using System.IO;
using Unity.InferenceEngine;
using UnityEngine;
using UnityEngine.Networking;

namespace Audio2Lipsync
{
    /// <summary>
    /// Locates and loads the packaged model with no setup step:
    /// - Editor: straight from the package's Model~ folder (nothing is copied into Assets).
    /// - Player: from StreamingAssets/Audio2Lipsync/, where the package's build hook puts it for
    ///   the duration of each build.
    /// </summary>
    public static class Audio2LipsyncModel
    {
        public const string FileName = "audio2lipsync.sentis";
        public const string StreamingAssetsFolder = "Audio2Lipsync";

        public static string StreamingAssetsPath =>
            Path.Combine(Application.streamingAssetsPath, StreamingAssetsFolder, FileName);

#if UNITY_EDITOR
        /// <summary>Model~/audio2lipsync.sentis inside the resolved package (editor only).</summary>
        public static string PackagedPath
        {
            get
            {
                var pkg = UnityEditor.PackageManager.PackageInfo.FindForAssembly(typeof(Audio2LipsyncModel).Assembly);
                return pkg == null ? null : Path.Combine(pkg.resolvedPath, "Model~", FileName);
            }
        }
#endif

        /// <summary>
        /// Where <see cref="LoadAsync"/> reads the model from: a model placed in
        /// StreamingAssets/Audio2Lipsync/ wins (override); otherwise, in the editor, the packaged one.
        /// </summary>
        public static string DefaultPath
        {
            get
            {
#if UNITY_EDITOR
                if (!File.Exists(StreamingAssetsPath) && PackagedPath != null) return PackagedPath;
#endif
                return StreamingAssetsPath;
            }
        }

        /// <summary>
        /// Loads the default model. Android / WebGL keep StreamingAssets inside the package or on a
        /// server, so those are fetched with UnityWebRequest; everywhere else it is a plain file read.
        /// </summary>
        public static async Awaitable<Model> LoadAsync()
        {
            var path = DefaultPath;
            if (path.Contains("://"))
            {
                using var req = UnityWebRequest.Get(path);
                await req.SendWebRequest();
                if (req.result != UnityWebRequest.Result.Success)
                    throw new FileNotFoundException($"Audio2Lipsync model not loaded from {path}: {req.error}");
                using var ms = new MemoryStream(req.downloadHandler.data);
                return ModelLoader.Load(ms);
            }
            if (!File.Exists(path))
                throw new FileNotFoundException(
                    $"Audio2Lipsync model not found: {path}. If the package came from git, install git-lfs and re-resolve it.");
            if (new FileInfo(path).Length < 1024 * 1024)
                throw new InvalidDataException($"{path} is a Git LFS pointer, not the model. Install git-lfs and re-resolve the package.");
            return ModelLoader.Load(path);
        }
    }
}