/*

Write a function that takes 2 colors as arguments and returns the average color.
- The parameters will be two 6-digit hexadecimal strings. This does not need to be validated.
- The return value should be a 6-digit hexadecimal string.
- The hexadecimal strings represent colors in RGB, much like in CSS.
- The average color is to be determined by taking the arithmetic mean for each component: red, green and blue.

*/

function get_components(color) {
    const r_hex = color.substr(0, 2);
    const g_hex = color.substr(2, 2);
    const b_hex = color.substr(4, 2);
    return {
        r: parseInt(r_hex, 16),
        g: parseInt(g_hex, 16),
        b: parseInt(b_hex, 16),
    }
}

function to_hexstring(x) {
    let result = x.toString(16);
    if (x < 16) {
        result = '0' + result;
    }
    return result;
}

function get_blend_color(color1, color2) {
    const color1_components = get_components(color1);
    const color2_components = get_components(color2);
    const r_avg = Math.round((color1_components.r + color2_components.r) / 2);
    const g_avg = Math.round((color1_components.g + color2_components.g) / 2);
    const b_avg = Math.round((color1_components.b + color2_components.b) / 2);
    const color3 = [r_avg, g_avg, b_avg].map(to_hexstring).join('');
    return color3;
}

console.assert(get_blend_color('ffffff', '000000') == '808080');
console.assert(get_blend_color('000000', 'ffffff') == '808080');
console.assert(get_blend_color('000000', '000000') == '000000');
console.assert(get_blend_color('ffffff', 'ffffff') == 'ffffff');
console.assert(get_blend_color('444444', 'afafaf') == '7a7a7a');