using DysonNetwork.Sphere.Account;
using Microsoft.EntityFrameworkCore;
using NodaTime;

namespace DysonNetwork.Sphere.Post;

public class PublisherSubscriptionService(AppDatabase db, NotificationService nty)
{
    /// <summary>
    /// Checks if a subscription exists between the account and publisher
    /// </summary>
    /// <param name="accountId">The account ID</param>
    /// <param name="publisherId">The publisher ID</param>
    /// <returns>True if a subscription exists, false otherwise</returns>
    public async Task<bool> SubscriptionExistsAsync(long accountId, long publisherId)
    {
        return await db.PublisherSubscriptions
            .AnyAsync(ps => ps.AccountId == accountId &&
                            ps.PublisherId == publisherId &&
                            ps.Status == SubscriptionStatus.Active);
    }

    /// <summary>
    /// Gets a subscription by account and publisher ID
    /// </summary>
    /// <param name="accountId">The account ID</param>
    /// <param name="publisherId">The publisher ID</param>
    /// <returns>The subscription or null if not found</returns>
    public async Task<PublisherSubscription?> GetSubscriptionAsync(long accountId, long publisherId)
    {
        return await db.PublisherSubscriptions
            .Include(ps => ps.Publisher)
            .FirstOrDefaultAsync(ps => ps.AccountId == accountId && ps.PublisherId == publisherId);
    }

    /// <summary>
    /// Notifies all subscribers about a new post from a publisher
    /// </summary>
    /// <param name="post">The new post</param>
    /// <returns>The number of subscribers notified</returns>
    public async Task<int> NotifySubscribersPostAsync(Post post)
    {
        var subscribers = await db.PublisherSubscriptions
            .Include(ps => ps.Account)
            .Where(ps => ps.PublisherId == post.Publisher.Id &&
                         ps.Status == SubscriptionStatus.Active)
            .ToListAsync();
        if (subscribers.Count == 0)
            return 0;

        // Create notification data
        var title = $"@{post.Publisher.Name} Posted";
        var message = !string.IsNullOrEmpty(post.Title)
            ? post.Title
            : (post.Content?.Length > 100
                ? string.Concat(post.Content.AsSpan(0, 97), "...")
                : post.Content);

        // Data to include with the notification
        var data = new Dictionary<string, object>
        {
            { "post_id", post.Id.ToString() },
            { "publisher_id", post.Publisher.Id.ToString() }
        };

        // Notify each subscriber
        var notifiedCount = 0;
        foreach (var subscription in subscribers)
        {
            try
            {
                await nty.SendNotification(
                    subscription.Account,
                    "posts.new",
                    title,
                    post.Description?.Length > 40 ? post.Description[..37] + "..." : post.Description,
                    message,
                    data
                );

                notifiedCount++;
            }
            catch (Exception)
            {
                // Log the error but continue with other notifications
                // We don't want one failed notification to stop the others
            }
        }

        return notifiedCount;
    }

    /// <summary>
    /// Gets all active subscriptions for an account
    /// </summary>
    /// <param name="accountId">The account ID</param>
    /// <returns>A list of active subscriptions</returns>
    public async Task<List<PublisherSubscription>> GetAccountSubscriptionsAsync(long accountId)
    {
        return await db.PublisherSubscriptions
            .Include(ps => ps.Publisher)
            .Where(ps => ps.AccountId == accountId && ps.Status == SubscriptionStatus.Active)
            .ToListAsync();
    }

    /// <summary>
    /// Gets all active subscribers for a publisher
    /// </summary>
    /// <param name="publisherId">The publisher ID</param>
    /// <returns>A list of active subscriptions</returns>
    public async Task<List<PublisherSubscription>> GetPublisherSubscribersAsync(long publisherId)
    {
        return await db.PublisherSubscriptions
            .Include(ps => ps.Account)
            .Where(ps => ps.PublisherId == publisherId && ps.Status == SubscriptionStatus.Active)
            .ToListAsync();
    }

    /// <summary>
    /// Creates a new subscription between an account and a publisher
    /// </summary>
    /// <param name="accountId">The account ID</param>
    /// <param name="publisherId">The publisher ID</param>
    /// <param name="tier">Optional subscription tier</param>
    /// <returns>The created subscription</returns>
    public async Task<PublisherSubscription> CreateSubscriptionAsync(
        long accountId,
        long publisherId,
        int tier = 0
    )
    {
        // Check if a subscription already exists
        var existingSubscription = await GetSubscriptionAsync(accountId, publisherId);

        if (existingSubscription != null)
        {
            // If it exists but is not active, reactivate it
            if (existingSubscription.Status == SubscriptionStatus.Active) return existingSubscription;
            existingSubscription.Status = SubscriptionStatus.Active;
            existingSubscription.Tier = tier;

            await db.SaveChangesAsync();
            return existingSubscription;

            // If it's already active, just return it
        }

        // Create a new subscription
        var subscription = new PublisherSubscription
        {
            AccountId = accountId,
            PublisherId = publisherId,
            Status = SubscriptionStatus.Active,
            Tier = tier,
        };

        db.PublisherSubscriptions.Add(subscription);
        await db.SaveChangesAsync();

        return subscription;
    }

    /// <summary>
    /// Cancels a subscription
    /// </summary>
    /// <param name="accountId">The account ID</param>
    /// <param name="publisherId">The publisher ID</param>
    /// <returns>True if the subscription was cancelled, false if it wasn't found</returns>
    public async Task<bool> CancelSubscriptionAsync(long accountId, long publisherId)
    {
        var subscription = await GetSubscriptionAsync(accountId, publisherId);
        if (subscription is not { Status: SubscriptionStatus.Active })
        {
            return false;
        }

        subscription.Status = SubscriptionStatus.Cancelled;
        await db.SaveChangesAsync();
        return true;
    }
}