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

namespace xAiModels.Providers.Enrichers
{
    public class XAiProjectEnricher : IXAiProjectEnricher
    {
        private readonly IXIdentityProvider identityProvider;
        private readonly IXAiProjectTitleResourceProvider projectTitleResourceProvider;
        private readonly IXAiConversationRepositoryService conversationRepositoryService;
        private readonly IXAiProjectDescriptionResourceProvider projectDescriptionResourceProvider;

        public XAiProjectEnricher(
            IXIdentityProvider identityProvider,
            IXAiProjectTitleResourceProvider projectTitleResourceProvider,
            IXAiConversationRepositoryService conversationRepositoryService,
            IXAiProjectDescriptionResourceProvider projectDescriptionResourceProvider
        )
        {
            this.identityProvider = identityProvider;
            this.projectTitleResourceProvider = projectTitleResourceProvider;
            this.conversationRepositoryService = conversationRepositoryService;
            this.projectDescriptionResourceProvider = projectDescriptionResourceProvider;
        }

        public async Task EnrichAsync(
            XAiProjectDto source,
            XAiProjectDto destination,
            CancellationToken cancellationToken = default
        )
        {
            await EnrichAsync(
                source: source,
                destination: destination,
                fillConversations: false,
                cancellationToken: cancellationToken
            );
        }

        public async Task EnrichAsync(
            XAiProjectDto source,
            XAiProjectDto destination,
            bool fillConversations = true,
            CancellationToken cancellationToken = default
        )
        {
            //
            // Run independent async operations concurrently
            var titleTask = ResolveTitleAsync(source.Title, cancellationToken);
            var ownerTask = ResolveOwnerAsync(source.OwnerId, cancellationToken);
            var conversationsTask = ResolveConversationsAsync(source.Id, cancellationToken);
            var descriptionTask = ResolveDescriptionAsync(source.Description, cancellationToken);

            //
            // wait until All Tasks Resolved ... 
            Task[] tasks =
            {
                titleTask,
                ownerTask,
                descriptionTask
            };
            if (fillConversations)
            {
                tasks = [.. tasks, conversationsTask];
            }
            await Task.WhenAll(tasks);

            //
            // Attached Resolved Info to Destination ...
            destination.Owner = ownerTask.Result;
            destination.TitleResource = titleTask.Result;
            destination.DescriptionResource = descriptionTask.Result;
            if (!conversationsTask.Result.IsNull())
            {
                destination.Conversations = [.. conversationsTask.Result];
            }
        }

        public async Task EnrichRangeAsync(
            IEnumerable<XAiProjectDto> sources,
            IEnumerable<XAiProjectDto> destinations,
            CancellationToken cancellationToken = default
        )
        {
            //
            // Make Tasks Ready ...
            var tasks = sources.Zip(destinations, (src, dst) =>
                EnrichAsync(src, dst, cancellationToken)
            );

            //
            await Task.WhenAll(tasks);
        }

        public async Task EnrichRangeAsync(
            IEnumerable<XAiProjectDto> sources,
            IEnumerable<XAiProjectDto> destinations,
            bool fillConversations = true,
            CancellationToken cancellationToken = default
        )
        {
            //
            // Make Tasks Ready ...
            var tasks = sources.Zip(destinations, (src, dst) =>
                EnrichAsync(src, dst,  fillConversations, 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>
        /// Retrieve Title Resource ...
        /// </summary>
        /// <param name="identifier"></param>
        /// <param name="cancellationToken"></param>
        /// <returns></returns>
        private async Task<XResourceDto> ResolveTitleAsync(
            string identifier,
            CancellationToken cancellationToken = default
        )
        {
            //
            XResourceDto result = null;

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

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

            //
            return result;
        }

        /// <summary>
        /// Retrieve Description Resource ...
        /// </summary>
        /// <param name="identifier"></param>
        /// <param name="cancellationToken"></param>
        /// <returns></returns>
        private async Task<XResourceDto> ResolveDescriptionAsync(
            string identifier,
            CancellationToken cancellationToken = default
        )
        {
            //
            XResourceDto result = null;

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

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

            //
            return result;
        }

        /// <summary>
        /// Retrieve Project Conversations ...
        /// </summary>
        /// <param name="projectId"></param>
        /// <param name="cancellationToken"></param>
        /// <returns></returns>
        private async Task<List<XAiConversationDto>> ResolveConversationsAsync(
            Guid projectId,
            CancellationToken cancellationToken = default
        )
        {
            //
            List<XAiConversationDto> result = [];

            //
            // Validate ...
            if (projectId.IsNull() ||
                projectId.IsDefaultGuid()
            )
            {
                return result;
            }

            //
            var items = await conversationRepositoryService.FindManyAsync(
                orderBuilder: null,
                includeBuilder: null,
                ignoreSoftDeleteds: true,
                predicate: x => x.Id == projectId,
                cancellationToken: cancellationToken
            );
            result = [.. items];

            //
            return result;
        }
        #endregion
    }
}