from dataclasses import dataclass
from const import *
from typing import List, Dict, Tuple

import numpy.typing as npt


@dataclass
class Position:
    row: int
    col: int


def dfs(grid: npt.NDArray, visited: Dict[Tuple[int, int], bool], position: Position, rows: int, cols: int) -> None:
    visited[(position.row, position.col)] = True

    row_vector = [0, 0, 1, -1]
    col_vector = [-1, 1, 0, 0]

    neighbours = []
    for i in range(4):
        rr = position.row + row_vector[i]
        cc = position.col + col_vector[i]
        if rr < 0 or rr >= ROWS:
            continue
        elif cc < 0 or cc >= COLUMNS:
            continue
        else:
            p = Position(rr, cc)
            if (p.row, p.col) in visited:
                neighbours.append(p)

    for neighbour in neighbours:
        if not visited[(neighbour.row, neighbour.col)]:
            dfs(grid, visited, neighbour, rows, cols)


def get_islands(grid: npt.NDArray, positions: List[Position], rows: int = ROWS, cols: int = COLUMNS) -> List[Position]:
    """it returns list of all islands roots"""
    visited = {}

    for position in positions:
        visited[(position.row, position.col)] = False

    islands = 0
    roots = []
    for position in positions:
        if not visited[(position.row, position.col)]:
            dfs(grid, visited, position, rows, cols)
            roots.append(position)
            islands += 1

    return roots