// This should be only set to false for debugging purposes
// If it's set to false, the upload requests will be synchronous
// and you will be able to see PHP's echo output in the browser
var FORM_ASYNC = true;

// A FileView is an entry inside the explorer window
class FileView {
    constructor(filename,  mimetype, is_directory, write_permissions) {
        this.filename     = filename;
        this.visuals      = null; // The DOM object with the icon and the filenam text
        this.mimetype     = mimetype;
        this.is_directory = is_directory;
        this.write_permissions = write_permissions;
    }
}

// An array of all fileviews currently open

class Window {
    constructor(pwd) {
        this.pwd = pwd;      // pwd = [ "Folder1", "Folder2" ] means the current directory of that window is /Folder1/Folder2
        this.visuals = null; // The DOM object
        this.h2 = null;      // The titlebar of the window
        this.fileview = null;
        this.files = [];
        this.txt_editor = null; // For editable text files, this is the DOM element the user can edit
    }
}

// An array with all the windows on the screen
var windows = [];

// The focused window
var focus = null;

// Those all belong to the hidden file upload form
const upload_form    = document.getElementById("upload_form");
const the_file       = document.getElementById("the_file");
const filename_input = document.getElementById("filename");
const override_input = document.getElementById("override_input");
const current_directory       = document.getElementById("current_directory");
const upload_parent_directory = document.getElementById("upload_parent_directory");

// If this is set to true, requests to uploads.php will be sent with the "override" flag
// which will override existing files with the same name
var override_file = false;
var override_file_filename = "";
var override_file_path = "";

var open_file = null;

// Some elements have custom right click context menus
// If there's a custom context menu active, this will be it
var context_menu = null;


// If we're currently dragging something (a window or a file), this is the DOM object we're dragging
// dragging_offset_x and dragging_offset_y are the difference between the objec's top left point and the cursor position
// this is then added to the cursor position when the mouse is moved
var dragging = null;
var dragging_offset_x = 0, dragging_offset_y = 0;

// If we have pressed down a window's title bar but haven't yet started dragging it, it's the drag candidate
// This is needed because we don't yet know whether we want to start dragging the window or click an element in the titlebar
// Once the mouse has moved sufficiently far away from dragging_candidate_x or y, we start dragging
var dragging_candidate = null;
var dragging_candidate_x, dragging_candidate_y;

// If we're dragging a fileview, this is set to the fileview class instance itself, because 'dragging' is just a DOM object
// The placeholder is a dummy DIV that we insert in the object's place on the grid to keep things nicely aligned
var dragging_fileview;
var dragging_placeholder = null;

// Windows have a z-index. When we click a window it is sent to the top this will be its new z-index
// We then increment the depth, and the next window we click will go on top of the current one
var depth = 20;



function main() {
    // Create a window that looks at the root directory
    var root_window = make_window([]);

    // Focus that window and load the directory
    focus_window(root_window);
    openfile(true, root_window);    
}

function focus_window(wnd) {
    // Unfocus the old window
    if (focus)
        focus.visuals.classList.remove('focus');
    focus = wnd;
    // And focus the new one!
    if (wnd) {
        wnd.visuals.classList.add('focus');
        wnd.visuals.style.zIndex = depth ++;
    }
}

// Delete the focused window
function delete_window(wnd) {
    var index = windows.indexOf(wnd);

    if (index >= 0)
        windows.splice(index, 1);
    
    wnd.visuals.parentNode.removeChild(wnd.visuals);
    if (wnd == focus)
        focus = null;
}

// Create a right click context menu
function context(e, entries) {
    if (context_menu)
        context_menu.remove();

    context_menu = mk(document.body, 'ul', 'context');

    context_menu.onmousedown = (e) => {
        e.stopPropagation();
    }
    
    context_menu.onclick = (_e) => {
        context_menu.remove();
        context_menu = null;
    }


    context_menu.style.left = e.clientX + "px";
    context_menu.style.top  = e.clientY + "px";

    for (const e of entries) {
        const li = document.createElement('li');
        li.innerText = e[0];
        li.onclick = e[1];
        context_menu.appendChild(li);
    }
}

