using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using LightRAG.Core;
using LightRAG.Core.Abstractions;
using LightRAG.Core.Extraction;
using LightRAG.Storage.FileBased;
using Newtonsoft.Json.Linq;
using Unity.InferenceEngine;
using UnityEditor;
using UnityEngine;
using OnDeviceAgent.AgentCore;
using OnDeviceAgent.RagLlm;

namespace OnDeviceAgent.AgentCore.Editor
{
public static class KnowledgeIngestMenu
{
    const string KnowledgeSubdir = "Knowledge";
    const string DbSubdir = "DB";
    const string ManifestFile = "db_manifest.txt";

    static volatile string s_Status = "Starting…";
    static volatile float s_Progress = 0f;

    // Reads ingest config from KnowledgeRagComponent in the active scene; falls back to defaults if absent.
    static (string endpoint, string model) ResolveIngestConfig()
    {
        var rag = UnityEngine.Object.FindAnyObjectByType<KnowledgeRagComponent>(FindObjectsInactive.Include);
        if (rag != null) return (rag.IngestEndpoint, rag.IngestModel);
        Debug.LogWarning("[RAG] No KnowledgeRagComponent found in the active scene, using defaults (http://localhost:11434 / gemma4:e2b). Add the component to choose a different ingest model.");
        return ("http://localhost:11434", "gemma4:e2b");
    }

    [MenuItem("OnDeviceAgent/RAG/Ingest Knowledge to DB")]
    static void Ingest()
    {
        var knowledgeDir = Path.Combine(Application.streamingAssetsPath, KnowledgeSubdir);
        var dbDir = Path.Combine(Application.streamingAssetsPath, DbSubdir);

        if (!Directory.Exists(knowledgeDir))
        {
            EditorUtility.DisplayDialog("LightRAG Ingest", "Missing StreamingAssets/Knowledge.", "OK");
            return;
        }
        var txts = Directory.GetFiles(knowledgeDir, "*.txt");
        if (txts.Length == 0)
        {
            EditorUtility.DisplayDialog("LightRAG Ingest", "No .txt files in StreamingAssets/Knowledge.", "OK");
            return;
        }

        var (endpoint, model) = ResolveIngestConfig();

        var choice = EditorUtility.DisplayDialogComplex(
            "LightRAG Ingest",
            $"Ingest {txts.Length} .txt file(s) from StreamingAssets/Knowledge into StreamingAssets/DB.\n" +
            $"LLM (entity extraction): {model} @ {endpoint}, a running Ollama server is required.\n" +
            "Embeddings: multilingual-e5-small (on-device). Progress shows live cache growth.",
            "Clean rebuild", "Cancel", "Incremental");
        if (choice == 1) return;
        if (choice == 0 && Directory.Exists(dbDir))
        {
            try { Directory.Delete(dbDir, true); }
            catch (Exception e) { Debug.LogException(e); }
        }
        Directory.CreateDirectory(dbDir);

        try { EnsureEmbedderLoaded(); }
        catch (Exception e)
        {
            Debug.LogException(e);
            EditorUtility.DisplayDialog("LightRAG Ingest", "Failed to load the text embedder, see console.", "OK");
            return;
        }

        var pump = new EditorPumpDispatcher();
        var cts = new CancellationTokenSource();
        var sw = System.Diagnostics.Stopwatch.StartNew();
        s_Status = "Initializing…";
        s_Progress = 0f;
        Task ingestTask = null;
        try
        {
            ingestTask = RunIngestAsync(dbDir, txts, endpoint, model, pump, cts.Token);
            while (!ingestTask.IsCompleted)
            {
                pump.Drain();

