using AutoMapper;
using GameIdeas.Shared.Dto;
using GameIdeas.Shared.Exceptions;
using GameIdeas.Shared.Model;
using GameIdeas.WebAPI.Context;
using Microsoft.EntityFrameworkCore;
using System.Threading.Tasks;

namespace GameIdeas.WebAPI.Services.Games;

public class GameWriteService(GameIdeasContext context, IMapper mapper) : IGameWriteService
{
    public async Task<GameDetailDto> CreateGame(GameDetailDto gameDto)
    {
        var gameToCreate = mapper.Map<Game>(gameDto);

        await HandleDeveloperPublisherCreation(gameToCreate);
        await context.Games.AddAsync(gameToCreate);
        await context.SaveChangesAsync();

        await HandlePlatformsCreation(gameDto.Platforms, gameToCreate.Id);
        await HandlePropertiesCreation(gameDto.Properties, gameToCreate.Id);
        await HandleTagsCreation(gameDto.Tags, gameToCreate.Id);

        await context.SaveChangesAsync();

        return mapper.Map<GameDetailDto>(gameToCreate);
    }

    public async Task<GameDetailDto> UpdateGame(GameDetailDto gameDto)
    {
        if (await context.Games.CountAsync(g => g.Id == gameDto.Id) == 0)
        {
            throw new NotFoundException($"[{typeof(Game).FullName}] with ID {gameDto.Id} has not been found in context");
        }

        var gameToUpdate = mapper.Map<Game>(gameDto);

        await HandleDeveloperPublisherCreation(gameToUpdate);
        await HandlePlatformsCreation(gameDto.Platforms, gameToUpdate.Id);
        await HandlePropertiesCreation(gameDto.Properties, gameToUpdate.Id);
        await HandleTagsCreation(gameDto.Tags, gameToUpdate.Id);

        context.Games.Update(gameToUpdate);
        await context.SaveChangesAsync();

        return mapper.Map<GameDetailDto>(gameToUpdate);
    }

    public async Task<bool> DeleteGame(int gameId)
    {
        await HandlePlatformsCreation([], gameId);
        await HandlePropertiesCreation([], gameId);
        await HandleTagsCreation([], gameId);

        var gameToRemove = await context.Games
            .FirstOrDefaultAsync(g => g.Id == gameId)
            ?? throw new NotFoundException($"[{typeof(Game).FullName}] with ID {gameId} has not been found in context");

        context.Games.Remove(gameToRemove);
        await context.SaveChangesAsync();

        context.Publishers.RemoveRange(
            context.Publishers.Include(p => p.Games)
                .Where(p => p.Games.Count == 0));

        context.Developers.RemoveRange(
            context.Developers.Include(d => d.Games)
                .Where(d => d.Games.Count == 0));

        await context.SaveChangesAsync();
        return true;
    }

    private async Task HandlePlatformsCreation(IEnumerable<PlatformDto>? categoriesToCreate, int gameId)
    {
        if (categoriesToCreate != null)
        {
            var gps = mapper.Map<ICollection<GamePlatform>>(categoriesToCreate);

            context.GamePlatforms.RemoveRange(
                context.GamePlatforms.Where(gp => gp.GameId == gameId));

            foreach (var gp in gps)
            {
                gp.GameId = gameId;
            }

            context.Platforms.AttachRange(gps.Select(gp => gp.Platform));
            await context.GamePlatforms.AddRangeAsync(gps);

            await context.SaveChangesAsync();

            context.Platforms.RemoveRange(
                context.Platforms.Include(p => p.GamePlatforms)
                    .Where(p => p.GamePlatforms.Count == 0));

            await context.SaveChangesAsync();
        }
    }

    private async Task HandlePropertiesCreation(IEnumerable<PropertyDto>? categoriesToCreate, int gameId)
    {
        if (categoriesToCreate != null)
        {
            var gps = mapper.Map<ICollection<GameProperty>>(categoriesToCreate);

            context.GameProperties.RemoveRange(
                context.GameProperties.Where(gp => gp.GameId == gameId));

            foreach (var gp in gps)
            {
                gp.GameId = gameId;
            }

            context.Properties.AttachRange(gps.Select(gp => gp.Property));
            await context.GameProperties.AddRangeAsync(gps);

            await context.SaveChangesAsync();

            context.Properties.RemoveRange(
                context.Properties.Include(p => p.GameProperties)
                    .Where(p => p.GameProperties.Count == 0));

            await context.SaveChangesAsync();
        }
    }

    private async Task HandleTagsCreation(IEnumerable<TagDto>? categoriesToCreate, int gameId)
    {
        if (categoriesToCreate != null)
        {
            var gts = mapper.Map<ICollection<GameTag>>(categoriesToCreate);

            context.GameTags.RemoveRange(
                context.GameTags.Where(gt => gt.GameId == gameId));

            foreach (var gt in gts)
            {
                gt.GameId = gameId;
            }

            context.Tags.AttachRange(gts.Select(gt => gt.Tag));
            await context.GameTags.AddRangeAsync(gts);

            await context.SaveChangesAsync();

            context.Tags.RemoveRange(
                context.Tags.Include(t => t.GameTags)
                    .Where(t => t.GameTags.Count == 0));

            await context.SaveChangesAsync();

        }
    }

    private async Task HandleDeveloperPublisherCreation(Game? game)
    {
        context.Publishers.RemoveRange(
            context.Publishers.Include(p => p.Games)
                .Where(p => p.Games.Count == 0));

        context.Developers.RemoveRange(
            context.Developers.Include(d => d.Games)
                .Where(d => d.Games.Count == 0));

        await context.SaveChangesAsync();

        if (game?.Publisher != null)
        {
            context.Publishers.Attach(game.Publisher);
        }

        if (game?.Developer != null)
        {
            context.Developers.Attach(game.Developer);
        }
    }
}