"use strict";

window.onerror = vis_exh;


function goto_up2k() {
    if (up2k === false)
        return goto('bup');

    if (!up2k)
        return setTimeout(goto_up2k, 100);

    up2k.init_deps();
}


// chrome requires https to use crypto.subtle,
// usually it's undefined but some chromes throw on invoke
var up2k = null;
try {
    crypto.subtle.digest(
        'SHA-512', new Uint8Array(1)
    ).then(
        function (x) { up2k = up2k_init(true) },
        function (x) { up2k = up2k_init(false) }
    );
}
catch (ex) {
    try {
        up2k = up2k_init(false);
    }
    catch (ex) { }
}


function up2k_flagbus() {
    var flag = {
        "id": Math.floor(Math.random() * 1024 * 1024 * 1023 * 2),
        "ch": new BroadcastChannel("up2k_flagbus"),
        "ours": false,
        "owner": null,
        "wants": null,
        "act": false,
        "last_tx": ["x", null]
    };
    var dbg = function (who, msg) {
        console.log('flagbus(' + flag.id + '): [' + who + '] ' + msg);
    };
    flag.ch.onmessage = function (ev) {
        var who = ev.data[0],
            what = ev.data[1];

        if (who == flag.id) {
            dbg(who, 'hi me (??)');
            return;
        }
        flag.act = new Date().getTime();
        if (what == "want") {
            // lowest id wins, don't care if that's us
            if (who < flag.id) {
                dbg(who, 'wants (ack)');
                flag.wants = [who, flag.act];
            }
            else {
                dbg(who, 'wants (ign)');
            }
        }
        else if (what == "have") {
            dbg(who, 'have');
            flag.owner = [who, flag.act];
        }
        else if (what == "give") {
            if (flag.owner && flag.owner[0] == who) {
                flag.owner = null;
                dbg(who, 'give (ok)');
            }
            else {
                dbg(who, 'give, INVALID, ' + flag.owner);
            }
        }
        else if (what == "hi") {
            dbg(who, 'hi');
            flag.ch.postMessage([flag.id, "hey"]);
        }
        else {
            dbg('?', ev.data);
        }
    };
    var tx = function (now, msg) {
        var td = now - flag.last_tx[1];
        if (td > 500 || flag.last_tx[0] != msg) {
            dbg('*', 'tx ' + msg);
            flag.ch.postMessage([flag.id, msg]);
            flag.last_tx = [msg, now];
        }
    };
    var do_take = function (now) {
        //dbg('*', 'do_take');
        tx(now, "have");
        flag.owner = [flag.id, now];
        flag.ours = true;
    };
    var do_want = function (now) {
        //dbg('*', 'do_want');
        tx(now, "want");
    };
    flag.take = function (now) {
        if (flag.ours) {
            do_take(now);
            return;
        }
        if (flag.owner && now - flag.owner[1] > 5000) {
            flag.owner = null;
        }
        if (flag.wants && now - flag.wants[1] > 5000) {
            flag.wants = null;
        }
        if (!flag.owner && !flag.wants) {
            do_take(now);
            return;
        }
        do_want(now);
    };
    flag.give = function () {
        dbg('#', 'put give');
        flag.ch.postMessage([flag.id, "give"]);
        flag.owner = null;
        flag.ours = false;
    };
    flag.ch.postMessage([flag.id, 'hi']);
    return flag;
}

function up2k_init(have_crypto) {
    //have_crypto = false;
    var need_filereader_cache = undefined;

    // show modal message
    function showmodal(msg) {
        ebi('u2notbtn').innerHTML = msg;
        ebi('u2btn').style.display = 'none';
        ebi('u2notbtn').style.display = 'block';
        ebi('u2conf').style.opacity = '0.5';
    }

    // hide modal message
    function unmodal() {
        ebi('u2notbtn').style.display = 'none';
        ebi('u2btn').style.display = 'block';
        ebi('u2conf').style.opacity = '1';
        ebi('u2notbtn').innerHTML = '';
    }

    var shame = 'your browser <a href="https://www.chromium.org/blink/webcrypto">disables sha512</a> unless you <a href="' + (window.location + '').replace(':', 's:') + '">use https</a>'
    var is_https = (window.location + '').indexOf('https:') === 0;
    if (is_https)
        // chrome<37 firefox<34 edge<12 ie<11 opera<24 safari<10.1
        shame = 'your browser is impressively ancient';

