using System;
using System.IO;
using System.Linq;
using UnityEditor;
using UnityEditor.Build.Reporting;
using UnityEditor.SceneManagement;
using UnityEngine;
using Unity.MLAgents.Policies;
using Unity.MLAgents.Actuators;

// Install in an isolated release-23 Project/Assets/Editor, then invoke
// -executeMethod VectorExtrasBuild.Build -simulationOutput <directory>.
public static class VectorExtrasBuild
{
    [Serializable] public class BehaviorInfo
    {
        public string name;
        public int team;
        public string stockPolicy;
        public string policyFile;
        public int continuous;
        public int[] branches;
    }
    [Serializable] public class Manifest
    {
        public string environment;
        public string sourceScene;
        public string unityVersion;
        public string platform;
        public bool modelRemoved;
        public BehaviorInfo[] behaviors;
        public string[] packedPolicies;
    }

    public static void Build()
    {
        try
        {
            var args = Environment.GetCommandLineArgs();
            int idx = Array.IndexOf(args, "-simulationOutput");
            if (idx < 0 || idx + 1 >= args.Length)
                throw new ArgumentException("-simulationOutput is required");
            string output = Path.GetFullPath(args[idx + 1]);
            int targetIndex = Array.IndexOf(args, "-simulationTarget");
            var target = targetIndex < 0 ? BuildTarget.StandaloneWindows64 :
                (BuildTarget)Enum.Parse(typeof(BuildTarget), args[targetIndex + 1]);
            if (target != BuildTarget.StandaloneWindows64 && target != BuildTarget.StandaloneLinux64)
                throw new ArgumentException("Only Windows64 and Linux64 are supported");
            string[] allNames = { "Match3VectorObs", "Basic", "3DBall", "PushBlockWithInput" };
            string[] allScenes = {
                "Match3/Scenes/Match3.unity", "Basic/Scenes/Basic.unity",
                "3DBall/Scenes/3DBall.unity", "PushBlockWithInput/Scenes/PushBlockWithInput.unity"
            };
            int selectionIndex = Array.IndexOf(args, "-simulationEnvironments");
            string[] names = selectionIndex < 0 ? allNames : args[selectionIndex + 1].Split(',');
            foreach (var name in names)
                if (!allNames.Contains(name)) throw new ArgumentException("Unknown scene: " + name);
            Directory.CreateDirectory("Assets/SimulationBuildScenes");
            AssetDatabase.Refresh();
            for (int i = 0; i < names.Length; i++)
            {
                string source = "Assets/ML-Agents/Examples/" + allScenes[Array.IndexOf(allNames, names[i])];
                var scene = EditorSceneManager.OpenScene(source, OpenSceneMode.Single);
                // Unpack copies so prefab model references cannot enter the build.
                foreach (var root in scene.GetRootGameObjects())
                    if (PrefabUtility.IsPartOfPrefabInstance(root))
                        PrefabUtility.UnpackPrefabInstance(root, PrefabUnpackMode.Completely,
                            InteractionMode.AutomatedAction);
                if (names[i] == "Match3VectorObs")
                {
                    var allBehaviors = scene.GetRootGameObjects()
                        .SelectMany(r => r.GetComponentsInChildren<BehaviorParameters>(true)).ToArray();
                    foreach (var b in allBehaviors)
                        if (b.BehaviorName != "Match3VectorObs")
                            UnityEngine.Object.DestroyImmediate(b.gameObject);
                }
                var behaviors = scene.GetRootGameObjects()
                    .SelectMany(r => r.GetComponentsInChildren<BehaviorParameters>(true)).ToArray();
                var info = behaviors.Select(b => new BehaviorInfo {
                    name = b.BehaviorName, team = b.TeamId,
                    stockPolicy = StockPolicyPath(names[i]),
                    policyFile = names[i] + ".onnx",
                    continuous = CombinedSpec(b).NumContinuousActions,
                    branches = CombinedSpec(b).BranchSizes
                }).GroupBy(b => b.name + "?team=" + b.team).Select(g => g.First()).ToArray();
                if (behaviors.Length == 0) throw new Exception("No behaviors in " + names[i]);
                foreach (var component in scene.GetRootGameObjects()
                    .SelectMany(r => r.GetComponentsInChildren<MonoBehaviour>(true)))
                    if (component != null && component.GetType().Name == "CameraSensorComponent")
                        throw new Exception("Unexpected camera sensor: " + component.name);
