using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;
using Lagerprogramm.Models;
using Lagerprogramm.Services;

namespace Lagerprogramm.ViewModels;

public partial class PartsViewModel : ObservableObject
{
    private readonly JsonDataService _dataService;
    private readonly AppData _appData;

    [ObservableProperty]
    private ObservableCollection<Part> _parts = new();

    [ObservableProperty]
    [NotifyPropertyChangedFor(nameof(CanSave))]
    private Part? _selectedPart;

    [ObservableProperty]
    [NotifyPropertyChangedFor(nameof(CanSave))]
    [NotifyCanExecuteChangedFor(nameof(SaveCommand))]
    private string _internalPartNumber = string.Empty;

    [ObservableProperty]
    [NotifyPropertyChangedFor(nameof(CanSave))]
    [NotifyCanExecuteChangedFor(nameof(SaveCommand))]
    private string _manufacturerPartNumber = string.Empty;

    [ObservableProperty]
    private string _ean = string.Empty;

    [ObservableProperty]
    private string _supplierPartNumber = string.Empty;

    [ObservableProperty]
    [NotifyPropertyChangedFor(nameof(CanSave))]
    [NotifyCanExecuteChangedFor(nameof(SaveCommand))]
    private string _manufacturer = string.Empty;

    [ObservableProperty]
    private string _supplier = string.Empty;

    [ObservableProperty]
    private string _storageLocation = string.Empty;

    [ObservableProperty]
    private string _storageLocationReserve = string.Empty;

    [ObservableProperty]
    private string _description = string.Empty;

    [ObservableProperty]
    private string _partComment = string.Empty;

    [ObservableProperty]
    [NotifyPropertyChangedFor(nameof(CanSave))]
    [NotifyCanExecuteChangedFor(nameof(SaveCommand))]
    private decimal _purchasePrice;

    [ObservableProperty]
    private decimal _msrp;

    [ObservableProperty]
    private int _stockQuantity;

    public bool CanSave =>
        !string.IsNullOrWhiteSpace(InternalPartNumber)
        && !string.IsNullOrWhiteSpace(ManufacturerPartNumber)
        && !string.IsNullOrWhiteSpace(Manufacturer)
        && PurchasePrice >= 0;

    public PartsViewModel(JsonDataService dataService, AppData appData)
    {
        _dataService = dataService;
        _appData = appData;
        foreach (var p in appData.Parts)
            Parts.Add(p);
    }

    partial void OnSelectedPartChanged(Part? value)
    {
        if (value is null)
        {
            ClearFields();
            return;
        }
        InternalPartNumber = value.InternalPartNumber;
        ManufacturerPartNumber = value.ManufacturerPartNumber;
        Ean = value.Ean;
        SupplierPartNumber = value.SupplierPartNumber;
        Manufacturer = value.Manufacturer;
        Supplier = value.Supplier;
        StorageLocation = value.StorageLocation;
        StorageLocationReserve = value.StorageLocationReserve;
        Description = value.Description;
        PartComment = value.Comment;
        PurchasePrice = value.PurchasePrice;
        Msrp = value.Msrp;
        StockQuantity = value.StockQuantity;
    }

    [RelayCommand(CanExecute = nameof(CanSave))]
    private void Save()
    {
        var existing = _appData.Parts.FirstOrDefault(p => p.InternalPartNumber == InternalPartNumber);
        if (existing is not null)
        {
            existing.ManufacturerPartNumber = ManufacturerPartNumber;
            existing.Ean = Ean;
            existing.SupplierPartNumber = SupplierPartNumber;
            existing.Manufacturer = Manufacturer;
            existing.Supplier = Supplier;
            existing.StorageLocation = StorageLocation;
            existing.StorageLocationReserve = StorageLocationReserve;
            existing.Description = Description;
            existing.Comment = PartComment;
            existing.PurchasePrice = PurchasePrice;
            existing.Msrp = Msrp;
            // StockQuantity not edited here
        }
        else
        {
            var part = new Part
            {
                InternalPartNumber = InternalPartNumber.Trim(),
                ManufacturerPartNumber = ManufacturerPartNumber.Trim(),
                Ean = Ean.Trim(),
                SupplierPartNumber = SupplierPartNumber.Trim(),
                Manufacturer = Manufacturer.Trim(),
                Supplier = Supplier.Trim(),
                StorageLocation = StorageLocation.Trim(),
                StorageLocationReserve = StorageLocationReserve.Trim(),
                Description = Description.Trim(),
                Comment = PartComment.Trim(),
                PurchasePrice = PurchasePrice,
                Msrp = Msrp,
                StockQuantity = 0
            };
            _appData.Parts.Add(part);
            Parts.Add(part);
        }
        _dataService.Save(_appData);
        SelectedPart = null;
        ClearFields();
    }

    [RelayCommand]
    private void NewPart()
    {
        SelectedPart = null;
        ClearFields();
    }

    [RelayCommand]
    private void DeletePart()
    {
        if (SelectedPart is null) return;
        _appData.Parts.Remove(SelectedPart);
        Parts.Remove(SelectedPart);
        _dataService.Save(_appData);
        SelectedPart = null;
    }

    [RelayCommand]
    private void SearchPart()
    {
    }

    private void ClearFields()
    {
        InternalPartNumber = string.Empty;
        ManufacturerPartNumber = string.Empty;
        Ean = string.Empty;
        SupplierPartNumber = string.Empty;
        Manufacturer = string.Empty;
        Supplier = string.Empty;
        StorageLocation = string.Empty;
        StorageLocationReserve = string.Empty;
        Description = string.Empty;
        PartComment = string.Empty;
        PurchasePrice = 0;
        Msrp = 0;
        StockQuantity = 0;
    }
}