    // upload ui hidden by default, clicking the header shows it
    function init_deps() {
        if (!have_crypto && !window.asmCrypto) {
            showmodal('<h1>loading sha512.js</h1><h2>since ' + shame + '</h2><h4>thanks chrome</h4>');
            import_js('/.cpr/deps/sha512.js', unmodal);

            if (is_https)
                ebi('u2foot').innerHTML = shame + ' so <em>this</em> uploader will do like 500kB/s at best';
            else
                ebi('u2foot').innerHTML = 'seems like ' + shame + ' so do that if you want more performance';
        }
    }

    // show uploader if the user only has write-access
    if (!ebi('files'))
        goto('up2k');

    // shows or clears an error message in the basic uploader ui
    function setmsg(msg) {
        if (msg !== undefined) {
            ebi('u2err').setAttribute('class', 'err');
            ebi('u2err').innerHTML = msg;
        }
        else {
            ebi('u2err').setAttribute('class', '');
            ebi('u2err').innerHTML = '';
        }
    }

    // switches to the basic uploader with msg as error message
    function un2k(msg) {
        setmsg(msg);
        return false;
    }

    // handle user intent to use the basic uploader instead
    ebi('u2nope').onclick = function (e) {
        e.preventDefault();
        setmsg();
        goto('bup');
    };

    if (!String.prototype.format) {
        String.prototype.format = function () {
            var args = arguments;
            return this.replace(/{(\d+)}/g, function (match, number) {
                return typeof args[number] != 'undefined' ?
                    args[number] : match;
            });
        };
    }

    function cfg_get(name) {
        var val = localStorage.getItem(name);
        if (val === null)
            return parseInt(ebi(name).value);

        ebi(name).value = val;
        return val;
    }

    function bcfg_get(name, defval) {
        var o = ebi(name);
        if (!o)
            return defval;

        var val = localStorage.getItem(name);
        if (val === null)
            val = defval;
        else
            val = (val == '1');

        o.checked = val;
        return val;
    }

    function bcfg_set(name, val) {
        localStorage.setItem(
            name, val ? '1' : '0');

        var o = ebi(name);
        if (o)
            o.checked = val;

        return val;
    }

    var parallel_uploads = cfg_get('nthread');
    var multitask = bcfg_get('multitask', true);
    var ask_up = bcfg_get('ask_up', true);
    var flag_en = bcfg_get('flag_en', false);
    var fsearch = bcfg_get('fsearch', false);

    var col_hashing = '#00bbff';
    var col_hashed = '#004466';
    var col_uploading = '#ffcc44';
    var col_uploaded = '#00bb00';
    var fdom_ctr = 0;
    var st = {
        "files": [],
        "todo": {
            "hash": [],
            "handshake": [],
            "upload": []
        },
        "busy": {
            "hash": [],
            "handshake": [],
            "upload": []
        },
        "bytes": {
            "hashed": 0,
            "uploaded": 0
        }
    };

    var bobslice = null;
    if (window.File)
        bobslice = File.prototype.slice || File.prototype.mozSlice || File.prototype.webkitSlice;

    if (!bobslice || !window.FileReader || !window.FileList)
        return un2k("this is the basic uploader; up2k needs at least<br />chrome 21 // firefox 13 // edge 12 // opera 12 // safari 5.1");

    var flag = false;
    apply_flag_cfg();
    apply_fsearch_cfg();

    function nav() {
        ebi('file' + fdom_ctr).click();
    }
    ebi('u2btn').addEventListener('click', nav, false);

    function ondrag(ev) {
        ev.stopPropagation();
        ev.preventDefault();
        ev.dataTransfer.dropEffect = 'copy';
        ev.dataTransfer.effectAllowed = 'copy';
    }
    ebi('u2btn').addEventListener('dragover', ondrag, false);
    ebi('u2btn').addEventListener('dragenter', ondrag, false);

    function gotfile(ev) {
        ev.stopPropagation();
        ev.preventDefault();

        var files;
        var is_itemlist = false;
        if (ev.dataTransfer) {
            if (ev.dataTransfer.items) {
                files = ev.dataTransfer.items; // DataTransferItemList
                is_itemlist = true;
            }
            else files = ev.dataTransfer.files; // FileList
        }
        else files = ev.target.files;

