import { board } from "../board.js"
import { Vector2 } from "../engine/vector2.js"

const SURROUNDING = [
    new Vector2(-1, 0),
    new Vector2(0, 1),
    new Vector2(0, -1),
    new Vector2(1, 0),
]

export function hasLiberties({
    position,
    team
}) {
    return checkLiberties({
        position,
        team
    })
}

function checkLiberties({
    position,
    team,
    checkedStones = [],
    checkedLiberties = [],
}) {
    if (
        Array.from(checkedStones)
            .some(p => Vector2.equals(p, position))
    ) {
        return false
    }

    checkedStones.push(position)

    let surroundingSquares = Array.from(SURROUNDING)
        .map(v => Vector2.sum(v, position))
        .filter(z => 0 <= z.x && z.x < board.size &&
            0 <= z.y && z.y < board.size
        )

    surroundingSquares
        .filter(z => board.stones[z.y][z.x] == undefined)
        .forEach(z => {
            if (!Array.from(checkedStones)
                .some(p => Vector2.equals(p, z))
            ) {
                checkedLiberties.push(z)
            }
        })

    surroundingSquares
        .filter(z => board.stones[z.y][z.x] != undefined)
        .filter(z => board.stones[z.y][z.x].team == team)
        .forEach(z => {
            checkLiberties({
                position: z,
                team: team,
                checkedStones: checkedStones,
                checkedLiberties: checkedLiberties,
            })
        })

    if (checkedLiberties.length > 0) {
        return true
    }

    return false
}