import os
import json
import argparse
import heapq
import math

# Hilfsfunktionen
def load_json(filepath):
    with open(filepath, 'r', encoding='utf-8') as f:
        return json.load(f)

def parse_pos(pos_str):
    """ Konvertiert '(x, y)' oder '(x, y, z)' in ein Tuple """
    try:
        return tuple(map(float, pos_str.strip('()').split(',')))
    except Exception:
        raise ValueError(f"Ungültiges Positionsformat: {pos_str}")

def distance(p1, p2):
    """ Euklidische Distanz in 2D """
    return math.sqrt((p1[0]-p2[0])**2 + (p1[1]-p2[1])**2)

def add_edge(graph, node1, node2, dist):
    """ Fügt eine Kante zwischen zwei Knoten im Graphen hinzu """
    if node1 not in graph:
        graph[node1] = []
    if node2 not in graph:
        graph[node2] = []
    graph[node1].append((node2, dist))
    graph[node2].append((node1, dist))

def project_point_on_segment(p, a, b):
    """Projektion eines Punktes p auf ein Liniensegment a-b"""
    ax, ay = a
    bx, by = b
    px, py = p

    dx = bx - ax
    dy = by - ay
    if dx == dy == 0:
        return a

    t = ((px - ax) * dx + (py - ay) * dy) / (dx * dx + dy * dy)
    t = max(0, min(1, t))  # Begrenze t auf [0,1]
    return (ax + t * dx, ay + t * dy)

def dijkstra(graph, start):
    """ Dijkstra-Algorithmus, um die kürzesten Wege im Graphen zu berechnen """
    distances = {node: float('inf') for node in graph}
    distances[start] = 0
    priority_queue = [(0, start)]  # (Distanz, Knoten)
    
    while priority_queue:
        current_distance, current_node = heapq.heappop(priority_queue)

        if current_distance > distances[current_node]:
            continue

        for neighbor, weight in graph[current_node]:
            distance = current_distance + weight

            if distance < distances[neighbor]:
                distances[neighbor] = distance
                heapq.heappush(priority_queue, (distance, neighbor))

    return distances


if __name__ == "__main__":
    parser = argparse.ArgumentParser(description='Berechne Wege von Sensoren zu Verteilern über Kabeltrassen')
    parser.add_argument('-c', '--console', action='store_true', help='Ausgabe auf Konsole')

    args = parser.parse_args()

    # Umgebungsvariablen
    work_dir = os.environ.get("PROJECT_WORK")
    config_dir = os.environ.get("PROJECT_CFG")

    # Pfade zu JSON-Dateien
    sensors_path = os.path.join(work_dir, "sensors.json")
    subdist_path = os.path.join(work_dir, "subdistributors.json")
    racks_path = os.path.join(work_dir, "racks.json")

    # Einlesen
    sensors = load_json(sensors_path)
    subdists = {k: parse_pos(v) for k, v in load_json(subdist_path).items()}
    racks = load_json(racks_path)

    # Graph erstellen
    graph = {}

    # Sensoren zu Kabeltrassen verbinden
    for sensor_id, sensor_info in sensors.items():  #über alle Sensoren und alle deren Infos laufen
        sensor_pos = tuple(sensor_info['pos'])      #sensor position als tuple übergeben
        for rack in racks:
            for segment_start, segment_end in zip(rack[:-1], rack[1:]):
                # Berechne Distanz von Sensor zur Kabeltrasse
                px, py = project_point_on_segment(sensor_pos, segment_start, segment_end)
                dist = distance(sensor_pos, (px, py))
                add_edge(graph, sensor_id, f"rack_{rack}", dist)

    # Unterverteiler zu Kabeltrassen verbinden
    for uc_id, uc_pos in subdists.items():
        for rack in racks:
            for segment_start, segment_end in zip(rack[:-1], rack[1:]):
                # Berechne Distanz von UC zur Kabeltrasse
                px, py = project_point_on_segment(uc_pos, segment_start, segment_end)
                dist = distance(uc_pos, (px, py))
                add_edge(graph, uc_id, f"rack_{rack}", dist)

    # Sensor zu UC verbinden (Routing von Sensoren zu den zugehörigen Unterverteilern)
    for sensor_id, sensor_info in sensors.items():
        subdist_id = None
        if 'KENNZEICHNUNG' in sensor_info:
            for uc_id in subdists:
                if uc_id in sensor_info['KENNZEICHNUNG']:
                    subdist_id = uc_id
                    break
        if subdist_id:
            # Verbinde den Sensor mit dem zugehörigen Unterverteiler
            sensor_pos = tuple(sensor_info['pos'])
            uc_pos = subdists[subdist_id]
            dist = distance(sensor_pos, uc_pos)
            add_edge(graph, sensor_id, subdist_id, dist)

    # Berechnung der kürzesten Wege mit Dijkstra
    routing_result = {}
    for sensor_id in sensors:
        distances = dijkstra(graph, sensor_id)
        routing_result[sensor_id] = distances

    if args.console:
        print(json.dumps(routing_result, indent=2))