import time

from dataclasses import dataclass

from maze import Maze
from strategies import PathFindingStrategy


@dataclass
class SearchStats:
    time_ms: float
    visited_cells: int
    path_length: int


class MazeSolver:

    def __init__(
        self,
        maze: Maze,
        strategy: PathFindingStrategy
    ):

        self.maze = maze
        self.strategy = strategy

        self.observers = []

    # =====================================
    # Observer
    # =====================================

    def add_observer(self, observer):

        self.observers.append(observer)

    def notify(self, event: str):

        for observer in self.observers:
            observer.update(event)

    # =====================================
    # Strategy
    # =====================================

    def set_strategy(
        self,
        strategy: PathFindingStrategy
    ):

        self.strategy = strategy

        self.notify(
            f"Strategy changed to {strategy.__class__.__name__}"
        )

    # =====================================
    # Solve
    # =====================================

    def solve(self):

        self.notify("Search started")

        start_time = time.perf_counter()

        path, visited_cells = self.strategy.find_path(
            self.maze,
            self.maze.start,
            self.maze.exit
        )

        end_time = time.perf_counter()

        stats = SearchStats(
            time_ms=(end_time - start_time) * 1000,
            visited_cells=visited_cells,
            path_length=len(path)
        )

        if path:
            self.notify("Path found")
        else:
            self.notify("No path found")

        return path, stats