// https://stackoverflow.com/a/9458996
function _bytesToBase64(bytes) {
    var binary = '';
    var len = bytes.byteLength;
    for (var i = 0; i < len; i++) {
        binary += String.fromCharCode(bytes[i]);
    }
    return window.btoa(binary);
}

// https://stackoverflow.com/a/21797381
function _base64ToBytes(base64) {
    var binary_string = window.atob(base64);
    var len = binary_string.length;
    var bytes = new Uint8Array(len);
    for (var i = 0; i < len; i++) {
        bytes[i] = binary_string.charCodeAt(i);
    }
    return bytes;
}

// Canvas used for image generation
var generationCanvas = document.createElement('canvas')

window.loadFileAsync = function(fullPath, bitmap, callback) {
    // noop
    callback = callback || (() => {});

    // Make cache object
    if (!window.fileAsyncCache) window.fileAsyncCache = {};

    // Check if already loaded
    if (window.fileAsyncCache.hasOwnProperty(fullPath)) return callback();

    // Show spinner
    if (!bitmap && window.setBusy) window.setBusy();

    // Get mapping key
    const mappingKey = fullPath.toLowerCase().replace(new RegExp("\\.[^/.]+$"), "");
    const mappingValue = mapping[mappingKey];

    // Check if this is a folder
    if (!mappingValue || mappingValue.endsWith("h=")) {
        console.error("Skipping loading", fullPath, mappingValue);
        return callback();
    }

    // Get target URL
    const iurl = "gameasync/" + mappingValue;

    // Get path and filename
    const path = "/game/" + mappingValue.substring(0, mappingValue.lastIndexOf("/"));
    const filename = mappingValue.substring(mappingValue.lastIndexOf("/") + 1).split("?")[0];

    // Main loading function
    const load = (cb1) => {
        getLazyAsset(iurl, filename, (data) => {
            // Delete original file if existent
            try { FS.unlink(path + "/" + filename); } catch (err) {}

            FS.createPreloadedFile(path, filename, new Uint8Array(data), true, true, function() {
                window.fileAsyncCache[fullPath] = 1;
                if (!bitmap && window.setNotBusy) window.setNotBusy();
                if (window.fileLoadedAsync) window.fileLoadedAsync(fullPath);
                callback();
                if (cb1) cb1();
            }, console.error);
        });
    }

    // Show progress if doing it synchronously only
    if (bitmap && bitmapSizeMapping[mappingKey]) {
        // Remove existing file
        try { FS.unlink(path + "/" + filename); } catch (err) {}

        // Get image
        const sm = bitmapSizeMapping[mappingKey];
        generationCanvas.width = sm[0];
        generationCanvas.height = sm[1];

        // Create dummy from data uri
        FS.createPreloadedFile(path, filename, generationCanvas.toDataURL(), true, true, function() {
            // Return control to C++
            callback(); callback = () => {};

            // Lazy load and refresh
            load(() => {
                const reloadBitmap = Module.cwrap('reloadBitmap', 'number', ['number'])
                reloadBitmap(bitmap);
            });
        }, console.error);
    } else {
        if (bitmap) {
            console.warn('No sizemap for image', mappingKey);
        }
        load();
    }
}