lab_palavras_sentence_class.ts

class Result{
    constructor(public title: string, public imagePath: string) { }
}

class Sentence{
    base: string;
    values: string[];
    results: { [id: string]: Result };
    
    constructor(base: string, values: string[], results: { [id: string]: Result }) {
        this.runValidations(base, values, results);
        this.base = base;
        this.values = values;
        this.results = results;
    }

    resultFor(values: string[]): Result {
        let resultStr: string = this.base
        values.forEach((v) => {
            resultStr = resultStr.replace(/{}/, v);
        });

        let result = this.results[resultStr]
        if (result) {
            return result;
        } else {
            throw `Undefined result for "${resultStr}"`;
        }
    }

    private runValidations(base: string, values: string[], results: { [a: string]: any}) {
        let numberOfPlaceholders: number = (base.match(/{}/g) || []).length
        if (numberOfPlaceholders < 2) { throw "Must have at least two placeholders."; }
        if (values.length != numberOfPlaceholders) { throw `Expected ${numberOfPlaceholders} values, got ${values.length}.`; }
        if (Object.keys(results).length != this.factorial(numberOfPlaceholders)) {
            throw `Expected ${this.factorial(numberOfPlaceholders)} values, got ${Object.keys(results).length}`;
        }
    }

    private factorial(n : number) : number {
        let rval=1;
        for (let i = 2; i <= n; i++)
            rval = rval * i;
        return rval;
    }
}

let sentence = new Sentence(
    "O {} atropelou o {}",
    ["carro", "menino"],
    {
        "O carro atropelou o menino": new Result("O carro atropelou o menino", "http://placekitten.com/200/300"),
        "O menino atropelou o carro": new Result("O menino atropelou o carro", "http://placekitten.com/300/200")
    }
);

console.log(sentence.resultFor(["menino", "carro"]))
console.log(sentence.resultFor(["carro", "menino"]))