const Matrices = {
    // A x A array of nulls; null-null relationships are omitted in chord diagram.
    createEmptyMatrix: (len) => {
        const empty = Array.apply(null, Array(len));
        return empty.map(() => empty.map(() => null));
    },

    // Scalar data points (sum of goals scored).
    buildMatrix: (json, eventKey) => {
        const teams = json.tourneys[eventKey].teams;
        const matrix = Matrices.createEmptyMatrix(teams.length);

        json.tourneys[eventKey].games.forEach(g => {
            const i1 = teams.findIndex(v => v.tId === g.t1);
            const i2 = teams.findIndex(v => v.tId === g.t2);

            let s1 = matrix[i1][i2] || 0;
            let s2 = matrix[i2][i1] || 0;

            if (g.sp1 !== null) {
                s1 += g.sp1;
            }
            else if (g.se1 !== null) {
                s1 += g.se1;
            }
            else {
                s1 += g.s1;
            }

            if (g.sp2 !== null) {
                s2 += g.sp2;
            }
            else if (g.se2 !== null) {
                s2 += g.se2;
            }
            else {
                s2 += g.s2;
            }
            
            matrix[i1][i2] = s1;
            matrix[i2][i1] = s2;
        }, []);

        return matrix;
    },

    swapIndices: (arr, i, j) => {
        const tmp = arr[i];
        arr[i] = arr[j];
        arr[j] = tmp;

        return arr;
    },
};

export default Matrices;