import { api } from '../services/api';

/**
 * Utility functions for exporting data
 */

/**
 * Converts array of objects to CSV string
 */
export function arrayToCSV<T extends Record<string, any>>(
  data: T[],
  columns?: string[]
): string {
  if (data.length === 0) return '';

  const headers = columns || Object.keys(data[0]);
  const rows = data.map((item) =>
    headers.map((header) => {
      const value = item[header];
      // Escape CSV special characters
      if (value === null || value === undefined) return '';
      const stringValue = String(value);
      if (stringValue.includes(',') || stringValue.includes('"') || stringValue.includes('\n')) {
        return `"${stringValue.replace(/"/g, '""')}"`;
      }
      return stringValue;
    })
  );

  return [headers.join(','), ...rows.map((row) => row.join(','))].join('\n');
}

/**
 * Triggers a file download in the browser
 */
export function downloadFile(content: string, filename: string, mimeType: string = 'text/plain') {
  const blob = new Blob([content], { type: mimeType });
  const url = URL.createObjectURL(blob);
  const link = document.createElement('a');
  link.href = url;
  link.download = filename;
  document.body.appendChild(link);
  link.click();
  document.body.removeChild(link);
  URL.revokeObjectURL(url);
}

/**
 * Exports data to CSV file
 */
export function exportToCSV<T extends Record<string, any>>(
  data: T[],
  filename: string = 'export.csv',
  columns?: string[]
) {
  const csv = arrayToCSV(data, columns);
  downloadFile(csv, filename, 'text/csv');
}

/**
 * Exports data to JSON file
 */
export function exportToJSON<T>(data: T, filename: string = 'export.json') {
  const json = JSON.stringify(data, null, 2);
  downloadFile(json, filename, 'application/json');
}

/**
 * Fetches and downloads export from API endpoint
 */
export async function exportFromAPI(
  endpoint: string,
  filename: string,
  format: 'csv' | 'json' = 'csv'
): Promise<void> {
  try {
    const response = await api.get(endpoint, {
      responseType: 'blob',
    });

    const url = URL.createObjectURL(response.data);
    const link = document.createElement('a');
    link.href = url;
    link.download = filename;
    document.body.appendChild(link);
    link.click();
    document.body.removeChild(link);
    URL.revokeObjectURL(url);
  } catch (error) {
    console.error('Export failed:', error);
    throw error;
  }
}

/**
 * Copies data to clipboard
 */
export async function copyToClipboard(text: string): Promise<boolean> {
  try {
    await navigator.clipboard.writeText(text);
    return true;
  } catch (error) {
    console.error('Failed to copy to clipboard:', error);
    return false;
  }
}

/**
 * Formats date for export filenames
 */
export function getExportFilename(prefix: string, extension: string): string {
  const date = new Date();
  const dateStr = date.toISOString().split('T')[0];
  const timeStr = date.toTimeString().split(' ')[0].replace(/:/g, '-');
  return `${prefix}_${dateStr}_${timeStr}.${extension}`;
}