const Rotation = require("./Rotation");

module.exports = class Matrix {
  /**
   * @param {string} axis_str xy
   * @param {boolean} inverse true := 90deg, -90deg otherwise
   */
  static rotHalfPI(axis_str = "xy", inverse = false) {
    let mat = Rotation["_rot" + axis_str];
    if (mat === undefined) {
      mat = Rotation["_rot" + axis_str.split("").reverse().join("")]; // reverse str, ex : given yx but it should be xy
    }
    if (mat === undefined) {
      throw Error("Rotation matrix " + axis_str + " does not exist");
    }
    // t = +- pi/2
    const cost = 0, sint = inverse ? -1 : 1;
    return mat(cost, sint);
  }

  static debug(mat, msg = "") {
    console.log(msg + "[");
    for (const row of mat) {
      console.log("", row);
    }
    console.log("]");
  }

  /**
   * @param {number[][]} A
   * @param {number[][]} B
   * @returns {number[][]}
   */
  static mult(A, B) {
    const dim = A.length;
    const res = new Array(dim);
    for (let i = 0; i < dim; i++) {
      res[i] = new Array(dim);
      for (let j = 0; j < dim; j++) {
        let s = 0;
        for (let k = 0; k < dim; k++) {
          s += A[i][k] * B[k][j];
        }
        res[i][j] = s;
      }
    }
    return res;
  }
};