// 聊天室字号偏好控制，保留旧的 localStorage key 以兼容已有用户设置。

export const CHAT_FONT_SIZE_STORAGE_KEY = "chat_font_size";
export const CHAT_DEFAULT_FONT_SIZE = 13;
export const CHAT_FONT_SIZE_MIN = 10;
export const CHAT_FONT_SIZE_MAX = 30;
let fontSizeEventsBound = false;

/**
 * 规整聊天室字号，过滤非法或越界的旧缓存值。
 *
 * @param {unknown} size 字号大小
 * @returns {number|null}
 */
export function normalizeChatFontSize(size) {
    const px = Number.parseInt(String(size ?? ""), 10);

    if (Number.isNaN(px) || px < CHAT_FONT_SIZE_MIN || px > CHAT_FONT_SIZE_MAX) {
        return null;
    }

    return px;
}

/**
 * 同步底部输入框上方工具按钮字号。
 *
 * @param {number} px 用户选择的聊天字号
 * @returns {void}
 */
function applyInputToolbarFontSize(px) {
    const toolbarRow = document.querySelector("#chat-form > .input-row");
    if (!(toolbarRow instanceof HTMLElement)) {
        return;
    }

    const toolbarFontSize = Math.max(1, px - 1);
    const fontSize = `${toolbarFontSize}px`;
    toolbarRow.style.fontSize = fontSize;
    toolbarRow.style.fontFamily = "inherit";
    toolbarRow.style.lineHeight = "1.2";
    toolbarRow.querySelectorAll([
        ":scope > label",
        ":scope > label select",
        ":scope > label input",
        ":scope > button",
        ":scope > div > button",
        "#feature-menu button",
        "#admin-menu button",
    ].join(",")).forEach((control) => {
        control.style.fontFamily = "inherit";
        control.style.fontSize = "inherit";
        control.style.lineHeight = "1.2";
        control.style.fontWeight = "400";
    });
}

/**
 * 应用字号到聊天消息窗口和输入栏工具按钮，并保存到 localStorage。
 *
 * @param {string|number} size 字号大小
 * @param {{syncContext?:boolean}} options 同步选项
 * @returns {boolean}
 */
export function applyFontSize(size, options = {}) {
    const px = normalizeChatFontSize(size);
    if (px === null) {
        return false;
    }

    const publicContainer = document.getElementById("chat-messages-container");
    const privateContainer = document.getElementById("chat-messages-container2");
    if (publicContainer) {
        publicContainer.style.fontSize = `${px}px`;
    }
    if (privateContainer) {
        privateContainer.style.fontSize = `${px}px`;
    }
    applyInputToolbarFontSize(px);

    localStorage.setItem(CHAT_FONT_SIZE_STORAGE_KEY, String(px));
    if (options.syncContext !== false && window.chatContext && typeof window.chatContext === "object") {
        window.chatContext.chatPreferences = {
            ...(window.chatContext.chatPreferences || {}),
            font_size: px,
        };
    }

    const selector = document.getElementById("font_size_select");
    if (selector) {
        selector.value = String(px);
    }

    return true;
}

/**
 * 从账号偏好或 localStorage 恢复已保存的聊天室字号。
 *
 * @returns {boolean}
 */
export function restoreChatFontSize() {
    const serverFontSize = normalizeChatFontSize(window.chatContext?.chatPreferences?.font_size);
    const localFontSize = normalizeChatFontSize(localStorage.getItem(CHAT_FONT_SIZE_STORAGE_KEY));
    const saved = serverFontSize ?? localFontSize ?? CHAT_DEFAULT_FONT_SIZE;

    return applyFontSize(saved, { syncContext: serverFontSize !== null });
}

/**
 * 绑定字号选择器事件。
 *
 * @returns {void}
 */
export function bindChatFontSizeControl() {
    if (fontSizeEventsBound || typeof document === "undefined") {
        return;
    }

    fontSizeEventsBound = true;
    document.addEventListener("change", (event) => {
        if (!(event.target instanceof HTMLSelectElement) || event.target.id !== "font_size_select") {
            return;
        }

        if (applyFontSize(event.target.value)) {
            void window.saveChatPreferences?.();
        }
    });
}