class MarkdownEditor {
    constructor() {
        this.initializeElements();
        this.initializeEventListeners();
        this.initializeAutoSave();
        this.initializeToolbar();
        this.initializeDragAndDrop();
        this.initializeLocalBackup();
        this.lastSaveTime = null;
    }

    initializeElements() {
        this.titleInput = document.getElementById('titleInput');
        this.contentInput = document.getElementById('contentInput');
        this.preview = document.getElementById('preview');
        this.imageInput = document.getElementById('imageInput');
        this.saveButton = document.querySelector('.save-button');
        this.wordCount = document.querySelector('.word-count');
        this.toolbar = document.querySelector('.editor-toolbar');
        
        this.isDirty = false;
        this.lastSavedContent = '';
        this.autoSaveInterval = null;

        // Clear localStorage if this is a new article
        const isNewArticle = window.location.pathname.endsWith('/editor');
        if (isNewArticle) {
            localStorage.removeItem('editor-content');
            localStorage.removeItem('editor-title');
            // Clear inputs for new article
            this.titleInput.value = '';
            this.contentInput.value = '';
        }
    }

    initializeEventListeners() {
        this.contentInput.addEventListener('input', () => {
            this.handleContentChange();
            this.updateWordCount();
            this.isDirty = true;
        });

        this.titleInput.addEventListener('input', () => {
            this.isDirty = true;
        });

        this.imageInput.addEventListener('change', (event) => {
            this.handleImageUpload(event);
        });

        this.contentInput.addEventListener('keydown', (event) => {
            this.handleShortcuts(event);
        });

        this.saveButton.addEventListener('click', () => {
            this.saveArticle();
        });

        window.addEventListener('beforeunload', (event) => {
            if (this.isDirty) {
                event.preventDefault();
                event.returnValue = '您有未保存的更改，确定要离开吗？';
            }
        });
    }

    handleContentChange() {
        this.updatePreview();
    }

    updatePreview() {
        try {
            const content = this.contentInput.value;
            const markedInstance = marked.parse || marked;
            this.preview.innerHTML = markedInstance(content, {
                breaks: true,
                gfm: true,
                highlight: function(code, lang) {
                    if (lang && hljs.getLanguage(lang)) {
                        return hljs.highlight(code, { language: lang }).value;
                    }
                    return code;
                }
            });
            
            this.preview.querySelectorAll('pre code').forEach(block => {
                hljs.highlightElement(block);
            });
        } catch (error) {
            console.error('预览渲染错误:', error);
            this.preview.innerHTML = '<div class="error">预览渲染失败</div>';
        }
    }

    initializeAutoSave() {
        this.autoSaveInterval = setInterval(() => {
            if (this.isDirty && this.lastSaveTime && 
                (Date.now() - this.lastSaveTime) >= 600000) { // 10 minutes
                this.autoSave();
            }
        }, 60000); // Check every minute
    }

    async autoSave() {
        if (!this.isDirty) return;

        const content = this.contentInput.value;
        const title = this.titleInput.value;
        
        if (content === this.lastSavedContent || !title.trim() || !content.trim()) {
            return;
        }

        try {
            const response = await this.saveArticle(true);
            if (response && response.ok) {
                this.lastSavedContent = content;
                this.showNotification('自动保存成功', 'success');
            }
        } catch (error) {
            console.error('自动保存失败:', error);
            this.showNotification('自动保存失败', 'error');
        }
    }

    insertText(before, after, defaultText = '') {
        const start = this.contentInput.selectionStart;
        const end = this.contentInput.selectionEnd;
        const content = this.contentInput.value;
        
        const selectedText = content.substring(start, end) || defaultText;
        const replacement = before + selectedText + after;
        
        this.contentInput.value = content.substring(0, start) + 
                                 replacement + 
                                 content.substring(end);
        
        this.contentInput.focus();
        const newCursorPos = start + before.length + selectedText.length;
        this.contentInput.setSelectionRange(newCursorPos, newCursorPos);
        
