using System;
using System.Collections;
using System.IO;
using System.Reflection;
using System.Text;
using BeatLeader.Utils;
using BeatSaberPlaylistsLib;
using BeatSaberPlaylistsLib.Types;
using UnityEngine;
using UnityEngine.Networking;
using IPALogger = IPA.Logging.Logger;

namespace Setlist
{
    /// <summary>
    /// Dev/test path: POST the on-disk playlist JSON to BeatLeader to prove authenticated updates work.
    /// Requires BeatLeader to have finished sign-in (Unity cookie cache). See docs/beatleader-playlist-api.md.
    /// </summary>
    internal static class BeatLeaderPlaylistUpdateTest
    {
        /// <summary>When this playlist title is locally owned (owner matches platform id), run POST test on startup.</summary>
        internal const string TargetPlaylistTitle = "2025-mapfilter-01";

        private const string AuthenticationTypeName = "BeatLeader.API.Authentication";
        private const string SignedInFieldName = "_signedIn";
        private const float SignInWaitTimeoutSeconds = 90f;
        private const int PostRequestTimeoutSeconds = 120;

        /// <summary>POST <c>/user/playlist</c> with the serialized playlist body (same shape as the website sample).</summary>
        internal static IEnumerator RunIfTargetOwned(
            IPlaylist playlist,
            bool hasSyncUrl,
            string beatLeaderGuid,
            string ownerId,
            string platformUserId,
            IPALogger log)
        {
            if (!string.Equals(playlist.Title, TargetPlaylistTitle, StringComparison.Ordinal))
            {
                yield break;
            }

            if (!IsLocallyOwnedBeatLeaderPlaylist(hasSyncUrl, beatLeaderGuid, ownerId, platformUserId))
            {
                log.Info(
                    $"Setlist BeatLeader POST test: skip \"{TargetPlaylistTitle}\" (not locally owned or missing BeatLeader fields).");
                yield break;
            }

            if (!TryGetBeatLeaderServerFields(playlist, out var serverPlaylistId, out var shared))
            {
                log.Info(
                    $"Setlist BeatLeader POST test: skip \"{TargetPlaylistTitle}\" (customData missing id or not parseable).");
                yield break;
            }

            var signedInField = TryResolveBeatLeaderSignedInField(log);
            if (signedInField == null)
            {
                yield break;
            }

            var waited = 0f;
            while (!IsSignedIn(signedInField))
            {
                if (waited >= SignInWaitTimeoutSeconds)
                {
                    log.Info(
                        $"Setlist BeatLeader POST test: BeatLeader login did not complete within {SignInWaitTimeoutSeconds:F0}s.");
                    yield break;
                }

                yield return new WaitForSeconds(1f);
                waited += 1f;
            }

            if (!TrySerializePlaylist(playlist, log, out var bodyJson))
            {
                yield break;
            }

            var url =
                $"{BLConstants.BEATLEADER_API_URL}/user/playlist?id={Uri.EscapeDataString(serverPlaylistId)}&shared="
                + (shared ? "true" : "false");

            byte[] bodyRaw = Encoding.UTF8.GetBytes(bodyJson);
            using (var request = new UnityWebRequest(url, UnityWebRequest.kHttpVerbPOST))
            {
                request.timeout = PostRequestTimeoutSeconds;
                request.uploadHandler = new UploadHandlerRaw(bodyRaw);
                request.downloadHandler = new DownloadHandlerBuffer();
                request.SetRequestHeader("Content-Type", "text/plain;charset=UTF-8");
                request.SetRequestHeader("User-Agent", "Setlist/" + GetAssemblyVersion());

                yield return request.SendWebRequest();

                if (request.result == UnityWebRequest.Result.ConnectionError)
                {
                    log.Info("Setlist BeatLeader POST test: network error: " + request.error);
                    yield break;
                }

