import { HistoryItem } from '@/components/ComparisonHistory';

export const saveToHistory = (
  item1: string,
  item2: string,
  description1: string,
  description2: string,
  result: string
) => {
  try {
    const historyItem: HistoryItem = {
      id: Date.now().toString(),
      item1,
      item2,
      description1,
      description2,
      result,
      timestamp: Date.now(),
    };

    const existing = localStorage.getItem('comparison-history');
    let history: HistoryItem[] = [];
    
    if (existing) {
      history = JSON.parse(existing);
    }

    // Add new item to the beginning
    history.unshift(historyItem);
    
    // Keep only last 50 items
    history = history.slice(0, 50);

    localStorage.setItem('comparison-history', JSON.stringify(history));
    
    // Dispatch custom event for same-page updates
    window.dispatchEvent(new Event('comparison-history-updated'));
    
    return historyItem;
  } catch (error) {
    console.error('Error saving to history:', error);
    return null;
  }
};

export const getHistory = (): HistoryItem[] => {
  try {
    const stored = localStorage.getItem('comparison-history');
    return stored ? JSON.parse(stored) : [];
  } catch (error) {
    console.error('Error loading history:', error);
    return [];
  }
};