/**
 * Frontend application for Transcription Service
 */

class TranscriptionApp {
    constructor() {
        this.ws = null;
        this.tasks = new Map();
        this.currentFile = null;
        this.init();
    }

    init() {
        this.connectWebSocket();
        this.setupUpload();
    }

    // ===== WebSocket =====
    connectWebSocket() {
        const protocol = window.location.protocol === 'https:' ? 'wss:' : 'ws:';
        this.ws = new WebSocket(`${protocol}//${window.location.host}/ws`);

        this.ws.onopen = () => {
            console.log('WebSocket connected');
            this.showToast('Подключено к серверу', 'success');
            this.requestTasks();
            this.requestTree();
        };

        this.ws.onmessage = (event) => {
            const data = JSON.parse(event.data);
            this.handleWebSocketMessage(data);
        };

        this.ws.onclose = () => {
            console.log('WebSocket disconnected, reconnecting in 3s...');
            setTimeout(() => this.connectWebSocket(), 3000);
        };

        this.ws.onerror = (error) => {
            console.error('WebSocket error:', error);
        };
    }

    sendWS(data) {
        if (this.ws && this.ws.readyState === WebSocket.OPEN) {
            this.ws.send(JSON.stringify(data));
        }
    }

    requestTasks() {
        this.sendWS({ action: 'get_tasks' });
    }

    requestTree() {
        this.sendWS({ action: 'get_tree' });
    }

    handleWebSocketMessage(data) {
        if (data.type === 'tasks_list') {
            this.updateTasks(data.tasks);
        } else if (data.type === 'file_tree') {
            this.renderFileTree(data.tree);
        } else if (data.task_id) {
            // Прогресс обработки
            this.updateTaskProgress(data);
        }
    }

    // ===== Upload =====
    setupUpload() {
        const dropZone = document.getElementById('dropZone');
        const fileInput = document.getElementById('fileInput');
        const browseLink = document.querySelector('.browse-link');

        // Click on browse link (stop propagation to avoid double click)
        browseLink.addEventListener('click', (e) => {
            e.stopPropagation();
            fileInput.click();
        });

        // Click on drop zone (but not on the file input itself)
        dropZone.addEventListener('click', (e) => {
            if (e.target === fileInput) return;
            fileInput.click();
        });

        // File input change - reset value after handling
        fileInput.addEventListener('change', (e) => {
            const files = e.target.files;
            if (files.length) {
                this.handleFiles(files);
            }
            // Reset so the same file can be selected again
            fileInput.value = '';
        });

        // Drag & drop
        dropZone.addEventListener('dragover', (e) => {
            e.preventDefault();
            dropZone.classList.add('drag-over');
        });

        dropZone.addEventListener('dragleave', () => {
            dropZone.classList.remove('drag-over');
        });

        dropZone.addEventListener('drop', (e) => {
            e.preventDefault();
            dropZone.classList.remove('drag-over');
            this.handleFiles(e.dataTransfer.files);
        });
    }

    async handleFiles(files) {
        if (!files.length) return;

        const formData = new FormData();
        for (const file of files) {
            formData.append('files', file);
        }

        try {
            this.showToast(`Загрузка ${files.length} файл(а)...`, 'info');

            const response = await fetch('/upload-batch', {
                method: 'POST',
                body: formData,
            });

            const result = await response.json();

            if (result.error) {
                this.showToast(`Ошибка: ${result.error}`, 'error');
            } else {
                this.showToast(`Загружено ${result.uploaded} файл(а). Начинается обработка...`, 'success');
                result.tasks.forEach(task => {
                    this.tasks.set(task.task_id, task);
                });
                this.renderTasks();
            }
        } catch (error) {
            this.showToast(`Ошибка загрузки: ${error.message}`, 'error');
        }
    }

    // ===== Tasks / Progress =====
    updateTasks(tasks) {
        tasks.forEach(task => {
            this.tasks.set(task.file + '_' + task.started, task);
        });
        this.renderTasks();
    }

    updateTaskProgress(data) {
        const existing = Array.from(this.tasks.values()).find(t => t.task_id === data.task_id);
        if (existing) {
            Object.assign(existing, data);
        } else {
            this.tasks.set(data.task_id, data);
        }
        this.renderTasks();

        if (data.status === 'completed') {
            this.showToast(`Готово: ${data.message}`, 'success');
            this.requestTree();
        } else if (data.status === 'error') {
            this.showToast(`Ошибка: ${data.message}`, 'error');
        }
    }

    renderTasks() {
        const container = document.getElementById('tasksList');
        const tasks = Array.from(this.tasks.values());

        if (tasks.length === 0) {
            container.innerHTML = '<p class="empty-state">Нет активных задач</p>';
            return;
        }

        container.innerHTML = tasks.map(task => this.renderTaskItem(task)).join('');
    }

    renderTaskItem(task) {
        const progress = task.progress || 0;
        const statusClass = task.status === 'completed' ? 'success' :
                           task.status === 'error' ? 'error' :
                           task.status === 'processing' ? 'processing' : 'queued';

        return `
            <div class="task-item ${statusClass}">
                <div class="task-header">
                    <span class="task-filename">${this.escapeHtml(task.file || '')}</span>
                    <span class="task-status-badge ${statusClass}">${this.getStatusLabel(task.status)}</span>
                </div>
                <div class="task-progress-bar">
                    <div class="task-progress-fill" style="width: ${progress}%"></div>
                </div>
                <div class="task-message">${this.escapeHtml(task.message || '')}</div>
            </div>
        `;
    }

    getStatusLabel(status) {
        const labels = {
            'queued': 'В очереди',
            'processing': 'Обработка',
            'completed': 'Готово',
            'error': 'Ошибка',
        };
        return labels[status] || status;
    }