                foreach (var b in behaviors)
                {
                    b.Model = null;
                    b.BehaviorType = BehaviorType.Default;
                    EditorUtility.SetDirty(b);
                }
                // Remove any other serialized ONNX/NN references on scene components.
                foreach (var component in scene.GetRootGameObjects()
                    .SelectMany(r => r.GetComponentsInChildren<MonoBehaviour>(true)))
                {
                    if (component == null) continue;
                    var serialized = new SerializedObject(component);
                    var property = serialized.GetIterator();
                    bool changed = false;
                    while (property.Next(true))
                    {
                        if (property.propertyType != SerializedPropertyType.ObjectReference) continue;
                        string path = AssetDatabase.GetAssetPath(property.objectReferenceValue);
                        if (path.EndsWith(".onnx", StringComparison.OrdinalIgnoreCase) ||
                            path.EndsWith(".nn", StringComparison.OrdinalIgnoreCase))
                        {
                            property.objectReferenceValue = null;
                            changed = true;
                        }
                    }
                    if (changed) serialized.ApplyModifiedPropertiesWithoutUndo();
                }
                string staged = "Assets/SimulationBuildScenes/" + names[i] + ".unity";
                if (!EditorSceneManager.SaveScene(scene, staged))
                    throw new Exception("Could not save " + staged);
                string envOutput = Path.Combine(output, names[i]);
                Directory.CreateDirectory(envOutput);
                foreach (var policy in info.Select(b => b.stockPolicy).Where(p => !string.IsNullOrEmpty(p)).Distinct())
                {
                    string policies = Path.Combine(output, "policies", names[i]);
                    Directory.CreateDirectory(policies);
                    File.Copy(policy, Path.Combine(policies, names[i] + ".onnx"), true);
                }
                var report = BuildPipeline.BuildPlayer(new BuildPlayerOptions {
                    scenes = new[] { staged },
                    locationPathName = Path.Combine(envOutput, names[i] +
                        (target == BuildTarget.StandaloneWindows64 ? ".exe" : ".x86_64")),
                    target = target,
                    options = BuildOptions.StrictMode
                });
                if (report.summary.result != BuildResult.Succeeded)
                    throw new Exception(names[i] + " build failed: " + report.summary.result);
                var packed = report.packedAssets.SelectMany(p => p.contents)
                    .Select(a => a.sourceAssetPath).Where(p => p.EndsWith(".onnx") || p.EndsWith(".nn"))
                    .Distinct().ToArray();
                var manifest = new Manifest {
                    environment = names[i], sourceScene = source,
                    unityVersion = Application.unityVersion, platform = target.ToString(),
                    modelRemoved = packed.Length == 0,
                    behaviors = info, packedPolicies = packed
                };
                File.WriteAllText(Path.Combine(envOutput, "simulation-build.json"), JsonUtility.ToJson(manifest, true));
                if (packed.Length > 0)
                    throw new Exception("Baked policies found: " + string.Join(", ", packed));
                Debug.Log("SIMULATION_BUILD_OK " + names[i] + " " + report.summary.totalSize);
            }
            EditorApplication.Exit(0);
        }
        catch (Exception error)
        {
            Debug.LogException(error);
            EditorApplication.Exit(1);
        }
    }

    static ActionSpec CombinedSpec(BehaviorParameters behavior)
    {
        var components = behavior.GetComponentsInChildren<ActuatorComponent>(true);
        return ActionSpec.Combine(new[] { behavior.BrainParameters.ActionSpec }
            .Concat(components.Select(c => c.ActionSpec)).ToArray());
    }

    static string StockPolicyPath(string environment)
    {
        string folder = environment == "Match3VectorObs" ? "Match3" : environment;
        string filename = environment == "PushBlockWithInput" ? "PushBlock" : environment;
        string path = "Assets/ML-Agents/Examples/" + folder + "/TFModels/" + filename + ".onnx";
        if (!File.Exists(path)) throw new Exception("Missing external policy: " + path);
        return path;
    }
}