import time
from vorlesung.L08_graphen.graph import AdjacencyListGraph

# AoC 2024, Tag 16 – erstes Beispiel-Labyrinth (Antwort: 7036)
GRID = """\
###############
#.......#....E#
#.#.###.#.###.#
#.....#.#...#.#
#.###.#####.#.#
#.#.#.......#.#
#.#.#####.###.#
#...........#.#
###.#.#####.#.#
#...#.....#.#.#
#.#.#.###.#.#.#
#.....#...#.#.#
#.###.#.#.#.#.#
#S..#.....#...#
###############""".strip().split('\n')

# Richtungen: 0=N, 1=O, 2=S, 3=W  (O = Ost = Startrichtung des Rentiers)
DR = [-1, 0, 1, 0]
DC = [0, 1, 0, -1]


def build_graph(grid):
    g = AdjacencyListGraph()
    rows, cols = len(grid), len(grid[0])
    start = end = None

    for r in range(rows):
        for c in range(cols):
            if grid[r][c] == '#':
                continue
            if grid[r][c] == 'S':
                start = (r, c)
            elif grid[r][c] == 'E':
                end = (r, c)
            for d in range(4):
                g.insert_vertex(f"{r},{c},{d}")

    for r in range(rows):
        for c in range(cols):
            if grid[r][c] == '#':
                continue
            for d in range(4):
                src = f"{r},{c},{d}"
                # Vorwärtsbewegen (Kosten 1)
                nr, nc = r + DR[d], c + DC[d]
                if 0 <= nr < rows and 0 <= nc < cols and grid[nr][nc] != '#':
                    g.connect(src, f"{nr},{nc},{d}", 1)
                # Drehen links und rechts (Kosten 1000 je Drehung)
                g.connect(src, f"{r},{c},{(d - 1) % 4}", 1000)
                g.connect(src, f"{r},{c},{(d + 1) % 4}", 1000)

    return g, start, end


# --- a) + b) Graph aufbauen und Dijkstra ausführen ---

g, start, end = build_graph(GRID)
v_count = len(list(g.all_vertices()))
e_count = len(g.all_edges())
print(f"Graph: |V| = {v_count}, |E| = {e_count}")

start_state = f"{start[0]},{start[1]},1"    # Startposition, Blickrichtung Ost (1)
dist_map, pred_map = g.dijkstra(start_state)

# Bestes Zielfeld: E in beliebiger Richtung (4 zulässige Zielzustände)
end_vertices = [g.get_vertex(f"{end[0]},{end[1]},{d}") for d in range(4)]
best_end = min(end_vertices, key=lambda v: dist_map[v])
print(f"Gesamtkosten: {dist_map[best_end]}")     # Erwartung: 11048

pfad = g.path(best_end.value, pred_map)
print(f"Pfad: {len(pfad)} Zustände ({len(pfad) - 1} Schritte)")
print("Erste Schritte:", " -> ".join(pfad[:5]), "...")
print("Letzte Schritte: ...", " -> ".join(pfad[-3:]))

# --- c) Laufzeitmessung ---
t0 = time.perf_counter()
g.dijkstra(start_state)
t1 = time.perf_counter()
print(f"\nLaufzeit (Beispiel): {(t1 - t0) * 1000:.3f} ms")