import { useState, useEffect } from 'react';

export default function ActivityLog({ collectionId }) {
  const [activities, setActivities] = useState([]);
  const [loading, setLoading] = useState(true);
  const [showAll, setShowAll] = useState(false);

  useEffect(() => {
    if (collectionId) {
      fetchActivities();
    }
  }, [collectionId]);

  const fetchActivities = async () => {
    try {
      const response = await fetch(`/api/collections/${collectionId}/activity`);
      if (response.ok) {
        const data = await response.json();
        setActivities(data);
      }
    } catch (error) {
      console.error('Error fetching activities:', error);
    } finally {
      setLoading(false);
    }
  };

  const getActivityIcon = (action) => {
    switch (action) {
      case 'card_added': return '➕';
      case 'card_removed': return '➖';
      case 'card_quantity_updated': return '��';
      case 'collection_updated': return '✏️';
      case 'collection_deleted': return '🗑️';
      case 'user_invited': return '📧';
      case 'invitation_accepted': return '✅';
      case 'invitation_declined': return '❌';
      case 'permission_updated': return '🔐';
      case 'user_removed': return '👋';
      default: return '📝';
    }
  };

  const getActivityDescription = (activity) => {
    const { action, details } = activity;
    
    switch (action) {
      case 'card_added':
        return `added a card (qty: ${details.quantity})`;
      case 'card_removed':
        return details.reason === 'quantity_zero' 
          ? 'removed a card by setting quantity to 0'
          : 'removed a card from the collection';
      case 'card_quantity_updated':
        return details.oldQuantity 
          ? `updated card quantity from ${details.oldQuantity} to ${details.newQuantity}`
          : `updated card quantity to ${details.newQuantity}`;
      case 'collection_updated':
        return 'updated collection details';
      case 'collection_deleted':
        return 'deleted the collection';
      case 'user_invited':
        return `invited ${details.email} as ${details.role}`;
      case 'invitation_accepted':
        return 'accepted an invitation';
      case 'invitation_declined':
        return 'declined an invitation';
      case 'permission_updated':
        return `updated user permissions to ${details.role}`;
      case 'user_removed':
        return 'removed a user from the collection';
      default:
        return action.replace(/_/g, ' ');
    }
  };

  const formatTimeAgo = (timestamp) => {
    const now = new Date();
    const activityTime = new Date(timestamp);
    const diffMs = now - activityTime;
    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 `${diffMins}m ago`;
    if (diffHours < 24) return `${diffHours}h ago`;
    if (diffDays < 7) return `${diffDays}d ago`;
    return activityTime.toLocaleDateString();
  };

  if (loading) {
    return (
      <div className="p-6 rounded-xl" style={{ backgroundColor: 'var(--bg-secondary)' }}>
        <div className="animate-pulse">
          <div className="h-4 bg-gray-300 rounded w-1/4 mb-4"></div>
          <div className="space-y-3">
            <div className="h-8 bg-gray-300 rounded"></div>
            <div className="h-8 bg-gray-300 rounded"></div>
            <div className="h-8 bg-gray-300 rounded"></div>
          </div>
        </div>
      </div>
    );
  }

  const displayedActivities = showAll ? activities : activities.slice(0, 5);

  return (
    <div className="p-6 rounded-xl" style={{ backgroundColor: 'var(--bg-secondary)' }}>
      <div className="flex items-center justify-between mb-6">
        <h3 className="text-xl font-bold" style={{ color: 'var(--text-primary)' }}>
          Recent Activity
        </h3>
        {activities.length > 5 && (
          <button
            onClick={() => setShowAll(!showAll)}
            className="text-sm font-medium hover:underline"
            style={{ color: 'var(--text-accent)' }}
          >
            {showAll ? 'Show Less' : `View All (${activities.length})`}
          </button>
        )}
      </div>

      <div className="space-y-3">
        {displayedActivities.map((activity) => (
          <div 
            key={activity.id}
            className="flex items-start space-x-3 p-3 rounded-lg"
            style={{ backgroundColor: 'var(--bg-primary)' }}
          >
            <div className="text-lg mt-0.5">
              {getActivityIcon(activity.action)}
            </div>
            <div className="flex-1 min-w-0">
              <div className="flex items-center justify-between">
                <p className="text-sm" style={{ color: 'var(--text-primary)' }}>
                  <span className="font-medium">{activity.user_email || 'System'}</span>
                  {' '}
                  <span>{getActivityDescription(activity)}</span>
                </p>
                <span className="text-xs whitespace-nowrap ml-2" style={{ color: 'var(--text-secondary)' }}>
                  {formatTimeAgo(activity.created_at)}
                </span>
              </div>
              {activity.details && Object.keys(activity.details).length > 0 && (
                <div className="mt-1 text-xs" style={{ color: 'var(--text-secondary)' }}>
                  {activity.action === 'collection_updated' && activity.details.name && (
                    <span>Name: "{activity.details.name}"</span>
                  )}
                  {activity.action === 'user_invited' && activity.details.message && (
                    <span>Message: "{activity.details.message}"</span>
                  )}
                </div>
              )}
            </div>
          </div>
        ))}

        {activities.length === 0 && (
          <div className="text-center py-8">
            <div className="text-4xl mb-4">📝</div>
            <p style={{ color: 'var(--text-secondary)' }}>
              No activity yet. Start collaborating to see updates here!
            </p>
          </div>
        )}
      </div>
    </div>
  );
}