using System;
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 AdditionsViewModel : ObservableObject
{
    private readonly JsonDataService _dataService;
    private readonly AppData _appData;

    public AppData AppData => _appData;

    [ObservableProperty]
    private ObservableCollection<Addition> _additions = new();

    [ObservableProperty]
    private ObservableCollection<TransactionLine> _lines = new();

    [ObservableProperty]
    private DateTime _date = DateTime.Now;

    [ObservableProperty]
    private string _comment = string.Empty;

    public ObservableCollection<string> PartNumbers { get; } = new();

    public AdditionsViewModel(JsonDataService dataService, AppData appData)
    {
        _dataService = dataService;
        _appData = appData;
        RefreshPartNumbers();
        foreach (var a in appData.Additions.OrderByDescending(a => a.Date))
            Additions.Add(a);
        Lines.Add(new TransactionLine());
    }

    [RelayCommand]
    private void AddLine() => Lines.Add(new TransactionLine());

    [RelayCommand]
    private void RemoveLine(TransactionLine? line)
    {
        if (line is null) return;
        Lines.Remove(line);
    }

    [RelayCommand]
    private void SearchPart(TransactionLine? line)
    {
    }

    [RelayCommand]
    private void SearchAddition()
    {
    }

    [RelayCommand]
    private void Save()
    {
        if (Lines.Count == 0) return;
        if (Lines.Any(l => string.IsNullOrWhiteSpace(l.PartInternalNumber) || l.Quantity <= 0))
            return;

        var addition = new Addition
        {
            Date = Date,
            Comment = Comment.Trim(),
            Lines = Lines.Select(l => new TransactionLine
            {
                PartInternalNumber = l.PartInternalNumber.Trim(),
                Quantity = l.Quantity
            }).ToList()
        };
        _appData.Additions.Add(addition);
        Additions.Insert(0, addition);

        foreach (var line in addition.Lines)
        {
            var part = _appData.Parts.FirstOrDefault(p => p.InternalPartNumber == line.PartInternalNumber);
            if (part is not null)
                part.StockQuantity += line.Quantity;
        }

        _dataService.Save(_appData);
        Comment = string.Empty;
        Date = DateTime.Now;
        Lines.Clear();
        Lines.Add(new TransactionLine());
        RefreshPartNumbers();
    }

    [RelayCommand]
    private void DeleteAddition(Addition? addition)
    {
        if (addition is null) return;
        foreach (var line in addition.Lines)
        {
            var part = _appData.Parts.FirstOrDefault(p => p.InternalPartNumber == line.PartInternalNumber);
            if (part is not null)
                part.StockQuantity -= line.Quantity;
        }
        _appData.Additions.Remove(addition);
        Additions.Remove(addition);
        _dataService.Save(_appData);
        RefreshPartNumbers();
    }

    private void RefreshPartNumbers()
    {
        PartNumbers.Clear();
        foreach (var p in _appData.Parts.OrderBy(p => p.InternalPartNumber))
            PartNumbers.Add(p.InternalPartNumber);
    }
}