using System.IO;
using UnityEditor;
using UnityEditor.SceneManagement;
using UnityEngine;

namespace HexapodSim
{
    // Batch-mode check of the OpenSCAD model in Main.unity, without entering
    // Play mode: builds the model from the DLL's geometry, poses the legs in
    // the firmware's standing pose and renders the main camera to PNGs.
    //   Unity.exe -batchmode -projectPath . -executeMethod HexapodSim.OpenScadModelSnapshot.Run
    //             -snapshotDir <folder> -quit
    public static class OpenScadModelSnapshot
    {
        public static void Run()
        {
            string dir = Arg("-snapshotDir") ?? Path.GetFullPath("Temp/OpenScadSnapshot");
            Directory.CreateDirectory(dir);
            EditorSceneManager.OpenScene("Assets/Main.unity");

            Transform chassis = null;
            foreach (var t in Object.FindObjectsByType<Transform>())
                if (t.name == "Leg" && t.Find("hip1") != null) { chassis = t.parent; break; }
            if (chassis == null) { Debug.LogError("[Snapshot] no leg rig in Main.unity"); EditorApplication.Exit(1); return; }

            string dll = Path.GetFullPath(Path.Combine(Application.dataPath, "..", "..", "sim", "build", "hexapod_sim.dll"));
            HxGeometry g;
            using (var native = HexapodSimNative.Load(dll)) g = native.Geometry;
            OpenScadModel.Build(chassis, g, ForwardAxis.NegativeX, 0.1f);

            // Firmware stance: coxa 0, femur -1.2, tibia -98.3 (HexapodSimulation.ApplyJoints).
            foreach (Transform leg in chassis)
            {
                if (leg.name != "Leg" || !leg.gameObject.activeSelf) continue;
                var hip2 = leg.Find("hip1/Hip2");
                var knie = leg.Find("hip1/Hip2/Knie");
                hip2.localRotation = Quaternion.Euler(1.2f, 0, 0);
                knie.localRotation = Quaternion.Euler(-(-98.3f + 90f), 0, 0);
            }

            var cam = Camera.main;
            if (cam == null) cam = new GameObject("SnapshotCamera").AddComponent<Camera>();
            Vector3 c = chassis.position;
            Shoot(cam, c + new Vector3(-30, 22, -38), c, Path.Combine(dir, "front_left.png"));
            Shoot(cam, c + new Vector3(42, 30, 20), c, Path.Combine(dir, "rear_right.png"));
            Shoot(cam, c + new Vector3(0.01f, 60, 0), c, Path.Combine(dir, "top.png"));
            Debug.Log("[Snapshot] wrote " + dir);
            EditorApplication.Exit(0);
        }

        static void Shoot(Camera cam, Vector3 pos, Vector3 target, string file)
        {
            cam.transform.position = pos;
            cam.transform.LookAt(target);
            cam.fieldOfView = 45;
            var rt = new RenderTexture(1280, 900, 24);
            cam.targetTexture = rt;
            cam.Render();
            RenderTexture.active = rt;
            var tex = new Texture2D(rt.width, rt.height, TextureFormat.RGB24, false);
            tex.ReadPixels(new Rect(0, 0, rt.width, rt.height), 0, 0);
            tex.Apply();
            File.WriteAllBytes(file, tex.EncodeToPNG());
            cam.targetTexture = null;
            RenderTexture.active = null;
        }

        static string Arg(string name)
        {
            var a = System.Environment.GetCommandLineArgs();
            for (int i = 0; i < a.Length - 1; i++) if (a[i] == name) return a[i + 1];
            return null;
        }
    }
}