using Hamakaze;
using SharpChat.Users;
using SharpChat.Users.Remote;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text.Json;

namespace SharpChat.DataProvider.Misuzu.Users {
    public class MisuzuUserClient : IRemoteUserClient {
        private MisuzuDataProvider DataProvider { get; }
        private HttpClient HttpClient { get; }

        private const string AUTH_URL = @"/verify";
        private const string BUMP_URL = @"/bump";
        private const string RESOLVE_URL = @"/resolve?m={0}&p={1}";

        private Dictionary<long, (DateTimeOffset age, MisuzuUser mui)> UserIdCache { get; } = new();
        private readonly object UserIdCacheSync = new();
        private static readonly TimeSpan CacheMaxAge = TimeSpan.FromMinutes(1);

        public MisuzuUserClient(MisuzuDataProvider dataProvider, HttpClient httpClient) {
            DataProvider = dataProvider ?? throw new ArgumentNullException(nameof(dataProvider));
            HttpClient = httpClient ?? throw new ArgumentNullException(nameof(httpClient));
        }

        public void AuthenticateUser(UserAuthRequest request, Action<IUserAuthResponse> onSuccess, Action<Exception> onFailure) {
            if(request == null)
                throw new ArgumentNullException(nameof(request));
            if(onSuccess == null)
                throw new ArgumentNullException(nameof(onSuccess));
            if(onFailure == null)
                throw new ArgumentNullException(nameof(onFailure));

#if DEBUG
            if(request.UserId >= 10000) {
                onSuccess.Invoke(new MisuzuUserAuthResponse {
                    Success = true,
                    UserId = request.UserId,
                    UserName = @"Misaka-" + (request.UserId - 10000),
                    ColourRaw = (RNG.Next(0, 255) << 16) | (RNG.Next(0, 255) << 8) | RNG.Next(0, 255),
                    Rank = 0,
                    SilencedUntil = DateTimeOffset.MinValue,
                    Permissions = UserPermissions.SendMessage | UserPermissions.EditOwnMessage | UserPermissions.DeleteOwnMessage,
                });
                return;
            }
#endif
            MisuzuUserAuthRequest mar = new(request);

            HttpRequestMessage req = new(HttpRequestMessage.POST, DataProvider.GetURL(AUTH_URL));
            req.SetHeader(@"X-SharpChat-Signature", DataProvider.GetSignedHash(mar));
            req.SetBody(JsonSerializer.SerializeToUtf8Bytes(mar));

            HttpClient.SendRequest(
                req,
                onComplete: (t, r) => {
                    using MemoryStream ms = new();
                    r.Body.CopyTo(ms);
                    MisuzuUserAuthResponse res = JsonSerializer.Deserialize<MisuzuUserAuthResponse>(ms.ToArray());
                    if(res.Success)
                        onSuccess.Invoke(res);
                    else
                        onFailure.Invoke(new UserAuthFailedException(res.Reason));
                },
                onError: (t, e) => {
                    Logger.Write(@"An error occurred during authentication.");
                    Logger.Debug(e);
                    onFailure.Invoke(e);
                }
            );
        }

        public void BumpUsers(IEnumerable<UserBumpInfo> users, Action onSuccess, Action<Exception> onFailure) {
            if(users == null)
                throw new ArgumentNullException(nameof(users));
            if(onSuccess == null)
                throw new ArgumentNullException(nameof(onSuccess));
            if(onFailure == null)
                throw new ArgumentNullException(nameof(onFailure));
            if(!users.Any())
                return;

            byte[] data = JsonSerializer.SerializeToUtf8Bytes(users.Select(ubi => new MisuzuUserBumpInfo(ubi)));

            HttpRequestMessage request = new(HttpRequestMessage.POST, DataProvider.GetURL(BUMP_URL));
            request.SetHeader(@"X-SharpChat-Signature", DataProvider.GetSignedHash(data));
            request.SetBody(data);

            HttpClient.SendRequest(
                request,
                disposeRequest: false,
                onComplete: (t, r) => { request.Dispose(); onSuccess?.Invoke(); },
                onError: (t, e) => {
                    Logger.Write(@"User bump request failed. Retrying once...");
                    Logger.Debug(e);

                    HttpClient.SendRequest(
                        request,
                        onComplete: (t, r) => {
                            Logger.Write(@"Second user bump attempt succeeded!");
                            onSuccess?.Invoke();
                        },
                        onError: (t, e) => {
                            Logger.Write(@"User bump request failed again.");
                            Logger.Debug(e);
                            onFailure?.Invoke(e);
                        }
                    );
                }
            );
        }

        private const string RESOLVE_ID = @"id";
        private const string RESOLVE_NAME = @"name";

        public void ResolveUser(long userId, Action<IRemoteUser> onSuccess, Action<Exception> onFailure) {
            ResolveUser(RESOLVE_ID, userId, onSuccess, onFailure);
        }

        public void ResolveUser(string userName, Action<IRemoteUser> onSuccess, Action<Exception> onFailure) {
            ResolveUser(RESOLVE_NAME, userName, onSuccess, onFailure);
        }

        public void ResolveUser(IUser localUser, Action<IRemoteUser> onSuccess, Action<Exception> onFailure) {
            if(localUser == null)
                onSuccess(null);
            else
                ResolveUser(RESOLVE_ID, localUser.UserId, onSuccess, onFailure);
        }

        private void ResolveUser(string method, object param, Action<IRemoteUser> onSuccess, Action<Exception> onFailure) {
            if(method == null)
                throw new ArgumentNullException(nameof(method));
            if(param == null)
                throw new ArgumentNullException(nameof(param));
            if(onSuccess == null)
                throw new ArgumentNullException(nameof(onSuccess));
            if(onFailure == null)
                throw new ArgumentNullException(nameof(onFailure));

            if(method == RESOLVE_ID) {
                MisuzuUser mui = null;
                lock(UserIdCacheSync)
                    if(UserIdCache.TryGetValue((long)param, out (DateTimeOffset age, MisuzuUser mui) cache)
                        && (DateTimeOffset.Now - cache.age) < CacheMaxAge)
                        mui = cache.mui;

                if(mui != null) {
                    onSuccess(mui);
                    return;
                }
            }

            HttpRequestMessage req = new(HttpRequestMessage.GET, DataProvider.GetURL(
                string.Format(RESOLVE_URL, method, param)
            ));
            req.SetHeader(@"X-SharpChat-Signature", DataProvider.GetSignedHash(string.Format(
                @"resolve#{0}#{1}", method, param
            )));

            HttpClient.SendRequest(
                req,
                (t, r) => {
                    try {
                        MisuzuUser mui = JsonSerializer.Deserialize<MisuzuUser>(r.GetBodyBytes());
                        lock(UserIdCacheSync)
                            UserIdCache[mui.UserId] = (DateTimeOffset.Now, mui);
                        onSuccess.Invoke(mui);
                    } catch(Exception ex) {
                        Logger.Debug(ex);
                        onFailure.Invoke(ex);
                    }
                },
                (t, e) => { Logger.Debug(e); onFailure.Invoke(e); }
            );
        }
    }
}