using CommunityToolkit.Mvvm.ComponentModel;
using Sms.TaskTwo.Core.Models;
using Sms.TaskTwo.Core.Services;

namespace Sms.TaskTwo.ViewModels;

public sealed partial class EnvironmentVariableRowViewModel : ObservableObject
{
    private readonly EnvironmentVariablesService _service;
    private readonly Action? _onCustomRemoved;
    private bool _isLoading;

    public EnvironmentVariableRowViewModel(
        EnvironmentVariableRow row,
        EnvironmentVariablesService service,
        Action? onCustomRemoved = null)
    {
        Field = row.Field;
        IsFromAppSettings = row.IsFromAppSettings;
        IsCustom = row.IsCustom;
        _service = service;
        _onCustomRemoved = onCustomRemoved;
        ApplySnapshot(row, suppressSave: true);
        RefreshActualValue(_service.GetProcessValue(Field));
    }

    public string Field { get; }

    public bool IsFromAppSettings { get; }

    public bool IsCustom { get; }

    public bool CanChangeUserStore => !IsFromAppSettings;

    [ObservableProperty]
    private bool _useUserStore;

    [ObservableProperty]
    private string _actualValue = string.Empty;

    public string ActualValueDisplay =>
        string.IsNullOrEmpty(ActualValue) ? "<нет>" : ActualValue;

    [ObservableProperty]
    private string _requiredValue = string.Empty;

    [ObservableProperty]
    private string _comment = string.Empty;

    partial void OnUseUserStoreChanged(bool value)
    {
        RowAppearanceChanged?.Invoke(this, EventArgs.Empty);

        if (_isLoading)
        {
            return;
        }

        if (IsFromAppSettings && !value)
        {
            BeginLoad();
            UseUserStore = true;
            EndLoad();
            return;
        }

        if (value)
        {
            _service.SaveValue(Field, RequiredValue);
            RefreshActualValue(_service.GetProcessValue(Field));
            return;
        }

        if (IsCustom)
        {
            _service.RemoveVariable(Field);
            _onCustomRemoved?.Invoke();
            return;
        }

        _service.DeleteFromUserStore(Field);
        BeginLoad();
        RequiredValue = _service.GetDisplayValue(Field);
        EndLoad();
        RefreshActualValue(_service.GetProcessValue(Field));
    }

    partial void OnActualValueChanged(string value) => OnPropertyChanged(nameof(ActualValueDisplay));

    partial void OnRequiredValueChanged(string value)
    {
        if (_isLoading || !UseUserStore)
        {
            return;
        }

        _service.SaveValue(Field, value);
        RefreshActualValue(_service.GetProcessValue(Field));
    }

    public event EventHandler? RowAppearanceChanged;

    public void ApplySnapshot(EnvironmentVariableRow row, bool suppressSave = false)
    {
        if (suppressSave)
        {
            BeginLoad();
        }

        RequiredValue = row.Value;
        Comment = row.Comment;
        UseUserStore = row.IsFromAppSettings || row.IsPersistedInUserStore;

        if (suppressSave)
        {
            EndLoad();
        }
    }

    public void RefreshActualValue(string? processValue)
    {
        ActualValue = processValue ?? string.Empty;
    }

    public void BeginLoad() => _isLoading = true;

    public void EndLoad() => _isLoading = false;

    partial void OnCommentChanged(string value)
    {
        if (_isLoading)
        {
            return;
        }

        _service.SaveComment(Field, value);
    }
}