                if (request.result == UnityWebRequest.Result.ProtocolError)
                {
                    log.Info(
                        $"Setlist BeatLeader POST test: HTTP {request.responseCode} body="
                        + TruncateForLog(request.downloadHandler?.text));
                    yield break;
                }

                log.Info(
                    "Setlist BeatLeader POST test: success HTTP "
                    + request.responseCode
                    + " body="
                    + TruncateForLog(request.downloadHandler?.text));
            }
        }

        private static bool IsLocallyOwnedBeatLeaderPlaylist(
            bool hasSyncUrl,
            string beatLeaderGuid,
            string ownerId,
            string platformUserId)
        {
            return hasSyncUrl
                && !string.IsNullOrEmpty(beatLeaderGuid)
                && !string.IsNullOrEmpty(ownerId)
                && !string.IsNullOrEmpty(platformUserId)
                && string.Equals(ownerId, platformUserId, StringComparison.Ordinal);
        }

        private static bool TryGetBeatLeaderServerFields(IPlaylist playlist, out string serverPlaylistId, out bool shared)
        {
            serverPlaylistId = null;
            shared = false;

            if (!playlist.TryGetCustomData("id", out var idObj) || idObj == null)
            {
                return false;
            }

            serverPlaylistId = Convert.ToString(idObj);
            if (string.IsNullOrWhiteSpace(serverPlaylistId))
            {
                return false;
            }

            if (playlist.TryGetCustomData("shared", out var sharedObj) && sharedObj != null)
            {
                if (sharedObj is bool b)
                {
                    shared = b;
                }
                else if (bool.TryParse(Convert.ToString(sharedObj), out var parsed))
                {
                    shared = parsed;
                }
            }

            return true;
        }

        private static bool TrySerializePlaylist(IPlaylist playlist, IPALogger log, out string json)
        {
            json = null;
            var mgr = PlaylistManager.DefaultManager;
            IPlaylistHandler handler = null;
            if (!string.IsNullOrEmpty(playlist.SuggestedExtension))
            {
                handler = mgr.GetHandlerForExtension(playlist.SuggestedExtension);
            }

            if (handler == null)
            {
                handler = mgr.GetHandlerForPlaylistType(playlist.GetType());
            }

            if (handler == null)
            {
                log.Info("Setlist BeatLeader POST test: no IPlaylistHandler for playlist type.");
                return false;
            }

            try
            {
                using (var stream = new MemoryStream())
                {
                    handler.Serialize(playlist, stream);
                    json = Encoding.UTF8.GetString(stream.ToArray());
                }

                return !string.IsNullOrEmpty(json);
            }
            catch (Exception ex)
            {
                log.Info("Setlist BeatLeader POST test: serialize failed: " + ex.Message);
                return false;
            }
        }

        private static FieldInfo TryResolveBeatLeaderSignedInField(IPALogger log)
        {
            var beatLeaderAssembly = typeof(BLConstants).Assembly;
            var authType = beatLeaderAssembly.GetType(AuthenticationTypeName);
            if (authType == null)
            {
                log.Info($"Setlist BeatLeader POST test: assembly has no {AuthenticationTypeName}.");
                return null;
            }

            var field = authType.GetField(SignedInFieldName, BindingFlags.NonPublic | BindingFlags.Static);
            if (field == null)
            {
                log.Info(
                    $"{AuthenticationTypeName} has no static field '{SignedInFieldName}' (BeatLeader API changed?).");
                return null;
            }

            return field;
        }

        private static bool IsSignedIn(FieldInfo signedInField)
        {
            var value = signedInField.GetValue(null);
            return value is bool b && b;
        }

        private static string GetAssemblyVersion()
        {
            var asm = typeof(BeatLeaderPlaylistUpdateTest).Assembly;
            return asm.GetName().Version?.ToString() ?? "0.0.0";
        }

        private static string TruncateForLog(string s, int maxLen = 512)
        {
            if (string.IsNullOrEmpty(s))
            {
                return "";
            }

            return s.Length <= maxLen ? s : s.Substring(0, maxLen) + "…";
        }
    }
}