//********************************** Banshee Engine (www.banshee3d.com) **************************************************//
//**************** Copyright (c) 2016 Marko Pintera (marko.pintera@gmail.com). All rights reserved. **********************//
using System;
using System.Runtime.CompilerServices;
using bs;

namespace bs.Editor
{
    /** @addtogroup GUI-Editor 
     *  @{
     */

    /// <summary>
    /// Editor GUI element that displays a color and an optional label. Allows the user to select a color using the color 
    /// picker.
    /// </summary>
    public sealed class GUIColorField : GUIElement
    {
        public delegate void OnChangedDelegate(Color newValue);

        /// <summary>
        /// Triggered when the color in the field changes.
        /// </summary>
        public event OnChangedDelegate OnChanged;

        /// <summary>
        /// Color displayed by the field.
        /// </summary>
        public Color Value
        {
            get
            {
                Color value;
                Internal_GetValue(mCachedPtr, out value);
                return value;
            }

            set { Internal_SetValue(mCachedPtr, ref value); }
        }

        /// <summary>
        /// Creates a new color field element with a label.
        /// </summary>
        /// <param name="title">Content to display on the label.</param>
        /// <param name="titleWidth">Width of the title label in pixels.</param>
        /// <param name="style">Optional style to use for the element. Style controls the look of the element, as well as 
        ///                     default layout options. Style will be retrieved from the active GUISkin. If not specified 
        ///                     default element style is used.</param>
        /// <param name="options">Options that allow you to control how is the element  positioned and sized. This will 
        ///                       override any similar options set by style.</param>
        public GUIColorField(GUIContent title, int titleWidth = 100, string style = "", params GUIOption[] options)
        {
            Internal_CreateInstance(this, ref title, titleWidth, style, options, true);
        }

        /// <summary>
        /// Creates a new color field element without a label.
        /// </summary>
        /// <param name="style">Optional style to use for the element. Style controls the look of the element, as well as 
        ///                     default layout options. Style will be retrieved from the active GUISkin. If not specified 
        ///                     default element style is used.</param>
        /// <param name="options">Options that allow you to control how is the element  positioned and sized. This will 
        ///                       override any similar options set by style.</param>
        public GUIColorField(string style = "", params GUIOption[] options)
        {
            GUIContent emptyContent = new GUIContent();
            Internal_CreateInstance(this, ref emptyContent, 0, style, options, false);
        }

        /// <summary>
        /// Colors the element with a specific tint.
        /// </summary>
        /// <param name="color">Tint to apply to the element.</param>
        public void SetTint(Color color)
        {
            Internal_SetTint(mCachedPtr, ref color);
        }

        /// <summary>
        /// Triggered when the user closes the color picker window.
        /// </summary>
        /// <param name="selected">True if the user confirms color selection, false if he cancels.</param>
        /// <param name="color">Newly selected color.</param>
        private void ColorPickerClosed(bool selected, Color color)
        {
            if (!selected)
                return;

            if (Value != color)
            {
                Value = color;
                OnChanged?.Invoke(color);
            }
        }

        /// <summary>
        /// Triggered by the runtime when the user clicks on the color field.
        /// </summary>
        private void Internal_DoOnClicked()
        {
            ColorPicker.Show(Value, ColorPickerClosed);
        }

        [MethodImpl(MethodImplOptions.InternalCall)]
        private static extern void Internal_CreateInstance(GUIColorField instance, ref GUIContent title, int titleWidth,
            string style, GUIOption[] options, bool withTitle);

        [MethodImpl(MethodImplOptions.InternalCall)]
        private static extern void Internal_GetValue(IntPtr nativeInstance, out Color value);

        [MethodImpl(MethodImplOptions.InternalCall)]
        private static extern void Internal_SetValue(IntPtr nativeInstance, ref Color value);

        [MethodImpl(MethodImplOptions.InternalCall)]
        private static extern void Internal_SetTint(IntPtr nativeInstance, ref Color color);
    }

    /** @} */
}