using System.Collections.Concurrent;
using Pf2eModel;
using Pf2eModel.Model.Base;
using Pf2eModel.Model.Enum;

namespace Pf2eViewer.DatabaseViewer;

internal class DatabaseQueryPerformer
{
    public required EntityType Type;

    public required int Page;

    public required int PerPage;

    public required string Search = "";

    private readonly Thread _queryThread;

    public DatabaseQueryPerformer()
    {
        _queryThread = new(PerformQuery);
    }

    public void Query()
    {
        _queryThread.Start();
    }

    public void Abort()
    {
        _queryThread.Interrupt();
    }

    private void PerformQuery()
    {
        try
        {
            Pf2eDbContext dbContext = new();

            IQueryable<Entity> query =
                Search == ""
                    ? dbContext.Entities.Where(e => e.Type == Type)
                    :
                    // ReSharper disable once EntityFramework.UnsupportedServerSideFunctionCall
                    dbContext.Entities.Where(e =>
                        e.Type == Type && Pf2eDbContext.LocaleSearch(e.Name, Search)
                    );

            int count = query.Count();

            List<Entity> entities = query
                .OrderBy(e => e.Id)
                .Skip((Page - 1) * PerPage)
                .Take(PerPage)
                .ToList();

            DatabaseQueryResult result = new(count, entities);

            OnQueryCompleted?.Invoke(this, result);
        }
        catch (ThreadInterruptedException)
        {
            // Ignore
        }
    }

    public delegate void DatabaseQueryPerformerDelegate(
        DatabaseQueryPerformer sender,
        DatabaseQueryResult result
    );
    public event DatabaseQueryPerformerDelegate? OnQueryCompleted;
}

internal class DatabaseQueryResult(int count, ICollection<Entity> entities)
{
    public int Count { get; } = count;

    public ConcurrentBag<Entity> Entities { get; } = new(entities);
}