        this.updatePreview();
        this.isDirty = true;
    }

    async handleImageUpload(event) {
        const file = event.target.files[0];
        if (!file) return;

        if (!file.type.startsWith('image/')) {
            this.showNotification('请选择图片文件', 'error');
            return;
        }

        const formData = new FormData();
        formData.append('file', file);

        try {
            this.showNotification('正在上传图片...', 'info');
            const response = await fetch('/api/upload', {
                method: 'POST',
                body: formData
            });
            
            const data = await response.json();
            
            if (data.url) {
                this.insertText(`![${file.name}](${data.url})`, '');
                this.showNotification('图片上传成功', 'success');
            } else {
                throw new Error(data.error || '上传失败');
            }
        } catch (error) {
            console.error('图片上传错误:', error);
            this.showNotification('图片上传失败', 'error');
        }
    }

    handleShortcuts(event) {
        if (event.ctrlKey || event.metaKey) {
            switch (event.key.toLowerCase()) {
                case 's':
                    event.preventDefault();
                    this.saveArticle();
                    break;
                case 'b':
                    event.preventDefault();
                    this.insertText('**', '**', '粗体文本');
                    break;
                case 'i':
                    event.preventDefault();
                    this.insertText('*', '*', '斜体文本');
                    break;
            }
        }
    }

    async saveArticle(isAutoSave = false) {
        const title = this.titleInput.value.trim();
        const content = this.contentInput.value.trim();
        this.lastSaveTime = Date.now();
        
        if (!title || !content) {
            this.showNotification('标题和内容不能为空', 'error');
            return;
        }
        
        const articleSlug = window.location.pathname.split('/').pop();
        const isEdit = articleSlug !== 'editor';
        
        try {
            if (!isAutoSave) this.showNotification('正在保存...', 'info');
            
            const response = await fetch(`/api/articles${isEdit ? '/' + articleSlug : ''}`, {
                method: isEdit ? 'PUT' : 'POST',
                headers: {
                    'Content-Type': 'application/json'
                },
                body: JSON.stringify({
                    title,
                    content
                })
            });
            
            const data = await response.json();
            
            if (response.ok) {
                this.isDirty = false;
                if (!isAutoSave) {
                    this.showNotification('保存成功', 'success');
                    window.location.href = `/article/${data.slug || articleSlug}`;
                }
                return response;
            } else {
                throw new Error(data.error || '保存失败');
            }
        } catch (error) {
            console.error('保存文章错误:', error);
            this.showNotification(error.message, 'error');
            throw error;
        }
    }

    updateWordCount() {
        const content = this.contentInput.value;
        const wordCount = content.length;
        if (this.wordCount) {
            this.wordCount.textContent = `字数：${wordCount}`;
        }
    }

    showNotification(message, type = 'info') {
        const notification = document.createElement('div');
        notification.className = `notification ${type}`;
        notification.innerHTML = `
            <div class="notification-content">
                <span class="notification-message">${message}</span>
                <button class="notification-close">&times;</button>
            </div>
        `;

        document.body.appendChild(notification);

        const closeButton = notification.querySelector('.notification-close');
        closeButton.addEventListener('click', () => {
            notification.remove();
        });

        setTimeout(() => {
            notification.classList.add('fade-out');
            setTimeout(() => {
                notification.remove();
            }, 300);
        }, 3000);
    }

