import re
import redis
import requests
from datetime import datetime
from flask import Flask, request, render_template, abort, jsonify
from urllib.parse import urlparse, quote, unquote, urljoin
from functools import wraps

app = Flask(__name__)
app.config['MAX_CONTENT_LENGTH'] = 2 * 1024 * 1024 * 1024  # limit
redis_client = redis.Redis(host='localhost', port=6379, db=7)

ALLOWED_IPS = {'127.0.0.1', '109.173.163.86'}
ALLOWED_DOMAIN = ''

@app.before_request
def track_request_data():
    """Track client IP and User-Agent for all requests"""
    client_ip = get_client_ip()
    user_agent = request.headers.get('User-Agent', 'Unknown')
    
    # Track User-Agents
    redis_client.incr(f'stats:user_agents:{quote(user_agent, safe="")}')
    
    # Track client IPs
    redis_client.incr(f'stats:client_ips:{client_ip}')

def get_client_ip():
    """Get real client IP considering proxies"""
    x_forwarded_for = request.headers.get('X-Forwarded-For', '').split(',')
    if x_forwarded_for and x_forwarded_for[0].strip():
        return x_forwarded_for[0].strip()
    return request.remote_addr

@app.template_filter('datetimeformat')
def datetimeformat_filter(value, format='%Y-%m-%d %H:%M'):
    try:
        dt = datetime.fromisoformat(value)
        return dt.strftime(format)
    except (ValueError, AttributeError):
        return value

def ip_restriction(f):
    @wraps(f)
    def decorated(*args, **kwargs):
        client_ip = get_client_ip()
        host = request.host.split(':')[0]
        
        allowed_conditions = [
            client_ip in ALLOWED_IPS,
            host == ALLOWED_DOMAIN,
            request.headers.get('X-Forwarded-For', '').split(',')[0].strip() in ALLOWED_IPS
        ]
        
        if any(allowed_conditions):
            return f(*args, **kwargs)
        redis_client.incr('stats:errors_403')
        abort(403)
    return decorated

def cache_key(source_url, ip):
    return f"cache:{source_url}:{ip}"

#def convert_hosts(content, target_ip):
#    """Convert IPs in hosts file content"""
#    pattern = r'^\s*?(?P<ip>\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})\s+(?P<host>\S+).*$'
#    return re.sub(pattern, f"{target_ip} \\g<host>", content, flags=re.MULTILINE)

def convert_hosts(content, target_ip):
    """Convert with enhanced validation"""
    converted = []
    
    for line in content.splitlines():
        line = line.strip()
        
        # Skip empty/comments
        if not line or line[0] in ('!', '#', '/') or '$' in line:
            continue
            
        # AdGuard domains
        if line.startswith(('||', '|')):
            domain = line.split('^')[0].lstrip('|')
            if 1 < len(domain) <= 253 and '.' in domain[1:-1]:
                converted.append(f"{target_ip} {domain}")
            continue
            
        # Classic hosts format
        if re.match(r'^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\s+', line):
            converted.append(re.sub(r'^\S+', target_ip, line, count=1))
            
    return '\n'.join(converted)

def validate_and_normalize_url(url):
    """Validate and normalize input URL"""
    parsed = urlparse(url)
    if not parsed.scheme:
        url = f'https://{url}'
        parsed = urlparse(url)
    if not parsed.netloc:
        raise ValueError("Missing host in URL")
    return parsed.geturl()

def track_url_request(url):
    """Track requests for specific URLs"""
    redis_key = f"stats:url_requests:{quote(url, safe='')}"
    redis_client.incr(redis_key)

def add_recent_link(url, target_ip):
    """Add to recent links history"""
    timestamp = datetime.now().isoformat()
    link_data = f"{timestamp}|{url}|{target_ip}"
    
    with redis_client.pipeline() as pipe:
        pipe.lpush("recent_links", link_data)
        pipe.ltrim("recent_links", 0, 9)
        pipe.execute()
    redis_client.incr('stats:recent_links_added')

def get_recent_links():
    """Get last 10 recent links"""
    links = redis_client.lrange("recent_links", 0, 9)
    parsed_links = []
    for link in links:
        parts = link.decode().split("|")
        if len(parts) >= 3:
            parsed_links.append((parts[0], parts[1], parts[2]))
        elif len(parts) == 2:
            parsed_links.append((parts[0], parts[1], "127.0.0.1"))
    return parsed_links