// This is called whenever the <input type="file">'s value changes
function on_file_added(_e) {
    if (the_file.files.length >= 1) {

        if (override_file) {
            filename_input.value          = override_file_filename;
            override_input.value          = "1";
            upload_parent_directory.value = override_file_path;
            console.log(filename_input.value, override_input.value, upload_parent_directory.value);
        } else {
            filename_input.value          = the_file.files[0].name;
            override_input.value          = "0";
            upload_parent_directory.value = get_path(focus);
        }

        if (!FORM_ASYNC) {
            upload_form.submit();
            return;
        }

        // Send the form asynchronously through the fetch api
        fetch(upload_form.action, {
            method: upload_form.method,
            body: new FormData(upload_form)
        }).then((resp) => {
            if (resp.status == 200) {
                // Reload the directory so the user can see the newly uploaded file
                openfile(true, focus);
            } else {
                alert("Upload failed");
            }
        }, () => {
            alert("Upload failed")
        });
    }
    else {
        alert("No files selected");
    }
}

// It's honestly really sad that we need this
// We have an image viewer, but we load the uploaded via the XMLHttpRequest API, which gives us an array buffer
// We need to base64 encode the image data so we can feed it into the <img src="...">
// and the standart base64 encode API is shit
// https://stackoverflow.com/questions/7370943/retrieving-binary-file-content-using-javascript-base64-encode-it-and-reverse-de
function base64ArrayBuffer(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

  // Main loop deals with bytes in chunks of 3
  for (var i = 0; i < mainLength; i = i + 3) {
    // Combine the three bytes into a single integer
    chunk = (bytes[i] << 16) | (bytes[i + 1] << 8) | bytes[i + 2]

    // Use bitmasks to extract 6-bit segments from the triplet
    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]
  }

  // Deal with the remaining bytes and padding
  if (byteRemainder == 1) {
    chunk = bytes[mainLength]

    a = (chunk & 252) >> 2 // 252 = (2^6 - 1) << 2

    // Set the 4 least significant bits to zero
    b = (chunk & 3)   << 4 // 3   = 2^2 - 1

    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

    // Set the 2 least significant bits to zero
    c = (chunk & 15)    <<  2 // 15    = 2^4 - 1

    base64 += encodings[a] + encodings[b] + encodings[c] + '='
  }

  return base64
}


// This updates the path of the window's DOM (the "Root > Folder1 > Folder2 > foo.png")
function update_path_visuals(wnd) {
    if (!wnd) {
        alert("YOU ARE NOT SUPPOSED TO SEE THIS. PLEASE COPY THE STACKTRACE FROM THE CONSOLE AND SEND IT TO THE NEAREST DEVELOPER");
        wnd = focus;
    }

    var the_path = wnd.visuals.getElementsByClassName('path')[0];

    // Remove the old path
    while (the_path.children.length > 0)
        the_path.removeChild(the_path.lastChild);

    for (let i = -1; i < wnd.pwd.length; i++) {
        var d;
        // For each element after the first create a separator
        if (i >= 0) {
            d = wnd.pwd[i];
            var separator_div = mk(the_path, 'div', 'separator');
            separator_div.innerText = "»";
        }
        else
            d = "Root";

        var entry = mk(the_path, 'button', 'pathentry');
        entry.innerText = d;

        // When we click the entry, go to its folder
        entry.onclick = (_e) => {
            if (length < wnd.pwd.length) {
                wnd.pwd.length = i + 1;
                openfile(true, wnd);
            }
        }
    
        // We can drop files onto the path, which will omve them to teh folder
        entry.onmouseup = (e) => {
            if (dragging && dragging_fileview) {
                var new_folder = get_path(wnd, i + 1);
                move_file(new_folder, dragging_fileview.filename, wnd);
                end_drag();
    
                e.preventDefault();
                e.stopPropagation();
            }
        }
    }
}


// This asks the server for the contents of the specified file
// The 'cb' callback is then called, which gives you the file as either text or binary
// depending on whether or not text is true/false
function read_file_contents(text, cb, folder, filename) {
    var data = new FormData();
    data.append('folder', folder);
    data.append('filename', filename);

    let xhr = new XMLHttpRequest();
    xhr.open('POST', '/php/readfile.php', true);

    if (text) {
        xhr.onload = function () {
            cb(xhr.responseText);
        };
    } else {
        xhr.responseType = 'arraybuffer';
        xhr.onload = function () {
            cb(xhr.response);
        };
    }

    xhr.send(data);
}


// This opens a file.
// If the file has image/* mimetype, it will be displayed as an image
// otherwise it will be displayed as plaintext
function openfile_nondir(wnd) {

    while (wnd.filecontents.children.length > 0)
        wnd.filecontents.removeChild(wnd.filecontents.lastChild);