        if (files.length == 0)
            return alert('no files selected??');

        more_one_file();
        var bad_files = [];
        var good_files = [];
        for (var a = 0; a < files.length; a++) {
            var fobj = files[a];
            if (is_itemlist) {
                if (fobj.kind !== 'file')
                    continue;

                fobj = fobj.getAsFile();
            }
            try {
                if (fobj.size < 1)
                    throw 1;
            }
            catch (ex) {
                bad_files.push(fobj.name);
                continue;
            }
            good_files.push(fobj);
        }

        if (bad_files.length > 0) {
            var msg = 'These {0} files (of {1} total) were skipped because they are empty:\n'.format(bad_files.length, files.length);
            for (var a = 0; a < bad_files.length; a++)
                msg += '-- ' + bad_files[a] + '\n';

            if (files.length - bad_files.length <= 1 && /(android)/i.test(navigator.userAgent))
                msg += '\nFirefox-Android has a bug which prevents selecting multiple files. Try selecting one file at a time. For more info, see firefox bug 1456557';

            alert(msg);
        }

        var msg = ['upload these ' + good_files.length + ' files?'];
        for (var a = 0; a < good_files.length; a++)
            msg.push(good_files[a].name);

        if (ask_up && !fsearch && !confirm(msg.join('\n')))
            return;

        for (var a = 0; a < good_files.length; a++) {
            var fobj = good_files[a];
            var now = new Date().getTime();
            var lmod = fobj.lastModified || now;
            var entry = {
                "n": parseInt(st.files.length.toString()),
                "t0": now,  // TODO remove probably
                "fobj": fobj,
                "name": fobj.name,
                "size": fobj.size,
                "lmod": lmod / 1000,
                "purl": get_vpath(),
                "done": false,
                "hash": []
            };

            var skip = false;
            for (var b = 0; b < st.files.length; b++)
                if (entry.name == st.files[b].name &&
                    entry.size == st.files[b].size)
                    skip = true;

            if (skip)
                continue;

            var tr = document.createElement('tr');
            tr.innerHTML = '<td id="f{0}n"></td><td id="f{0}t">hashing</td><td id="f{0}p" class="prog"></td>'.format(st.files.length);
            tr.getElementsByTagName('td')[0].innerHTML = fsearch ? entry.name : linksplit(esc(entry.purl + entry.name)).join(' ');
            ebi('u2tab').appendChild(tr);

            st.files.push(entry);
            st.todo.hash.push(entry);
        }
    }
    ebi('u2btn').addEventListener('drop', gotfile, false);

    function more_one_file() {
        fdom_ctr++;
        var elm = document.createElement('div')
        elm.innerHTML = '<input id="file{0}" type="file" name="file{0}[]" multiple="multiple" />'.format(fdom_ctr);
        ebi('u2form').appendChild(elm);
        ebi('file' + fdom_ctr).addEventListener('change', gotfile, false);
    }
    more_one_file();

    function u2cleanup(e) {
        ev(e);
        for (var a = 0; a < st.files.length; a++) {
            var t = st.files[a];
            if (t.done && t.name) {
                var tr = ebi('f{0}p'.format(t.n)).parentNode;
                tr.parentNode.removeChild(tr);
                t.name = undefined;
            }
        }
    }
    ebi('u2cleanup').onclick = u2cleanup;

    /////
    ////
    ///   actuator
    //

    function handshakes_permitted() {
        var lim = multitask ? 1 : 0;
        return lim >=
            st.todo.upload.length +
            st.busy.upload.length;
    }

    function hashing_permitted() {
        if (multitask) {
            var ahead = st.bytes.hashed - st.bytes.uploaded;
            return ahead < 1024 * 1024 * 128;
        }
        return handshakes_permitted() && 0 ==
            st.todo.handshake.length +
            st.busy.handshake.length;
    }

    var tasker = (function () {
        var mutex = false;
        var was_busy = false;

        function taskerd() {
            if (mutex)
                return;

            mutex = true;
            while (true) {
                if (false) {
                    ebi('srv_info').innerHTML =
                        new Date().getTime() + ", " +
                        st.todo.hash.length + ", " +
                        st.todo.handshake.length + ", " +
                        st.todo.upload.length + ", " +
                        st.busy.hash.length + ", " +
                        st.busy.handshake.length + ", " +
                        st.busy.upload.length;
                }