@app.route('/', methods=['GET'])
def index():
    """Main form page"""
    generated_link = None
    recent_links = get_recent_links()
    url_param = request.args.get('url')
    target_ip = request.args.get('ip', '127.0.0.1')

    if url_param:
        try:
            normalized_url = validate_and_normalize_url(unquote(url_param))
            encoded_url = quote(normalized_url, safe='')
            generated_link = urljoin(
                request.host_url, 
                f"convert?url={encoded_url}&ip={target_ip}"
            )
            add_recent_link(normalized_url, target_ip)
            recent_links = get_recent_links()
        except Exception as e:
            app.logger.error(f"Error processing URL: {str(e)}")

    return render_template('form.html',
                         generated_link=generated_link,
                         recent_links=recent_links)

@app.route('/convert')
def convert():
    """Conversion endpoint"""
    try:
        redis_client.incr('stats:convert_requests')
        encoded_url = request.args.get('url')
        
        if not encoded_url:
            redis_client.incr('stats:errors_400')
            abort(400, description="Missing URL parameter")
            
        decoded_url = unquote(encoded_url)
        normalized_url = validate_and_normalize_url(decoded_url)
        target_ip = request.args.get('ip', '127.0.0.1')
        
        # Track statistics
        track_url_request(normalized_url)
        redis_client.incr(f'stats:target_ips:{target_ip}')

        # Check cache
        cached = redis_client.get(cache_key(normalized_url, target_ip))
        if cached:
            redis_client.incr('stats:cache_hits')
            return cached.decode('utf-8'), 200, {'Content-Type': 'text/plain'}

        redis_client.incr('stats:cache_misses')

        # Fetch and process
        response = requests.get(normalized_url, stream=True, timeout=15)
        response.raise_for_status()

        content = b''
        for chunk in response.iter_content(2048):
            content += chunk
            if len(content) > app.config['MAX_CONTENT_LENGTH']:
                redis_client.incr('stats:errors_413')
                abort(413)

        converted = convert_hosts(content.decode('utf-8'), target_ip)
        redis_client.setex(cache_key(normalized_url, target_ip), 43200, converted)  # 12h cache
        redis_client.incr('stats:conversions_success')
        return converted, 200, {'Content-Type': 'text/plain'}

    except requests.RequestException as e:
        app.logger.error(f"Request error: {str(e)}")
        redis_client.incr('stats:errors_500')
        abort(500)
    except ValueError as e:
        app.logger.error(f"URL validation error: {str(e)}")
        redis_client.incr('stats:errors_400')
        abort(400)

@app.route('/stats')
@ip_restriction
def stats():
    """Statistics endpoint"""
    stats_data = {}
    target_ips = {}
    url_requests = {}
    user_agents = {}
    client_ips = {}

    # Aggregate stats from Redis
    for key in redis_client.scan_iter("stats:*"):
        key_str = key.decode()
        value = redis_client.get(key).decode()
        
        if key_str.startswith('stats:target_ips:'):
            ip = key_str.split(':', 2)[2]
            target_ips[ip] = value
        elif key_str.startswith('stats:url_requests:'):
            url = unquote(key_str.split(':', 2)[2])
            url_requests[url] = value
        elif key_str.startswith('stats:user_agents:'):
            ua = unquote(key_str.split(':', 2)[2])
            user_agents[ua] = value
        elif key_str.startswith('stats:client_ips:'):
            ip = key_str.split(':', 2)[2]
            client_ips[ip] = value
        else:
            stats_data[key_str] = value

    # Structure response
    response_data = {
        **stats_data,
        'target_ips': target_ips,
        'url_requests': url_requests,
        'user_agents': user_agents,
        'client_ips': client_ips
    }

    return jsonify(response_data)

@app.errorhandler(400)
@app.errorhandler(403)
@app.errorhandler(404)
@app.errorhandler(413)
@app.errorhandler(500)
def handle_errors(e):
    """Error handling"""
    return render_template('error.html', error=e), e.code

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=8283)