/* eslint-disable no-param-reassign */
import sharp from 'sharp';

/** image size supported */
const Sizes = [50, 100, 200, 300, 400, 500, 600, 700, 800];

function transformer(options, transformOptions) {
    let imageStream = sharp();

    if (transformOptions.resize) {
        const keys = Object.keys(options);
        for (let index = 0; index < keys.length; index += 1) {
            const value = options[keys[index]];
            if (value) {
                imageStream = resolveImageStream(
                    keys[index],
                    value,
                    transformOptions.resize,
                    imageStream
                );
            }
        }
    }

    return imageStream;
}

const objectHasOwnProperty = (source, prop) =>
    Object.prototype.hasOwnProperty.call(source, prop);

const hasProp = (value) =>
    typeof value === 'object' && objectHasOwnProperty(value, 'type');

const validateFormat = (value) => {
    if (hasProp(value)) {
        return value.type;
    }
    return value;
};

const validateValue = (value) => {
    if (typeof value === 'boolean') {
        return null;
    }
    return value;
};

const resolveImageStream = (key, value, size, imageStream) => {
    if (key === 'resize') {
        imageStream = imageStream.resize(
            size.width,
            size.height,
            Object.assign(value, size.options)
        );
    } else if (key === 'crop') {
        imageStream = imageStream[key](value);
    } else if (key === 'toFormat') {
        imageStream = imageStream.toFormat(
            validateFormat(value),
            value.options
        );
    } else {
        const valid = validateValue(value);
        imageStream = imageStream[key](valid);
    }
    return imageStream;
};

const getSharpOptions = (options) => ({
    resize: options.resize,
    background: options.background,
    crop: options.crop,
    embed: options.embed,
    max: options.max,
    min: options.min,
    toFormat: options.toFormat,
    extract: options.extract,
    trim: options.trim,
    flatten: options.flatten,
    extend: options.extend,
    negate: options.negate,
    rotate: options.rotate,
    flip: options.flip,
    flop: options.flop,
    blur: options.blur,
    sharpen: options.sharpen,
    gamma: options.gamma,
    grayscale: options.grayscale,
    greyscale: options.greyscale,
    normalize: options.normalize,
    normalise: options.normalise,
    convolve: options.convolve,
    threshold: options.threshold,
    toColourspace: options.toColourspace,
    toColorspace: options.toColorspace,
    ignoreAspectRatio: options.ignoreAspectRatio,
    withMetadata: options.withMetadata,
    withoutEnlargement: options.withoutEnlargement
});

module.exports = { Sizes, transformer, getSharpOptions };