                // Progress bar uses a time-based asymptote toward 0.9 (per-file granularity is useless for single-file ingest); elapsed time is the liveness signal.
                var elapsedSec = sw.Elapsed.TotalSeconds;
                var timeRamp = (float)(elapsedSec / (elapsedSec + 30.0)) * 0.9f;
                var progress = Mathf.Clamp01(Mathf.Max(s_Progress, timeRamp));
                var info = $"{s_Status} · elapsed {elapsedSec:0}s";

                if (EditorUtility.DisplayCancelableProgressBar("LightRAG Ingest", info, progress))
                {
                    cts.Cancel();
                    break;
                }
                Thread.Sleep(1);
            }
            while (!ingestTask.IsCompleted)
            {
                pump.Drain();
                Thread.Sleep(1);
            }
            pump.Drain();

            if (ingestTask.IsFaulted)
            {
                Debug.LogException(ingestTask.Exception);
                EditorUtility.DisplayDialog("LightRAG Ingest", "Ingest failed, see console.", "OK");
            }
            else if (ingestTask.IsCanceled || cts.IsCancellationRequested)
            {
                Debug.LogWarning("[RAG] Ingest canceled.");
            }
            else
            {
                Debug.Log($"[RAG] Ingest complete in {sw.Elapsed.TotalSeconds:0}s. DB at: {dbDir}");
            }
        }
        finally
        {
            cts.Dispose();
            EditorUtility.ClearProgressBar();
            AssetDatabase.Refresh();
        }
    }

    public static void IngestHeadless()
    {
        // Strip stack traces from Log in batchmode - heartbeat fires every 10s and traces would bury progress. Warnings/errors keep theirs.
        Application.SetStackTraceLogType(LogType.Log, StackTraceLogType.None);

        // Batchmode has no scene loaded, so open the sample scene first so ResolveIngestConfig() can read the component's inspector values.
        const string RagScenePath = "Assets/Examples/VoiceAgent/VoiceAgentSample.unity";
        if (File.Exists(RagScenePath))
        {
            UnityEditor.SceneManagement.EditorSceneManager.OpenScene(
                RagScenePath,
                UnityEditor.SceneManagement.OpenSceneMode.Single);
            Debug.Log($"[RAG] Loaded scene for ingest config: {RagScenePath}");
        }
        else
        {
            Debug.LogWarning($"[RAG] Scene not found at {RagScenePath}, falling back to ResolveIngestConfig defaults.");
        }

        var knowledgeDir = Path.Combine(Application.streamingAssetsPath, KnowledgeSubdir);
        var dbDir = Path.Combine(Application.streamingAssetsPath, DbSubdir);
        if (!Directory.Exists(knowledgeDir)) { Debug.LogError("[RAG] Missing StreamingAssets/Knowledge."); return; }
        var txts = Directory.GetFiles(knowledgeDir, "*.txt");
        if (txts.Length == 0) { Debug.LogError("[RAG] No .txt files in StreamingAssets/Knowledge."); return; }

        var (endpoint, model) = ResolveIngestConfig();

        if (Directory.Exists(dbDir)) { try { Directory.Delete(dbDir, true); } catch (Exception e) { Debug.LogException(e); } }
        Directory.CreateDirectory(dbDir);

        try { EnsureEmbedderLoaded(); } catch (Exception e) { Debug.LogException(e); return; }

        var pump = new EditorPumpDispatcher();
        var sw = System.Diagnostics.Stopwatch.StartNew();
        Debug.Log($"[RAG] Headless ingest start: {txts.Length} file(s), LLM {model} @ {endpoint}.");
        s_Status = "Initializing…";
        s_Progress = 0f;
        try
        {
            var task = RunIngestAsync(dbDir, txts, endpoint, model, pump, CancellationToken.None);

            // Report LLM cache file size as forward-progress proxy (per-file granularity is useless for single-file); +0 KB across heartbeats = stuck.
            var cachePath = Path.Combine(dbDir, "kv_store_llm_response_cache.json");
            string lastStatus = null;
            long lastCacheBytes = 0;
            var heartbeat = System.Diagnostics.Stopwatch.StartNew();
            const double heartbeatIntervalSec = 10.0;
            while (!task.IsCompleted)
            {
                pump.Drain();
                Thread.Sleep(2);