    // Send a request to readfile.php, which will give us the contents
    var data = new FormData();
    data.append('folder', get_path(wnd, wnd.pwd.length - 1));
    data.append('filename', wnd.pwd[wnd.pwd.length - 1]);

    var xhr = new XMLHttpRequest();

    update_path_visuals(wnd);

    xhr.open('POST', '/php/readfile.php', true);

    wnd.filecontents.innerText = "";
    wnd.filecontentsroot.style.display = 'flex';
    wnd.foldercontents.style.display   = 'none';

    let is_image = open_file.mimetype.split("/")[0] == "image";
    wnd.save_btn_container.style.display = (open_file.write_permissions && !is_image) ? "flex" : "none";

    if (is_image) {
        xhr.responseType = 'arraybuffer';
        xhr.onload = function () {
            let b = `data:image/png;base64,${base64ArrayBuffer(xhr.response)}`;
            wnd.filecontents.style.backgroundImage = `url('${b}')`;
            wnd.filecontents.classList.add('imgview');
        }
    }
    else {
        wnd.filecontents.classList.remove('imgview');
        wnd.filecontents.style.backgroundImage = "unset";

        wnd.txt_editor = mk(wnd.filecontents, 'pre');

        xhr.onload = function () {
            wnd.txt_editor.innerText = xhr.responseText;
            if (open_file.write_permissions)
                wnd.txt_editor.contentEditable = "true";
        };
    }

    xhr.send(data);
}

// This is a tiny wrapper around the share_window.
function share(in_file, filename, wnd) {
    if (in_file) {
        var folder = get_path(wnd, wnd.pwd.length - 1);
        filename = wnd.pwd[wnd.pwd.length - 1];
    } else {
        var folder = get_path(wnd);
    }

    var wnd = make_share_window(folder, filename);
    focus_window(wnd);
}

// Replace an existing file with a new one
function replace_file(in_file, filename, wnd) {
    if (in_file) {
        var folder = get_path(wnd, wnd.pwd.length - 1);
        filename = wnd.pwd[wnd.pwd.length - 1];
    } else {
        var folder = get_path(wnd);
    }

    override_file = true;
    override_file_path     = folder;
    override_file_filename = filename;
    the_file.click();
}

// This loads the contents of the current directory
function openfile_dir(wnd) { 
    update_path_visuals(wnd);

    var data = new FormData();
    data.append('path', get_path(wnd));

    var xhr = new XMLHttpRequest();
    xhr.open('POST', '/php/readdir.php', true);
    xhr.onload = function () {
        for (const f of wnd.files)
            f.visuals.remove();
        wnd.files = [];

        var json = JSON.parse(xhr.responseText);
        if (!json)
            return;

        // Create the FileViews from the json response
        for (const f of json) {
            var view = new FileView(f.name, 
                                    f.mimetype, 
                                    f.is_directory && f.is_directory != "0", 
                                    f.can_edit     && f.can_edit     != "0");
            wnd.files.push(view);
        }

        // Sort the files nicely before adding their visuals
        // Folders come first, then files, then the special trash directory
        // Everything inside the categories is lexically sorted
        wnd.files.sort((a, b) => {
            if (wnd.pwd.length == 0 && a.filename == "share")
                return -10;
            if (wnd.pwd.length == 0 && b.filename == "share")
                return 10;

            if (wnd.pwd.length == 0 && a.filename == "trash")
                return 10;
            if (wnd.pwd.length == 0 && b.filename == "trash")
                return -10;
            if (a.is_directory && !b.is_directory)
                return -1;
            if (!a.is_directory && b.is_directory)
                return 1;
            return a.filename.localeCompare(b.filename);
        });

        for (const f of wnd.files) {
            add_file_visuals(f, wnd);
        }

    };
    xhr.send(data);

    wnd.filecontentsroot.style.display = 'none';
    wnd.foldercontents.style.display   = 'flex';
}


function openfile(is_directory, wnd) {
    if (!wnd) { 
        alert(451);
        console.trace();
        wnd = focus;
    }

    if (is_directory) {
        openfile_dir(wnd);
    } else {
        openfile_nondir(wnd);
    }
}