    initializeToolbar() {
        const tools = [
            {
                name: 'bold',
                icon: '<i class="fas fa-bold"></i>',
                title: '粗体 (Ctrl+B)',
                action: () => this.insertText('**', '**', '粗体文本')
            },
            {
                name: 'italic',
                icon: '<i class="fas fa-italic"></i>',
                title: '斜体 (Ctrl+I)',
                action: () => this.insertText('*', '*', '斜体文本')
            },
            {
                name: 'heading1',
                icon: '<i class="fas fa-heading"></i>',
                title: '一级标题',
                action: () => this.insertText('\n# ', '', '标题')
            },
            {
                name: 'heading2',
                icon: '<i class="fas fa-heading fa-sm"></i>',
                title: '二级标题',
                action: () => this.insertText('\n## ', '', '标题')
            },
            {
                name: 'code',
                icon: '<i class="fas fa-code"></i>',
                title: '代码块',
                action: () => this.insertText('\n```\n', '\n```\n', '在此输入代码')
            },
            {
                name: 'link',
                icon: '<i class="fas fa-link"></i>',
                title: '链接',
                action: () => this.insertText('[', '](https://)', '链接文本')
            },
            {
                name: 'image',
                icon: '<i class="fas fa-image"></i>',
                title: '图片',
                action: () => this.imageInput.click()
            },
            {
                name: 'list',
                icon: '<i class="fas fa-list-ul"></i>',
                title: '无序列表',
                action: () => this.insertText('\n- ', '', '列表项')
            },
            {
                name: 'numbered-list',
                icon: '<i class="fas fa-list-ol"></i>',
                title: '有序列表',
                action: () => this.insertText('\n1. ', '', '列表项')
            },
            {
                name: 'quote',
                icon: '<i class="fas fa-quote-right"></i>',
                title: '引用',
                action: () => this.insertText('\n> ', '', '引用文本')
            },
            {
                name: 'divider',
                icon: '<i class="fas fa-minus"></i>',
                title: '分隔线',
                action: () => this.insertText('\n---\n', '', '')
            }
        ];

        tools.forEach(tool => {
            const button = document.createElement('button');
            button.className = `toolbar-button ${tool.name}`;
            button.innerHTML = tool.icon;
            button.title = tool.title;
            button.addEventListener('click', (e) => {
                e.preventDefault();
                tool.action();
            });
            this.toolbar.appendChild(button);
        });
    }

    initializeDragAndDrop() {
        const dropZone = this.contentInput;
        
        ['dragenter', 'dragover', 'dragleave', 'drop'].forEach(eventName => {
            dropZone.addEventListener(eventName, (e) => {
                e.preventDefault();
                e.stopPropagation();
            });
        });

        ['dragenter', 'dragover'].forEach(eventName => {
            dropZone.addEventListener(eventName, () => {
                dropZone.classList.add('drag-over');
            });
        });

        ['dragleave', 'drop'].forEach(eventName => {
            dropZone.addEventListener(eventName, () => {
                dropZone.classList.remove('drag-over');
            });
        });

        dropZone.addEventListener('drop', (e) => {
            const files = e.dataTransfer.files;
            if (files.length > 0 && files[0].type.startsWith('image/')) {
                this.imageInput.files = files;
                this.handleImageUpload({ target: this.imageInput });
            }
        });
    }

    initializeLocalBackup() {
        // Only restore from local storage if we're editing an existing article
        const isNewArticle = window.location.pathname.endsWith('/editor');
        if (!isNewArticle) {
            const savedContent = localStorage.getItem('editor-content');
            const savedTitle = localStorage.getItem('editor-title');
            
            if (savedContent && !this.contentInput.value) {
                this.contentInput.value = savedContent;
                this.updatePreview();
            }
            
            if (savedTitle && !this.titleInput.value) {
                this.titleInput.value = savedTitle;
            }
        }

        // Save to local storage periodically
        setInterval(() => {
            if (this.isDirty) {
                localStorage.setItem('editor-content', this.contentInput.value);
                localStorage.setItem('editor-title', this.titleInput.value);
            }
        }, 10000);
    }

    destroy() {
        clearInterval(this.autoSaveInterval);
        localStorage.removeItem('editor-content');
        localStorage.removeItem('editor-title');
    }
}

// Initialize editor when the DOM is ready
document.addEventListener('DOMContentLoaded', () => {
    const editor = new MarkdownEditor();
});