                var is_busy = 0 !=
                    st.todo.hash.length +
                    st.todo.handshake.length +
                    st.todo.upload.length +
                    st.busy.hash.length +
                    st.busy.handshake.length +
                    st.busy.upload.length;

                if (was_busy != is_busy) {
                    was_busy = is_busy;

                    if (is_busy)
                        window.addEventListener("beforeunload", warn_uploader_busy);
                    else
                        window.removeEventListener("beforeunload", warn_uploader_busy);
                }

                if (flag) {
                    if (is_busy) {
                        var now = new Date().getTime();
                        flag.take(now);
                        if (!flag.ours) {
                            setTimeout(taskerd, 100);
                            mutex = false;
                            return;
                        }
                    }
                    else if (flag.ours) {
                        flag.give();
                    }
                }

                var mou_ikkai = false;

                if (st.todo.handshake.length > 0 &&
                    st.busy.handshake.length == 0 && (
                        st.todo.handshake[0].t3 || (
                            handshakes_permitted() &&
                            st.busy.upload.length < parallel_uploads
                        )
                    )
                ) {
                    exec_handshake();
                    mou_ikkai = true;
                }

                if (handshakes_permitted() &&
                    st.todo.handshake.length > 0 &&
                    st.busy.handshake.length == 0 &&
                    st.busy.upload.length < parallel_uploads) {
                    exec_handshake();
                    mou_ikkai = true;
                }

                if (st.todo.upload.length > 0 &&
                    st.busy.upload.length < parallel_uploads) {
                    exec_upload();
                    mou_ikkai = true;
                }

                if (hashing_permitted() &&
                    st.todo.hash.length > 0 &&
                    st.busy.hash.length == 0) {
                    exec_hash();
                    mou_ikkai = true;
                }

                if (!mou_ikkai) {
                    setTimeout(taskerd, 100);
                    mutex = false;
                    return;
                }
            }
        }
        taskerd();
        return taskerd;
    })();

    /////
    ////
    ///   hashing
    //

    // https://gist.github.com/jonleighton/958841
    function buf2b64(arrayBuffer) {
        var base64 = '';
        var encodings = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_';
        var bytes = new Uint8Array(arrayBuffer);
        var byteLength = bytes.byteLength;
        var byteRemainder = byteLength % 3;
        var mainLength = byteLength - byteRemainder;
        var a, b, c, d;
        var chunk;

        for (var i = 0; i < mainLength; i = i + 3) {
            chunk = (bytes[i] << 16) | (bytes[i + 1] << 8) | bytes[i + 2];
            // create 8*3=24bit segment then split into 6bit segments
            a = (chunk & 16515072) >> 18; // 16515072 = (2^6 - 1) << 18
            b = (chunk & 258048) >> 12; // 258048   = (2^6 - 1) << 12
            c = (chunk & 4032) >> 6; // 4032     = (2^6 - 1) << 6
            d = chunk & 63;               // 63       = 2^6 - 1

            // Convert the raw binary segments to the appropriate ASCII encoding
            base64 += encodings[a] + encodings[b] + encodings[c] + encodings[d];
        }

        if (byteRemainder == 1) {
            chunk = bytes[mainLength];
            a = (chunk & 252) >> 2; // 252 = (2^6 - 1) << 2
            b = (chunk & 3) << 4; // 3   = 2^2 - 1  (zero 4 LSB)
            base64 += encodings[a] + encodings[b];//+ '==';
        }
        else if (byteRemainder == 2) {
            chunk = (bytes[mainLength] << 8) | bytes[mainLength + 1];
            a = (chunk & 64512) >> 10; // 64512 = (2^6 - 1) << 10
            b = (chunk & 1008) >> 4; // 1008  = (2^6 - 1) << 4
            c = (chunk & 15) << 2; // 15    = 2^4 - 1  (zero 2 LSB)
            base64 += encodings[a] + encodings[b] + encodings[c];//+ '=';
        }

        return base64;
    }

    function get_chunksize(filesize) {
        var chunksize = 1024 * 1024;
        var stepsize = 512 * 1024;
        while (true) {
            for (var mul = 1; mul <= 2; mul++) {
                var nchunks = Math.ceil(filesize / chunksize);
                if (nchunks <= 256 || chunksize >= 32 * 1024 * 1024)
                    return chunksize;