    // ===== File Tree =====
    renderFileTree(tree) {
        const container = document.getElementById('fileTree');

        if (!tree || tree.length === 0) {
            container.innerHTML = '<p class="empty-state">Нет обработанных файлов</p>';
            return;
        }

        container.innerHTML = tree.map(folder => this.renderFolder(folder)).join('');
    }

    renderFolder(folder) {
        const files = folder.files.map(file => {
            const isMd = file.ext === '.md';
            const isDocx = file.ext === '.docx';
            const icon = isMd ? '📝' : isDocx ? '📄' : '📎';
            const clickable = isMd ? 'clickable' : '';

            return `
                <div class="file-item ${clickable}" data-path="${this.escapeHtml(file.path)}" data-ext="${file.ext}">
                    <span class="file-icon">${icon}</span>
                    <span class="file-name">${this.escapeHtml(file.name)}</span>
                    <span class="file-size">${this.formatBytes(file.size)}</span>
                </div>
            `;
        }).join('');

        return `
            <div class="folder-item">
                <div class="folder-header">
                    <span class="folder-toggle">▼</span>
                    <span class="folder-icon">📁</span>
                    <span class="folder-name">${this.escapeHtml(folder.name)}</span>
                    <span class="folder-date">${this.formatDate(folder.created)}</span>
                </div>
                <div class="folder-files">
                    ${files}
                </div>
            </div>
        `;
    }

    setupFileTreeEvents() {
        const container = document.getElementById('fileTree');

        container.addEventListener('click', (e) => {
            const folderHeader = e.target.closest('.folder-header');
            if (folderHeader) {
                const folder = folderHeader.closest('.folder-item');
                const files = folder.querySelector('.folder-files');
                const toggle = folderHeader.querySelector('.folder-toggle');

                if (files.style.display === 'none') {
                    files.style.display = 'block';
                    toggle.textContent = '▼';
                } else {
                    files.style.display = 'none';
                    toggle.textContent = '▶';
                }
            }

            const fileItem = e.target.closest('.file-item.clickable');
            if (fileItem) {
                const path = fileItem.dataset.path;
                const ext = fileItem.dataset.ext;
                this.loadFileContent(path, ext);
            }
        });
    }

    // ===== Viewer =====
    async loadFileContent(path, ext) {
        const viewer = document.getElementById('viewer');

        if (ext === '.md') {
            try {
                const response = await fetch(`/api/files/content?path=${encodeURIComponent(path)}`);
                const result = await response.json();

                if (result.error) {
                    viewer.innerHTML = `<div class="error">${this.escapeHtml(result.error)}</div>`;
                    return;
                }

                // Render markdown
                const html = marked.parse(result.content);
                viewer.innerHTML = `
                    <div class="md-content">
                        <div class="md-header">
                            <span class="md-title">${this.escapeHtml(path)}</span>
                            <a href="/api/files/download?path=${encodeURIComponent(path)}" 
                               class="btn-download" download>⬇️ Скачать</a>
                        </div>
                        <div class="md-body">${html}</div>
                    </div>
                `;
                this.currentFile = path;
            } catch (error) {
                viewer.innerHTML = `<div class="error">Ошибка загрузки: ${this.escapeHtml(error.message)}</div>`;
            }
        } else if (ext === '.docx') {
            viewer.innerHTML = `
                <div class="file-preview">
                    <p>Для просмотра DOCX скачайте файл:</p>
                    <a href="/api/files/download?path=${encodeURIComponent(path)}" 
                       class="btn-download" download>⬇️ Скачать ${this.escapeHtml(path)}</a>
                </div>
            `;
        }
    }

    // ===== Utilities =====
    showToast(message, type = 'info') {
        const container = document.getElementById('toastContainer');
        const toast = document.createElement('div');
        toast.className = `toast toast-${type}`;
        toast.textContent = message;
        container.appendChild(toast);

        setTimeout(() => {
            toast.classList.add('toast-hide');
            setTimeout(() => toast.remove(), 300);
        }, 4000);
    }

    escapeHtml(text) {
        const div = document.createElement('div');
        div.textContent = text;
        return div.innerHTML;
    }

    formatBytes(bytes) {
        if (bytes === 0) return '0 B';
        const k = 1024;
        const sizes = ['B', 'KB', 'MB', 'GB'];
        const i = Math.floor(Math.log(bytes) / Math.log(k));
        return parseFloat((bytes / Math.pow(k, i)).toFixed(1)) + ' ' + sizes[i];
    }

    formatDate(isoDate) {
        const date = new Date(isoDate);
        return date.toLocaleString('ru-RU', {
            day: '2-digit',
            month: '2-digit',
            year: 'numeric',
            hour: '2-digit',
            minute: '2-digit',
        });
    }
}

// Initialize
document.addEventListener('DOMContentLoaded', () => {
    const app = new TranscriptionApp();
    app.setupFileTreeEvents();
});