using LiteCqrs;
using Microsoft.EntityFrameworkCore;
using TeleWave.Application.Common.Interfaces;
using TeleWave.Application.Common.Models;

namespace TeleWave.Application.Broadcast.AddChannelAd;

public sealed class AddChannelAdCommandHandler(IAppDbContext dbContext)
    : ICommandHandler<AddChannelAdCommand, Result<Guid>>
{
    public async Task<Result<Guid>> Handle(
        AddChannelAdCommand command,
        CancellationToken cancellationToken
    )
    {
        var channel = await dbContext
            .Channels.Include(c => c.Ads)
            .FirstOrDefaultAsync(c => c.Id == command.ChannelId, cancellationToken);
        if (channel is null)
            return Result.Failure<Guid>(ChannelErrors.NotFound);

        var assetExists = await dbContext.MediaAssets.AnyAsync(
            a => a.Id == command.MediaAssetId,
            cancellationToken
        );
        if (!assetExists)
            return Result.Failure<Guid>(ChannelErrors.AssetNotFound);

        if (channel.HasAd(command.MediaAssetId))
            return Result.Failure<Guid>(ChannelErrors.AdAlreadyAdded);

        var ad = channel.AddAd(command.MediaAssetId);
        return Result.Success(ad.Id);
    }
}