using AsbCloudApp.Data;
using AsbCloudApp.Services;
using AsbCloudDb.Model;
using Mapster;
using Microsoft.EntityFrameworkCore;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;

namespace AsbCloudInfrastructure.Services
{
    public class FileService : IFileService
    {
        public string RootPath { get; private set; }
        private readonly IAsbCloudDbContext db;

        public FileService(IAsbCloudDbContext db)
        {
            RootPath = "files";
            this.db = db;
        }

        public IDictionary<string, int> SaveFilesPropertiesToDb(int idWell, int idCategory,
            IEnumerable<(string fileName, int idWell, int idCategory, DateTime date, int idUser)> filesInfo)
        {
            var fileIdsToNames = new Dictionary<string, int>();

            foreach (var fileInfo in filesInfo)
            {
                var file = new FileInfo()
                {
                    Name = fileInfo.fileName,
                    IdWell = fileInfo.idWell,
                    IdCategory = fileInfo.idCategory,
                    UploadDate = fileInfo.date,
                    IdAuthor = fileInfo.idUser
                };

                db.Files.Add(file);
                db.SaveChanges();
                fileIdsToNames.Add(file.Name, file.Id);
            }

            return fileIdsToNames;
        }

        public async Task<PaginationContainer<FileInfoDto>> GetFilesInfoAsync(int idWell,
            int idCategory, DateTime begin = default, DateTime end = default,
            int skip = 0, int take = 32, CancellationToken token = default)
        {
            var query = db.Files
                .Include(f => f.Author)
                .Where(e => e.IdWell == idWell &&
                    e.IdCategory == idCategory);

            query = query.Where(e => !e.IsDeleted);

            if (begin != default)
                query = query.Where(e => e.UploadDate >= begin);

            if (end != default)
                query = query.Where(e => e.UploadDate <= end);

            var count = await query.CountAsync(token).ConfigureAwait(false);

            var result = new PaginationContainer<FileInfoDto>(count) {
                Skip = skip, 
                Take = take,
                Count = count,
            };

            if (count <= skip)
                return result;

            query = query.OrderBy(e => e.UploadDate);

            if (skip > 0)
                query = query.Skip(skip);
            query = query.Take(take);

            var entities = await query
                .Take(take).AsNoTracking().ToListAsync(token)
                .ConfigureAwait(false);

            foreach (var item in entities)
            {
                var filePropertiesDto = item.Adapt<FileInfoDto>();
                filePropertiesDto.AuthorName = item.Author.Name;
                result.Items.Add(filePropertiesDto);
            }

            return result;
        }

        public async Task<FileInfoDto> GetFileInfoAsync(int fileId,
            CancellationToken token = default)
        {
            var entity = await db.Files
                .Include(f => f.Author)
                .AsNoTracking()
                .FirstOrDefaultAsync(f => f.Id == fileId, token)
                .ConfigureAwait(false);

            if (entity is null)
                return null;

            var dto = entity.Adapt<FileInfoDto>();
            dto.AuthorName = entity.Author.Name;
            return dto;
        }
    }
}