using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
using xAiModels.Interfaces;
using xAiModels.Interfaces.Dtos;
using xAiModels.Interfaces.Enrichers;
using xAiModels.Models.Dtos;
using xCommons.Extensions;
using xIdentityService.Interfaces;
using xIdentityService.Extensions;
using xModels.Dtos;
using System.Linq;

namespace xAiModels.Providers.Enrichers
{
    public class XAiConversationEnricher : IXAiConversationEnricher
    {
        private readonly IXIdentityProvider identityProvider;
        private readonly IXAiProjectRepositoryService projectRepositoryService;
        private readonly IXAiConversationTitleResourceProvider conversationTitleResourceProvider;

        public XAiConversationEnricher(
            IXIdentityProvider identityProvider,
            IXAiProjectRepositoryService projectRepositoryService,
            IXAiConversationTitleResourceProvider conversationTitleResourceProvider
        )
        {
            //
            this.identityProvider = identityProvider;
            this.projectRepositoryService = projectRepositoryService;
            this.conversationTitleResourceProvider = conversationTitleResourceProvider;
        }

        /// <summary>
        /// Converts a Signle Entity to Dto ...
        /// </summary>
        /// <param name="source"></param>
        /// <param name="destination"></param>
        /// <param name="cancellationToken"></param>
        /// <returns></returns>
        public async Task EnrichAsync(
            XAiConversationDto source,
            XAiConversationDto destination,
            CancellationToken cancellationToken = default
        )
        {
            await EnrichAsync(
                source: source,
                fillMessages: false,
                destination: destination,
                cancellationToken: cancellationToken
            );
        }

        /// <summary>
        /// Converts a Collection of Entities to Dtos ...
        /// </summary>
        /// <param name="sources"></param>
        /// <param name="destinations"></param>
        /// <param name="cancellationToken"></param>
        /// <returns></returns>
        public async Task EnrichRangeAsync(
            IEnumerable<XAiConversationDto> sources,
            IEnumerable<XAiConversationDto> destinations,
            CancellationToken cancellationToken = default
        )
        {
            await EnrichRangeAsync(
                sources: sources,
                fillMessages: false,
                destinations: destinations,
                cancellationToken: cancellationToken
            );
        }

        /// <summary>
        /// Converts a Signle Entity to Dto ...
        /// </summary>
        /// <param name="source"></param>
        /// <param name="destination"></param>
        /// <param name="fillMessages"></param>
        /// <param name="cancellationToken"></param>
        /// <returns></returns>
        public async Task EnrichAsync(
            XAiConversationDto source,
            XAiConversationDto destination,
            bool fillMessages = false,
            CancellationToken cancellationToken = default
        )
        {
            //
            // Run independent async operations concurrently
            var ownerTask = ResolveOwnerAsync(source.OwnerId, cancellationToken);
            var projectTask = ResolveProjectAsync(source.ProjectId, cancellationToken);
            var titleLocalesTask = ResolveTitleLocalesAsync(source.Title, cancellationToken);
            var messagesTask = ResolveMessagesAsync(source.Id, cancellationToken);

            //
            // wait until All Tasks Resolved ... 
            Task[] tasks = [
                ownerTask,
                projectTask,
                titleLocalesTask
            ];
            if (fillMessages)
            {
                tasks = [.. tasks, messagesTask];
            }
            await Task.WhenAll(tasks);

            //
            // Attached Resolved Info to Destination ...
            destination.Owner = ownerTask.Result;
            destination.TitleResource = titleLocalesTask.Result;
            var project = projectTask.Result;
            if (!project.IsNullOrDefault())
            {
                destination.ProjectTitle = project.Title;
                destination.ProjectDescription = project.Description;
                destination.ProjectTitleResource = project.TitleResource;
                destination.ProjectDescriptionResource = project.DescriptionResource;
            }
            if (!messagesTask.Result.IsNull())
            {
                destination.Messages = [.. messagesTask.Result];
            }
        }

        /// <summary>
        /// Converts a Collection of Entities to Dtos ...
        /// </summary>
        /// <param name="sources"></param>
        /// <param name="destinations"></param>
        /// <param name="fillMessages"></param>
        /// <param name="cancellationToken"></param>
        /// <returns></returns>
        public async Task EnrichRangeAsync(
            IEnumerable<XAiConversationDto> sources,
            IEnumerable<XAiConversationDto> destinations,
            bool fillMessages = false,
            CancellationToken cancellationToken = default
        )
        {
            //
            // Make Tasks Ready ...
            var tasks = sources.Zip(destinations, (src, dst) =>
                EnrichAsync(src, dst, cancellationToken)
            );

            //
            await Task.WhenAll(tasks);
        }

        //
        #region Private ...
        /// <summary>
        /// Reading Owner User Info ...
        /// </summary>
        /// <param name="ownerId"></param>
        /// <param name="cancellationToken"></param>
        /// <returns></returns>
        private async Task<XPersonDto> ResolveOwnerAsync(
            string ownerId,
            CancellationToken cancellationToken = default
        )
        {
            //
            XPersonDto result = null;

            //
            // Validate ...
            if (ownerId.IsNullOrEmpty())
            {
                return result;
            }

            //
            // Try to Retrieve User Info ...
            var device = identityProvider.GetDevice();
            var userInfo = await identityProvider.GetUserInfo(
                device: device,
                userSelectByParam: ownerId
            );
            result = userInfo.ToXPersonDto();

            //
            return result;
        }

        /// <summary>
        /// Reading Title Locales ...
        /// </summary>
        /// <param name="title"></param>
        /// <param name="cancellationToken"></param>
        /// <returns></returns>
        private async Task<XResourceDto> ResolveTitleLocalesAsync(
            string title,
            CancellationToken cancellationToken = default
        )
        {
            //
            XResourceDto result = null;
            if (title.IsNullOrEmpty())
            {
                return result;
            }

            //
            result = await conversationTitleResourceProvider.GetResource(
                owner: null,
                identifier: title,
                cancellationToken: cancellationToken
            );

            //
            return result;
        }

        /// <summary>
        /// Retrieve Project ...
        /// </summary>
        /// <param name="projectId"></param>
        /// <param name="cancellationToken"></param>
        /// <returns></returns>
        private async Task<XAiProjectDto> ResolveProjectAsync(
            Guid projectId,
            CancellationToken cancellationToken = default
        )
        {
            //
            XAiProjectDto result = null;
            if (projectId.IsNull() || projectId.IsDefaultGuid())
            {
                return result;
            }

            //
            result = await projectRepositoryService.GetAsync(
                id: projectId,
                includeBuilder: null,
                ignoreSoftDeleteds: true,
                cancellationToken: cancellationToken
            );

            //
            return result;
        }

        /// <summary>
        /// Retrieve Specified Conversation Messages ...
        /// </summary>
        /// <param name="conversationId"></param>
        /// <param name="cancellationToken"></param>
        /// <returns></returns>
        private async Task<IEnumerable<XAiMessageDto>> ResolveMessagesAsync(
            Guid conversationId,
            CancellationToken cancellationToken = default
        )
        {
            //
            var result = new List<XAiMessageDto>();

            //
            if (conversationId.IsDefaultGuid())
            {
                return result;
            }

            //
            return result;
        }
        #endregion
    }
}