import requests
import re
import json
import socket
import textwrap
import os
import ipaddress
from dotenv import load_dotenv

load_dotenv()

TRANSIT_COMMUNITIES = set(filter(None, os.getenv('BGP_COMMUNITIES_TRANSIT', '').split(',')))
IX_COMMUNITIES = set(filter(None, os.getenv('BGP_COMMUNITIES_IX', '').split(',')))
CUSTOMER_COMMUNITIES = set(filter(None, os.getenv('BGP_COMMUNITIES_CUSTOMER', '').split(',')))

API_URL = os.getenv('BGP_API_URL', 'http://127.0.0.1:5000/bgp-route/lookup')
AS_NAME_CACHE = {}
AS_NAME_WRAP_WIDTH = 25
ROUTER_NAME = os.getenv('BGP_VIS_ROUTER_NAME', 'My Router')

def _bulk_get_as_names(asn_numbers: list[str]):
    lookup_list = [asn for asn in asn_numbers if asn not in AS_NAME_CACHE]
    if not lookup_list: return
    query = "begin\n" + "\n".join(f"AS{asn}" for asn in lookup_list) + "\nend\n"
    try:
        with socket.create_connection(('bgp.tools', 43), timeout=10) as s:
            s.sendall(query.encode('utf-8'))
            response_data = b""
            while True:
                chunk = s.recv(4096)
                if not chunk: break
                response_data += chunk
            response_str = response_data.decode('utf-8')
            for line in response_str.splitlines():
                parts = line.split('|')
                if len(parts) > 1:
                    asn_num_str = parts[0].strip()
                    as_name = parts[-1].strip()
                    if asn_num_str.isdigit(): AS_NAME_CACHE[asn_num_str] = as_name
    except (socket.error, socket.timeout) as e:
        print(f"Bulk AS name lookup failed: {e}")
    for asn in lookup_list:
        if asn not in AS_NAME_CACHE: AS_NAME_CACHE[asn] = ""

def _get_bgp_data(ip_address: str, ip_version: str) -> str | None:
    print(f"Querying API for {ip_version} address: {ip_address}...")
    payload = {"ip_version": ip_version, "bgprouteprefix": ip_address}
    headers = {"Content-Type": "application/json"}
    try:
        response = requests.post(API_URL, json=payload, headers=headers, timeout=10)
        response.raise_for_status()
        data = response.json()
        if data.get("success") and data.get("data"): return data["data"]
        else: return None
    except requests.exceptions.RequestException: return None

def _parse_bgp_paths_to_graph(bgp_data: str) -> dict:
    prefix_match = re.search(r"BGP routing table entry for ([\w:./-]+)", bgp_data)
    prefix = prefix_match.group(1) if prefix_match else "Unknown Prefix"
    lines = bgp_data.split('\n')
    
    path_blocks = []
    try:
        paths_header_index = next(i for i, line in enumerate(lines) if "Paths:" in line)
        current_block = []
        for line in lines[paths_header_index + 1:]:
            stripped_line = line.strip()
            if not stripped_line: continue
            
            is_new_path_line = False
            if line.startswith('  ') and not line.startswith('   '):
                first_word = stripped_line.split(' ')[0]
                
                cleaned_first_word = first_word.replace(',', '')
                if cleaned_first_word.isdigit() or stripped_line == "Local":
                    is_new_path_line = True
            
            if is_new_path_line:
                if current_block: path_blocks.append(current_block)
                current_block = [line]
            elif current_block:
                current_block.append(line)
        
        if current_block: path_blocks.append(current_block)
    except StopIteration:
        return {"nodes": [], "edges": []}

    all_paths_info, best_path_info = [], None
    for block in path_blocks:
        block_text_full = "\n".join(block)
        clean_lines = [line for line in block if not line.strip().startswith("AddPath ID:")]
        block_text_for_check = "\n".join(clean_lines)
        is_best = bool(re.search(r'\bbest\b', block_text_for_check, re.IGNORECASE))
        is_multipath = 'multipath' in block_text_for_check.lower()
        
        path_line = block[0].strip()
        path_asns_raw = []
        if path_line != "Local":
            for part in path_line.split(' '):
                clean_part = part.replace(',', '').strip()
                if clean_part.isdigit():
                    path_asns_raw.append(clean_part)
                else:
                    break
        
        path_asns = path_asns_raw
        
        local_pref_match = re.search(r'localpref (\d+)', block_text_full)
        local_pref = int(local_pref_match.group(1)) if local_pref_match else None
        next_hop_match = re.search(r'^\s*([\da-fA-F:.]+)\s+from', block_text_full, re.MULTILINE)
        next_hop = next_hop_match.group(1) if next_hop_match else None
        community_match = re.search(r'Large Community: ([\d:]+)', block_text_full)
        community = community_match.group(1) if community_match else None
        category = 'other'
        if community:
            if community in TRANSIT_COMMUNITIES: category = 'transit'
            elif community in IX_COMMUNITIES: category = 'ix'
            elif community in CUSTOMER_COMMUNITIES: category = 'customer'
        path_info = {"asns": path_asns, "local_pref": local_pref, "next_hop": next_hop, "is_best": is_best, "is_multipath": is_multipath, "community": community, "category": category}
        all_paths_info.append(path_info)
        if is_best and not best_path_info:
            best_path_info = path_info