                chunksize += stepsize;
                stepsize *= mul;
            }
        }
    }

    function test_filereader_speed(segm_err) {
        var f = st.todo.hash[0].fobj,
            sz = Math.min(2, f.size),
            reader = new FileReader(),
            t0, ctr = 0;

        var segm_next = function () {
            var t = new Date().getTime(),
                td = t - t0;

            if (++ctr > 2) {
                need_filereader_cache = td > 50;
                st.busy.hash.pop();
                return;
            }
            t0 = t;
            reader.onload = segm_next;
            reader.onerror = segm_err;
            reader.readAsArrayBuffer(
                bobslice.call(f, 0, sz));
        };

        segm_next();
    }

    function ensure_rendered(func) {
        var hidden = false;
        var keys = ['hidden', 'msHidden', 'webkitHidden'];
        for (var a = 0; a < keys.length; a++)
            if (typeof document[keys[a]] !== "undefined")
                hidden = document[keys[a]];

        if (hidden)
            return func();

        window.requestAnimationFrame(func);
    }

    function exec_hash() {
        if (need_filereader_cache === undefined) {
            st.busy.hash.push(1);
            return test_filereader_speed(segm_err);
        }

        var t = st.todo.hash.shift();
        st.busy.hash.push(t);
        st.bytes.hashed += t.size;
        t.bytes_uploaded = 0;
        t.t1 = new Date().getTime();

        var nchunk = 0;
        var chunksize = get_chunksize(t.size);
        var nchunks = Math.ceil(t.size / chunksize);

        // android-chrome has 180ms latency on FileReader calls,
        // detect this and do 32MB at a time
        var cache_buf = undefined,
            cache_ofs = 0,
            subchunks = 2;

        while (subchunks * chunksize <= 32 * 1024 * 1024)
            subchunks++;

        subchunks--;
        if (!need_filereader_cache)
            subchunks = 1;

        var pb_html = '';
        var pb_perc = 99.9 / nchunks;
        for (var a = 0; a < nchunks; a++)
            pb_html += '<div id="f{0}p{1}" style="width:{2}%"><div></div></div>'.format(
                t.n, a, pb_perc);

        ebi('f{0}p'.format(t.n)).innerHTML = pb_html;

        var reader = new FileReader();

        var segm_next = function () {
            if (cache_buf) {
                return hash_calc();
            }
            reader.onload = segm_load;
            reader.onerror = segm_err;

            var car = nchunk * chunksize;
            var cdr = car + chunksize * subchunks;
            if (cdr >= t.size)
                cdr = t.size;

            reader.readAsArrayBuffer(
                bobslice.call(t.fobj, car, cdr));

            prog(t.n, nchunk, col_hashing);
        };

        var segm_load = function (ev) {
            cache_buf = ev.target.result;
            cache_ofs = 0;
            hash_calc();
        };

        var hash_calc = function () {
            var buf = cache_buf;
            if (chunksize >= buf.byteLength)
                cache_buf = undefined;
            else {
                var ofs = cache_ofs;
                var ofs2 = ofs + Math.min(chunksize, cache_buf.byteLength - cache_ofs);
                cache_ofs = ofs2;
                buf = new Uint8Array(cache_buf).subarray(ofs, ofs2);
                if (ofs2 >= cache_buf.byteLength)
                    cache_buf = undefined;
            }

            var func = function () {
                if (have_crypto)
                    crypto.subtle.digest('SHA-512', buf).then(hash_done);
                else {
                    var hasher = new asmCrypto.Sha512();
                    hasher.process(new Uint8Array(buf));
                    hasher.finish();
                    hash_done(hasher.result);
                }
            };

            if (cache_buf)
                ensure_rendered(func);
            else
                func();
        };

        var hash_done = function (hashbuf) {
            var hslice = new Uint8Array(hashbuf).subarray(0, 32);
            var b64str = buf2b64(hslice).replace(/=$/, '');
            t.hash.push(b64str);

            prog(t.n, nchunk, col_hashed);
            if (++nchunk < nchunks) {
                prog(t.n, nchunk, col_hashing);
                return segm_next();
            }

