import pygame
import math
from game.config import (
    CELL_SIZE, GRID_COLS, GRID_ROWS, UI_TOP_HEIGHT,
    COLOR_GRASS, COLOR_PATH, COLOR_GRID_LINE,
    PATH_WAYPOINTS,
)


class GameMap:
    def __init__(self):
        self.path_cells = set()
        self._calc_path_cells()

    def _calc_path_cells(self):
        for i in range(len(PATH_WAYPOINTS) - 1):
            x1, y1 = PATH_WAYPOINTS[i]
            x2, y2 = PATH_WAYPOINTS[i + 1]
            dx = x2 - x1
            dy = y2 - y1
            dist = math.hypot(dx, dy)
            steps = int(dist / (CELL_SIZE / 2))
            for s in range(steps + 1):
                t = s / max(steps, 1)
                px = x1 + dx * t
                py = y1 + dy * t
                col = int(px // CELL_SIZE)
                row = int((py - UI_TOP_HEIGHT) // CELL_SIZE)
                if 0 <= col < GRID_COLS and 0 <= row < GRID_ROWS:
                    self.path_cells.add((col, row))

    def is_buildable(self, col, row):
        if col < 0 or col >= GRID_COLS or row < 0 or row >= GRID_ROWS:
            return False
        return (col, row) not in self.path_cells

    def pixel_to_grid(self, px, py):
        col = int(px // CELL_SIZE)
        row = int((py - UI_TOP_HEIGHT) // CELL_SIZE)
        return col, row

    def grid_to_pixel(self, col, row):
        px = col * CELL_SIZE + CELL_SIZE // 2
        py = row * CELL_SIZE + CELL_SIZE // 2 + UI_TOP_HEIGHT
        return px, py

    def draw(self, surface):
        for row in range(GRID_ROWS):
            for col in range(GRID_COLS):
                rect = pygame.Rect(
                    col * CELL_SIZE,
                    row * CELL_SIZE + UI_TOP_HEIGHT,
                    CELL_SIZE, CELL_SIZE,
                )
                color = COLOR_PATH if (col, row) in self.path_cells else COLOR_GRASS
                pygame.draw.rect(surface, color, rect)
                pygame.draw.rect(surface, COLOR_GRID_LINE, rect, 1)

        for i in range(len(PATH_WAYPOINTS) - 1):
            pygame.draw.line(surface, (180, 150, 120), PATH_WAYPOINTS[i], PATH_WAYPOINTS[i + 1], 3)