// ==UserScript==
// @name MAB file picker
// @version 1.0
// @match https://*.myairbridge.com/*
// @run-at document-idle
// ==/UserScript==

(function() {
"use strict";

function main() {
    "use strict";

    const api = (function() {
        const crc32 = (function() {
            const table = new Uint32Array(256);

            for (let i = 0; i < 256; ++i) {
                let crc = i;
                for (let j = 0; j < 8; ++j)
                    crc = (crc & 1) ? 3988292384 ^ crc >>> 1 : crc >>> 1;
                table[i] = crc;
            }

            return function crc32(s) {
                let crc = -1;
                for (let i = 0; i < s.length; ++i)
                    crc = crc >>> 8 ^ table[(crc ^ s.charCodeAt(i)) & 255];
                return (crc ^ -1) >>> 0;
            }
        })();

        function request(path, action, data) {
            const req = {
                r: JSON.stringify({
                    action,
                    lang: "en",  // unneeded
                    data,
                    token: ""    // unneeded
                }),
                p: "json",
                v: "2.0",
                s: ""  // unneeded
            };
            req.s = crc32(
                unescape(encodeURIComponent([req.r, req.p, req.v].join("|")))
            ).toString(16);

            return $.post(path, req, undefined, "json");
        }

        return {
            getUploadDetail: (id) => request(
                "/api2/common/",
                "GetUploadDetail",
                {
                    id,
                    login_token: ""  // unneeded
                }
            ),
            createTicket: (upload, files) => request(
                "/download/api/",
                "CreateTicket",
                {
                    files,
                    src: 1,     // unneeded
                    token: "",  // unneeded
                    upload      // unneeded
                }
            ),
            createDownload: (content_id, channel, ticket) => request(
                "/download/api/",
                "createDownload",
                {
                    channel,
                    content_id,
                    download_type: "file",
                    login_token: "",       // unneeded
                    source: "html5_beta",  // unneeded
                    ticket
                }
            ),
            createDownloadPackage: (content_id, files, ticket) => request(
                "/download/api/",
                "CreateDownloadPackage",
                {
                    content_id,
                    files,
                    login_token: "",       // unneeded
                    source: "html5_beta",  // unneeded
                    ticket
                }
            )
        };
    })();

    api.getUploadDetail(
        window.location.href.match(/\/link\/([^/]+)/)[1]
    ).then(({data: {id, channel, files}}) => {
        document.head.insertAdjacentHTML(
            "beforeend",
            `<style type="text/css">
                .base_download > .button:not(.dlbutton) {
                    display: none !important;
                }
            </style>`
        );

        const selected = new Set();

        if (files.length > 1) {
            document.head.insertAdjacentHTML(
                "beforeend",
                `<style type="text/css">
                    .file > .name {
                        cursor: pointer !important;
                    }
                    .file.selected,
                    .file.selected > .name > .fade {
                        background: #f5f5f5 !important;
                    }
                    .file.selected > .name,
                    .file.selected > .control {
                        color: #359bce !important;
                        font-weight: bold !important;
                    }
                </style>`
            );

            $(".base_download > .files").on("click", ".file", (e) => {
                const el = $(e.currentTarget);
                const file_id = files[el.index()].id;
                if (!el.hasClass("selected")) {
                    el.addClass("selected");
                    selected.add(file_id);
                } else {
                    el.removeClass("selected");
                    selected.delete(file_id);
                }
            });
        }

        const button = $("<a class=\"button dlbutton\">Download</a>");
        button.on("click", () => {
            const ids = (selected.size === 0) ? files.map((f) => f.id)
                                              : [...selected];
            api.createTicket(id, ids).then(({data: {ticket}}) => {
                const dl = (ids.length > 1) ? api.createDownloadPackage(id, ids, ticket)
                                            : api.createDownload(ids[0], channel, ticket);
                dl.then(({data: {link}}) => window.location.assign(link));
            });
        });
        $(".base_download > .button").first().before(button);
    });
}

function inject(fn) {
    const script = document.createElement("script");
    script.type = "text/javascript";
    script.textContent = "(" + fn.toString() + ")();";
    document.documentElement.appendChild(script);
    document.documentElement.removeChild(script);
}

// Wait for a download button to become visible before injecting (to ensure that
// the page is fully constructed and the upload is complete, etc).
(new MutationObserver((ms, ob) => {
    const isDownloadButton = (el) => (
        el.nodeType === 1 &&
        el.classList.contains("button") &&
        /^Download/.test(el.textContent) &&
        el.style.display === "inline-block"
    );

    for (let i = 0; i < ms.length; ++i) {
        if (isDownloadButton(ms[i].target)) {
            ob.disconnect();
            inject(main);
            return;
        }
    }
})).observe(
    document.body,
    {subtree: true, attributes: true, attributeFilter: ["style"]}
);

})();