import os
import ipaddress
import json
import re
from flask import Flask, render_template, jsonify, request, Response
from dotenv import load_dotenv

from modules.network_tools import execute_command_streaming
from modules.visual_route import generate_visual_route_graph

load_dotenv()

app = Flask(__name__)

FQDN_REGEX = re.compile(r'^(?!-)(?:[a-zA-Z0-9-]{0,62}[a-zA-Z0-9]\.){1,126}(?!-d$)[a-zA-Z0-9-]{2,63}$')
MAX_TARGET_LENGTH = 255

def is_valid_ip_or_prefix(target: str) -> bool:
    try:
        if '/' in target:
            ipaddress.ip_network(target, strict=False)
        else:
            ipaddress.ip_address(target)
        return True
    except ValueError:
        return False

def is_valid_hostname(hostname: str) -> bool:
    if len(hostname) > MAX_TARGET_LENGTH:
        return False
    if is_valid_ip_or_prefix(hostname):
        return False
    return FQDN_REGEX.match(hostname) is not None

def get_ip_version(target):
    try:
        ip = ipaddress.ip_address(target)
        return f"ipv{ip.version}"
    except ValueError:
        try:
            net = ipaddress.ip_network(target, strict=False)
            return f"ipv{net.version}"
        except ValueError:
            return 'ipv4'

@app.route('/')
def index():
    return render_template('looking_glass.html')

@app.route('/api/locations')
def get_locations():
    locations_str = os.getenv('LOCATIONS', '{}')
    try:
        locations = json.loads(locations_str)
        config_data = {
            "locations": locations,
            "client_ip_api": {
                "v4": os.getenv('CLIENT_IPV4_API_URL'),
                "v6": os.getenv('CLIENT_IPV6_API_URL')
            }
        }
        return jsonify(config_data)
    except json.JSONDecodeError:
        return jsonify({"error": "Invalid LOCATIONS format in .env file"}), 500

@app.route('/api/client-ip')
def client_ip():
    client_ip_addr = request.headers.get('X-Forwarded-for', request.remote_addr)
    if client_ip_addr and client_ip_addr.startswith('::ffff:'):
        client_ip_addr = client_ip_addr[7:]
    return jsonify({'ip': client_ip_addr})


@app.route('/api/execute', methods=['POST'])
def execute_command():
    data = request.json
    method = data.get('method')
    target = data.get('target', '').strip()

    if not target:
        return Response("Error: A target is required.", status=400, mimetype='text/plain')
        
    if len(target) > MAX_TARGET_LENGTH:
        return Response(f"Error: Target exceeds maximum length.", status=400, mimetype='text/plain')
        
    if target.startswith('-'):
        return Response("Error: Target cannot start with a hyphen.", status=400, mimetype='text/plain')

    is_ip = is_valid_ip_or_prefix(target)
    is_host = is_valid_hostname(target)

    if not (is_ip or is_host):
        return Response(
            "Error: Invalid input. Please provide a valid IP, prefix, or fully qualified domain name.",
            status=400,
            mimetype='text/plain'
        )

    version = get_ip_version(target)
    
    if version == 'ipv6' and method in ['ping', 'mtr', 'traceroute']:
        method += '6'

    return Response(execute_command_streaming(method, target), mimetype='text/plain')


@app.route('/api/visualize', methods=['POST'])
def visualize_route():
    ip_address_str = request.json.get('ip_address')
    
    graph_data = generate_visual_route_graph(ip_address_str)
    
    if "error" in graph_data:
        return jsonify(graph_data), 400
        
    return jsonify(graph_data)


if __name__ == '__main__':
    app.run(host='0.0.0.0', port=5008, debug=True)