// ReSharper disable MemberCanBePrivate.Global
// ReSharper disable UnusedMember.Global
// ReSharper disable AutoPropertyCanBeMadeGetOnly.Global

using System;
using System.Buffers;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.CompilerServices;

namespace RGB.NET.Core;

/// <inheritdoc cref="AbstractBindable" />
/// <inheritdoc cref="IRGBDevice{TDeviceInfo}" />
/// <summary>
/// Represents a generic RGB-device.
/// </summary>
public abstract class AbstractRGBDevice<TDeviceInfo> : Placeable, IRGBDevice<TDeviceInfo>
    where TDeviceInfo : class, IRGBDeviceInfo
{
    private RGBSurface? _surface;

    #region Properties & Fields

    RGBSurface? IRGBDevice.Surface
    {
        get => _surface;
        set
        {
            if (SetProperty(ref _surface, value))
            {
                if (value == null) OnDetached();
                else OnAttached();
            }
        }
    }

    /// <inheritdoc />
    public TDeviceInfo DeviceInfo { get; }

    /// <inheritdoc />
    IRGBDeviceInfo IRGBDevice.DeviceInfo => DeviceInfo;

    /// <inheritdoc />
    public IList<IColorCorrection> ColorCorrections { get; } = new List<IColorCorrection>();

    /// <summary>
    /// Gets or sets if the device needs to be flushed on every update.
    /// </summary>
    protected bool RequiresFlush { get; set; } = false;

    /// <summary>
    /// Gets a dictionary containing all <see cref="Led"/> of the <see cref="IRGBDevice"/>.
    /// </summary>
    protected Dictionary<LedId, Led> LedMapping { get; } = [];

    /// <summary>
    /// Gets the update queue used to update this device.
    /// </summary>
    protected IUpdateQueue UpdateQueue { get; }

    #region Indexer

    /// <inheritdoc />
    Led? IRGBDevice.this[LedId ledId] => LedMapping.TryGetValue(ledId, out Led? led) ? led : null;

    /// <inheritdoc />
    Led? IRGBDevice.this[Point location] => LedMapping.Values.FirstOrDefault(x => x.Boundary.Contains(location));

    /// <inheritdoc />
    IEnumerable<Led> IRGBDevice.this[Rectangle referenceRect, double minOverlayPercentage]
        => LedMapping.Values.Where(x => referenceRect.CalculateIntersectPercentage(x.Boundary) >= minOverlayPercentage);

    #endregion

    #endregion

    #region Constructors

    /// <summary> 
    /// Initializes a new instance of the <see cref="AbstractRGBDevice{T}"/> class.
    /// </summary>
    /// <param name="deviceInfo">The device info of this device.</param>
    /// <param name="updateQueue">The queue used to update this device.</param>
    protected AbstractRGBDevice(TDeviceInfo deviceInfo, IUpdateQueue updateQueue)
    {
        this.DeviceInfo = deviceInfo;
        this.UpdateQueue = updateQueue;

        UpdateQueue.AddReferencingObject(this);
    }

    #endregion

    #region Methods

    /// <inheritdoc />
    public virtual void Update(bool flushLeds = false)
    {
        // Device-specific updates
        DeviceUpdate();

        // Send LEDs to SDK
        UpdateLeds(GetLedsToUpdate(flushLeds));
    }

    /// <summary>
    /// Gets an enumerable of LEDs that are changed and requires an update.
    /// </summary>
    /// <param name="flushLeds">Forces all LEDs to be treated as dirty.</param>
    /// <returns>The collection LEDs to update.</returns>
    protected virtual IEnumerable<Led> GetLedsToUpdate(bool flushLeds) => ((RequiresFlush || flushLeds || UpdateQueue.RequiresFlush) ? LedMapping.Values : LedMapping.Values.Where(x => x.IsDirty)).Where(led => led.RequestedColor?.A > 0);

    /// <summary>
    /// Gets an enumerable of a custom data and color tuple for the specified leds.
    /// </summary>
    /// <remarks>
    /// Applies all <see cref="ColorCorrections"/>.
    /// if no <see cref="Led.CustomData"/> ist specified the <see cref="Led.Id"/> is used.
    /// </remarks>
    /// <param name="leds">The enumerable of leds to convert.</param>
    /// <returns>The enumerable of custom data and color tuples for the specified leds.</returns>
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    protected (object key, Color color) GetUpdateData(Led led)
    {
        Color color = led.Color;
        object key = led.CustomData ?? led.Id;

