const UI = {
    text(value) {
        return document.createTextNode(value);
    },

    button(text, callback, select=false) {
        let button = document.createElement("button");
        button.innerText = text;
        if(select) { button.setAttribute("class", "selected"); }
        if(callback !== null) { button.addEventListener("click", callback); }
        return button;
    },

    submit(text) {
        let button = document.createElement("input");
        button.setAttribute("type", "submit");
        button.value = text;
        return button;
    },

    slider(id, callback) {
        let input = document.createElement("input");
        if(id !== null) { input.setAttribute("id", id); }
        input.setAttribute("type", "range");
        input.setAttribute("value", "0");
        input.setAttribute("min", "0");
        input.setAttribute("max", "0");
        if(callback !== null) { input.addEventListener("input", callback); }
        return input;
    },

    checkbox(id, callback) {
        let input = document.createElement("input");
        if(id !== null) { input.setAttribute("id", id); }
        input.setAttribute("type", "checkbox");
        if(callback !== null) { input.addEventListener("change", callback); }
        return input;
    },

    textbox(id, placeholder) {
        let input = document.createElement("input");
        input.setAttribute("type", "text");
        if(id !== null) { input.setAttribute("id", id); }
        input.setAttribute("placeholder", placeholder);
        return input;
    },

    password(id) {
        let input = document.createElement("input");
        input.setAttribute("type", "password");
        if(id !== null) { input.setAttribute("id", id); }
        return input;
    },

    label(name, id) {
        let label = document.createElement("label");
        label.setAttribute("for", id);
        label.innerText = name;
        return label;
    },

    span(children, attr_class) {
        let span = document.createElement("span");
        if(attr_class !== undefined) { span.setAttribute("class", attr_class); }
        for(child of children) { span.appendChild(child); }
        return span;
    },

    div(children, attr_class) {
        let div = document.createElement("div");
        if(attr_class !== undefined) { div.setAttribute("class", attr_class); }
        for(child of children) { div.appendChild(child); }
        return div;
    },

    table_content(header, rows) {
        let tbody = document.createElement("tbody");

        if(header !== null) {
            let row = document.createElement("tr");
            for(head of header) {
                let cell = document.createElement("th");
                cell.innerText = head;
                row.appendChild(cell);
            }
            tbody.appendChild(row);
        }

        for(row of rows) {
            let tr = document.createElement("tr");
            for(node of row) {
                let cell = document.createElement("td");
                if(Array.isArray(node)) { for(item of node) { cell.appendChild(item); } }
                else { cell.appendChild(node); }
                tr.appendChild(cell);
            }
            tbody.appendChild(tr);
        }

        return tbody;
    },

    table(header, rows) {
        let table = document.createElement("table");
        table.appendChild(this.table_content(header, rows));
        return table;
    },

    mainnav(left_children, right_children, features={}) {
        let header = document.createElement("nav");
        let left = document.createElement("section");

        if(sessionStorage.getItem("auth") === null) {
            if(features.auth === true) {
                left.appendChild(UI.button(LANG("register"), () => { LOAD(SCENES.Register); }));
                left.appendChild(UI.button(LANG("login"), () => { LOAD(SCENES.Authenticate); }));
            }
        } else {
            if(features.session === true) {
                //left.appendChild(UI.button("Await", () => { }));
                left.appendChild(UI.button(LANG("challenge"), () => { LOAD(SCENES.Challenge); }));
            }
        }

        for(child of left_children) { left.appendChild(child); }

        let right = document.createElement("section");
        for(child of right_children) { right.appendChild(child); }

        header.appendChild(left);
        header.appendChild(right);

        MAIN.appendChild(header);
    },

    nav(top, bottom) {
        let section = document.createElement("section");
        for(node of top) { section.appendChild(node); }
        MENU.appendChild(section);

        section = document.createElement("section");
        for(node of bottom) { section.appendChild(node); }
        MENU.appendChild(section);
    },

    mainmenu(page) {
        if(SOCKET !== null) {
            let top = [ ];
            let bottom = [ ];

            top.push(UI.button(LANG("browse"), () => { LOAD(SCENES.Browse); }, page == "browse"));
            if(sessionStorage.getItem("auth") !== null) {
                top.push(UI.button(LANG("resume"), () => { LOAD(SCENES.Continue); }, page == "continue"));
                //top.push(UI.button("Join", () => { LOAD(SCENES.Join); }, page == "join"));
            }
            top.push(UI.button(LANG("live"), () => { LOAD(SCENES.Live); }, page == "live"));
            top.push(UI.button(LANG("history"), () => { LOAD(SCENES.History); }, page == "history"));
            top.push(UI.button(LANG("practice"), () => { LOAD(SCENES.GamePractice); }, page == "practice"));
            top.push(UI.button(LANG("guide"), () => { LOAD(SCENES.Guide); }, page == "guide"));
            top.push(UI.button(LANG("about"), () => { LOAD(SCENES.About); }, page == "about"));

            if(sessionStorage.getItem("auth") !== null) {
                bottom.push(UI.button("Logout", () => {
                    MESSAGE_COMPOSE([
                        PACK.u16(OpCode.Deauthenticate),
                    ]);
                    sessionStorage.clear();
                    LOAD_URL();
                }));
            }

