#if POSTGRES
using MVC_SimpleCRUD_Layered.Data.Data.Postgres;
#else
using MVC_SimpleCRUD_Layered.Data.Data.MSSQL;
#endif
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Options;
using MVC_SimpleCRUD_Layered.Application.Models;
using MVC_SimpleCRUD_Layered.Application.Util.Extensions;
using MVC_SimpleCRUD_Layered.Data.Models;
using Sieve.Models;
using Sieve.Services;

namespace MVC_SimpleCRUD_Layered.Application.People;

public class PeopleService : IPeopleService
{
  private readonly EventsContext ctx;
  private readonly ISieveProcessor sieveProcessor;
  private readonly PagingSettings pagingSettings;

  public PeopleService(EventsContext ctx, IOptionsSnapshot<PagingSettings> pagingSettings, ISieveProcessor sieveProcessor)
  {
    this.ctx = ctx;
    this.sieveProcessor = sieveProcessor;
    this.pagingSettings = pagingSettings.Value;
  }

  public async Task<List<PersonInfo>> GetAllForSimpleListAsync()
  {
    return await ProjectPeople
      .OrderBy(p => p.LastNameTranscription)
      .ToListAsync();
  }

  public async Task<PagedList<PersonInfo>> GetPagedListAsync(PeopleIndexRequest request)
  {
    var page = request.Page < 1 ? 1 : request.Page;
    var pageSize = request.PageSize <= 0 ? pagingSettings.PageSize : request.PageSize;
    var sorts = request.Sorts.NullIfWhiteSpace() ?? nameof(PersonInfo.LastNameTranscription);

    var sieveModel = new SieveModel
    {
      Page = page,
      PageSize = pageSize,
      Sorts = sorts
    };

    var totalCount = await ctx.People.CountAsync();
    var query = ProjectPeople;

    int filteredCount;
    var searchText = request.SearchText.NullIfWhiteSpace();
    if (searchText is not null)
    {
      sieveModel.Filters = $"({nameof(PersonInfo.FirstNameTranscription)}|{nameof(PersonInfo.LastNameTranscription)}|{nameof(PersonInfo.CountryName)})@=*{searchText}";
      filteredCount = await sieveProcessor
        .Apply(sieveModel, query, applyPagination: false, applySorting: false)
        .CountAsync();
    }
    else
    {
      filteredCount = totalCount;
    }

    var pagingInfo = new PagingInfo
    {
      FilteredItemsCount = filteredCount,
      TotalItemsCount = totalCount,
      ItemsPerPage = pageSize,
      CurrentPage = page,
      Sorts = sorts,
      SearchText = searchText
    };

    if (pagingInfo.CurrentPage > pagingInfo.TotalPages)
    {
      pagingInfo.CurrentPage = pagingInfo.TotalPages;
      sieveModel.Page = pagingInfo.CurrentPage;
    }

    var people = filteredCount > 0
      ? await sieveProcessor.Apply(sieveModel, query).ToListAsync()
      : [];

    return new PagedList<PersonInfo>(people, pagingInfo);
  }

  public async Task<PersonForm?> GetFormForEditAsync(int id, PeopleIndexRequest returnRequest)
  {
    var person = await ctx.People.AsNoTracking().FirstOrDefaultAsync(p => p.Id == id);
    return person is null ? null : CreateForm(person, returnRequest);
  }

  public async Task<List<CountryOption>> GetCountryOptionsAsync()
  {
    return await ctx.Countries
      .OrderBy(d => d.Name)
      .Select(d => new CountryOption(d.Code, d.Name))
      .ToListAsync();
  }

  public async Task<SavePersonResult> CreateAsync(PersonForm form)
  {
    var person = new Person();
    CopyToPerson(form, person);
    ctx.People.Add(person);

    try
    {
      await ctx.SaveChangesAsync();
      return SavePersonResult.Ok(GetDisplayName(person));
    }
    catch (DbUpdateException exc)
    {
      return SavePersonResult.Failed(GetErrorMessage(exc));
    }
  }

  public async Task<SavePersonResult> UpdateAsync(int id, PersonForm form)
  {
    var person = await ctx.People.FindAsync(id);
    if (person is null)
    {
      return SavePersonResult.Failed($"Person with id {id} was not found.");
    }

    CopyToPerson(form, person);

    try
    {
      await ctx.SaveChangesAsync();
      return SavePersonResult.Ok(GetDisplayName(person));
    }
    catch (DbUpdateException exc)
    {
      return SavePersonResult.Failed(GetErrorMessage(exc));
    }
  }

  public async Task<DeletePersonResult> DeleteAsync(int id)
  {
    var person = await ctx.People.FindAsync(id);
    if (person is null)
    {
      return DeletePersonResult.NotFound();
    }

    var personName = GetDisplayName(person);
    ctx.People.Remove(person);

    try
    {
      await ctx.SaveChangesAsync();
      return DeletePersonResult.Deleted(personName);
    }
    catch (DbUpdateException exc)
    {
      return DeletePersonResult.Failed(personName, GetErrorMessage(exc));
    }
  }

  private IQueryable<PersonInfo> ProjectPeople => ctx.People
      .Select(p => new PersonInfo
      {
        Id = p.Id,
        FirstName = p.FirstName,
        LastName = p.LastName,
        FirstNameTranscription = p.FirstNameTranscription,
        LastNameTranscription = p.LastNameTranscription,
        BirthDate = p.BirthDate,
        CountryName = p.CountryCodeNavigation.Name,
      });

  private static PersonForm CreateForm(Person person, PeopleIndexRequest returnRequest)
  {
    return new PersonForm
    {
      Id = person.Id,
      FirstName = person.FirstName,
      LastName = person.LastName,
      FirstNameTranscription = person.FirstNameTranscription,
      LastNameTranscription = person.LastNameTranscription,
      AddressLine = person.AddressLine,
      PostalCode = person.PostalCode,
      City = person.City,
      AddressCountry = person.AddressCountry,
      Email = person.Email,
      ContactPhone = person.ContactPhone,
      BirthDate = person.BirthDate,
      DocumentNumber = person.DocumentNumber,
      CountryCode = person.CountryCode,
      Page = returnRequest.Page,
      PageSize = returnRequest.PageSize,
      Sorts = returnRequest.Sorts,
      SearchText = returnRequest.SearchText
    };
  }

  private static void CopyToPerson(PersonForm form, Person person)
  {
    person.FirstName = form.FirstName.NullIfWhiteSpace();
    person.LastName = form.LastName.NullIfWhiteSpace();
    person.FirstNameTranscription = form.FirstNameTranscription;
    person.LastNameTranscription = form.LastNameTranscription;
    person.AddressLine = form.AddressLine.NullIfWhiteSpace();
    person.PostalCode = form.PostalCode.NullIfWhiteSpace();
    person.City = form.City.NullIfWhiteSpace();
    person.AddressCountry = form.AddressCountry.NullIfWhiteSpace();
    person.Email = form.Email.NullIfWhiteSpace();
    person.ContactPhone = form.ContactPhone.NullIfWhiteSpace();
    person.BirthDate = form.BirthDate!.Value;
    person.DocumentNumber = form.DocumentNumber;
    person.CountryCode = form.CountryCode;
  }

  private static string GetDisplayName(Person person) => $"{person.FirstNameTranscription} {person.LastNameTranscription}";

  private static string GetErrorMessage(DbUpdateException exc) => exc.InnerException?.Message ?? exc.Message;
}