// 
//     Kerbal Engineer Redux
// 
//     Copyright (C) 2014 CYBUTEK
// 
//     This program is free software: you can redistribute it and/or modify
//     it under the terms of the GNU General Public License as published by
//     the Free Software Foundation, either version 3 of the License, or
//     (at your option) any later version.
// 
//     This program is distributed in the hope that it will be useful,
//     but WITHOUT ANY WARRANTY; without even the implied warranty of
//     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//     GNU General Public License for more details.
// 
//     You should have received a copy of the GNU General Public License
//     along with this program.  If not, see <http://www.gnu.org/licenses/>.
// 
 
#region Using Directives
 
using KerbalEngineer.Extensions;
using KerbalEngineer.Helpers;
 
using UnityEngine;
 
#endregion
 
namespace KerbalEngineer.Flight.Sections
{
    public class SectionWindow : MonoBehaviour
    {
        #region Fields
 
        private bool resizeRequested;
        private int windowId;
        private Rect windowPosition;
 
        #endregion
 
        #region Properties
 
        /// <summary>
        ///     Gets and sets the parent section for the floating section window.
        /// </summary>
        public SectionModule ParentSection { get; set; }
 
        /// <summary>
        ///     Gets and sets the window position.
        /// </summary>
        public Rect WindowPosition
        {
            get { return this.windowPosition; }
            set { this.windowPosition = value; }
        }
 
        #endregion
 
        #region GUIStyles
 
        #region Fields
 
        private GUIStyle hudWindowBgStyle;
        private GUIStyle hudWindowStyle;
        private GUIStyle windowStyle;
 
        #endregion
 
        /// <summary>
        ///     Initialises all the styles required for this object.
        /// </summary>
        private void InitialiseStyles()
        {
            this.windowStyle = new GUIStyle(HighLogic.Skin.window)
            {
                margin = new RectOffset(),
                padding = new RectOffset(5, 5, 0, 5),
            };
 
            this.hudWindowStyle = new GUIStyle(this.windowStyle)
            {
                normal =
                {
                    background = null
                },
                onNormal =
                {
                    background = null
                },
                padding = new RectOffset(5, 5, 0, 8),
            };
 
            this.hudWindowBgStyle = new GUIStyle(this.hudWindowStyle)
            {
                normal =
                {
                    background = TextureHelper.CreateTextureFromColour(new Color(0.0f, 0.0f, 0.0f, 0.5f))
                },
                onNormal =
                {
                    background = TextureHelper.CreateTextureFromColour(new Color(0.0f, 0.0f, 0.0f, 0.5f))
                }
            };
        }
 
        private void OnSizeChanged()
        {
            this.InitialiseStyles();
            this.RequestResize();
        }
 
        #endregion
 
        #region Drawing
 
        /// <summary>
        ///     Called to draw the floating section window when the UI is enabled.
        /// </summary>
        private void Draw()
        {
            if (this.ParentSection == null || !this.ParentSection.IsVisible || (DisplayStack.Instance.Hidden && !this.ParentSection.IsHud) || !FlightEngineerCore.IsDisplayable)
            {
                return;
            }
 
            if (this.resizeRequested)
            {
                this.windowPosition.width = 0;
                this.windowPosition.height = 0;
                this.resizeRequested = false;
            }
            GUI.skin = null;
            this.windowPosition = GUILayout.Window(this.windowId, this.windowPosition, this.Window, string.Empty,
                                                   (!this.ParentSection.IsHud || this.ParentSection.IsEditorVisible) ? this.windowStyle
                                                       : this.ParentSection.IsHudBackground && this.ParentSection.LineCount > 0
                                                           ? this.hudWindowBgStyle
                                                           : this.hudWindowStyle);
 
            windowPosition = (ParentSection.IsHud) ? windowPosition.ClampInsideScreen() : windowPosition.ClampToScreen();
 
 
            this.ParentSection.FloatingPositionX = this.windowPosition.x;
            this.ParentSection.FloatingPositionY = this.windowPosition.y;
        }
 
        /// <summary>
        ///     Draws the floating section window.
        /// </summary>
        private void Window(int windowId)
        {
            this.ParentSection.Draw();
 
            if (!this.ParentSection.IsHud || this.ParentSection.IsEditorVisible)
            {
                GUI.DragWindow();
            }
        }
 
        #endregion
 
        #region Destruction
 
        /// <summary>
        ///     Runs when the object is destroyed.
        /// </summary>
        private void OnDestroy()
        {
            RenderingManager.RemoveFromPostDrawQueue(0, this.Draw);
            GuiDisplaySize.OnSizeChanged -= this.OnSizeChanged;
        }
 
        #endregion
 
        #region Methods
 
        /// <summary>
        ///     Request that the floating section window's size is reset in the next draw call.
        /// </summary>
        public void RequestResize()
        {
            this.resizeRequested = true;
        }
 
        #endregion
 
        #region Methods: private
 
        /// <summary>
        ///     Initialises the object's state on creation.
        /// </summary>
        private void Start()
        {
            this.windowId = this.GetHashCode();
            this.InitialiseStyles();
            RenderingManager.AddToPostDrawQueue(0, this.Draw);
            GuiDisplaySize.OnSizeChanged += this.OnSizeChanged;
        }
 
        #endregion
    }
}