNERABILITY SCAN')
    print('=' * 60)
    
    try:
        result = subprocess.run(
            [sys.executable, '-m', 'pip_audit', '--format', 'json'],
            capture_output=True,
            text=True,
            timeout=60
        )
        
        if result.returncode == 0:
            print('[OK] No known vulnerabilities found')
            return True
        else:
            try:
                data = json.loads(result.stdout)
                vulns = data.get('dependencies', [])
                if vulns:
                    for vuln in vulns:
                        print(f'[FAIL] {vuln["name"]}=={vuln["version"]}: {vuln.get("description", "Vulnerability found")}')
                    return False
                else:
                    print('[OK] No vulnerabilities found')
                    return True
            except json.JSONDecodeError:
                if result.stdout:
                    print(f'[INFO] {result.stdout.strip()}')
                if result.stderr:
                    print(f'[WARN] {result.stderr.strip()}')
                return True
    except FileNotFoundError:
        print('[SKIP] pip-audit not installed. Run: pip install pip-audit')
        return True
    except subprocess.TimeoutExpired:
        print('[WARN] pip-audit timed out')
        return True


def check_file_permissions():
    """Check for common security issues in the project structure.
    
    Returns:
        bool: True if no critical issues found.
    """
    print('\n' + '=' * 60)
    print('4. PROJECT FILES CHECK')
    print('=' * 60)
    
    all_ok = True
    
    # Check .gitignore exists and contains important patterns
    gitignore_path = os.path.join(os.getcwd(), '.gitignore')
    if os.path.exists(gitignore_path):
        required_patterns = ['.env', 'instance/', '*.db', '*.log']
        with open(gitignore_path, 'r') as f:
            content = f.read()
        
        for pattern in required_patterns:
            if pattern in content:
                print(f'[OK] .gitignore contains: {pattern}')
            else:
                print(f'[WARN] .gitignore missing: {pattern}')
                all_ok = False
    else:
        print('[FAIL] .gitignore file not found!')
        all_ok = False
    
    # Check for .env in working directory (should NOT be committed)
    env_path = os.path.join(os.getcwd(), '.env')
    if os.path.exists(env_path):
        print('[INFO] .env file exists (ensure it is NOT committed)')
    else:
        print('[WARN] No .env file found')
    
    # Check for leftover .pyc or __pycache__
    pycache_count = 0
    for root, dirs, files in os.walk(os.getcwd()):
        if '__pycache__' in dirs:
            pycache_count += 1
        for f in files:
            if f.endswith('.pyc'):
                pycache_count += 1
    if pycache_count == 0:
        print('[OK] No __pycache__ or .pyc files found')
    else:
        print(f'[INFO] Found {pycache_count} cache files/dirs (should be in .gitignore)')
    
    return all_ok


def check_flask_config():
    """Check Flask application configuration for security.
    
    Returns:
        bool: True if configuration looks secure.
    """
    print('\n' + '=' * 60)
    print('5. FLASK CONFIGURATION CHECK')
    print('=' * 60)
    
    all_ok = True
    
    try:
        from app import create_app
        app = create_app()
        
        # Check session cookie settings
        cookie_checks = [
            ('SESSION_COOKIE_SECURE', True, 'Secure cookies'),
            ('SESSION_COOKIE_HTTPONLY', True, 'HttpOnly cookies'),
            ('PERMANENT_SESSION_LIFETIME', 3600, 'Session timeout'),
        ]
        
        for config_key, expected, description in cookie_checks:
            value = app.config.get(config_key)
            if config_key == 'PERMANENT_SESSION_LIFETIME':
                if value and value <= 3600:
                    print(f'[OK] {description}: {value}s')
                else:
                    print(f'[WARN] {description}: {value}s (should be <= 1 hour)')
                    all_ok = False
            elif value == expected:
                print(f'[OK] {description}: enabled')
            else:
                print(f'[FAIL] {description}: {value}')
                all_ok = False
        
        # Check MAX_CONTENT_LENGTH
        max_content = app.config.get('MAX_CONTENT_LENGTH')
        if max_content:
            mb = max_content / (1024 * 1024)
            print(f'[OK] MAX_CONTENT_LENGTH: {mb}MB')
        else:
            print('[WARN] MAX_CONTENT_LENGTH not set (unlimited uploads)')
            all_ok = False
            
        # Check CSRF
        csrf_enabled = app.config.get('WTF_CSRF_ENABLED')
        if csrf_enabled:
            print('[OK] CSRF protection: enabled')
        else:
            print('[FAIL] CSRF protection: disabled')
            all_ok = False
        
        # Check if app is in DEBUG mode
        if app.debug:
            print('[FAIL] DEBUG mode is enabled!')
            all_ok = False
        else:
            print('[OK] DEBUG mode: disabled')
            
    except Exception as e:
        print(f'[SKIP] Cannot check Flask config: {e}')
    
    return all_ok


def main():
    """Run all security checks and produce a summary report.
    
    Returns:
        int: 0 if all checks pass, 1 if any fail.
    """
    import argparse
    
    parser = argparse.ArgumentParser(description='Security validation scanner')
    parser.add_argument('--url', default='http://localhost:5000',
                       help='Application URL to check headers (default: http://localhost:5000)')
    args = parser.parse_args()
    
    print('╔══════════════════════════════════════════════════════════╗')
    print('║     TEAM TRYOUTS - SECURITY VALIDATION SCANNER          ║')
    print('╠══════════════════════════════════════════════════════════╣')
    print(f'║  Time: {datetime.now().strftime("%Y-%m-%d %H:%M:%S")}')
    print('╚══════════════════════════════════════════════════════════╝')
    
    checks = [
        check_environment,
        lambda: check_https_headers(args.url),
        check_dependencies,
        check_file_permissions,
        check_flask_config,
    ]
    
    results = []
    for check in checks:
        results.append(check())
    
    print('\n' + '=' * 60)
    print('SUMMARY')
    print('=' * 60)
    
    passed = sum(1 for r in results if r)
    failed = sum(1 for r in results if not r)
    total = len(results)
    
    print(f'Passed: {passed}/{total}')
    print(f'Failed: {failed}/{total}')
    
    if failed == 0:
        print('\n[OK] All security checks passed!')
        return 0
    else:
        print(f'\n[WARN] {failed} check(s) failed. Review the output above.')
        return 1


if __name__ == '__main__':
    sys.exit(main())