import re
from collections import defaultdict
from datetime import datetime

def parse_log_file(log_file_path):

    parsed_entries = []
    
    xss_patterns = [
        r'<\s*script\s*',
        r'javascript:',
        r'<\s*img\s*src\s*=?',
        r'<\s*a\s*href\s*=?',
        r'<\s*iframe\s*src\s*=?',
        r'on\w+\s*=?',
        r'<\s*input\s*[^>]*\s*value\s*=?',
        r'<\s*form\s*action\s*=?',
        r'<\s*svg\s*on\w+\s*=?',
        r'script',
        r'alert',
        r'onerror',
        r'onload',
    ]
    
    sql_patterns = [
        r'(union|select|insert|update|delete|drop)\s+(from|into|table)',
        r';\s*(union|select|insert|update|delete|drop)',
        r'substring\s*\(',
        r'extract\s*\(',
        r'order\s+by\s+\d+',
        r'--\+',
        r'1\s*=\s*1',
        r'@@\w+',
        r'`1',
        r'\|\|\s*chr\(',
    ]
    
    webshells_patterns = [
        r'eval\s*\(',
        r'system\s*\(',
        r'passthru\s*\(',
        r'shell_exec\s*\(',
        r'exec\s*\(',
        r'popen\s*\(',
        r'proc_open\s*\(',
        r'pcntl_exec\s*\(',
        r'\.php\?cmd=',
        r'\.php\?id=',
        r'backdoor|webshell|phpspy|c99|kacak|b374k|wsos|madspot|r57|c100|r57shell',
    ]
    
    xss_pattern = re.compile('|'.join(xss_patterns), re.IGNORECASE)
    sql_pattern = re.compile('|'.join(sql_patterns), re.IGNORECASE)
    webshell_pattern = re.compile('|'.join(webshells_patterns), re.IGNORECASE)
    
    try:
        with open(log_file_path, 'r') as log_file:
            log_lines = log_file.readlines()
        
        for line in log_lines:
            if not line.strip():
                continue
            
            match = re.search(
                r'(\w+\s+\d+\s\d+:\d+:\d+).*\s(\d+\.\d+\.\d+\.\d+).*"?\s*(GET|POST|PUT|DELETE|PATCH|HEAD|OPTIONS)\s+([^"\s]+)"?\s+(\d{3})',
                line
            )
            
            if not match:
                continue
            
            timestamp = match.group(1)
            ip_address = match.group(2)
            http_method = match.group(3)
            requested_url = match.group(4)
            status_code = int(match.group(5))
            
            threats = []
            threat_level = 'info'
            
            if xss_pattern.search(line):
                threats.append('XSS Attack')
                threat_level = 'danger'
            
            if sql_pattern.search(line):
                threats.append('SQL Injection')
                threat_level = 'danger'
            
            if webshell_pattern.search(line):
                threats.append('Webshell')
                threat_level = 'danger'
            
            if http_method == 'PUT':
                threats.append('Remote Upload')
                threat_level = 'warning'
            
            if 'admin' in requested_url.lower() or 'config' in requested_url.lower():
                if status_code == 403:
                    threats.append('Unauthorized Access')
                    threat_level = 'warning'
            
            status_category = 'info'
            if 200 <= status_code < 300:
                status_category = 'success'
            elif 300 <= status_code < 400:
                status_category = 'secondary'
            elif 400 <= status_code < 500:
                status_category = 'warning'
            elif status_code >= 500:
                status_category = 'danger'
            
            parsed_entries.append({
                'timestamp': timestamp,
                'ip_address': ip_address,
                'http_method': http_method,
                'requested_url': requested_url,
                'status_code': status_code,
                'status_category': status_category,
                'threats': threats if threats else ['None'],
                'threat_level': threat_level if threats else 'info',
                'is_threat': bool(threats),
            })
    
    except FileNotFoundError:
        return [{'error': f'Log file not found: {log_file_path}'}]
    except Exception as e:
        return [{'error': f'Error parsing log: {str(e)}'}]
    
    return parsed_entries


def get_log_statistics(parsed_entries):

    stats = {
        'total_requests': len(parsed_entries),
        'threat_count': sum(1 for e in parsed_entries if e.get('is_threat')),
        'status_codes': defaultdict(int),
        'http_methods': defaultdict(int),
        'top_ips': defaultdict(int),
        'threat_types': defaultdict(int),
    }
    
    for entry in parsed_entries:
        if 'error' in entry:
            continue
        
        stats['status_codes'][entry['status_code']] += 1
        stats['http_methods'][entry['http_method']] += 1
        stats['top_ips'][entry['ip_address']] += 1
        
        for threat in entry.get('threats', []):
            if threat != 'None':
                stats['threat_types'][threat] += 1
    
    stats['top_ips'] = sorted(
        stats['top_ips'].items(),
        key=lambda x: x[1],
        reverse=True
    )[:5]
    
    stats['status_codes'] = dict(stats['status_codes'])
    stats['http_methods'] = dict(stats['http_methods'])
    stats['threat_types'] = dict(stats['threat_types'])
    
    return stats


def filter_logs(parsed_entries, filters=None):
    if not filters:
        return parsed_entries
    
    filtered = parsed_entries
    
    if 'status_code' in filters and filters['status_code']:
        filtered = [e for e in filtered if e.get('status_code') == int(filters['status_code'])]
    
    if 'threat_level' in filters and filters['threat_level']:
        filtered = [e for e in filtered if e.get('threat_level') == filters['threat_level']]
    
    if 'http_method' in filters and filters['http_method']:
        filtered = [e for e in filtered if e.get('http_method') == filters['http_method']]
    
    if 'ip_address' in filters and filters['ip_address']:
        filtered = [e for e in filtered if e.get('ip_address') == filters['ip_address']]
    
    if 'has_threat' in filters and filters['has_threat']:
        filtered = [e for e in filtered if e.get('is_threat')]
    
    return filtered