using System;
using System.Collections.Generic;
using System.Net.Http;
using System.Threading;
using System.Threading.Tasks;
using CommunityToolkit.Mvvm.Messaging;
using Wino.Core.Domain.Entities.Shared;
using Wino.Core.Domain.Enums;
using Wino.Core.Domain.Interfaces;
using Wino.Core.Domain.Models.Accounts;
using Wino.Core.Requests.Bundles;
using Wino.Messaging.UI;

namespace Wino.Core.Synchronizers
{
    public abstract class BaseSynchronizer<TBaseRequest>
    {
        protected SemaphoreSlim synchronizationSemaphore = new(1);
        protected CancellationToken activeSynchronizationCancellationToken;

        protected List<IRequestBase> changeRequestQueue = [];
        public MailAccount Account { get; }

        private AccountSynchronizerState state;
        public AccountSynchronizerState State
        {
            get { return state; }
            set
            {
                state = value;

                WeakReferenceMessenger.Default.Send(new AccountSynchronizerStateChanged(Account.Id, value));
            }
        }

        protected BaseSynchronizer(MailAccount account)
        {
            Account = account;
        }


        /// <summary>
        /// Queues a single request to be executed in the next synchronization.
        /// </summary>
        /// <param name="request">Request to execute.</param>
        public void QueueRequest(IRequestBase request) => changeRequestQueue.Add(request);

        /// <summary>
        /// Runs existing queued requests in the queue.
        /// </summary>
        /// <param name="batchedRequests">Batched requests to execute. Integrator methods will only receive batched requests.</param>
        /// <param name="cancellationToken">Cancellation token</param>
        public abstract Task ExecuteNativeRequestsAsync(List<IRequestBundle<TBaseRequest>> batchedRequests, CancellationToken cancellationToken = default);

        // TODO: What if account is deleted during synchronization?
        public bool CancelActiveSynchronization() => true;

        /// <summary>
        /// Refreshes remote mail account profile if possible.
        /// Profile picture, sender name and mailbox settings (todo) will be handled in this step.
        /// </summary>
        public virtual Task<ProfileInformation> GetProfileInformationAsync() => default;

        /// <summary>
        /// Safely updates account's profile information.
        /// Database changes are reflected after this call.
        /// </summary>
        protected async Task<ProfileInformation> SynchronizeProfileInformationInternalAsync()
        {
            var profileInformation = await GetProfileInformationAsync();

            if (profileInformation != null)
            {
                Account.SenderName = profileInformation.SenderName;
                Account.Base64ProfilePictureData = profileInformation.Base64ProfilePictureData;

                if (!string.IsNullOrEmpty(profileInformation.AccountAddress))
                {
                    Account.Address = profileInformation.AccountAddress;
                }
            }

            return profileInformation;
        }

        /// <summary>
        /// Returns the base64 encoded profile picture of the account from the given URL.
        /// </summary>
        /// <param name="url">URL to retrieve picture from.</param>
        /// <returns>base64 encoded profile picture</returns>
        protected async Task<string> GetProfilePictureBase64EncodedAsync(string url)
        {
            using var client = new HttpClient();

            var response = await client.GetAsync(url).ConfigureAwait(false);
            var byteContent = await response.Content.ReadAsByteArrayAsync().ConfigureAwait(false);

            return Convert.ToBase64String(byteContent);
        }

        public List<IRequestBundle<TBaseRequest>> ForEachRequest<TWinoRequestType>(IEnumerable<TWinoRequestType> requests,
                    Func<TWinoRequestType, TBaseRequest> action)
                    where TWinoRequestType : IRequestBase
        {
            List<IRequestBundle<TBaseRequest>> ret = [];

            foreach (var request in requests)
                ret.Add(new HttpRequestBundle<TBaseRequest>(action(request), request));

            return ret;
        }
    }
}