/**
 * This file is part of Radicale Server - Calendar Server
 * Copyright © 2017-2024 Unrud <unrud@outlook.com>
 * Copyright © 2023-2024 Matthew Hana <matthew.hana@gmail.com>
 * Copyright © 2024-2025 Peter Bieringer <pb@bieringer.de>
 * Copyright © 2026-2026 Max Berger <max@berger.name>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

import { get_principal } from "./api.js";
import { CollectionsScene } from "./CollectionsScene.js";
import { LoadingScene } from "./LoadingScene.js";
import { Scene, pop_scene, push_scene, scene_stack } from "./scene_manager.js";

/**
 * @constructor
 * @implements {Scene}
 */
export class LoginScene {
    constructor() {
        /** @type {HTMLElement} */ let html_scene = document.getElementById("loginscene");
        /** @type {HTMLElement} */ let form = html_scene.querySelector("[data-name=form]");
        /** @type {HTMLInputElement} */ let user_form = html_scene.querySelector("[data-name=user]");
        /** @type {HTMLInputElement} */ let password_form = html_scene.querySelector("[data-name=password]");
        /** @type {HTMLElement} */ let error_form = html_scene.querySelector("[data-name=error]");
        /** @type {HTMLElement} */ let logout_view = document.getElementById("logoutview");
        /** @type {HTMLElement} */ let logout_user_form = logout_view.querySelector("[data-name=user]");
        /** @type {HTMLElement} */ let logout_btn = logout_view.querySelector("[data-name=logout]");
        /** @type {HTMLElement} */ let refresh_btn = logout_view.querySelector("[data-name=refresh]");

        /** @type {?number} */ let scene_index = null;
        let user = "";
        let error = "";
        /** @type {?XMLHttpRequest} */ let principal_req = null;

        function read_form() {
            user = user_form.value;
        }

        function fill_form() {
            user_form.value = user;
            password_form.value = "";
            if (error) {
                error_form.textContent = "Error: " + error;
                error_form.classList.remove("hidden");
            } else {
                error_form.classList.add("hidden");
            }
        }

        function onlogin() {
            try {
                read_form();
                let password = password_form.value;
                if (user) {
                    error = "";
                    // setup logout
                    logout_view.classList.remove("hidden");
                    logout_btn.onclick = onlogout;
                    refresh_btn.onclick = refresh;
                    logout_user_form.textContent = user + "'s Collections";
                    // Fetch principal
                    let loading_scene = new LoadingScene();
                    push_scene(loading_scene, false);
                    principal_req = get_principal(user, password, function (collection, error1) {
                        if (scene_index === null) {
                            return;
                        }
                        principal_req = null;
                        if (error1) {
                            error = error1;
                            pop_scene(scene_index);
                        } else {
                            // show collections
                            let saved_user = user;
                            user = "";
                            let collections_scene = new CollectionsScene(
                                saved_user, password, collection, function (error1) {
                                    error = error1;
                                    user = saved_user;
                                });
                            push_scene(collections_scene, true);
                        }
                    });
                } else {
                    error = "Username is empty";
                    fill_form();
                }
            } catch (err) {
                console.error(err);
            }
            return false;
        }

        function onlogout() {
            try {
                if (scene_index === null) {
                    return false;
                }
                user = "";
                pop_scene(scene_index);
            } catch (err) {
                console.error(err);
            }
            return false;
        }

        function remove_logout() {
            logout_view.classList.add("hidden");
            logout_btn.onclick = null;
            refresh_btn.onclick = null;
            logout_user_form.textContent = "";
        }

        function refresh() {
            //The easiest way to refresh is to push a LoadingScene onto the stack and then pop it
            //forcing the scene below it, the Collections Scene to refresh itself.
            push_scene(new LoadingScene(), false);
            pop_scene(scene_stack.length - 2);
        }

        this.show = function () {
            remove_logout();
            fill_form();
            form.onsubmit = onlogin;
            html_scene.classList.remove("hidden");
            scene_index = scene_stack.length - 1;
            user_form.focus();
        };
        this.hide = function () {
            read_form();
            html_scene.classList.add("hidden");
            form.onsubmit = null;
        };
        this.release = function () {
            scene_index = null;
            // cancel pending requests
            if (principal_req !== null) {
                principal_req.abort();
                principal_req = null;
            }
            remove_logout();
        };
    }
}