        // ReSharper disable once ForCanBeConvertedToForeach - This causes an allocation that's not really needed here
        for (int i = 0; i < ColorCorrections.Count; i++)
            ColorCorrections[i].ApplyTo(ref color);

        return (key, color);
    }

    /// <summary>
    /// Sends all the updated <see cref="Led"/> to the device.
    /// </summary>
    protected virtual void UpdateLeds(IEnumerable<Led> ledsToUpdate)
    {
        (object key, Color color)[] buffer = ArrayPool<(object, Color)>.Shared.Rent(LedMapping.Count);

        int counter = 0;
        foreach (Led led in ledsToUpdate)
        {
            led.Update();

            buffer[counter] = GetUpdateData(led);
            ++counter;
        }

        UpdateQueue.SetData(new ReadOnlySpan<(object, Color)>(buffer)[..counter]);

        ArrayPool<(object, Color)>.Shared.Return(buffer);
    }

    /// <inheritdoc />
    public virtual void Dispose()
    {
        try
        {
            UpdateQueue.RemoveReferencingObject(this);
            if (!UpdateQueue.HasActiveReferences())
                UpdateQueue.Dispose();
        }
        catch { /* :( */ }
        try { LedMapping.Clear(); } catch { /* this really shouldn't happen */ }

        IdGenerator.ResetCounter(GetType().Assembly);

        GC.SuppressFinalize(this);
    }

    /// <summary>
    /// Performs device specific updates.
    /// </summary>
    protected virtual void DeviceUpdate()
    { }

    /// <inheritdoc />
    public virtual Led? AddLed(LedId ledId, Point location, Size size, object? customData = null)
    {
        if ((ledId == LedId.Invalid) || LedMapping.ContainsKey(ledId)) return null;

        Led led = new(this, ledId, location, size, customData ?? GetLedCustomData(ledId));
        LedMapping.Add(ledId, led);
        return led;
    }

    /// <inheritdoc />
    public virtual Led? RemoveLed(LedId ledId)
    {
        if (ledId == LedId.Invalid) return null;
        if (!LedMapping.TryGetValue(ledId, out Led? led)) return null;

        LedMapping.Remove(ledId);
        return led;
    }

    /// <summary>
    /// Gets the custom data associated with the specified LED.
    /// </summary>
    /// <param name="ledId">The id of the led.</param>
    /// <returns>The custom data for the specified LED.</returns>
    protected virtual object? GetLedCustomData(LedId ledId) => null;

    /// <summary>
    /// Called when the device is attached to a surface.
    /// </summary>
    /// <remarks> 
    /// When overriden base should be called to validate boundries.
    /// </remarks>
    protected virtual void OnAttached()
    {
        if (Location == Point.Invalid) Location = new Point(0, 0);
        if (Size == Size.Invalid)
        {
            Rectangle ledRectangle = new(this.Select(x => x.Boundary));
            Size = ledRectangle.Size + new Size(ledRectangle.Location.X, ledRectangle.Location.Y);
        }
    }

    /// <summary>
    /// Called when the device is detached from a surface.
    /// </summary>
    protected virtual void OnDetached() { }

    #region Enumerator

    /// <inheritdoc />
    /// <summary>
    /// Returns an enumerator that iterates over all <see cref="T:RGB.NET.Core.Led" /> of the <see cref="T:RGB.NET.Core.IRGBDevice" />.
    /// </summary>
    /// <returns>An enumerator for all <see cref="T:RGB.NET.Core.Led" /> of the <see cref="T:RGB.NET.Core.IRGBDevice" />.</returns>
    public IEnumerator<Led> GetEnumerator() => LedMapping.Values.GetEnumerator();

    /// <inheritdoc />
    /// <summary>
    /// Returns an enumerator that iterates over all <see cref="T:RGB.NET.Core.Led" /> of the <see cref="T:RGB.NET.Core.IRGBDevice" />.
    /// </summary>
    /// <returns>An enumerator for all <see cref="T:RGB.NET.Core.Led" /> of the <see cref="T:RGB.NET.Core.IRGBDevice" />.</returns>
    IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();

    #endregion

    #endregion
}