import uuid from "react-native-uuid";
import convert, { Area, Length } from "convert";

export type Id = string;

export type Currency = "USD";

export type ProductAttributes = {
    id?: string,
    name?: string,
    image?: string,
    description?: string,
    depth?: string,
    currency?: Currency,
    // [index:string]: any,
}

export type ProductData = {
    id?: Id,
    pricePerUnit: number,
    measurement: {
        unit: string,
        value: number,
        dimension: number,
    },
    attributes?: ProductAttributes,
};

export type length_t = {
    l: number, u: Length
}

export type area_t = length_t & {
    w: number,
}

export type dimensions_t = area_t | length_t;

export type product_type_t = "area" | "length";

export const isArea = (d: dimensions_t) => ("width" in d);
export const isLength = (d: dimensions_t) => (!("width" in d));
export const dimensionType = (d: dimensions_t) => isArea(d) ? "area" : "length"

export class Product {
    public id: string;
    public area?: area_t;
    public length?: length_t;
    public presentUnits: Length;

    constructor(public pricePerUnit: number, dimensions: dimensions_t, public attributes: ProductAttributes = {},) {
        this.id = attributes.id || uuid.v4().toString();
        this.presentUnits = dimensions.u;
        if ("w" in dimensions) {
            this.area = {
                l: convert(dimensions.l, dimensions.u).to("meter"),
                w: convert(dimensions.w, dimensions.u).to("meter"),
                u: "meter"
            }
        } else {
            this.length = {
                l: convert(dimensions.l, dimensions.u).to("meter"),
                u: "meter"
            };
        }
    }

    public priceFor(dimensions: dimensions_t): number {
        if (this.area && "w" in dimensions) {
            const thisA = this.area.l * this.area.w;
            const otherA = convert(
                dimensions.w,
                dimensions.u
            ).to("meter") * convert(
                dimensions.l,
                dimensions.u
            ).to("meter");
            return (otherA / thisA) * this.pricePerUnit;
        } if (this.length) {
            const thisL = this.length.l;
            const otherL = convert(
                dimensions.l,
                dimensions.u
            ).to("meter");
            return (otherL / thisL) * this.pricePerUnit;
        }
        throw new Error(`Invalid dimensions: ${dimensions}`);
    }

    get attributesAsList() {
        return Object.entries(this.attributes).map(([key, value]) => {
            return { key, value }
        })
    }

    public removeAttribute(key: string) {
        delete this.attributes[key];
    }
}