using System;

using Unity.Collections;
using UnityEngine;
using UnityEngine.UIElements;

namespace CrosshairComponents {
    public class ThreeArmCrosshair : VisualElement {
        // Need this uxml traits and factory for it to show up in editor
        public new class UxmlTraits : VisualElement.UxmlTraits {
            public override void Init(VisualElement ve, IUxmlAttributes bag, CreationContext cc) {
                base.Init(ve, bag, cc);
            }
        }
        public new class UxmlFactory : UxmlFactory<ThreeArmCrosshair, UxmlTraits> { }

        static CustomStyleProperty<Color> s_TrackColor = new CustomStyleProperty<Color>("--track-color");
        static CustomStyleProperty<Color> s_ProgressColor = new CustomStyleProperty<Color>("--progress-color");

        Color m_TrackColor = Color.white;
        Color m_SpeedColor = Color.white;

        // This is the label that displays the percentage.
        Label m_Label;

        // This is the number that the Label displays as a percentage.
        float m_Speed;

        public float speed {
            get => m_Speed;
            set {
                // Whenever the progress property changes, MarkDirtyRepaint() is named. This causes a call to the
                // generateVisualContents callback.
                m_Speed = value;
                m_Label.text = Mathf.Clamp(Mathf.Round(value), 0, 100) + "%";
                MarkDirtyRepaint();
            }
        }

        public ThreeArmCrosshair() {
            // Create a Label, add a USS class name, and add it to this visual tree.
            m_Label = new Label();
            Add(m_Label);

            // Register a callback after custom style resolution.
            RegisterCallback<CustomStyleResolvedEvent>(evt => CustomStylesResolved(evt));

            // Register a callback to generate the visual content of the control.
            generateVisualContent += GenerateVisualContent;
        }

        static void CustomStylesResolved(CustomStyleResolvedEvent evt) {
            ThreeArmCrosshair element = (ThreeArmCrosshair)evt.currentTarget;
            element.UpdateCustomStyles();
        }

        // After the custom colors are resolved, this method uses them to color the meshes and (if necessary) repaint
        // the control.
        void UpdateCustomStyles() {
            bool repaint = false;
            if (customStyle.TryGetValue(s_ProgressColor, out m_SpeedColor))
                repaint = true;

            if (customStyle.TryGetValue(s_TrackColor, out m_TrackColor))
                repaint = true;

            if (repaint)
                MarkDirtyRepaint();
        }

        void GenerateVisualContent(MeshGenerationContext context) {
            float width = contentRect.width;
            float height = contentRect.height;

            float length = height / 100;

            Vector2 centre = new Vector2(width / 2, height / 2);
            Vector2 centreArm = new Vector2(centre.x, centre.y - length);

            float angle = (float)(Math.PI / 3);
            float angleSin = (float)Math.Sin(angle);
            Vector2 rightArm = new Vector2(centre.x + angleSin * length, centre.y + angleSin * length);
            Vector2 leftArm = new Vector2(centre.x - angleSin * length, centre.y + angleSin * length);

            var painter = context.painter2D;
            painter.lineWidth = 1.0f;
            painter.lineCap = LineCap.Butt;
            painter.strokeColor = m_TrackColor;

            painter.BeginPath();
            painter.MoveTo(centre);
            painter.LineTo(centreArm);
            painter.Stroke();

            painter.BeginPath();
            painter.MoveTo(centre);
            painter.LineTo(rightArm);
            painter.Stroke();

            painter.BeginPath();
            painter.MoveTo(centre);
            painter.LineTo(leftArm);
            painter.Stroke();
        }
    }

    public class FourArmCrosshair : VisualElement {
        // Need this uxml traits and factory for it to show up in editor
        public new class UxmlTraits : VisualElement.UxmlTraits {
            public override void Init(VisualElement ve, IUxmlAttributes bag, CreationContext cc) {
                base.Init(ve, bag, cc);
            }
        }
        public new class UxmlFactory : UxmlFactory<FourArmCrosshair, UxmlTraits> { }

        // These are USS class names for the control overall and the label.
        public static readonly string ussClassName = "crosshair";
        public static readonly string ussLabelClassName = "crosshair__label";

        static CustomStyleProperty<Color> s_TrackColor = new CustomStyleProperty<Color>("--track-color");
        static CustomStyleProperty<Color> s_ProgressColor = new CustomStyleProperty<Color>("--progress-color");

        Color m_TrackColor = Color.white;
        Color m_SpeedColor = Color.white;

        // This is the label that displays the percentage.
        Label m_Label;

        // This is the number that the Label displays as a percentage.
        float m_Speed;

        public float speed {
            get => m_Speed;
            set {
                // Whenever the progress property changes, MarkDirtyRepaint() is named. This causes a call to the
                // generateVisualContents callback.
                m_Speed = value;
                m_Label.text = Mathf.Clamp(Mathf.Round(value), 0, 100) + "%";
                MarkDirtyRepaint();
            }
        }

        public FourArmCrosshair() {
            // Create a Label, add a USS class name, and add it to this visual tree.
            m_Label = new Label();
            Add(m_Label);

            // Register a callback after custom style resolution.
            RegisterCallback<CustomStyleResolvedEvent>(evt => CustomStylesResolved(evt));

            // Register a callback to generate the visual content of the control.
            generateVisualContent += GenerateVisualContent;
        }

        static void CustomStylesResolved(CustomStyleResolvedEvent evt) {
            FourArmCrosshair element = (FourArmCrosshair)evt.currentTarget;
            element.UpdateCustomStyles();
        }

        // After the custom colors are resolved, this method uses them to color the meshes and (if necessary) repaint
        // the control.
        void UpdateCustomStyles() {
            bool repaint = false;
            if (customStyle.TryGetValue(s_ProgressColor, out m_SpeedColor))
                repaint = true;

            if (customStyle.TryGetValue(s_TrackColor, out m_TrackColor))
                repaint = true;

            if (repaint)
                MarkDirtyRepaint();
        }

        void GenerateVisualContent(MeshGenerationContext context) {
            float width = contentRect.width;
            float height = contentRect.height;

            float length = height / 100;

            Vector2 centre = new Vector2(width / 2, height / 2);
            Vector2 topArm = new Vector2(centre.x, centre.y - length);
            Vector2 rightArm = new Vector2(centre.x + length, centre.y);
            Vector2 leftArm = new Vector2(centre.x - length, centre.y);
            Vector2 bottomArm = new Vector2(centre.x, centre.y + length);

            var painter = context.painter2D;
            painter.lineWidth = 1.0f;
            painter.lineCap = LineCap.Butt;
            painter.strokeColor = m_TrackColor;

            painter.BeginPath();
            painter.MoveTo(centre);
            painter.LineTo(topArm);
            painter.Stroke();

            painter.BeginPath();
            painter.MoveTo(centre);
            painter.LineTo(bottomArm);
            painter.Stroke();

            painter.BeginPath();
            painter.MoveTo(centre);
            painter.LineTo(rightArm);
            painter.Stroke();

            painter.BeginPath();
            painter.MoveTo(centre);
            painter.LineTo(leftArm);
            painter.Stroke();
        }
    }
}