            UI.nav(top, bottom);
        }
    },

    session_table(records) {
        let rows = [ ];

        for(let r = 0; r < records.length; ++r) {
            let buttons = [ ];
            let join_callback = function() {
                LOAD(SCENES.Game, {
                    token:this.token,
                    mode:INTERFACE.Mode.Player,
                });
                MESSAGE_SESSION_VIEW(this.token, true);
            };
            join_callback = join_callback.bind({token: records[r].token});

            let spectate_callback = function() {
                LOAD(SCENES.Game, {
                    token:this.token,
                    mode:INTERFACE.Mode.Review,
                });
                MESSAGE_SESSION_VIEW(this.token, false);
            };
            spectate_callback = spectate_callback.bind({token: records[r].token});

            if(records[r].player != 0) {
                let button_resume = UI.button(LANG("resume"), join_callback);
                if(records[r].is_turn) {
                    button_resume.setAttribute("class", "highlight");
                }

                buttons.push(button_resume);
                buttons.push(UI.button(LANG("review"), spectate_callback));
            } else {
                buttons.push(UI.button(LANG("view"), spectate_callback));
            }

            let dawn = UI.text(records[r].dawn);
            let dusk = UI.text(records[r].dusk);

            rows.push([
                dawn,
                dusk,
                UI.text(records[r].turn),
                UI.text(records[r].viewers),
                buttons,
            ]);
        }

        let tbody = UI.table_content(
            [ LANG("dawn"), LANG("dusk"), LANG("turn"), LANG("viewers"), "" ],
            rows,
        );

        return tbody;
    },

    session_table_resume(records) {
        let rows = [ ];

        for(let r = 0; r < records.length; ++r) {
            let buttons = [ ];
            let join_callback = function() {
                SCENE_FORWARD = SCENE;
                LOAD(SCENES.Game, {
                    token:this.token,
                    mode:INTERFACE.Mode.Player,
                });
                MESSAGE_SESSION_VIEW(this.token, true);
            };
            join_callback = join_callback.bind({token: records[r].token});

            let spectate_callback = function() {
                SCENE_FORWARD = SCENE;
                LOAD(SCENES.Game, {
                    token:this.token,
                    mode:INTERFACE.Mode.Review,
                });
                MESSAGE_SESSION_VIEW(this.token, false);
            };
            spectate_callback = spectate_callback.bind({token: records[r].token});

            let button_resume = UI.button(LANG("resume"), join_callback);
            if(records[r].is_turn) {
                button_resume.setAttribute("class", "highlight");
            }

            buttons.push(button_resume);
            buttons.push(UI.button(LANG("review"), spectate_callback));

            let handle = records[r].dawn;
            if(records[r].player == 1) { handle = records[r].dusk; }

            rows.push([
                UI.text(handle),
                UI.text(records[r].turn),
                UI.text(records[r].viewers),
                buttons,
            ]);
        }

        let tbody = UI.table_content(
            [ LANG("handle"), LANG("turn"), LANG("viewers"), "" ],
            rows,
        );

        return tbody;
    },

    /*session_table_join(records) {
        let rows = [ ];

        for(let r = 0; r < records.length; ++r) {
            let buttons = [ ];
            let join_callback = function() {
                LOAD(SCENES.Game, {
                    token:this.token,
                    mode:INTERFACE.Mode.Player,
                });
                MESSAGE_SESSION_VIEW(this.token, true);
            };
            join_callback = join_callback.bind({token: records[r].token});

            if(records[r].player) {
                buttons.push(UI.button("View", join_callback));
            } else {
                buttons.push(UI.button("Join", join_callback));
            }

            let host = UI.text(records[r].dawn);
            if(records[r].dawn == "") { dawn = UI.span([UI.text("Vacant")], "text-system"); }

            rows.push([
                host,
                buttons,
            ]);
        }

        let tbody = UI.table_content(
            [ "Host", "" ],
            rows,
        );

        return tbody;
    },*/

    session_table_history(records) {
        let rows = [ ];

        for(let r = 0; r < records.length; ++r) {
            let buttons = [ ];
            let view_callback = function() {
                SCENE_FORWARD = SCENE;
                LOAD(SCENES.Game, {
                    token:this.token,
                    mode:INTERFACE.Mode.Review,
                });
                MESSAGE_SESSION_VIEW(this.token, false);
            };
            view_callback = view_callback.bind({token: records[r].token});

            buttons.push(UI.button(LANG("review"), view_callback));

            let dawn = UI.text(records[r].dawn);
            let dusk = UI.text(records[r].dusk);

            rows.push([
                dawn,
                dusk,
                UI.text(records[r].turn),
                buttons,
            ]);
        }

        let tbody = UI.table_content(
            [ LANG("dawn"), LANG("dusk"), LANG("turns"), "" ],
            rows,
        );

        return tbody;
    },

    page_indicator(first, last, total) {
        let ind = document.getElementById("indicator-page");
        UI.clear(ind);
        ind.appendChild(UI.text(LANG_PAGEOF(first, last, total)));
    },

    clear(dom) {
        while(dom.lastChild !== null) { dom.removeChild(dom.lastChild); }
    },

    rebuild() {
        this.clear(document.body);

        MENU = document.createElement("nav");
        let title = document.createElement("header");
        title.innerText = "Omen";
        MENU.appendChild(title);
    
        MAIN = document.createElement("main");
    
        document.body.appendChild(MENU);
        document.body.appendChild(MAIN);
    },
};