// This formats dict as a string suitable as test name.
// format_value() is provided by testharness.js,
// which also preserves sign for -0.
function format_dict(dict) {
  const props = [];
  for (let prop in dict) {
    props.push(`${prop}: ${format_value(dict[prop])}`);
  }
  return `{${props.join(', ')}}`;
}

// Create a normal JS object with the expected properties
// from a dict with only m11..m44 specified (not a..f).
function matrix3D(dict) {
  const matrix = {m11: 1, m12: 0, m13: 0, m14: 0,
                  m21: 0, m22: 1, m23: 0, m24: 0,
                  m31: 0, m32: 0, m33: 1, m34: 0,
                  m41: 0, m42: 0, m43: 0, m44: 1}
  matrix.is2D = false;
  for (let member in dict) {
    matrix[member] = dict[member];
  }
  matrix.a = matrix.m11;
  matrix.b = matrix.m12;
  matrix.c = matrix.m21;
  matrix.d = matrix.m22;
  matrix.e = matrix.m41;
  matrix.f = matrix.m42;
  return matrix;
}

function matrix2D(dict) {
  const matrix = matrix3D(dict);
  matrix.is2D = true;
  return matrix;
}

function checkMatrix(actual, expected, { epsilon = Number.MIN_VALUE } = {}) {
  for (let member in expected) {
    if (epsilon && typeof expected[member] === "number") {
      assert_approx_equals(actual[member], expected[member], epsilon, member);
    } else {
      assert_equals(actual[member], expected[member], member);
    }
  }
}

// checkMatrix and checkDOMMatrix should probably be merged...
function checkDOMMatrix(m, exp, is2D) {
    if (is2D === undefined) {
        is2D = exp.is2D;
    }
    assert_equals(m.m11, exp.m11, "Expected value for m11 is " + exp.m11);
    assert_equals(m.m12, exp.m12, "Expected value for m12 is " + exp.m12);
    assert_equals(m.m13, exp.m13, "Expected value for m13 is " + exp.m13);
    assert_equals(m.m14, exp.m14, "Expected value for m14 is " + exp.m14);
    assert_equals(m.m21, exp.m21, "Expected value for m21 is " + exp.m21);
    assert_equals(m.m22, exp.m22, "Expected value for m22 is " + exp.m22);
    assert_equals(m.m23, exp.m23, "Expected value for m23 is " + exp.m23);
    assert_equals(m.m24, exp.m24, "Expected value for m24 is " + exp.m24);
    assert_equals(m.m31, exp.m31, "Expected value for m31 is " + exp.m31);
    assert_equals(m.m32, exp.m32, "Expected value for m32 is " + exp.m32);
    assert_equals(m.m33, exp.m33, "Expected value for m33 is " + exp.m33);
    assert_equals(m.m34, exp.m34, "Expected value for m34 is " + exp.m34);
    assert_equals(m.m41, exp.m41, "Expected value for m41 is " + exp.m41);
    assert_equals(m.m42, exp.m42, "Expected value for m42 is " + exp.m42);
    assert_equals(m.m43, exp.m43, "Expected value for m43 is " + exp.m43);
    assert_equals(m.m44, exp.m44, "Expected value for m44 is " + exp.m44);
    assert_equals(m.is2D, is2D, "Expected value for is2D is " + is2D);
    assert_equals(m.isIdentity, exp.isIdentity, "Expected value for isIdentity is " + exp.isIdentity);
}


function identity() {
    return new DOMMatrix(
    [1, 0, 0, 0,
        0, 1, 0 ,0,
        0, 0, 1, 0,
        0, 0, 0, 1]);
}

function update(matrix, f) {
    f(matrix);
    return matrix;
}