using System.Collections.Generic;
using System.ComponentModel;
using System.Runtime.CompilerServices;

namespace RGB.NET.Core;

/// <inheritdoc />
/// <summary>
/// Represents a basic bindable class which notifies when a property value changes.
/// </summary>
public abstract class AbstractBindable : IBindable
{
    #region Events

    /// <summary>
    /// Occurs when a property value changes.
    /// </summary>
    public event PropertyChangedEventHandler? PropertyChanged;

    #endregion

    #region Methods

    /// <summary>
    /// Checks if the property already matches the desired value or needs to be updated.
    /// </summary>
    /// <typeparam name="T">Type of the property.</typeparam>
    /// <param name="storage">Reference to the backing-filed.</param>
    /// <param name="value">Value to apply.</param>
    /// <returns><c>true</c> if the value needs to be updated; otherwise <c>false</c>.</returns>
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    protected bool RequiresUpdate<T>(ref T storage, T value) => !EqualityComparer<T>.Default.Equals(storage, value);

    /// <summary>
    /// Checks if the property already matches the desired value and updates it if not.
    /// </summary>
    /// <typeparam name="T">Type of the property.</typeparam>
    /// <param name="storage">Reference to the backing-filed.</param>
    /// <param name="value">Value to apply.</param>
    /// <param name="propertyName">Name of the property used to notify listeners. This value is optional 
    /// and can be provided automatically when invoked from compilers that support <see cref="CallerMemberNameAttribute"/>.</param>
    /// <returns><c>true</c> if the value was changed, <c>false</c> if the existing value matched the desired value.</returns>
    protected bool SetProperty<T>(ref T storage, T value, [CallerMemberName] string? propertyName = null)
    {
        if (!RequiresUpdate(ref storage, value)) return false;

        storage = value;
        // ReSharper disable once ExplicitCallerInfoArgument
        OnPropertyChanged(propertyName);
        return true;
    }

    /// <summary>
    /// Triggers the <see cref="PropertyChanged"/>-event when a a property value has changed.
    /// </summary>
    /// <param name="propertyName">Name of the property used to notify listeners. This value is optional 
    /// and can be provided automatically when invoked from compilers that support <see cref="CallerMemberNameAttribute"/>.</param>
    protected void OnPropertyChanged([CallerMemberName] string? propertyName = null)
        => PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));

    #endregion
}