function move_to_trash(wnd, filename) {
    move_file("/trash", filename, path_combine(get_path(wnd), filename), wnd);
}

function restore_from_trash(wnd, filename) {
    var split = filename.split("/");
    var new_filename = split.pop();
    var new_directory = "/" + split.join("/");

    move_file(new_directory, filename, new_filename, wnd);
}


// This deletes the file, *for real*
// move_to_trash is what is actually called when the user clicks 'Delete'
function delete_file(wnd, filename) {
    var data = new FormData();
    data.append('folder', get_path(wnd));
    data.append('filename', filename);

    var xhr = new XMLHttpRequest();
    xhr.open('POST', '/php/delete.php', true);
    xhr.onload = function () {
        openfile(true, wnd);
    };
    xhr.send(data);
}

function rename_file(filename, wnd) {
    var new_name = prompt(`Rename ${filename} to`, filename);
    if (!new_name)
        return;

    var data = new FormData();
    data.append('folder', get_path(wnd));
    data.append('old_filename', filename);
    data.append('new_filename', new_name);

    var xhr = new XMLHttpRequest();
    xhr.open('POST', '/php/rename.php', true);
    xhr.onload = function () {
        openfile(true, wnd);
    };
    xhr.send(data);
}

function move_file(new_folder, filename, new_filename, wnd) {
    if (!new_filename)
        new_filename = filename;

    var data = new FormData();
    data.append('old_folder',  get_path(wnd));
    data.append('new_folder',  new_folder);
    data.append('filename',    filename);
    data.append('new_filename',new_filename);

    var xhr = new XMLHttpRequest();
    xhr.open('POST', '/php/move.php', true);
    xhr.onload = () => {
        openfile(true, wnd);
    };
    xhr.send(data);
}

function new_folder(wnd) { 
    var dirname = prompt(`Directory name`, "New Folder");
    if (!dirname)
        return;

    var data = new FormData();
    data.append('parent_directory', get_path(wnd));
    data.append('dirname', dirname);

    var xhr = new XMLHttpRequest();
    xhr.open('POST', '/php/mkdir.php', true);
    xhr.onload = function () {
        openfile(true, wnd);
    };
    xhr.send(data);
}


// Dragging a fileview is a bit different from dragging a window
// This does some setup work before calling the common begin_drag
function begin_drag_fileview(e, fileview) {
    if (dragging)
        end_drag();

    // The dragging_placeholder is inserted into its place by the begin_drag function
    dragging_placeholder = document.createElement('div');
    dragging_fileview = fileview;

    dragging = fileview.visuals;
    dragging.style.zIndex = 50000;

    begin_drag(e, fileview.visuals);
}

// Start dragging the 'obj' DOM element
// e is a DOM event, this should only get called in response of a DOM event
function begin_drag(e, obj, dont_set_width) {
    set_iframe_enabled(false);
    dragging = obj;
    dragging_candidate = null;
    dragging.classList.add("dragged");

    var elemRect = dragging.getBoundingClientRect();
    dragging_offset_x = e.clientX - elemRect.left;
    dragging_offset_y = -e.clientY + elemRect.top;

    if (dragging_placeholder)
        obj.parentNode.insertBefore(dragging_placeholder, obj);

    dragging.style.left = (e.clientX - dragging_offset_x) + "px";
    dragging.style.top  = (e.clientY + dragging_offset_y) + "px";

    if (!dont_set_width) {
        dragging.style.width  = elemRect.width  + "px";
        dragging.style.height = elemRect.height + "px";
    }

    dragging.style.position = "absolute";
    document.body.appendChild(dragging);
}

function end_drag(_e) {
    set_iframe_enabled(true);

    // If there's a dragging palceholder remove it and put the dragged node back into its place
    if (dragging_placeholder) {
        dragging_placeholder.parentNode.insertBefore(dragging, dragging_placeholder);
        dragging_placeholder.remove();
        dragging_placeholder = null;
    }

