/*
┌──────────────────────────────────────────────────────────────────┐
│  Author: Ivan Murzak (https://github.com/IvanMurzak)             │
│  Repository: GitHub (https://github.com/IvanMurzak/Unity-MCP)    │
│  Copyright (c) 2025 Ivan Murzak                                  │
│  Licensed under the Apache License, Version 2.0.                 │
│  See the LICENSE file in the project root for more information.  │
└──────────────────────────────────────────────────────────────────┘
*/

#nullable enable
using System.ComponentModel;
using com.IvanMurzak.McpPlugin;
using com.IvanMurzak.McpPlugin.Common.Model;
using com.IvanMurzak.ReflectorNet.Utils;
using UnityEditor;
using UnityEngine;

namespace com.IvanMurzak.Unity.MCP.Editor.API
{
    public partial class Tool_Screenshot
    {
        public const string ScreenshotSceneViewToolId = "screenshot-scene-view";
        [AiTool
        (
            ScreenshotSceneViewToolId,
            Title = "Screenshot / Scene View",
            ReadOnlyHint = true,
            IdempotentHint = true,
            Enabled = false
        )]
        [AiSkillDescription("Capture a screenshot from the Unity Editor Scene View at the requested size. " +
            "Renders via the Scene View's active camera onto a temporary `RenderTexture`. Requires an open Scene View.")]
        [AiSkillBody("Captures a screenshot from the Unity Editor Scene View and returns it as an image. " +
            "Returns the image directly for visual inspection by the LLM.\n\n" +
            "## Inputs\n\n" +
            "- `width` (default 1920) / `height` (default 1080) — output pixels. Must be > 0 and ≤ `MaxDimension`.\n\n" +
            "## Behavior\n\n" +
            "Uses `SceneView.lastActiveSceneView` (falls back to the first window in `SceneView.sceneViews`). Allocates " +
            "a temporary `RenderTexture`, swaps it onto the Scene View's camera, calls `Render`, reads back with " +
            "`Texture2D.ReadPixels`, encodes PNG, and restores the camera's prior `targetTexture`. Throws/errors when " +
            "no Scene View is open or the Scene View camera is null.")]
        [Description("Captures a screenshot from the Unity Editor Scene View and returns it as an image. " +
            "Returns the image directly for visual inspection by the LLM.")]
        public ResponseCallTool ScreenshotSceneView
        (
            [Description("Width of the screenshot in pixels.")]
            int width = 1920,
            [Description("Height of the screenshot in pixels.")]
            int height = 1080
        )
        {
            if (width <= 0 || height <= 0)
                return ResponseCallTool.Error($"Width and height must be greater than 0. Got {width}x{height}.");
            if (width > MaxDimension || height > MaxDimension)
                return ResponseCallTool.Error($"Width and height must not exceed {MaxDimension} pixels. Got {width}x{height}.");

            // Keep the encoded PNG within the MCP transport limit so the screenshot is not
            // dropped in transit; an oversized request is scaled down (aspect preserved).
            (width, height) = ClampToTransportLimit(width, height);

            return MainThread.Instance.Run(() =>
            {
                var sceneView = SceneView.lastActiveSceneView;
                if (sceneView == null && SceneView.sceneViews.Count > 0)
                    sceneView = SceneView.sceneViews[0] as SceneView;

                if (sceneView == null)
                    return ResponseCallTool.Error("No Scene View window is open.");

                var sceneCamera = sceneView.camera;
                if (sceneCamera == null)
                    return ResponseCallTool.Error("Scene View camera is not available.");

                var rt = new RenderTexture(width, height, 24);
                var prevTarget = sceneCamera.targetTexture;
                var prevActive = RenderTexture.active;
                Texture2D? tex = null;
                byte[]? pngBytes = null;
                try
                {
                    sceneCamera.targetTexture = rt;
                    sceneCamera.Render();

                    RenderTexture.active = rt;
                    tex = new Texture2D(width, height, TextureFormat.RGB24, false);
                    tex.ReadPixels(new Rect(0, 0, width, height), 0, 0);
                    tex.Apply();

                    pngBytes = tex.EncodeToPNG();
                }
                finally
                {
                    sceneCamera.targetTexture = prevTarget;
                    RenderTexture.active = prevActive;
                    Object.DestroyImmediate(rt);
                    if (tex != null)
                        Object.DestroyImmediate(tex);
                }

                return ResponseCallTool.Image(pngBytes, McpPlugin.Common.Consts.MimeType.ImagePng,
                    $"Screenshot from Scene View ({width}x{height})");
            });
        }
    }
}