// ===============================================================================
// MeasureTool - Smart Scene Measurement & Analysis
//
// Creator: Scove
// Last Updated: 2024-05-08
// Version: 3.0
//
// Purpose:
// A professional measurement tool that visualizes distances between objects
// in the Scene View. Supports single distance, chain distance, and axis breakdown.
//
// Key Features:
// 1. Two-Point & Chain Mode: Select 2 or more objects to measure.
// 2. Axis Breakdown: Shows Delta X, Y, Z with Unity-standard colors.
// 3. Scene Overlay: On-screen toggle and settings directly in Scene View.
// 4. Readable UI: High-contrast labels with background for any lighting condition.
//
// How to Use:
// 1. Place in an 'Editor' folder.
// 2. Select 2 or more GameObjects in the Hierarchy.
// 3. Use the "MEASURE" overlay in the Scene View to toggle axis details.
// ===============================================================================

using UnityEditor;
using UnityEngine;
using System.Collections.Generic;

namespace Editor
{
    [InitializeOnLoad]
    public class MeasureTool
    {
        // Settings (Persisted via EditorPrefs)
        private static bool IsEnabled = true;
        private static bool ShowAxisBreakdown = true;
        private static bool ShowTotalDistance = true;

        static MeasureTool()
        {
            IsEnabled = EditorPrefs.GetBool("MeasureTool_Enabled", true);
            ShowAxisBreakdown = EditorPrefs.GetBool("MeasureTool_Axis", true);
            
            SceneView.duringSceneGui += OnSceneGUI;
        }

        private static void OnSceneGUI(SceneView view)
        {
            DrawOverlay(view);

            if (!IsEnabled || Selection.transforms.Length < 2) return;

            Transform[] selected = Selection.transforms;
            
            // Draw measurement for each pair in the selection
            for (int i = 0; i < selected.Length - 1; i++)
            {
                DrawDistance(selected[i].position, selected[i + 1].position);
            }
        }

        private static void DrawDistance(Vector3 p1, Vector3 p2)
        {
            float distance = Vector3.Distance(p1, p2);
            Vector3 midPoint = (p1 + p2) * 0.5f;

            // 1. Draw the Main Dotted Line
            Handles.color = Color.cyan;
            Handles.DrawDottedLine(p1, p2, 4f);
            
            // Draw small spheres at start/end points for clarity
            Handles.SphereHandleCap(0, p1, Quaternion.identity, 0.1f, EventType.Repaint);
            Handles.SphereHandleCap(0, p2, Quaternion.identity, 0.1f, EventType.Repaint);

            // 2. Draw Main Label (Total Distance)
            if (ShowTotalDistance)
            {
                GUIStyle labelStyle = GetLabelStyle(Color.white, new Color(0, 0, 0, 0.6f));
                string labelText = $"Dist: {distance:F2}m";
                Handles.Label(midPoint + (Vector3.up * 0.1f), labelText, labelStyle);
            }

            // 3. Draw Axis Breakdown (X, Y, Z Delta)
            if (ShowAxisBreakdown)
            {
                Vector3 delta = new Vector3(Mathf.Abs(p1.x - p2.x), Mathf.Abs(p1.y - p2.y), Mathf.Abs(p1.z - p2.z));
                
                // We only show axis delta if it's significant (> 0.01)
                string axisText = "";
                if (delta.x > 0.01f) axisText += $"<color=#FF5555>X: {delta.x:F2}</color>  ";
                if (delta.y > 0.01f) axisText += $"<color=#55FF55>Y: {delta.y:F2}</color>  ";
                if (delta.z > 0.01f) axisText += $"<color=#5555FF>Z: {delta.z:F2}</color>";

                if (!string.IsNullOrEmpty(axisText))
                {
                    GUIStyle axisStyle = GetLabelStyle(Color.white, new Color(0.1f, 0.1f, 0.1f, 0.8f));
                    axisStyle.richText = true;
                    axisStyle.fontSize = 11;
                    Handles.Label(midPoint - (Vector3.up * 0.3f), axisText, axisStyle);
                }
            }
        }

        private static void DrawOverlay(SceneView view)
        {
            Handles.BeginGUI();
            
            // Positioning the overlay in the bottom right
            float width = 140;
            float height = 90;
            Rect rect = new Rect(view.position.width - width - 10, view.position.height - height - 30, width, height);

            GUILayout.BeginArea(rect, "MEASURE TOOL", GUI.skin.window);
            
            EditorGUI.BeginChangeCheck();
            
            IsEnabled = GUILayout.Toggle(IsEnabled, " Enable Tool");
            ShowTotalDistance = GUILayout.Toggle(ShowTotalDistance, " Show Total");
            ShowAxisBreakdown = GUILayout.Toggle(ShowAxisBreakdown, " Axis Breakdown");

            if (EditorGUI.EndChangeCheck())
            {
                EditorPrefs.SetBool("MeasureTool_Enabled", IsEnabled);
                EditorPrefs.SetBool("MeasureTool_Axis", ShowAxisBreakdown);
                SceneView.RepaintAll();
            }

            GUILayout.EndArea();
            Handles.EndGUI();
        }

        private static GUIStyle GetLabelStyle(Color textColor, Color bgColor)
        {
            GUIStyle style = new GUIStyle();
            style.normal.textColor = textColor;
            style.fontSize = 13;
            style.fontStyle = FontStyle.Bold;
            style.alignment = TextAnchor.MiddleCenter;
            style.padding = new RectOffset(4, 4, 2, 2);

            // Create a background texture dynamically
            Texture2D tex = new Texture2D(1, 1);
            tex.SetPixel(0, 0, bgColor);
            tex.Apply();
            style.normal.background = tex;

            return style;
        }
    }
}