using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using System;
using System.Linq;

namespace Barotrauma
{
    public class GUIProgressBar : GUIComponent
    {
        private bool isHorizontal;
        private readonly GUIFrame frame, slider;
        private float barSize;
        private readonly bool showFrame;
                
        public delegate float ProgressGetterHandler();
        public ProgressGetterHandler ProgressGetter;

        public bool IsHorizontal
        {
            get { return isHorizontal; }
            set { isHorizontal = value; }
        }

        public float BarSize
        {
            get { return barSize; }
            set
            {
                if (!MathUtils.IsValid(value))
                {
                    GameAnalyticsManager.AddErrorEventOnce(
                        "GUIProgressBar.BarSize_setter", 
                        GameAnalyticsManager.ErrorSeverity.Error,
                        "Attempted to set the BarSize of a GUIProgressBar to an invalid value (" + value + ")\n" + Environment.StackTrace.CleanupStackTrace());
                    return;
                }
                barSize = MathHelper.Clamp(value, 0.0f, 1.0f);
                //UpdateRect();
            }
        }
        
        public GUIProgressBar(RectTransform rectT, float barSize, Color? color = null, string style = "", bool showFrame = true) : base(style, rectT)
        {
            if (color.HasValue)
            {
                this.color = color.Value;
            }
            isHorizontal = (Rect.Width > Rect.Height);
            frame = new GUIFrame(new RectTransform(Vector2.One, rectT));
            GUIStyle.Apply(frame, "", this);
            slider = new GUIFrame(new RectTransform(Vector2.One, rectT));
            GUIStyle.Apply(slider, "Slider", this);
            this.showFrame = showFrame;
            this.barSize = barSize;
            Enabled = true;
        }

        /// <summary>
        /// Get the area the slider should be drawn inside
        /// </summary>
        /// <param name="fillAmount">0 = empty, 1 = full</param>
        public Rectangle GetSliderRect(float fillAmount)
        {
            Rectangle sliderArea = new Rectangle(
                frame.Rect.X + (int)Style.Padding.X,
                frame.Rect.Y + (int)Style.Padding.Y,
                (int)(frame.Rect.Width - Style.Padding.X - Style.Padding.Z),
                (int)(frame.Rect.Height - Style.Padding.Y - Style.Padding.W));

            Vector4 sliceBorderSizes = Vector4.Zero;
            if (slider.sprites.ContainsKey(slider.State) && (slider.sprites[slider.State].First()?.Slice ?? false))
            {
                var slices = slider.sprites[slider.State].First().Slices;
                sliceBorderSizes = new Vector4(slices[0].Width, slices[0].Height, slices[8].Width, slices[8].Height);
                sliceBorderSizes *= slider.sprites[slider.State].First().GetSliceBorderScale(sliderArea.Size);
            }

            Rectangle sliderRect = IsHorizontal ?
                new Rectangle(
                    sliderArea.X + (int)sliceBorderSizes.X,
                    sliderArea.Y,
                    (int)Math.Round((sliderArea.Width - sliceBorderSizes.X - sliceBorderSizes.Z) * fillAmount),
                    sliderArea.Height)
                :
                new Rectangle(
                    sliderArea.X,
                    (int)Math.Round(sliderArea.Bottom - (sliderArea.Height - sliceBorderSizes.Y - sliceBorderSizes.W) * fillAmount - sliceBorderSizes.W),
                    sliderArea.Width,
                    (int)Math.Round((sliderArea.Height - sliceBorderSizes.Y - sliceBorderSizes.W) * fillAmount));

            sliderRect.Width = Math.Max(sliderRect.Width, 1);
            sliderRect.Height = Math.Max(sliderRect.Height, 1);

            return sliderRect;
        }

        protected override void Draw(SpriteBatch spriteBatch)
        {
            if (!Visible) { return; }

            if (ProgressGetter != null)
            {
                float newSize = MathHelper.Clamp(ProgressGetter(), 0.0f, 1.0f);
                if (!MathUtils.IsValid(newSize))
                {
                    GameAnalyticsManager.AddErrorEventOnce(
                        "GUIProgressBar.Draw:GetProgress",
                        GameAnalyticsManager.ErrorSeverity.Error,
                        "ProgressGetter of a GUIProgressBar (" + ProgressGetter.Target.ToString() + " - " + ProgressGetter.Method.ToString() + ") returned an invalid value (" + newSize + ")\n" + Environment.StackTrace.CleanupStackTrace());
                }
                else
                {
                    BarSize = newSize;
                }
            }

            var sliderRect = GetSliderRect(barSize);

            slider.RectTransform.AbsoluteOffset = new Point((int)Style.Padding.X, (int)Style.Padding.Y);
            slider.RectTransform.MaxSize = new Point(
                (int)(Rect.Width - Style.Padding.X + Style.Padding.Z), 
                (int)(Rect.Height - Style.Padding.Y + Style.Padding.W));
            frame.Visible = showFrame;
            slider.Visible = BarSize > 0.0f;

            if (showFrame)
            {
                if (AutoDraw)
                {
                    frame.DrawAuto(spriteBatch);
                }
                else
                {
                    frame.DrawManually(spriteBatch);
                }
            }

            Rectangle prevScissorRect = spriteBatch.GraphicsDevice.ScissorRectangle;
            if (BarSize <= 1.0f)
            {
                spriteBatch.End();
                spriteBatch.GraphicsDevice.ScissorRectangle = Rectangle.Intersect(prevScissorRect, sliderRect);
                spriteBatch.Begin(SpriteSortMode.Deferred, samplerState: GUI.SamplerState, rasterizerState: GameMain.ScissorTestEnable);
            }

            Color currColor = GetColor(State);

            slider.Color = currColor;
            if (AutoDraw)
            {
                slider.DrawAuto(spriteBatch);
            }
            else
            {
                slider.DrawManually(spriteBatch);
            }
            //hide the slider, we've already drawn it manually
            frame.Visible = false;
            slider.Visible = false;
            if (BarSize <= 1.0f)
            {
                spriteBatch.End();
                spriteBatch.Begin(SpriteSortMode.Deferred, rasterizerState: GameMain.ScissorTestEnable);
                spriteBatch.GraphicsDevice.ScissorRectangle = prevScissorRect;
            }
        }
    }
}