            t.t2 = new Date().getTime();
            if (t.n == 0 && window.location.hash == '#dbg') {
                var spd = (t.size / ((t.t2 - t.t1) / 1000.)) / (1024 * 1024.);
                alert('{0} ms, {1} MB/s\n'.format(t.t2 - t.t1, spd.toFixed(3)) + t.hash.join('\n'));
            }

            ebi('f{0}t'.format(t.n)).innerHTML = 'connecting';
            st.busy.hash.splice(st.busy.hash.indexOf(t), 1);
            st.todo.handshake.push(t);
        };

        var segm_err = function () {
            alert('y o u   b r o k e    i t\n\n(was that a folder? just files please)');
        };

        segm_next();
    }

    /////
    ////
    ///   handshake
    //

    function exec_handshake() {
        var t = st.todo.handshake.shift();
        st.busy.handshake.push(t);

        var xhr = new XMLHttpRequest();
        xhr.onload = function (ev) {
            if (xhr.status == 200) {
                var response = JSON.parse(xhr.responseText);

                if (!response.name) {
                    var msg = '';
                    var smsg = '';
                    if (!response || !response.length) {
                        msg = 'not found on server';
                        smsg = '404';
                    }
                    else {
                        smsg = 'found';
                        var hit = response[0],
                            msg = linksplit(hit.rp).join(''),
                            tr = unix2iso(hit.ts),
                            tu = unix2iso(t.lmod),
                            diff = parseInt(t.lmod) - parseInt(hit.ts),
                            cdiff = (Math.abs(diff) <= 2) ? '3c0' : 'f0b',
                            sdiff = '<span style="color:#' + cdiff + '">diff ' + diff;

                        msg += '<br /><small>' + tr + ' (srv), ' + tu + ' (You), ' + sdiff + '</span></span>';
                    }
                    ebi('f{0}p'.format(t.n)).innerHTML = msg;
                    ebi('f{0}t'.format(t.n)).innerHTML = smsg;
                    st.busy.handshake.splice(st.busy.handshake.indexOf(t), 1);
                    st.bytes.uploaded += t.size;
                    tasker();
                    return;
                }

                if (response.name !== t.name) {
                    // file exists; server renamed us
                    t.name = response.name;
                    ebi('f{0}n'.format(t.n)).innerHTML = linksplit(esc(t.purl + t.name)).join(' ');
                }

                t.postlist = [];
                t.wark = response.wark;
                var missing = response.hash;
                for (var a = 0; a < missing.length; a++) {
                    var idx = t.hash.indexOf(missing[a]);
                    if (idx < 0)
                        return alert('wtf negative index for hash "{0}" in task:\n{1}'.format(
                            missing[a], JSON.stringify(t)));

                    t.postlist.push(idx);
                }
                for (var a = 0; a < t.hash.length; a++)
                    prog(t.n, a, (t.postlist.indexOf(a) == -1)
                        ? col_uploaded : col_hashed);

                var done = true;
                var msg = '&#x1f3b7;&#x1f41b;';
                if (t.postlist.length > 0) {
                    for (var a = 0; a < t.postlist.length; a++)
                        st.todo.upload.push({
                            'nfile': t.n,
                            'npart': t.postlist[a]
                        });

                    msg = 'uploading';
                    done = false;
                }
                ebi('f{0}t'.format(t.n)).innerHTML = msg;
                st.busy.handshake.splice(st.busy.handshake.indexOf(t), 1);

                if (done) {
                    t.done = true;
                    st.bytes.uploaded += t.size - t.bytes_uploaded;
                    var spd1 = (t.size / ((t.t2 - t.t1) / 1000.)) / (1024 * 1024.);
                    var spd2 = (t.size / ((t.t3 - t.t2) / 1000.)) / (1024 * 1024.);
                    ebi('f{0}p'.format(t.n)).innerHTML = 'hash {0}, up {1} MB/s'.format(
                        spd1.toFixed(2), spd2.toFixed(2));
                }
                else t.t3 = undefined;

                tasker();
            }
            else {
                var err = "";
                var rsp = (xhr.responseText + '');
                if (rsp.indexOf('partial upload exists') !== -1 ||
                    rsp.indexOf('file already exists') !== -1) {
                    err = rsp;
                    var ofs = err.lastIndexOf(' : ');
                    if (ofs > 0)
                        err = err.slice(0, ofs);

