export const cssUnitCalc = (input: number | string) => {
    return typeof input === 'string' ? input : input + 'px';
};

export const mountContainer = (id: string) => {
    let node = document.getElementById(id);
    if (!node) {
        document.body.insertAdjacentHTML('beforeend', `<div id="${id}"></div>`);
        node = document.getElementById(id);
    }
    return node as HTMLElement;
};

export function getTextWidth(text: string, element: HTMLElement): number {
    // re-use canvas object for better performance
    const canvas = (getTextWidth as any).canvas || ((getTextWidth as any).canvas = document.createElement('canvas'));
    const style: CSSStyleDeclaration = window.getComputedStyle(element);
    const fontMap = (getTextWidth as any).fontFamilyMap || ((getTextWidth as any).fontFamilyMap = new WeakMap());
    let fontFamily;
    const cachedFF = fontMap.get(element);
    if (cachedFF) {
        fontFamily = cachedFF;
    } else {
        fontFamily = renderedFont(element);
        fontMap.set(element, fontFamily);
    }
    const context = canvas.getContext('2d');
    context.font = `${style.fontSize} ${fontFamily}`;
    return context.measureText(text).width;
}

export function renderedFont(ele: HTMLElement) {
    var fonts: any = getComputedStyle(ele).fontFamily;
    var fontsArray = fonts.split(',');
    var canvas = document.createElement('canvas');
    var ctx: any = canvas.getContext('2d');
    var testString = '和那要下看天时过出小么起你都把好还多没为又abcdefghijklmnopqrstuvwxyz!@#$%^&*()ñ1234567890';
    var prevImageData;
    document.body.appendChild(canvas);
    canvas.width = 500;
    canvas.height = 300;
    fontsArray.unshift('"Font That Doesnt Exists ' + Math.random() + '"');

    for (var i = 0; i < fontsArray.length; i++) {
        var fontName = fontsArray[i].trim();
        ctx.clearRect(0, 0, canvas.width, canvas.height);
        ctx.font = '16px ' + fontName + ', monospace';
        ctx.fillText(testString, 10, 100);
        var idata = ctx.getImageData(0, 0, canvas.width, canvas.height);
        var data = idata.data;
        if (prevImageData) {
            for (var j = 0; j < data.length; j += 3) {
                if (prevImageData[j + 3] !== data[j + 3]) {
                    document.body.removeChild(canvas);
                    return fontName;
                }
            }
        }
        prevImageData = data;
    }

    document.body.removeChild(canvas);
    return 'monospace';
}

export const getDescendantProp = (obj: any, path: string) =>
    path
        .split('.')
        .filter(Boolean)
        .reduce((acc, part) => acc && acc[part], obj);

export const buildNestedObj = (obj: any, path: string, value: any) => {
    const pathArr = path.split('.').filter(Boolean);
    const lastKeyIndex = pathArr.length - 1;
    for (var i = 0; i < lastKeyIndex; ++i) {
        const key = pathArr[i];
        if (!(key in obj)) obj[key] = {};
        obj = obj[key];
    }
    obj[pathArr[lastKeyIndex]] = value;
    return obj;
};

export const getImgDimension = (file: File) => {
    return new Promise((resolve, reject) => {
        let img = new Image();
        img.onload = function() {
            resolve({ width: img.width, height: img.height, size: file.size });
        };
        img.src = window.URL.createObjectURL(file);
    });
};

export function genUUID() {
    // Public Domain/MIT
    var d = new Date().getTime();
    if (typeof performance !== 'undefined' && typeof performance.now === 'function') {
        d += performance.now(); //use high-precision timer if available
    }
    return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
        var r = (d + Math.random() * 16) % 16 | 0;
        d = Math.floor(d / 16);
        return (c === 'x' ? r : (r & 0x3) | 0x8).toString(16);
    });
}

export default {
    downloadObjectAsJson(obj: string, filename: string) {
        const dataStr = 'data:text/json;charset=utf-8,' + encodeURIComponent(JSON.stringify(obj, null, 4));
        const a = document.createElement('a');
        a.setAttribute('href', dataStr);
        a.setAttribute('download', filename + '.json');
        document.body.appendChild(a);
        a.click();
        a.remove();
    },
    getNumbersArray(max: number) {
        let res = [];
        for (let i = 0; i <= max; i++) {
            res.push(+i);
        }
        return res;
    },
    concatClassNames(...args: string[]) {
        let res = [];
        for (let i = 0; i < args.length; i++) {
            let arr = args[i].split(' ');
            for (let k = 0; k < arr.length; k++) {
                if (arr[k] !== '') {
                    res.push(arr[k]);
                }
            }
        }
        return res.join(' ');
    },
    cssUnitCalc,
    getDescendantProp,
    buildNestedObj,
};