                var status = s_Status;
                if (status != lastStatus || heartbeat.Elapsed.TotalSeconds >= heartbeatIntervalSec)
                {
                    long cacheBytes = 0;
                    try { if (File.Exists(cachePath)) cacheBytes = new FileInfo(cachePath).Length; }
                    catch { /* file may be mid-write, best-effort sampling */ }
                    var delta = cacheBytes - lastCacheBytes;
                    var sinceLastSec = heartbeat.Elapsed.TotalSeconds;
                    Debug.Log(
                        $"[RAG] {status} (cache {cacheBytes / 1024} KB, +{delta / 1024} KB in {sinceLastSec:0}s, elapsed {sw.Elapsed.TotalSeconds:0}s)");
                    lastCacheBytes = cacheBytes;
                    lastStatus = status;
                    heartbeat.Restart();
                }
            }
            pump.Drain();

            if (task.IsFaulted)
            {
                Debug.LogException(task.Exception);
                Debug.LogError("[RAG] Headless ingest FAILED.");
            }
            else
            {
                Debug.Log($"[RAG] Headless ingest COMPLETE in {sw.Elapsed.TotalSeconds:0}s. DB: {dbDir}");
            }
        }
        finally
        {
            AssetDatabase.Refresh();
        }
    }

    static IChatLlm BuildChatLlm(string ollamaEndpoint, string ollamaModel, int numCtx)
    {
        var liteBase = Environment.GetEnvironmentVariable("LITELLM_BASE");
        if (!string.IsNullOrEmpty(liteBase))
        {
            var liteModel = Environment.GetEnvironmentVariable("LITELLM_MODEL");
            if (string.IsNullOrEmpty(liteModel)) liteModel = ollamaModel;
            var key = Environment.GetEnvironmentVariable("LITELLM_API_KEY");
            Debug.Log($"[RAG] LLM provider: LiteLLM model={liteModel} @ {liteBase}");
            return new LiteLlmChatLlm(liteModel, liteBase, key);
        }
        Debug.Log($"[RAG] LLM provider: Ollama model={ollamaModel} @ {ollamaEndpoint}");
        return new OllamaChatLlm(ollamaModel, ollamaEndpoint, numCtx);
    }

    static E5TextEmbedder s_E5;

    static ITextEmbedder ActiveEmbedder => s_E5;

    // Must be called on the Unity main thread (AssetDatabase + Sentis worker creation). Idempotent.
    static void EnsureEmbedderLoaded()
    {
        if (s_E5 != null) return;
        var e5 = new E5TextEmbedder(BackendType.CPU, Debug.Log);
        if (!e5.Load("Model/E5/e5_small_fp16.sentis", "Model/E5/tokenizer.json"))
            throw new Exception("[RAG] e5 embedder load failed (run OnDeviceAgent ▸ RAG ▸ Convert e5 ONNX to fp16 .sentis first)");
        s_E5 = e5;
    }

    static EmbeddingFunc BuildEmbedding(EditorPumpDispatcher pump)
    {
        var e = ActiveEmbedder;
        if (e == null) throw new InvalidOperationException("[RAG] embedder not pre-loaded (call EnsureEmbedderLoaded on the main thread).");
        Debug.Log("[RAG] embedder: multilingual-e5-small (384)");
        return e.AsEmbeddingFunc(pump);
    }

    static async Task RunIngestAsync(
        string dbDir, string[] txts, string endpoint, string model,
        EditorPumpDispatcher pump, CancellationToken ct)
    {
        IChatLlm llm = BuildChatLlm(endpoint, model, 8192);
        // Tuned for local 12B-class Ollama: MaxAsync=2 avoids tail-of-queue starvation, LlmTimeout=900s outlasts slow decodes, MaxGleaning=0 halves LLM calls at small recall cost.
        var config = new LightRagConfig
        {
            Temperature = 0,
            MaxAsync = 2,
            LlmTimeout = TimeSpan.FromSeconds(900),
            Extraction = new ExtractionOptions { MaxGleaning = 0 },
        };
        var embedding = BuildEmbedding(pump);
        var rag = FileBasedLightRag.Create(dbDir, llm, embedding, config);
        await rag.InitializeAsync().ConfigureAwait(false);