    // If we were dragging a FileView, we need to reset some CSS
    if (dragging_fileview) {
        dragging.style.removeProperty("position");
        dragging.style.removeProperty("width");
        dragging.style.removeProperty("height");
        dragging.style.removeProperty("left");
        dragging.style.removeProperty("top");
        dragging_fileview = null;
    }

    dragging.classList.remove("dragged");
    dragging = null;
}

// This creates the parts of a window that are common between all window types
// This should only really be called by another function that will then fill up the window
function make_window_base(pwd, x, y, w, h) {
    var wnd = new Window(pwd);
    windows.push(wnd);

    wnd.visuals = mk(document.body, 'div', 'window');

    wnd.visuals.style.width    = w + "px";
    wnd.visuals.style.height   = h ? (h + "px") : "unset";
    wnd.visuals.style.position = "absolute";
    wnd.visuals.style.left     = x + "px";
    wnd.visuals.style.top      = y + "px";

    wnd.h2 = mk(wnd.visuals, 'h2');

    wnd.visuals.onmousedown = (_e) => { 
        focus_window(wnd); 
    }

    wnd.h2.onmousedown = (e) => {
        if (!dragging) {
            dragging_candidate = wnd.visuals;
            dragging_candidate_x = e.clientX;
            dragging_candidate_y = e.clientY;
        }
    };

    return wnd;
}

// This is a widely abused helper function that creates a DOM element, attaches it as the 
// last child of 'parent' and possibly gives it a class
function mk(parent, type, _class) {
    var el = document.createElement(type);
    parent.appendChild(el);
    if (_class)
        el.classList.add(_class);
    return el;
}

// Crate a horizontal div
function mkhdiv(parent) {
    var hdiv = mk(parent, 'div');
    hdiv.style.display    = "flex";
    hdiv.style.alignItems = "center";
    hdiv.style.padding    = "0.3rem";
    hdiv.style.gap        = "0.3rem";
    return hdiv;
}

// Create a checkbocx with a label.
// togglefn will be called when its value changes with an argument that's either true/false
function mkcheckbox(parent, label, togglefn) {
    var hdiv = mkhdiv(parent);

    var write_checkbox = mk(hdiv, 'input');
    write_checkbox.type = 'checkbox';

    var write_checkbox_label = mk(hdiv, 'label');
    write_checkbox_label.innerText = label;
    write_checkbox_label.onclick = (_e) => { write_checkbox.click(); }
    write_checkbox_label.classList.add('noselect');

    write_checkbox.onchange = (_e) => {
        togglefn(write_checkbox.checked);
    };
}

// This monstrocity creates the 'Share file' window
function make_share_window(folder, filename) {
    var wnd = make_window_base(null, 400, 400, 400, 0);

    wnd.h2.style.display = 'flex';

    // The title of the window. WE set its 'flex' to 1 1 0 so it fills up the titlebar
    // and pushes the X button to the very right
    var heading = mk(wnd.h2, 'span', 'wndtitle');
    heading.innerText = "Share " + filename;

    // Close button
    var x_button = mk(wnd.h2, 'button', 'close_button');
    x_button.innerText = "X";
    x_button.onclick = () => delete_window(wnd);

    wnd.foldercontents = mk(wnd.visuals, 'div', 'share_dialog_contents');
    wnd.foldercontents.style.padding = "0.5rem";

    // This is the data that will be sent when we hit "Generate link"
    var data = {
        write_permissions: false,
        private: false,
        has_password: false,
        password: "",
        userlist: [],
    }

    // If private link is clicked, show the "Add user" button and the user list
    var userlist, add_user;
    mkcheckbox(wnd.foldercontents, "Private link", (toggled) => {
        add_user.style.display = toggled ? "block" : "none";
        userlist.style.display = toggled ? "block" : "none";
        data.private = toggled;
    });

    userlist = mk(wnd.foldercontents, 'div');
    userlist.style.display = "none";
    add_user = mk(wnd.foldercontents, 'button');
    add_user.innerText = "Add user";
    add_user.style.display = "none";

    // When we hit 'Add user', add an input field for a new user
    add_user.onclick = (_e) => {
        var i = mk(userlist, 'input');
        i.value = 'John Doe';

        let index = data.userlist.length;
        data.userlist.push(i.value);

        i.onchange = (_e) => {
            data.userlist[index] = i.value;
        }
    }

    // Click the add_user once to add a default user, since a URL that nobody can use makes no sense
    add_user.click();

    mkcheckbox(wnd.foldercontents, "Give write permissions", (toggled) => {
        data.write_permissions = toggled;
    });

