using Entity;
using Microsoft.EntityFrameworkCore;
using Shared;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Xml.Linq;

namespace Contextlib
{
    public class DbImagesManager : IImagesService<Images>
    {
        private WTFContext _context;

        public DbImagesManager(WTFContext context)
        {
            _context = context ?? throw new ArgumentNullException(nameof(context), "Database context cannot be null.");
        }

        public async Task AddImage(Images image)
        {
            await _context.AddAsync(image);
            await _context.SaveChangesAsync();
        }

        public async Task<PaginationResult<Images>> GetAllImage()
        {
            var images = await _context.images.ToListAsync();
            return new PaginationResult<Images>(images.Count, 0, images.Count, images);
        }

        public async Task<Images> GetImageById(int id)
        {
            var image = await _context.images.Where(x => x.Id == id).FirstOrDefaultAsync();
            if (image == null)
            {
                throw new KeyNotFoundException($"No image found with the given ID: {id}.");
            }
            return image;
        }

        public async Task<int> GetLastImageId()
        {
            var last = await _context.images.OrderByDescending(x => x.Id).FirstOrDefaultAsync();
            if (last == null)
            {
                return 0;
            }
            return last.Id;
        }

        public async Task<PaginationResult<Images>> GetSomeImage(int index, int pageSize)
        {
            var images = await _context.images.ToListAsync();
            if (!images.Any())
            {
                throw new KeyNotFoundException($"No images found");
            }
            if ((index * pageSize + pageSize) > images.Count)
            {
                if (pageSize > images.Count)
                {
                    return new PaginationResult<Images>(images.Count(), index, pageSize, images);
                }
                else
                {
                    return new PaginationResult<Images>(pageSize, index, pageSize, images.Skip(index * pageSize - (((index * pageSize) + pageSize) - images.Count)).Take(pageSize).ToList());
                }
            }
            return new PaginationResult<Images>(images.Count, index, pageSize, images.Skip(index * pageSize).Take(pageSize).ToList());
        }

        public async Task RemoveImage(int id)
        {
            var image = await _context.images.Where(x => x.Id == id).FirstOrDefaultAsync();
            if (image == null)
            {
                throw new KeyNotFoundException($"No image found with the given ID: {id}.");
            }
            _context.images.Remove(image);
            await _context.SaveChangesAsync();
        }

        public async Task UpdateImage(int id, Images image)
        {
            var modif = false;
            var img = await _context.images.Where(x => x.Id == id).FirstOrDefaultAsync();
            if (image == null) 
            {
                throw new ArgumentNullException(nameof(image), "The updated image data cannot be null.");
            }
            if (img == null)
            {
                throw new KeyNotFoundException($"No image found with the given ID: {id}.");
            }
            if (image.ImgPath != null)
            {
                img.ImgPath = image.ImgPath;
                modif = true;
            }
            if (modif)
            {
                await _context.SaveChangesAsync();
            }
        }
    }
}