using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.IO.Compression;
using System.Text;
using UnityEngine;
using UnityEngine.Networking;

public class BeatSageUploader : MonoBehaviour
{
    private const string BASE_URL     = "https://beatsage.com";
    private const string CREATE_EP    = "/beatsaber_custom_level_create";
    private const string HEARTBEAT_EP = "/beatsaber_custom_level_heartbeat/{0}";
    private const string DOWNLOAD_EP  = "/beatsaber_custom_level_download/{0}";

    private const float POLL_INTERVAL = 5f;
    private const float POLL_TIMEOUT  = 300f;

    private static readonly Dictionary<string, string> DiffNames = new()
    {
        { "normal",     "Normal"     },
        { "hard",       "Hard"       },
        { "expert",     "Expert"     },
        { "expertplus", "ExpertPlus" },
    };

    private static readonly Dictionary<string, string> DatFileNames = new()
    {
        { "normal",     "Normal.dat"     },
        { "hard",       "Hard.dat"       },
        { "expert",     "Expert.dat"     },
        { "expertplus", "ExpertPlus.dat" },
    };

    public string       CurrentStatus { get; private set; } = "";
    public SongMetadata LastMetadata  { get; private set; }

    // Upload from local file path
    public IEnumerator Upload(
        string audioPath,
        List<string> difficulties,
        float bpm,
        Action<float> onProgress,
        Action<Dictionary<string, List<NoteData>>> onComplete,
        Action<string> onError)
    {
        SetStatus("[1/4] Uploading audio...");
        string levelId = null;

        yield return CreateLevel(audioPath, difficulties, id => levelId = id, onError);
        if (levelId == null) yield break;
        onProgress?.Invoke(0.15f);

        yield return PollAndDownload(levelId, difficulties, bpm, onProgress, onComplete, onError);
    }

    // Upload from direct audio URL (Beat Sage downloads it server-side)
    public IEnumerator UploadFromUrl(
        string audioUrl,
        List<string> difficulties,
        float bpm,
        Action<float> onProgress,
        Action<Dictionary<string, List<NoteData>>> onComplete,
        Action<string> onError)
    {
        SetStatus("[1/4] Sending URL to Beat Sage...");
        string levelId = null;

        yield return CreateLevelFromUrl(audioUrl, difficulties, id => levelId = id, onError);
        if (levelId == null) yield break;
        onProgress?.Invoke(0.15f);

        yield return PollAndDownload(levelId, difficulties, bpm, onProgress, onComplete, onError);
    }

    // Shared poll + download + convert phase
    private IEnumerator PollAndDownload(
        string levelId,
        List<string> difficulties,
        float bpm,
        Action<float> onProgress,
        Action<Dictionary<string, List<NoteData>>> onComplete,
        Action<string> onError)
    {
        SetStatus("[2/4] Generating beatmap...");
        bool  ready   = false;
        float elapsed = 0f;

        while (!ready && elapsed < POLL_TIMEOUT)
        {
            yield return new WaitForSeconds(POLL_INTERVAL);
            elapsed += POLL_INTERVAL;

            bool error = false;
            yield return PollHeartbeat(levelId,
                status =>
                {
                    ready = string.Equals(status, "generated", StringComparison.OrdinalIgnoreCase)
                         || string.Equals(status, "done",      StringComparison.OrdinalIgnoreCase);
                    error = string.Equals(status, "error",     StringComparison.OrdinalIgnoreCase);
                },
                onError);

            if (error) { onError?.Invoke("Beat Sage generation failed (error status)"); yield break; }

            onProgress?.Invoke(0.15f + Mathf.Clamp01(elapsed / POLL_TIMEOUT) * 0.6f);
            SetStatus($"[2/4] Generating... {(int)elapsed}s elapsed");
        }

        if (!ready) { onError?.Invoke("Beat Sage timeout (>5 min)"); yield break; }

        SetStatus("[3/4] Downloading result...");
        byte[] zipBytes = null;
        yield return DownloadZip(levelId, b => zipBytes = b, onError);
        if (zipBytes == null) yield break;
        onProgress?.Invoke(0.9f);

