import type { Building, Production } from "./types";
import type { VillageState } from "./village";


function _reduceResources(acc: Production, item: Production): Production {
    return {
        wood: acc.wood + item.wood,
        stone: acc.stone + item.stone,
        iron: acc.iron + item.iron,
        food: acc.food + item.food,
    };
}


export function getEmptyResources(): Production {
    return {
        wood: 0,
        stone: 0,
        iron: 0,
        food: 0,
    };
}


export function getProduction(villageState: VillageState): Production {
    return villageState.buildings
        .filter(b => b.behavior.production)
        .map(b => {
            if (b.behavior.production) {
                return b.behavior.production(villageState, b);
            }
        })
        .reduce(_reduceResources, getEmptyResources());
}


export function getStorage(villageState: VillageState): Production {
    return villageState.buildings
        .filter(b => b.behavior.storage)
        .map(b => {
            if (b.behavior.storage) {
                return b.behavior.storage(villageState, b);
            }
        })
        .reduce(_reduceResources, getEmptyResources());
}


export function getBuilding(V: VillageState, buildingId: number): Building {
    const building = V.buildings.find(b => b.id === buildingId);
    if (!building) {
        throw new Error(`Cannot find building with id "${buildingId}"`);
    }
    return building;
}


export function getKeysAsNumbers(dict: Object): Array<number> {
    return Object.keys(dict).map(i => parseInt(i)).sort((a, b) => a - b);
}


/**
 * Creates an array of shuffled values, using a version of the
 * [Fisher-Yates shuffle](https://en.wikipedia.org/wiki/Fisher-Yates_shuffle).
 *
 * @since 0.1.0
 * @category Array
 * @param {Array} array The array to shuffle.
 * @returns {Array} Returns the new shuffled array.
 * @example
 *
 * shuffle([1, 2, 3, 4])
 * // => [4, 1, 3, 2]
 */
export function shuffle<T>(array: Array<T>): Array<T> {
    const length = array.length;
    if (!length) {
        return [];
    }
    let index = -1;
    const lastIndex = length - 1;
    const result = [ ...array ];
    while (++index < length) {
        const rand = index + Math.floor(Math.random() * (lastIndex - index + 1));
        [ result[rand], result[index] ] = [ result[index], result[rand] ];
    }
    return result;
}