using AutoMapper;
using SmallSoftwareContracts.DataModels;
using SmallSoftwareContracts.Exceptions;
using SmallSoftwareContracts.StoragesContracts;
using SmallSoftwareDatabase.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace SmallSoftwareDatabase.Implementations;

internal class WorkerStorageContract : IWorkerStorageContract
{
    private readonly SmallSoftwareDbContext _dbContext;
    private readonly Mapper _mapper;
    public WorkerStorageContract(SmallSoftwareDbContext dbContext)
    {
        _dbContext = dbContext;
        var config = new MapperConfiguration(cfg =>
        {
            cfg.CreateMap<Post, PostDataModel>() 
        .ForMember(x => x.Id, x => x.MapFrom(src =>
        src.PostId));
            cfg.CreateMap<Worker, WorkerDataModel>();
            cfg.CreateMap<WorkerDataModel, Worker>()
            .ForMember(x => x.Post, x => x.Ignore());
        });
        _mapper = new Mapper(config);
    }
    public List<WorkerDataModel> GetList(bool onlyActive = true, string? postId
    = null, DateTime? fromBirthDate = null, DateTime? toBirthDate = null, DateTime?
    fromEmploymentDate = null, DateTime? toEmploymentDate = null)
    {
        try
        {
            var query = _dbContext.Workers.AsQueryable();
            if (onlyActive)
            {
                query = query.Where(x => !x.IsDeleted);
            }
            if (postId is not null)
            {
                query = query.Where(x => x.PostId == postId);
            }
            if (fromBirthDate is not null && toBirthDate is not null)
            {
                query = query.Where(x => x.BirthDate >= fromBirthDate &&
                x.BirthDate <= toBirthDate);
            }
            if (fromEmploymentDate is not null && toEmploymentDate is not
            null)
            {
                query = query.Where(x => x.EmploymentDate >=
                fromEmploymentDate && x.EmploymentDate <= toEmploymentDate);
            }
            return [.. JoinPost(query).Select(x => _mapper.Map<WorkerDataModel>(x))];
        }
        catch (Exception ex)
        {
            _dbContext.ChangeTracker.Clear();
            throw new StorageException(ex);
        }
    }
    public WorkerDataModel? GetElementById(string id)
    {
        try
        {
            return _mapper.Map<WorkerDataModel>(GetWorkerById(id));
        }
        catch (Exception ex)
        {
            _dbContext.ChangeTracker.Clear();
            throw new StorageException(ex);
        }
    }
    public WorkerDataModel? GetElementByFIO(string fio)
    {
        try
        { 
        return
        _mapper.Map<WorkerDataModel>(AddPost(_dbContext.Workers.FirstOrDefault(x => x.FIO == fio && !x.IsDeleted)));
        }
        catch (Exception ex)
        {
            _dbContext.ChangeTracker.Clear();
            throw new StorageException(ex);
        }
    }
    public void AddElement(WorkerDataModel workerDataModel)
    {
        try
        {
            _dbContext.Workers.Add(_mapper.Map<Worker>(workerDataModel));
            _dbContext.SaveChanges();
        }
        catch (InvalidOperationException ex) when (ex.TargetSite?.Name == "ThrowIdentityConflict")
        {
            _dbContext.ChangeTracker.Clear();
            throw new ElementExistsException("Id", workerDataModel.Id);
        }
        catch (Exception ex)
        {
            _dbContext.ChangeTracker.Clear();
            throw new StorageException(ex);
        }
    }
    public void UpdElement(WorkerDataModel workerDataModel)
    {
        try
        {
            var element = GetWorkerById(workerDataModel.Id) ?? throw new
            ElementNotFoundException(workerDataModel.Id);
            _dbContext.Workers.Update(_mapper.Map(workerDataModel,
            element));
            _dbContext.SaveChanges();
        }
        catch (ElementNotFoundException)
        {
            _dbContext.ChangeTracker.Clear();
            throw;
        }
        catch (Exception ex)
        {
            _dbContext.ChangeTracker.Clear();
            throw new StorageException(ex);
        }
    }
    public void DelElement(string id)
    {
        try
        {
            var element = GetWorkerById(id) ?? throw new
            ElementNotFoundException(id);
            element.IsDeleted = true;
            _dbContext.SaveChanges();
        }
        catch (ElementNotFoundException)
        { 
        _dbContext.ChangeTracker.Clear();
            throw;
        }
        catch (Exception ex)
        {
            _dbContext.ChangeTracker.Clear();
            throw new StorageException(ex);
        }
    }
    private Worker? GetWorkerById(string id) =>
    AddPost(_dbContext.Workers.FirstOrDefault(x => x.Id == id && !x.IsDeleted));
    private IQueryable<Worker> JoinPost(IQueryable<Worker> query)
    => query.GroupJoin(_dbContext.Posts.Where(x => x.IsActual), x =>
    x.PostId, y => y.PostId, (x, y) => new { Worker = x, Post = y })
    .SelectMany(xy => xy.Post.DefaultIfEmpty(), (x, y) =>
    x.Worker.AddPost(y));
    private Worker? AddPost(Worker? worker)
    => worker?.AddPost(_dbContext.Posts.FirstOrDefault(x => x.PostId ==
    worker.PostId && x.IsActual));
}