/**
 * Date utility functions for formatting and parsing dates
 */

export function formatDateTime(dateString) {
    if (!dateString) return '';
    const date = new Date(dateString);
    const now = new Date();
    const diffMs = now - date;
    const diffDays = Math.floor(diffMs / (1000 * 60 * 60 * 24));

    if (diffDays === 0) {
        return 'Today at ' + date.toLocaleTimeString('en-US', { hour: 'numeric', minute: '2-digit', hour12: true });
    } else if (diffDays === 1) {
        return 'Yesterday at ' + date.toLocaleTimeString('en-US', { hour: 'numeric', minute: '2-digit', hour12: true });
    } else if (diffDays < 7) {
        const dayName = date.toLocaleDateString('en-US', { weekday: 'long' });
        return dayName + ' at ' + date.toLocaleTimeString('en-US', { hour: 'numeric', minute: '2-digit', hour12: true });
    } else {
        return date.toLocaleDateString('en-US', { year: 'numeric', month: 'short', day: 'numeric' });
    }
}

export function formatTimeAgo(dateString) {
    if (!dateString) return '';
    const date = new Date(dateString);
    const now = new Date();
    const diffMs = now - date;
    const diffMins = Math.floor(diffMs / 60000);
    const diffHours = Math.floor(diffMs / 3600000);
    const diffDays = Math.floor(diffMs / 86400000);

    if (diffMins < 1) return 'Just now';
    if (diffMins < 60) return `${diffMins} minute${diffMins > 1 ? 's' : ''} ago`;
    if (diffHours < 24) return `${diffHours} hour${diffHours > 1 ? 's' : ''} ago`;
    if (diffDays < 30) return `${diffDays} day${diffDays > 1 ? 's' : ''} ago`;

    const diffMonths = Math.floor(diffDays / 30);
    if (diffMonths < 12) return `${diffMonths} month${diffMonths > 1 ? 's' : ''} ago`;

    const diffYears = Math.floor(diffDays / 365);
    return `${diffYears} year${diffYears > 1 ? 's' : ''} ago`;
}

export function formatDuration(seconds) {
    if (!seconds || seconds < 0) return '0:00';
    const hrs = Math.floor(seconds / 3600);
    const mins = Math.floor((seconds % 3600) / 60);
    const secs = Math.floor(seconds % 60);

    if (hrs > 0) {
        return `${hrs}:${mins.toString().padStart(2, '0')}:${secs.toString().padStart(2, '0')}`;
    }
    return `${mins}:${secs.toString().padStart(2, '0')}`;
}

export function parseDateRange(preset) {
    const now = new Date();
    const today = new Date(now.getFullYear(), now.getMonth(), now.getDate());

    switch (preset) {
        case 'today':
            return { start: today, end: new Date() };
        case 'yesterday':
            const yesterday = new Date(today);
            yesterday.setDate(yesterday.getDate() - 1);
            return { start: yesterday, end: today };
        case 'week':
            const weekStart = new Date(today);
            weekStart.setDate(weekStart.getDate() - 7);
            return { start: weekStart, end: new Date() };
        case 'month':
            const monthStart = new Date(today);
            monthStart.setMonth(monthStart.getMonth() - 1);
            return { start: monthStart, end: new Date() };
        case 'year':
            const yearStart = new Date(today);
            yearStart.setFullYear(yearStart.getFullYear() - 1);
            return { start: yearStart, end: new Date() };
        default:
            return { start: null, end: null };
    }
}