using MessengerApi.Configuration.Model;
using MessengerApi.Contracts.Factories;
using Microsoft.EntityFrameworkCore;

namespace MessengerApi.Handlers
{
    public class HousekeepingHandler
    {
        private readonly ILogger logger;
        private readonly MessengerConfiguration configuration;
        private readonly IDbContextFactory dbContextFactory;

        public HousekeepingHandler(
            ILogger logger,
            IDbContextFactory dbContextFactory,
            MessengerConfiguration configuration)
        {
            this.logger = logger;
            this.dbContextFactory = dbContextFactory;
            this.configuration = configuration;
        }

        public async Task RemoveOldMessages()
        {
            this.logger.Trace($"Executing {nameof(this.RemoveOldMessages)}.");

            var timestamp = DateTime.UtcNow;
            var cutoff = timestamp.AddMinutes(-this.configuration.HousekeepingMessageAgeInMinutes);
            using var ctx = this.dbContextFactory.CreateDbContext();
            await ctx.Messages.Where(x => x.CreatedUtc < cutoff).ExecuteDeleteAsync();

            if (this.configuration.HousekeepingMessageState != Configuration.Enums.HousekeepingMessageStates.None)
            {
                this.logger.Trace($"Executing additional message state cleaning in {nameof(this.RemoveOldMessages)}.");

                if (this.configuration.HousekeepingMessageState == Configuration.Enums.HousekeepingMessageStates.Delivered)
                {
                    await ctx.Messages.Where(x => x.IsDelivered).ExecuteDeleteAsync();
                }
                else if (this.configuration.HousekeepingMessageState == Configuration.Enums.HousekeepingMessageStates.Acknowledged)
                {
                    await ctx.Messages.Where(x => x.IsAcknowledged).ExecuteDeleteAsync();
                }
            }
        }
    }
}