import color from "color";

/**
 * Turn the main color of a line into a color suitable for using as a border.
 * @param {string} mainColor Original color.
 * @returns {string} Hexadecimal representation of the border color.
 */
export const makeBorderColor = mainColor => {
    return color(mainColor).darken(0.2).hex();
};

/**
 * Turn the main color of a line into a color suitable for using as a border.
 * @param {string} mainColor Original color.
 * @returns {string} Hexadecimal representation of the border color.
 */
export const makeCourseColor = mainColor => {
    return color(mainColor).lighten(0.2).hex();
};

/**
 * Make an OpenLayers style function cache its results.
 * @param {Function} createStyle Create a style based on the cache key value.
 * @param {Function} [cacheKey] Return the cache key for each feature
 * (default: identity function).
 * @return {Function} Style function that caches the generated styles.
 */
export const cacheStyle = (createStyle, cacheKey = x => x) => {
    const cache = {};
    return (feature) => {
        const key = cacheKey(feature);

        if (!(key in cache)) {
            cache[key] = createStyle(key);
        }

        return cache[key];
    };
};

export const sizes = {
    segmentOuter: 8,
    segmentInner: 6,
    stopRadius: 6,
    stopBorder: 1.5,
    courseSize: 15,
    courseOuterBorder: 13,
    courseBorder: 10,
    courseInnerBorder: 7
};