        SetStatus("[3/4] Converting map data...");
        Dictionary<string, List<NoteData>> maps = null;
        try   { maps = ExtractAndConvert(zipBytes, difficulties, bpm); }
        catch (Exception e) { onError?.Invoke($"Conversion failed: {e.Message}"); yield break; }

        onProgress?.Invoke(1f);
        SetStatus("[3/4] Conversion complete.");
        onComplete?.Invoke(maps);
    }

    private IEnumerator CreateLevelFromUrl(string audioUrl, List<string> difficulties,
        Action<string> onSuccess, Action<string> onError)
    {
        var mappedDiffs = new List<string>();
        foreach (string d in difficulties)
            if (DiffNames.TryGetValue(d, out var n)) mappedDiffs.Add(n);

        if (mappedDiffs.Count == 0)
        {
            onError?.Invoke("No supported difficulties selected.");
            yield break;
        }

        var form = new List<IMultipartFormSection>
        {
            new MultipartFormDataSection("audio_url",             audioUrl),
            new MultipartFormDataSection("audio_metadata_title",  " "),
            new MultipartFormDataSection("audio_metadata_artist", " "),
            new MultipartFormDataSection("difficulties",          string.Join(",", mappedDiffs)),
            new MultipartFormDataSection("modes",                 "Standard"),
            new MultipartFormDataSection("events",                "DotBlocks,Obstacles,Bombs"),
            new MultipartFormDataSection("environment",           "DefaultEnvironment"),
            new MultipartFormDataSection("system_tag",            "v2"),
        };

        using var req = UnityWebRequest.Post(BASE_URL + CREATE_EP, form);
        req.SetRequestHeader("Accept",     "*/*");
        req.SetRequestHeader("User-Agent", "VRBeatSaber/1.0");
        yield return req.SendWebRequest();

        if (req.result != UnityWebRequest.Result.Success)
        {
            onError?.Invoke($"Level create (URL) failed: {req.error}");
            yield break;
        }

        string levelId = ParseJsonString(req.downloadHandler.text, "id");
        if (string.IsNullOrEmpty(levelId))
        {
            onError?.Invoke($"Failed to parse levelId. Response: {req.downloadHandler.text}");
            yield break;
        }

        onSuccess?.Invoke(levelId);
    }

    private IEnumerator CreateLevel(string audioPath, List<string> difficulties,
        Action<string> onSuccess, Action<string> onError)
    {
        byte[] audioBytes = File.ReadAllBytes(audioPath);
        string fileName   = Path.GetFileName(audioPath);

        var mappedDiffs = new List<string>();
        foreach (string d in difficulties)
            if (DiffNames.TryGetValue(d, out var n)) mappedDiffs.Add(n);

        if (mappedDiffs.Count == 0)
        {
            onError?.Invoke("No supported difficulties selected (use Normal/Hard/Expert/ExpertPlus).");
            yield break;
        }

        var form = new List<IMultipartFormSection>
        {
            new MultipartFormFileSection("audio_file", audioBytes, fileName, "audio/mpeg"),
            new MultipartFormDataSection("audio_metadata_title",  " "),
            new MultipartFormDataSection("audio_metadata_artist", " "),
            new MultipartFormDataSection("difficulties",          string.Join(",", mappedDiffs)),
            new MultipartFormDataSection("modes",                 "Standard"),
            new MultipartFormDataSection("events",                "DotBlocks,Obstacles,Bombs"),
            new MultipartFormDataSection("environment",           "DefaultEnvironment"),
            new MultipartFormDataSection("system_tag",            "v2"),
        };

        using var req = UnityWebRequest.Post(BASE_URL + CREATE_EP, form);
        req.SetRequestHeader("Accept",     "*/*");
        req.SetRequestHeader("User-Agent", "VRBeatSaber/1.0");
        yield return req.SendWebRequest();