                    ofs = err.indexOf('\n/');
                    if (ofs !== -1) {
                        err = err.slice(0, ofs + 1) + linksplit(err.slice(ofs + 2, -1)).join(' ');
                    }
                }
                if (err != "") {
                    ebi('f{0}t'.format(t.n)).innerHTML = "ERROR";
                    ebi('f{0}p'.format(t.n)).innerHTML = err;

                    st.busy.handshake.splice(st.busy.handshake.indexOf(t), 1);
                    tasker();
                    return;
                }
                alert("server broke (error {0}):\n\"{1}\"\n".format(
                    xhr.status,
                    (xhr.response && xhr.response.err) ||
                    (xhr.responseText && xhr.responseText) ||
                    "no further information"));
            }
        };

        var req = {
            "name": t.name,
            "size": t.size,
            "lmod": t.lmod,
            "hash": t.hash
        };
        if (fsearch)
            req.srch = 1;

        xhr.open('POST', t.purl + 'handshake.php', true);
        xhr.responseType = 'text';
        xhr.send(JSON.stringify(req));
    }

    /////
    ////
    ///   upload
    //

    function exec_upload() {
        var upt = st.todo.upload.shift();
        st.busy.upload.push(upt);

        var npart = upt.npart;
        var t = st.files[upt.nfile];

        prog(t.n, npart, col_uploading);

        var chunksize = get_chunksize(t.size);
        var car = npart * chunksize;
        var cdr = car + chunksize;
        if (cdr >= t.size)
            cdr = t.size;

        var reader = new FileReader();

        reader.onerror = function () {
            alert('y o u   b r o k e    i t\n\n(was that a folder? just files please)');
        };

        reader.onload = function (ev) {
            var xhr = new XMLHttpRequest();
            xhr.upload.onprogress = function (xev) {
                var perc = xev.loaded / (cdr - car) * 100;
                prog(t.n, npart, '', perc);
            };
            xhr.onload = function (xev) {
                if (xhr.status == 200) {
                    prog(t.n, npart, col_uploaded);
                    st.bytes.uploaded += cdr - car;
                    t.bytes_uploaded += cdr - car;
                    st.busy.upload.splice(st.busy.upload.indexOf(upt), 1);
                    t.postlist.splice(t.postlist.indexOf(npart), 1);
                    if (t.postlist.length == 0) {
                        t.t3 = new Date().getTime();
                        ebi('f{0}t'.format(t.n)).innerHTML = 'verifying';
                        st.todo.handshake.unshift(t);
                    }
                    tasker();
                }
                else
                    alert("server broke (error {0}):\n\"{1}\"\n".format(
                        xhr.status,
                        (xhr.response && xhr.response.err) ||
                        (xhr.responseText && xhr.responseText) ||
                        "no further information"));
            };
            xhr.open('POST', t.purl + 'chunkpit.php', true);
            //xhr.setRequestHeader("X-Up2k-Hash", t.hash[npart].substr(1) + "x");
            xhr.setRequestHeader("X-Up2k-Hash", t.hash[npart]);
            xhr.setRequestHeader("X-Up2k-Wark", t.wark);
            xhr.setRequestHeader('Content-Type', 'application/octet-stream');
            xhr.overrideMimeType('Content-Type', 'application/octet-stream');
            xhr.responseType = 'text';
            xhr.send(ev.target.result);
        };

        reader.readAsArrayBuffer(bobslice.call(t.fobj, car, cdr));
    }

    /////
    ////
    ///   progress bar
    //

    function prog(nfile, nchunk, color, percent) {
        var n1 = ebi('f{0}p{1}'.format(nfile, nchunk));
        var n2 = n1.getElementsByTagName('div')[0];
        if (percent === undefined) {
            n1.style.background = color;
            n2.style.display = 'none';
        }
        else {
            n2.style.width = percent + '%';
            n2.style.display = 'block';
        }
    }

    /////
    ////
    ///   config ui
    //

    function onresize(ev) {
        var bar = ebi('ops'),
            wpx = innerWidth,
            fpx = parseInt(getComputedStyle(bar)['font-size']),
            wem = wpx * 1.0 / fpx,
            wide = wem > 54,
            parent = ebi(wide ? 'u2btn_cw' : 'u2btn_ct'),
            btn = ebi('u2btn');