    all_asns_in_graph = {asn for path in all_paths_info for asn in path['asns']}
    if all_asns_in_graph:
        _bulk_get_as_names(list(all_asns_in_graph))

    ordered_paths = sorted(all_paths_info, key=lambda p: (not p['is_best'], not p['is_multipath']))

    nodes, edges = [], []
    X_SEPARATION, Y_SEPARATION = 300, 200
    max_path_len = max((len(p['asns']) for p in ordered_paths if p['asns']), default=0)
    nodes.append({"id": ROUTER_NAME, "label": f"<b>{ROUTER_NAME}</b>", "color": '#FADBD8', "x": 0, "y": 0, "fixed": True, "path_category": "global", "is_active": True})
    nodes.append({"id": prefix, "label": f"<b>{prefix}</b>", "color": '#FADBD8', "x": (max_path_len + 1) * X_SEPARATION, "y": 0, "fixed": True, "path_category": "global", "is_active": True})
    
    y_pos_counter_up, y_pos_counter_down = 1, 1
    for i, path_info in enumerate(ordered_paths):
        lane_y = 0
        if i > 0:
            if y_pos_counter_up <= y_pos_counter_down: lane_y = y_pos_counter_up * Y_SEPARATION; y_pos_counter_up += 1
            else: lane_y = -y_pos_counter_down * Y_SEPARATION; y_pos_counter_down += 1
        
        style, is_active_path = {}, False
        if path_info['is_best']:
            style = {"node_color": '#FADBD8', "edge_color": '#C0392B', "width": 3, "dashes": False, "path_type": " (best)"}; is_active_path = True
        elif path_info['is_multipath']:
            style = {"node_color": '#FDEBD0', "edge_color": '#F39C12', "width": 2, "dashes": False, "path_type": " (multipath)"}; is_active_path = True
        else:
            style = {"node_color": '#D6DBDF', "edge_color": '#2C3E50', "width": 1, "dashes": True, "path_type": ""}; is_active_path = False
            
        path_node_ids = []
        for j, asn in enumerate(path_info['asns']):
            unique_node_id = f"AS{asn}-{i}-{j}"
            path_node_ids.append(unique_node_id)
            as_name = AS_NAME_CACHE.get(asn, ""); wrapped_name = '\n'.join(textwrap.wrap(as_name, width=AS_NAME_WRAP_WIDTH)) if as_name else ""
            base_label = f"<b>AS{asn}</b>"
            if j == 0 and path_info['local_pref'] is not None: base_label += f" (LP: {path_info['local_pref']})"
            label = f"{base_label}\n{wrapped_name}"
            if j == 0 and path_info['next_hop']: label += f"\n<i>Next Hop: {path_info['next_hop']}{style['path_type']}</i>"
            nodes.append({"id": unique_node_id, "label": label, "color": style['node_color'], "x": (j + 1) * X_SEPARATION, "y": lane_y, "fixed": True, "path_category": path_info['category'], "is_active": is_active_path})

        full_chain = [ROUTER_NAME] + path_node_ids + [prefix]
        smooth_config = {"enabled": True, "type": "cubicBezier", "forceDirection": "horizontal", "roundness": 0.85}
        for j in range(len(full_chain) - 1):
            edges.append({"from": full_chain[j], "to": full_chain[j+1], "color": style['edge_color'], "width": style['width'], "dashes": style['dashes'], "path_category": path_info['category'], "is_active": is_active_path, "smooth": smooth_config})
            
    return {"nodes": nodes, "edges": edges, "path_count": len(ordered_paths)}


def generate_visual_route_graph(ip_address_str: str) -> dict:
    if not ip_address_str:
        return {"error": "IP address is required."}
    address_to_lookup, ip_version = "", ""
    if '/' in ip_address_str:
        try:
            net_obj = ipaddress.ip_network(ip_address_str, strict=False)
            ip_version, address_to_lookup = f"ipv{net_obj.version}", net_obj.with_prefixlen
        except ValueError:
            return {"error": f"Invalid CIDR notation: {ip_address_str}"}
    else:
        try:
            ip_obj = ipaddress.ip_address(ip_address_str)
            ip_version, address_to_lookup = f"ipv{ip_obj.version}", ip_address_str
        except ValueError:
            return {"error": f"Invalid IP address: {ip_address_str}"}
    bgp_data = _get_bgp_data(address_to_lookup, ip_version)
    if not bgp_data:
        return {"error": f"Failed to retrieve BGP data for {address_to_lookup}."}
    graph_data = _parse_bgp_paths_to_graph(bgp_data)
    if not graph_data.get("nodes"):
         return {"error": "Could not parse valid AS paths from the API response."}
    return graph_data