    // If 'Password protected' is checked, show the password field
    let password_container;
    mkcheckbox(wnd.foldercontents, "Password protected", (toggled) => {
        data.has_password = toggled;
        password_container.style.display = toggled ? "flex" : "none";
    });

    password_container = mkhdiv(wnd.foldercontents);
    password_container.style.display = 'none'
    var password_label = mk(password_container, 'label');
    password_label.innerText = "Password";
    var password_input = mk(password_container, 'input');
    password_input.type = 'password';
    password_input.autocomplete = 'off'

    password_input.style.flex = "1 0 0";
    password_input.onchange = (_e) => {
        data.password = password_input.value;
    };

    var generate_url_button = mk(wnd.foldercontents, 'button');
    generate_url_button.innerText = "Generate link";

    generate_url_button.onclick = () => {
        // The backend expects the users to be either an empty string, if the URL is public
        // or a comma separated list of usernaems
        var users = "";
        if (data.private) {
            users = data.userlist.join(',');
        }

        var form_data = new FormData();
        form_data.append('folder', folder);
        form_data.append('filename', filename);
        form_data.append('users', users);
        // 0 = No permissions, 1 = Read only, 2 = Write , 1|2 = 3 = RW
        // Only 1 and 3 make sense in the context of a URL
        form_data.append('permissions', data.write_permissions ? 3 : 1);
        form_data.append('password', data.has_password ? data.password : "");

        var xhr = new XMLHttpRequest();
        xhr.open('POST', '/php/share.php', true);
        xhr.onload = function () {
            alert(xhr.response);
        }

        xhr.send(form_data);
        delete_window(wnd);
    }

    return wnd;
}

function download_file(in_file, filename, wnd) {
    if (!wnd) {
        alert (802);
        wnd = focus;
    }
    if (in_file) {
        var folder = get_path(wnd, wnd.pwd.length - 1);
        filename = wnd.pwd[wnd.pwd.length - 1];
    } else {
        var folder = get_path(wnd);
    }

    // Read the file contents and then do DISGUSTING javascript things to download the ifle
    // We create a invisible <a> that we click and then delete
    // That <a> has its download attribute set so we download the contents instead of opening it in a new tab
    // and of course its href is a virtual object URL that has its content set to a blob 
    read_file_contents(false, (x) => {
        var blob = new Blob([new Uint8Array(x, 0, x.length)]);
        var url = URL.createObjectURL(blob);
        var a = document.createElement('a');
        a.href = url;
        a.download = filename;
        document.body.appendChild(a);
        a.click();
        setTimeout(() => {
            document.body.removeChild(a);
            URL.revokeObjectURL(url);
        });
    }, folder, filename);

    return;
}


// make_window creates an explorer window - the kind that can list directories/open files
function make_window(pwd, has_close) {
    var wnd = make_window_base(pwd, 100, 100, 800, 600);

    path = mk(wnd.h2, 'div', 'path');

    if (has_close) {
        var x_button = mk(wnd.h2, 'button', 'close_button');
        x_button.innerText = "X";
        x_button.onclick = () => delete_window(wnd);
    }

    // wnd.foldercontents is where the FileViews will be stored
    // it also has a subheader (h3) with 'Upload' and 'New FOlder' buttons
    {
        wnd.foldercontents = mk(wnd.visuals, 'div', 'foldercontents');
        var h3 = mk(wnd.foldercontents, 'h3');

        var upload_btn = mk(h3, 'button');
        upload_btn.innerText = "Upload";

        upload_btn.onclick = () => { 
            override_file = false; 
            the_file.click(); 
        }

        mk(h3, 'div', 'separator');

        var new_folder_btn = mk(h3, 'button');
        new_folder_btn.innerText = "New Folder";
        new_folder_btn.onclick = () => { new_folder(wnd); }

        mk(h3, 'div', 'separator');

        wnd.filegrid = mk(wnd.foldercontents, 'div', 'files');
    }

    // wnd.filecontentsroot is where the filedata will be stored for open files
    // it also has a subheader (h3) with Share and Download buttons
    {
        wnd.filecontentsroot = mk(wnd.visuals, 'div', 'filecontentsroot');
        var h3 = mk(wnd.filecontentsroot, 'h3');

        let download_btn = mk(h3, 'button');
        download_btn.innerText = "Download";
        download_btn.onclick = () => { download_file(true); }
        mk(h3, 'div', 'separator');

        let share_btn = mk(h3, 'button');
        share_btn.innerText = "Share";
        share_btn.onclick = () => { share(true, wnd); }
        mk(h3, 'div', 'separator');