        if (req.result != UnityWebRequest.Result.Success)
        {
            onError?.Invoke($"Level create request failed: {req.error}");
            yield break;
        }

        string levelId = ParseJsonString(req.downloadHandler.text, "id");
        if (string.IsNullOrEmpty(levelId))
        {
            onError?.Invoke($"Failed to parse levelId. Response: {req.downloadHandler.text}");
            yield break;
        }

        onSuccess?.Invoke(levelId);
    }

    private IEnumerator PollHeartbeat(string levelId,
        Action<string> onStatus, Action<string> onError)
    {
        using var req = UnityWebRequest.Get(BASE_URL + string.Format(HEARTBEAT_EP, levelId));
        yield return req.SendWebRequest();

        if (req.result != UnityWebRequest.Result.Success)
        {
            onError?.Invoke($"Heartbeat check failed: {req.error}");
            yield break;
        }

        onStatus?.Invoke(ParseJsonString(req.downloadHandler.text, "status") ?? "");
    }

    private IEnumerator DownloadZip(string levelId,
        Action<byte[]> onSuccess, Action<string> onError)
    {
        string url = BASE_URL + string.Format(DOWNLOAD_EP, levelId);

        for (int attempt = 1; attempt <= 3; attempt++)
        {
            using var req = UnityWebRequest.Get(url);
            yield return req.SendWebRequest();

            if (req.result == UnityWebRequest.Result.Success)
            {
                onSuccess?.Invoke(req.downloadHandler.data);
                yield break;
            }

            // 500 오류는 Beat Sage 처리 지연일 수 있으므로 재시도
            if (req.responseCode == 500 && attempt < 3)
            {
                SetStatus($"[3/4] Server error, retrying ({attempt}/3)...");
                yield return new WaitForSeconds(5f);
                continue;
            }

            onError?.Invoke($"ZIP download failed: {req.error} (HTTP {req.responseCode})");
            yield break;
        }
    }

    private Dictionary<string, List<NoteData>> ExtractAndConvert(
        byte[] zipBytes, List<string> difficulties, float fallbackBpm)
    {
        var result = new Dictionary<string, List<NoteData>>();

        using var ms      = new MemoryStream(zipBytes);
        using var archive = new ZipArchive(ms, ZipArchiveMode.Read);

        // Read info.dat first to get auto-detected BPM and metadata
        float bpm = fallbackBpm;
        foreach (var e in archive.Entries)
        {
            if (!string.Equals(e.Name, "info.dat", StringComparison.OrdinalIgnoreCase)) continue;
            using var r = new StreamReader(e.Open(), Encoding.UTF8);
            var meta = BeatSageConverter.ParseInfoDat(r.ReadToEnd());
            if (meta != null)
            {
                LastMetadata = meta;
                if (meta.bpm > 0) bpm = meta.bpm;
            }
            break;
        }

        foreach (string diff in difficulties)
        {
            if (!DatFileNames.TryGetValue(diff, out string datName)) continue;

            ZipArchiveEntry entry = null;
            foreach (var e in archive.Entries)
                if (string.Equals(e.Name, datName, StringComparison.OrdinalIgnoreCase))
                { entry = e; break; }

            if (entry == null) { Debug.LogWarning($"[BeatSageUploader] {datName} not found — skipped."); continue; }

            using var reader = new StreamReader(entry.Open(), Encoding.UTF8);
            result[diff] = BeatSageConverter.Convert(reader.ReadToEnd(), bpm);
        }

        return result;
    }

    private static string ParseJsonString(string json, string key)
    {
        string search = $"\"{key}\":\"";
        int start = json.IndexOf(search, StringComparison.Ordinal);
        if (start < 0) return null;
        start += search.Length;
        int end = json.IndexOf('"', start);
        return end > start ? json.Substring(start, end - start) : null;
    }

    private void SetStatus(string msg) => CurrentStatus = msg;
}