// Initialize after page loading is complete
document.addEventListener('DOMContentLoaded', function() {
    initializeCategoryDownload();
});

/**
 * Trigger file download from database
 * @param {string} filename - Name of the file to be downloaded (e.g., 'all_data.csv', 'ph.csv')
 */
async function downloadFile(filename) {
    try {
        // Extract type from filename (remove .csv extension)
        const type = filename.replace('.csv', '');
        
        // Map filename to API type
        const typeMap = {
            'all_data': 'all_data',
            'ph': 'ph',
            'temperature': 'temperature',
            'oxygen': 'oxygen',
            'culture_medium': 'culture_medium',
            'max_growth_rate': 'max_growth_rate'
        };
        
        const apiType = typeMap[type];
        if (!apiType) {
            alert(`Unsupported download type: ${type}`);
            return;
        }
        
        // Show loading toast
        showDownloadToast(filename, true);
        
        // Fetch data from API
        const response = await fetch(`/api/download-data/${apiType}?cultured_type=cultured`);
        
        if (!response.ok) {
            throw new Error(`HTTP error! status: ${response.status}`);
        }
        
        // Get CSV content
        const csvContent = await response.text();
        
        // Create blob and download
        const blob = new Blob([csvContent], { type: 'text/csv;charset=utf-8;' });
        const link = document.createElement('a');
        link.href = URL.createObjectURL(blob);
        link.download = filename;
        link.style.visibility = 'hidden';
        document.body.appendChild(link);
        link.click();
        document.body.removeChild(link);
        
        // Clean up blob URL
        URL.revokeObjectURL(link.href);
        
        // Show success toast
        showDownloadToast(filename, false);
        
    } catch (error) {
        console.error('Download failed:', error);
        alert(`下载失败: ${error.message}`);
        showDownloadToast(filename, false, true);
    }
}

/**
 * Initialize category-based download functionality
 */
function initializeCategoryDownload() {
    const categorySelect = document.getElementById('category-select');
    const downloadBtn = document.getElementById('category-download-btn');
    
    // Listen for selection changes
    categorySelect.addEventListener('change', function() {
        downloadBtn.disabled = !this.value;
        if (this.value) {
            downloadBtn.classList.add('active');
        } else {
            downloadBtn.classList.remove('active');
        }
    });
}

/**
 * Download file based on selected category and taxonomy
 */
function downloadByCategory() {
    const categorySelect = document.getElementById('category-select');
    const taxonomySelect = document.getElementById('taxonomy-select');
    
    const category = categorySelect.value;
    const taxonomy = taxonomySelect.value;
    
    if (!category) {
        alert('Please select a data category first.');
        return;
    }
    
    // Construct filename
    let filename = category;
    if (taxonomy) {
        filename += `_${taxonomy}`;
    }
    filename += '.csv';
    
    // Download file
    downloadFile(filename);
}

/**
 * Show download status toast notification
 * @param {string} filename - Name of the file being downloaded
 * @param {boolean} loading - Whether to show loading state
 * @param {boolean} error - Whether to show error state
 */
function showDownloadToast(filename, loading = false, error = false) {
    // Remove existing toast if any
    const existingToast = document.querySelector('.download-toast');
    if (existingToast) {
        existingToast.remove();
    }
    
    // Create download prompt element
    const toast = document.createElement('div');
    toast.className = 'download-toast';
    
    let iconClass = 'icon-success';
    let message = `正在下载 ${filename}...`;
    
    if (error) {
        iconClass = 'icon-error';
        message = `下载 ${filename} 失败`;
    } else if (!loading) {
        iconClass = 'icon-success';
        message = `已成功下载 ${filename}`;
    }
    
    toast.innerHTML = `
        <i class="iconfont ${iconClass}"></i>
        <span>${message}</span>
    `;
    
    document.body.appendChild(toast);
    
    // Show animation
    setTimeout(() => {
        toast.classList.add('show');
    }, 100);
    
    // Remove after 3 seconds
    setTimeout(() => {
        toast.classList.remove('show');
        setTimeout(() => {
            if (toast.parentNode) {
                document.body.removeChild(toast);
            }
        }, 300);
    }, 3000);
}