        wnd.save_btn_container = mk(h3, 'div');
        wnd.save_btn_container.style.display = 'flex';

        let save_btn = mk(wnd.save_btn_container, 'button');
        save_btn.innerText = "Save";
        save_btn.onclick = () => save_open_text_file(wnd);
        mk(wnd.save_btn_container, 'div', 'separator');

        wnd.filecontents = mk(wnd.filecontentsroot, 'div', 'filecontents');
    }

    return wnd;
}


function save_open_text_file(wnd) {
    const contents = wnd.txt_editor.innerText;
    let xhr = new XMLHttpRequest();
    xhr.open('POST', '/php/upload.php', true);

    var data = new FormData();
    data.append('parent_directory', get_path (wnd.pwd.length - 1));
    data.append('filename',         wnd.pwd[wnd.pwd.length - 1]);
    data.append('content',          contents);
    data.append('overwrite',        '1');

    xhr.send(data);
}


// Create the visuals for a FileView
function add_file_visuals(fileview, wnd) {
    // Are we in a subdirectory of the trash folder?
    var is_in_trash = wnd.pwd.length > 0 && wnd.pwd[0] == "trash";

    // Is the current filewview the trash folder itself?
    var is_trash    = wnd.pwd.length == 0 && fileview.filename == "trash";
    var is_share    = wnd.pwd.length == 0 && fileview.filename == "share";

    var visuals = mk(wnd.filegrid, 'div');
    fileview.visuals = visuals;

    var img = document.createElement('img');
    var filename = document.createElement('div');

    if (fileview.is_directory) {
        if (get_path(wnd) == "/" && fileview.filename == "trash")
            img.src="/mimeicons/user-trash.png";
        else if (get_path(wnd) == "/" && fileview.filename == "share")
            img.src = "/mimeicons/user-share.png";
        else
            img.src="/mimeicons/directory.png";
    } else {
        img.src=`/mimeicons/${fileview.mimetype.replace("/", "-")}.png`;
    }

    fileview.visuals.onclick = () => {
        wnd.pwd.push(fileview.filename);
        if (!fileview.is_directory) {
            open_file = fileview;
        }
        openfile(fileview.is_directory, wnd);
    }

    visuals.oncontextmenu = (e) => {
        if (!dragging) {

            var context_list = [
                // Open is always in the context list
                ['Open', () => {
                    wnd.pwd.push(fileview.filename);
                    openfile(fileview.is_directory, wnd);
                }], 
                ['Open in New Window', () => {
                    var new_pwd = wnd.pwd.slice();
                    new_pwd.push(fileview.filename);
                    var new_wnd = make_window(new_pwd, true);
                    focus_window(new_wnd);
                    open_file = fileview;
                    openfile(fileview.is_directory, wnd);
                }], 
            ];

            if (is_in_trash) {
                // If we're in the trash, we can restore files or delete them forever
                context_list.push(['Restore', () => {  restore_from_trash(wnd, fileview.filename); }]);
                context_list.push(['Delete forever', () => { delete_file(wnd, fileview.filename); }]);
            } else if (!is_trash && !is_share) {
                // If we;'re not in trash we can rename/share/download/move files to trash
                context_list.push(
                    ['Rename', () => { rename_file(fileview.filename, wnd); }],
                );
                if (!fileview.is_directory) {
                    for (let a of actions) {
                        if (fileview.filename.endsWith(a.extension)) {
                            context_list.push(
                                [a.text, () => { 
                                    read_file_contents(true, (x) => {
                                        const ue = encodeURIComponent(x);
                                        let url = a.url.replace("$content_urlencoded", ue)
                                                       .replace("$filename", fileview.filename);

                                        if (a.open_in_iframe) {
                                            const wnd = make_window_base([], 10, 10, 800, 600);

                                            var title = mk(wnd.h2, 'span', 'wndtitle');
                                            title.innerText = fileview.filename;

                                            // Close button
                                            var x_button = mk(wnd.h2, 'button', 'close_button');
                                            x_button.innerText = "X";
                                            x_button.onclick = () => delete_window(wnd);

                                            const contents = mk(wnd.visuals, 'div', 'filecontentsroot');
                                            const iframe = mk(contents, 'iframe');
                                            iframe.style.flex = '1 0 0';
                                            iframe.src = url;