        //console.log([wpx, fpx, wem]);
        if (btn.parentNode !== parent) {
            parent.appendChild(btn);
            ebi('u2conf').setAttribute('class', wide ? 'has_btn' : '');
        }
    }
    window.onresize = onresize;
    onresize();

    function desc_show(ev) {
        var msg = this.getAttribute('alt');
        msg = msg.replace(/\$N/g, "<br />");
        var cdesc = ebi('u2cdesc');
        cdesc.innerHTML = msg;
        cdesc.setAttribute('class', 'show');
    }
    function desc_hide(ev) {
        ebi('u2cdesc').setAttribute('class', '');
    }
    var o = document.querySelectorAll('#u2conf *[alt]');
    for (var a = o.length - 1; a >= 0; a--) {
        o[a].parentNode.getElementsByTagName('input')[0].setAttribute('alt', o[a].getAttribute('alt'));
    }
    var o = document.querySelectorAll('#u2conf *[alt]');
    for (var a = 0; a < o.length; a++) {
        o[a].onfocus = desc_show;
        o[a].onblur = desc_hide;
        o[a].onmouseenter = desc_show;
        o[a].onmouseleave = desc_hide;
    }

    function bumpthread(dir) {
        try {
            dir.stopPropagation();
            dir.preventDefault();
        } catch (ex) { }

        var obj = ebi('nthread');
        if (dir.target) {
            obj.style.background = '#922';
            var v = Math.floor(parseInt(obj.value));
            if (v < 1 || v > 8 || v !== v)
                return;

            parallel_uploads = v;
            localStorage.setItem('nthread', v);
            obj.style.background = '#444';
            return;
        }

        parallel_uploads += dir;

        if (parallel_uploads < 1)
            parallel_uploads = 1;

        if (parallel_uploads > 8)
            parallel_uploads = 8;

        obj.value = parallel_uploads;
        bumpthread({ "target": 1 })
    }

    function tgl_multitask() {
        multitask = !multitask;
        bcfg_set('multitask', multitask);
    }

    function tgl_ask_up() {
        ask_up = !ask_up;
        bcfg_set('ask_up', ask_up);
    }

    function tgl_fsearch() {
        fsearch = !fsearch;
        bcfg_set('fsearch', fsearch);
        apply_fsearch_cfg();
    }

    function apply_fsearch_cfg() {
        try {
            var fun = fsearch ? 'add' : 'remove';
            ebi('op_up2k').classList[fun]('srch');
        }
        catch (ex) { }
    }

    function set_fsearch() {
        if (!fsearch)
            tgl_fsearch();
    }

    function tgl_flag_en() {
        flag_en = !flag_en;
        bcfg_set('flag_en', flag_en);
        apply_flag_cfg();
    }

    function apply_flag_cfg() {
        if (flag_en && !flag) {
            try {
                flag = up2k_flagbus();
            }
            catch (ex) {
                console.log("flag error: " + ex.toString());
                tgl_flag_en();
            }
        }
        else if (!flag_en && flag) {
            flag.ch.close();
            flag = false;
        }
    }

    function nop(ev) {
        ev.preventDefault();
        this.click();
    }

    ebi('nthread_add').onclick = function (ev) {
        ev.preventDefault();
        bumpthread(1);
    };
    ebi('nthread_sub').onclick = function (ev) {
        ev.preventDefault();
        bumpthread(-1);
    };

    ebi('nthread').addEventListener('input', bumpthread, false);
    ebi('multitask').addEventListener('click', tgl_multitask, false);
    ebi('ask_up').addEventListener('click', tgl_ask_up, false);
    ebi('flag_en').addEventListener('click', tgl_flag_en, false);
    var o = ebi('fsearch');
    if (o)
        o.addEventListener('click', tgl_fsearch, false);

    var nodes = ebi('u2conf').getElementsByTagName('a');
    for (var a = nodes.length - 1; a >= 0; a--)
        nodes[a].addEventListener('touchend', nop, false);

    var perms = document.body.getAttribute('perms');
    if (perms && perms.indexOf('write') === -1)
        set_fsearch();

    bumpthread({ "target": 1 })

    return { "init_deps": init_deps, "set_fsearch": set_fsearch }
}


function warn_uploader_busy(e) {
    e.preventDefault();
    e.returnValue = '';
    return "upload in progress, click abort and use the file-tree to navigate instead";
}


if (document.querySelector('#op_up2k.act'))
    goto_up2k();