        for (var i = 0; i < txts.Length; i++)
        {
            ct.ThrowIfCancellationRequested();
            var name = Path.GetFileName(txts[i]);
            s_Status = $"Ingesting {name} ({i + 1}/{txts.Length})…";
            s_Progress = txts.Length == 0 ? 0f : (float)i / txts.Length;
            var text = File.ReadAllText(txts[i]);
            await rag.InsertAsync(text, name).ConfigureAwait(false);
        }
        s_Status = "Flushing DB…";
        s_Progress = 0.99f;
        await rag.FinalizeAsync().ConfigureAwait(false);
        WriteManifest(dbDir);
    }

    static void WriteManifest(string dbDir)
    {
        try
        {
            var files = Directory.GetFiles(dbDir, "*", SearchOption.AllDirectories);
            using var writer = new StreamWriter(Path.Combine(dbDir, ManifestFile), false);
                // Timestamp in header ensures each ingest yields a different manifest - StreamingDbInstaller byte-compares to detect stale installs.
                writer.WriteLine("# ingested-at: " + DateTime.UtcNow.ToString("o"));
                foreach (var f in files)
                {
                    var rel = f.Substring(dbDir.Length).TrimStart('/', '\\').Replace('\\', '/');
                    if (rel == ManifestFile || rel.EndsWith(".meta", StringComparison.OrdinalIgnoreCase))
                        continue;
                    writer.WriteLine(rel);
                }
            }
            catch (Exception e) { Debug.LogException(e); }
        }

        sealed class EditorPumpDispatcher : IUnityMainThreadDispatcher
        {
            readonly ConcurrentQueue<Action> m_Queue = new ConcurrentQueue<Action>();
            readonly Thread m_MainThread = Thread.CurrentThread;

            public bool IsOnMainThread => Thread.CurrentThread == m_MainThread;

            public void Post(Action action)
            {
                if (action != null) m_Queue.Enqueue(action);
            }

            public Task RunOnMainAsync(Func<Task> work)
            {
                var tcs = new TaskCompletionSource<bool>(TaskCreationOptions.RunContinuationsAsynchronously);
                m_Queue.Enqueue(() =>
                {
                    try
                    {
                        var t = work();
                        Bridge(t, tcs, _ => true);
                    }
                    catch (Exception e) { tcs.TrySetException(e); }
                });
                return tcs.Task;
            }

            public Task<T> RunOnMainAsync<T>(Func<Task<T>> work)
            {
                var tcs = new TaskCompletionSource<T>(TaskCreationOptions.RunContinuationsAsynchronously);
                m_Queue.Enqueue(() =>
                {
                    try
                    {
                        var t = work();
                        Bridge(t, tcs, x => x.Result);
                    }
                    catch (Exception e) { tcs.TrySetException(e); }
                });
                return tcs.Task;
            }

            public void Drain()
            {
                while (m_Queue.TryDequeue(out var action))
                {
                    try { action(); }
                    catch (Exception e) { Debug.LogException(e); }
                }
            }

            static void Bridge<TIn, TOut>(Task<TIn> t, TaskCompletionSource<TOut> tcs, Func<Task<TIn>, TOut> select)
            {
                void Complete(Task<TIn> x)
                {
                    if (x.IsFaulted) tcs.TrySetException(x.Exception!.InnerExceptions);
                    else if (x.IsCanceled) tcs.TrySetCanceled();
                    else tcs.TrySetResult(select(x));
                }
                if (t.IsCompleted) Complete(t);
                else t.ContinueWith(Complete, TaskScheduler.Default);
            }

            static void Bridge(Task t, TaskCompletionSource<bool> tcs, Func<Task, bool> _)
            {
                void Complete(Task x)
                {
                    if (x.IsFaulted) tcs.TrySetException(x.Exception!.InnerExceptions);
                    else if (x.IsCanceled) tcs.TrySetCanceled();
                    else tcs.TrySetResult(true);
                }
                if (t.IsCompleted) Complete(t);
                else t.ContinueWith(Complete, TaskScheduler.Default);
            }
        }
    }
}