                                            focus_window(wnd);
                                        } else {
                                            window.location = url;
                                        }
                                    }, get_path(wnd), fileview.filename);
                                }]
                            );
                        }
                    }

                    if (fileview.write_permissions) {
                        context_list.push(
                            ['Replace',  () => { replace_file(false, fileview.filename, wnd); }],
                        );
                    }
                    context_list.push(
                        ['Share',    () => { share(false, fileview.filename, wnd); }],
                        ['Download', () => { download_file(false, fileview.filename); }],
                    );
                }
                context_list.push(
                    ['Delete', () => {  move_to_trash(wnd, fileview.filename); }]
                );
            }

            context(e, context_list);
        }
        e.preventDefault();
        e.stopPropagation();
    }

    visuals.ondragstart = (e) => {
        if (is_trash || is_in_trash || is_share) {
            e.preventDefault();
            return;
        }
        begin_drag_fileview(e, fileview);
        e.preventDefault();
    };

    visuals.onmouseup = (e) => {
        if (dragging) {
            if (fileview.is_directory) {
                if (get_path(wnd) == "/" && fileview.filename == "trash") {
                    // If we've dragged something onto the trashcan, it's trash
                    move_to_trash(wnd, dragging_fileview.filename);
                } 
                else if (get_path(wnd) == "/" && fileview.filename == "share") {
                    // move to 'share' is invalid
                } else {
                    // If we've dragged something onto a directory, move it into that directory
                    move_file(path_combine(get_path(wnd), fileview.filename), dragging_fileview.filename, wnd);
                } 
            } else {
                // alert(`Dropped ${dst.filename} on ${src.filename}`);
            }
            end_drag();
        }
        e.preventDefault();
    };

    visuals.classList.add('file');
    filename.classList.add('filename');

    if (is_in_trash) {
        var split = fileview.filename.split("/");
        filename.innerText = split[split.length - 1];
    } else if (is_trash) {
        filename.innerText = "Trash";
    } else if (is_share) {
        var x = mk(filename, 'span');
        x.style.fontSize = "0.8rem";
        x.innerText = "Shared with me";
    } else{
        filename.innerText = fileview.filename;
    }

    visuals.appendChild(img);
    visuals.appendChild(filename);
}


// Reads the 'pwd' of the focused window
// If pwd is ['foo', 'bar', 'baz'], this returns '/foo/bar/baz' 
function get_path(wnd, max_length) {
    if (!wnd) {
        alert("YOU ARE NOT SUPPOSED TO SEE THIS. PLEASE COPY THE STACKTRACE FROM THE CONSOLE AND SEND IT TO THE NEAREST DEVELOPER");
        console.trace();
        wnd = focus;
    }
    if (max_length == undefined) {
        max_length = wnd.pwd.length;
    }

    var path = "/";
    for (let i = 0; i < max_length; i++) {
        path += wnd.pwd[i];
        if (i != max_length - 1)
            path += "/";
    }
    return path;
}

function path_combine(a, b) {
    const last_char = a.slice(-1);
    if (last_char == "/")
        return a + b;
    else
        return a + "/" + b;
}


// When we click anywhere, remove the context menu
// The context menu itself has a onmousedown that prevents propagation so we can click its elements
document.body.onmousedown = (_e) => {
    if (context_menu) {
        context_menu.remove();
        context_menu = null;
    }
}

document.body.onmousemove = (e) => {
    if (dragging) {
        dragging.style.left = (e.clientX - dragging_offset_x) + "px";
        dragging.style.top  = (e.clientY + dragging_offset_y) + "px";
    }
    else if (dragging_candidate) {
        var d = Math.abs(e.clientX - dragging_candidate_x) + Math.abs(e.clientY - dragging_candidate_y);
        if (d > 15)
            begin_drag(e, dragging_candidate, true);
    }
}

document.body.onmouseup = (_e) => {
    if (dragging_candidate)
        dragging_candidate = null;
    if (dragging)
        end_drag();
}

document.body.oncontextmenu = (e) => {
    if (dragging) {
        end_drag();
        e.preventDefault();
    }
    if (context_menu) {
        context_menu.remove();
        context_menu = null;
    }
}

the_file.onchange = (e) => { on_file_added(e); };

function set_iframe_enabled(en) {
    for (const iframe of document.getElementsByTagName('iframe'))
        iframe.hidden = !en;
}

main();