const { createApp, ref, computed, onMounted, watch } = Vue;

createApp({
    setup() {
        const markdown = ref(`# 欢迎使用微信 Markdown 编辑器

这是一个专为微信公众号设计的 **Markdown** 编辑器。

## 新增功能 ✨

- **一键格式化**：自动在中英文之间添加空格（盘古之白）。
- **多主题支持**：新增 **Notion** 风格。
- **图片美化**：支持圆角和阴影。
- **字数统计**：实时显示字数和阅读时间。

## 代码示例

\`\`\`python
def hello_world():
    print("Hello, WeChat!")
\`\`\`

## 引用链接

微信公众号不支持外部链接，本编辑器会自动将链接转换为脚注。
例如：[GitHub](https://github.com) 和 [Google](https://google.com)。

> 极致的排版体验。
`);
        
        const currentTheme = ref('default');
        const imgStyle = ref('none'); // none, rounded, shadow, both
        const copied = ref(false);
        const editorRef = ref(null);
        const previewRef = ref(null);
        let isScrolling = false;

        // Statistics
        const wordCount = computed(() => {
            // Simple logic: remove markdown symbols and count
            const text = markdown.value.replace(/[#*>\`\-]/g, '').trim();
            return text.length;
        });
        
        const readTime = computed(() => {
            return Math.ceil(wordCount.value / 400); // 400 chars per minute
        });

        // Pangu (Auto Space) Logic
        const formatContent = () => {
            let text = markdown.value;
            // Add space between CJK and English/Number
            text = text.replace(/([\u4e00-\u9fa5])([a-zA-Z0-9])/g, '$1 $2');
            text = text.replace(/([a-zA-Z0-9])([\u4e00-\u9fa5])/g, '$1 $2');
            markdown.value = text;
        };

        // Markdown-it setup
        const md = window.markdownit({
            html: true,
            breaks: true,
            linkify: true,
            typographer: true,
            highlight: function (str, lang) {
                if (lang && hljs.getLanguage(lang)) {
                    try {
                        return hljs.highlight(str, { language: lang, ignoreIllegals: true }).value;
                    } catch (__) {}
                }
                return ''; 
            }
        });

        // Footnotes logic
        const defaultRender = md.renderer.rules.link_open || function(tokens, idx, options, env, self) {
            return self.renderToken(tokens, idx, options);
        };

        let footnotes = [];

        md.renderer.rules.link_open = function (tokens, idx, options, env, self) {
            const href = tokens[idx].attrGet('href');
            if (!href || href.startsWith('#')) {
                return defaultRender(tokens, idx, options, env, self);
            }
            footnotes.push(href);
            return `<span class="link-text">`; 
        };

        md.renderer.rules.link_close = function (tokens, idx, options, env, self) {
             const n = footnotes.length;
             return `<sup>[${n}]</sup></span>`;
        };

        const htmlContent = computed(() => {
            footnotes = [];
            let rendered = md.render(markdown.value);
            
            if (footnotes.length > 0) {
                rendered += `<div class="footnotes-sep"></div><div class="footnotes-list">`;
                rendered += `<h3>引用链接</h3><ol>`;
                footnotes.forEach((url) => {
                    rendered += `<li>${url}</li>`;
                });
                rendered += `</ol></div>`;
            }
            return rendered;
        });

        const updateTheme = () => {
            document.body.setAttribute('data-theme', currentTheme.value);
        };

        const updateImgStyle = () => {
            document.body.setAttribute('data-img-style', imgStyle.value);
        };

        const copyToWeChat = () => {
            const range = document.createRange();
            range.selectNode(document.getElementById('preview-content'));
            window.getSelection().removeAllRanges();
            window.getSelection().addRange(range);
            document.execCommand('copy');
            window.getSelection().removeAllRanges();
            
            copied.value = true;
            setTimeout(() => {
                copied.value = false;
            }, 2000);
        };

        // Insert Markdown syntax at cursor
        const insertSyntax = (type) => {
            const textarea = editorRef.value;
            const start = textarea.selectionStart;
            const end = textarea.selectionEnd;
            const text = markdown.value;
            const selected = text.substring(start, end);
            
            let before = '';
            let after = '';
            
            switch(type) {
                case 'bold': before = '**'; after = '**'; break;
                case 'italic': before = '*'; after = '*'; break;
                case 'code': before = '`'; after = '`'; break;
                case 'quote': before = '> '; after = ''; break;
                case 'link': before = '['; after = '](url)'; break;
                case 'image': before = '!['; after = '](https://)'; break;
                case 'h2': before = '## '; after = ''; break;
                case 'h3': before = '### '; after = ''; break;
                case 'hr': before = '\n---\n'; after = ''; break;
            }
            
            const newText = text.substring(0, start) + before + selected + after + text.substring(end);
            markdown.value = newText;
            
            // Restore focus (approximate)
            setTimeout(() => {
                textarea.focus();
                textarea.setSelectionRange(start + before.length, end + before.length);
            }, 0);
        };

        const handleScroll = (source) => {
            if (isScrolling) return;
            isScrolling = true;

            const editor = editorRef.value;
            const preview = previewRef.value;

            if (source === 'editor') {
                const percent = editor.scrollTop / (editor.scrollHeight - editor.clientHeight);
                preview.scrollTop = percent * (preview.scrollHeight - preview.clientHeight);
            } else {
                const percent = preview.scrollTop / (preview.scrollHeight - preview.clientHeight);
                editor.scrollTop = percent * (editor.scrollHeight - editor.clientHeight);
            }

            setTimeout(() => {
                isScrolling = false;
            }, 50);
        };

        onMounted(() => {
            updateTheme();
            updateImgStyle();
        });

        watch(currentTheme, updateTheme);
        watch(imgStyle, updateImgStyle);

        return {
            markdown,
            htmlContent,
            currentTheme,
            imgStyle,
            copied,
            wordCount,
            readTime,
            editorRef,
            previewRef,
            formatContent,
            copyToWeChat,
            insertSyntax,
            handleScroll
        };
    }
}).mount('#app');