import json
from flask import Flask, request, jsonify

from routes import app

# Directions mapping
DIRECTION_DELTAS = {
    'N': (-1, 0),
    'S': (1, 0),
    'W': (0, -1),
    'E': (0, 1)
}

class Block:
    def __init__(self, name, cells):
        self.name = name
        self.cells = set(cells)  # Set of (row, col) tuples
        self.update_dimensions()

    def update_dimensions(self):
        rows = [r for r, c in self.cells]
        cols = [c for r, c in self.cells]
        self.top = min(rows)
        self.bottom = max(rows)
        self.left = min(cols)
        self.right = max(cols)
        self.height = self.bottom - self.top + 1
        self.width = self.right - self.left + 1

    def move(self, direction, grid):
        delta_row, delta_col = DIRECTION_DELTAS[direction]
        new_cells = set()
        for r, c in self.cells:
            new_r, new_c = r + delta_row, c + delta_col
            new_cells.add((new_r, new_c))
        
        # Check boundaries and collisions
        for r, c in new_cells:
            if not (0 <= r < 5 and 0 <= c < 4):
                raise ValueError("Move out of bounds")
            if grid[r][c] not in ('@', self.name):
                raise ValueError("Collision detected")
        
        # Update grid
        for r, c in self.cells:
            grid[r][c] = '@'
        for r, c in new_cells:
            grid[r][c] = self.name
        
        self.cells = new_cells
        self.update_dimensions()

def parse_board(board_str):
    grid = []
    for i in range(0, 20, 4):
        grid.append(list(board_str[i:i+4]))
    
    blocks = {}
    for r in range(5):
        for c in range(4):
            char = grid[r][c]
            if char != '@':
                if char not in blocks:
                    blocks[char] = set()
                blocks[char].add((r, c))
    
    block_objects = {}
    for name, cells in blocks.items():
        block_objects[name] = Block(name, cells)
    
    return grid, block_objects

def serialize_grid(grid):
    return ''.join([''.join(row) for row in grid])

@app.route('/klotski', methods=['POST'])
def klotski():
    data = request.get_json()
    result = []

    for item in data:
        board_str = item['board']
        moves_str = item['moves']

        grid, blocks = parse_board(board_str)

        # Process moves in pairs
        for i in range(0, len(moves_str), 2):
            block_name = moves_str[i]
            direction = moves_str[i+1]
            block = blocks.get(block_name)
            if not block:
                raise ValueError(f"Block {block_name} not found")
            block.move(direction, grid)
        
        result.append(serialize_grid(grid))
    
    return jsonify(result)