/**
 * YCat Editor - 文章阅读进度条
 * 功能：实时显示当前阅读位置，点击进度条跳转到对应位置
 * 作者：QClaw（自主开发）
 * 日期：2026-06-20
 */

(function() {
    'use strict';

    // 进度条配置
    const PROGRESS_CONFIG = {
        height: '4px',           // 进度条高度
        bgColor: '#e0e0e0',      // 背景色
        fillColor: 'var(--brand)',   // 填充色（品牌 teal）
        zIndex: 50,               // 层级（低于顶栏/弹窗）
        position: 'bottom',       // 位置：top / bottom
        smooth: true,             // 是否平滑动画
        showPercentage: false      // 是否显示百分比文字
    };

    // 创建进度条元素
    function createProgressBar() {
        const progressBar = document.createElement('div');
        progressBar.id = 'reading-progress-bar';
        progressBar.style.cssText = `
            position: fixed;
            ${PROGRESS_CONFIG.position}: 0;
            left: 0;
            width: 100%;
            height: ${PROGRESS_CONFIG.height};
            background: ${PROGRESS_CONFIG.bgColor};
            z-index: ${PROGRESS_CONFIG.zIndex};
            cursor: pointer;
        `;

        const progressFill = document.createElement('div');
        progressFill.id = 'reading-progress-fill';
        progressFill.style.cssText = `
            width: 0%;
            height: 100%;
            background: ${PROGRESS_CONFIG.fillColor};
            ${PROGRESS_CONFIG.smooth ? 'transition: width 0.1s ease;' : ''}
        `;

        progressBar.appendChild(progressFill);

        // 点击进度条跳转
        progressBar.addEventListener('click', function(e) {
            const rect = this.getBoundingClientRect();
            const clickX = e.clientX - rect.left;
            const percentage = clickX / rect.width;
            const editorContent = document.querySelector('.w-e-text-container');
            if (editorContent) {
                const scrollHeight = editorContent.scrollHeight - editorContent.clientHeight;
                editorContent.scrollTop = scrollHeight * percentage;
            }
        });

        document.body.appendChild(progressBar);
        return progressFill;
    }

    // 更新进度条
    function updateProgress() {
        let scrollTop = 0, scrollHeight = 0;
        const editorContent = document.querySelector('.w-e-text-container');
        if (editorContent && (editorContent.scrollHeight - editorContent.clientHeight) > 0) {
            scrollTop = editorContent.scrollTop;
            scrollHeight = editorContent.scrollHeight - editorContent.clientHeight;
        } else {
            scrollTop = window.scrollY || document.documentElement.scrollTop;
            scrollHeight = (document.documentElement.scrollHeight - window.innerHeight);
        }
        const progress = scrollHeight > 0 ? (scrollTop / scrollHeight) * 100 : 0;

        const fill = document.getElementById('reading-progress-fill');
        if (fill) {
            fill.style.width = (Math.min(100, Math.max(0, progress))) + '%';
        }
    }

    // 初始化
    function initReadingProgress() {
        // 等待编辑器加载完成
        const checkEditor = setInterval(() => {
            const editorContent = document.querySelector('.w-e-text-container');
            if (editorContent) {
                clearInterval(checkEditor);

                // 创建进度条
                createProgressBar();

                // 监听滚动（编辑器内部 + 整页）
                editorContent.addEventListener('scroll', updateProgress);
                window.addEventListener('scroll', updateProgress, { passive: true });

                // 监听编辑器内容变化（重新计算）
                const observer = new MutationObserver(updateProgress);
                observer.observe(editorContent, { childList: true, subtree: true });

                console.log('[ReadingProgress] 初始化完成');
            }
        }, 500);

        // 超时保护（5秒）
        setTimeout(() => clearInterval(checkEditor), 5000);
    }

    // 页面加载完成后初始化
    if (document.readyState === 'loading') {
        document.addEventListener('DOMContentLoaded', initReadingProgress);
    } else {
        initReadingProgress();
    }

})();