var postcss = require('postcss');

function shouldSetZeroBasis(basisValue) {
    if (!basisValue) {
        return false;
    }
    return basisValue === '0' || basisValue.replace(/\s/g, '') === '0px';
}

function properBasis(basis) {
    if (shouldSetZeroBasis(basis)) {
        return '0%';
    }
    return basis;
}

module.exports = function(decl) {
    if (decl.prop === 'flex') {
        var values = postcss.list.space(decl.value);
        var flexGrow = values[0];
        var flexShrink = values[1] || '1';
        var flexBasis = values[2] || '0%';
        decl.value = flexGrow + ' ' + flexShrink + ' ' + properBasis(flexBasis);
    }
};