using AutoMapper;
using MagicCarpetContracts.DataModels;
using MagicCarpetContracts.Exceptions;
using MagicCarpetContracts.Mapper;
using MagicCarpetContracts.Resources;
using MagicCarpetContracts.StoragesContracts;
using MagicCarpetDatabase.Models;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Localization;
using Npgsql;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace MagicCarpetDatabase.Implementations;

internal class EmployeeStorageContract(MagicCarpetDbContext dbContext, IStringLocalizer<Messages> localizer) : IEmployeeStorageContract
{
    private readonly MagicCarpetDbContext _dbContext = dbContext;
    private readonly IStringLocalizer<Messages> _localizer = localizer;

    public List<EmployeeDataModel> GetList(bool onlyActive = true, string? postId = null, DateTime? fromBirthDate = null, DateTime? toBirthDate = null, DateTime? fromEmploymentDate = null, DateTime? toEmploymentDate = null)
    {
        try
        {
            var query = _dbContext.Employees.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 >= DateTime.SpecifyKind(fromBirthDate ?? DateTime.UtcNow, DateTimeKind.Utc) && x.BirthDate <= DateTime.SpecifyKind(toBirthDate ?? DateTime.UtcNow, DateTimeKind.Utc));
            }
            if (fromEmploymentDate is not null && toEmploymentDate is not null)
            {
                query = query.Where(x => x.EmploymentDate >= DateTime.SpecifyKind(fromEmploymentDate ?? DateTime.UtcNow, DateTimeKind.Utc) && x.EmploymentDate <= DateTime.SpecifyKind(toEmploymentDate ?? DateTime.UtcNow, DateTimeKind.Utc));
            }
            return [.. JoinPost(query).Select(x => CustomMapper.MapObject<EmployeeDataModel>(x))];
        }
        catch (Exception ex)
        {
            _dbContext.ChangeTracker.Clear();
            throw new StorageException(ex, _localizer);
        }
    }

    public EmployeeDataModel? GetElementById(string id)
    {
        try
        {
            return CustomMapper.MapObjectWithNull<EmployeeDataModel>(GetEmployeeById(id));
        }
        catch (Exception ex)
        {
            _dbContext.ChangeTracker.Clear();
            throw new StorageException(ex, _localizer);
        }
    }

    public EmployeeDataModel? GetElementByFIO(string fio)
    {
        try
        {
            return CustomMapper.MapObjectWithNull<EmployeeDataModel>(AddPost(_dbContext.Employees.FirstOrDefault(x => x.FIO == fio && !x.IsDeleted)));
        }
        catch (Exception ex)
        {
            _dbContext.ChangeTracker.Clear();
            throw new StorageException(ex, _localizer);
        }
    }

    public EmployeeDataModel? GetElementByEmail(string email)
    {
        try
        {
            return CustomMapper.MapObjectWithNull<EmployeeDataModel>(AddPost(_dbContext.Employees.FirstOrDefault(x => x.Email == email && !x.IsDeleted)));
        }
        catch (Exception ex)
        {
            _dbContext.ChangeTracker.Clear();
            throw new StorageException(ex, _localizer);
        }
    }

    public void AddElement(EmployeeDataModel employeeDataModel)
    {
        try
        {
            _dbContext.Employees.Add(CustomMapper.MapObject<Employee>(employeeDataModel));
            _dbContext.SaveChanges();
        }
        catch (InvalidOperationException ex) when (ex.TargetSite?.Name == "ThrowIdentityConflict")
        {
            _dbContext.ChangeTracker.Clear();
            throw new ElementExistsException("Id", employeeDataModel.Id, _localizer);
        }
        catch (DbUpdateException ex) when (ex.InnerException is PostgresException { ConstraintName: "PK_Employees" })
        {
            _dbContext.ChangeTracker.Clear();
            throw new ElementExistsException("Id", employeeDataModel.Id, _localizer);
        }
        catch (Exception ex)
        {
            _dbContext.ChangeTracker.Clear();
            throw new StorageException(ex, _localizer);
        }
    }

    public void UpdElement(EmployeeDataModel employeeDataModel)
    {
        try
        {
            var element = GetEmployeeById(employeeDataModel.Id) ?? throw new ElementNotFoundException(employeeDataModel.Id, _localizer);
            _dbContext.Employees.Update(CustomMapper.MapObject(employeeDataModel, element));
            _dbContext.SaveChanges();
        }
        catch (ElementNotFoundException)
        {
            _dbContext.ChangeTracker.Clear();
            throw;
        }
        catch (Exception ex)
        {
            _dbContext.ChangeTracker.Clear();
            throw new StorageException(ex, _localizer);
        }
    }

    public void DelElement(string id)
    {
        try
        {
            var element = GetEmployeeById(id) ?? throw new ElementNotFoundException(id, _localizer);
            element.IsDeleted = true;
            _dbContext.SaveChanges();
        }
        catch (ElementNotFoundException)
        {
            _dbContext.ChangeTracker.Clear();
            throw;
        }
        catch (Exception ex)
        {
            _dbContext.ChangeTracker.Clear();
            throw new StorageException(ex, _localizer);
        }
    }

    public int GetEmployeeTrend(DateTime fromPeriod, DateTime toPeriod)
    {
        try
        {
            var countWorkersOnBegining = _dbContext.Employees.Count(x => x.EmploymentDate < fromPeriod && (!x.IsDeleted || x.DateOfDelete > fromPeriod));
            var countWorkersOnEnding = _dbContext.Employees.Count(x => x.EmploymentDate < toPeriod && (!x.IsDeleted || x.DateOfDelete > toPeriod));
            return countWorkersOnEnding - countWorkersOnBegining;
        }
        catch (Exception ex)
        {
            _dbContext.ChangeTracker.Clear();
            throw new StorageException(ex, _localizer);
        }
    }

    private Employee? GetEmployeeById(string id) => AddPost(_dbContext.Employees.FirstOrDefault(x => x.Id == id && !x.IsDeleted));

    private IQueryable<Employee> JoinPost(IQueryable<Employee> query)
        => query.GroupJoin(_dbContext.Posts.Where(x => x.IsActual), x => x.PostId, y => y.PostId, (x, y) => new { Employee = x, Post = y })
                .SelectMany(xy => xy.Post.DefaultIfEmpty(), (x, y) => x.Employee.AddPost(y));

    private Employee? AddPost(Employee? employee)
        => employee == null ? null : employee.AddPost(_dbContext.Posts.FirstOrDefault(x => x.PostId == employee.PostId && x.IsActual));
}