using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using xCommons.Extensions;
using xExceptions.Constants;
using xIdentityModels.Models;
using xModels.Dtos;
using xPushService.Providers;
using xStringService.Extensions;
using xStringService.Interfaces;
using xStringService.Interfaces.Dtos;
using xStringService.Models.Dtos;
using xStringService.Models.Entities;
using xStringService.Providers.Dtos;

namespace xStringService.Providers
{
    public class XStringProvider : XBaseProvided<XString, XStringDto, int, XStringDtoHub>, IXStringProvider
    {
        public XStringProvider(
            IXStringServiceProvider provider
        ) : base(
            provider,
            permittedRoles: new string[] { }
        )
        { }

        public override bool IsOwned(
            XStringDto item,
            XUserClaimsInfoDto userInfo
        )
        {
            return !item.IsNullOrDefault();
        }

        public override bool IsOwned(
            XString item,
            XUserClaimsInfoDto userInfo
        )
        {
            return !item.IsNullOrDefault();
        }

        //
        #region Tools ...
        /// <summary>
        /// Retrieve a List of Exists Languages ...
        /// </summary>
        /// <param name="cancellationToken"></param>
        /// <returns></returns>
        public async Task<IEnumerable<string>> GetLanguages(
            CancellationToken cancellationToken = default
        )
        {
            //
            var result = (await GetAll(
                includeBuilder: null,
                cancellationToken: cancellationToken,
                orderBuilder: x => x.OrderBy(y => y.Language)
            ))
            .Select(x => x.Language)
            .Distinct()
            .ToList();

            //
            return result;
        }

        /// <summary>
        /// Retrieve a List of Resource Titles ...
        /// </summary>
        /// <param name="language">if provided, returns all language Specified resource titles, if not, all Resource Titles</param>
        /// <param name="cancellationToken"></param>
        /// <returns></returns>
        public async Task<IEnumerable<string>> GetResourceTitles(
            string language = null,
            CancellationToken cancellationToken = default
        )
        {
            //
            var result = (await FindMany(
                includeBuilder: null,
                cancellationToken: cancellationToken,
                orderBuilder: x => x.OrderBy(y => y.ResourceTitle),
                predicate: x =>
                    string.IsNullOrWhiteSpace(language) ||
                    x.Language.Equals(language, System.StringComparison.InvariantCultureIgnoreCase)
            ))
            .Select(x => x.ResourceTitle)
            .Distinct()
            .ToList();

            //
            return result;
        }

        /// <summary>
        /// Retrieve all Exists Items which belongs to Specified Resource Title ...
        /// </summary>
        /// <param name="resource">Specified Resource Title</param>
        /// <param name="cancellationToken"></param>
        /// <returns></returns>
        public async Task<IEnumerable<XStringDto>> GetResourceLocales(
            string resource,
            CancellationToken cancellationToken = default
        )
        {
            //
            var result = await FindMany(
                includeBuilder: null,
                cancellationToken: cancellationToken,
                orderBuilder: x => x.OrderBy(y => y.Language),
                predicate: x =>
                    !string.IsNullOrWhiteSpace(resource) &&
                    resource.Equals(x.ResourceTitle, System.StringComparison.InvariantCultureIgnoreCase)
            );

            //
            return result;
        }

        /// <summary>
        /// Extract Translation of a Resource in Specified Language ...
        /// </summary>
        /// <param name="language">Specified Language ...</param>
        /// <param name="resource">Specified Resource Title ...</param>
        /// <param name="cancellationToken"></param>
        /// <returns></returns>
        public async Task<string> GetResourceTranslation(
            string language,
            string resource,
            CancellationToken cancellationToken = default
        )
        {
            //
            var result = (await FindOne(
                includeBuilder: null,
                cancellationToken: cancellationToken,
                predicate: x =>
                    !string.IsNullOrWhiteSpace(language) &&
                    !string.IsNullOrWhiteSpace(resource) &&
                    x.Language.Equals(language, System.StringComparison.InvariantCultureIgnoreCase) &&
                    x.ResourceTitle.Equals(resource, System.StringComparison.InvariantCultureIgnoreCase)
            ))?
            .TranslatedValue ?? "";

            //
            return result;
        }

        /// <summary>
        /// Retrieve a Resource as Locale Model ...
        /// </summary>
        /// <param name="language">Specified Language ...</param>
        /// <param name="resource">Specified Resource Title ...</param>
        /// <param name="cancellationToken"></param>
        /// <returns></returns>
        public async Task<XLocaleResourceDto> GetLocale(
            string language,
            string resource,
            CancellationToken cancellationToken = default
        )
        {
            //
            var result = (await FindOne(
                includeBuilder: null,
                cancellationToken: cancellationToken,
                predicate: x =>
                    !string.IsNullOrWhiteSpace(language) &&
                    !string.IsNullOrWhiteSpace(resource) &&
                    x.Language.Equals(language, System.StringComparison.InvariantCultureIgnoreCase) &&
                    x.ResourceTitle.Equals(resource, System.StringComparison.InvariantCultureIgnoreCase)
            ))?
            .ToXLocaleResourceDto() ?? null;

            //
            return result;
        }

        /// <summary>
        /// Retrieve all Exists Resource Instances as Locale Models ...
        /// </summary>
        /// <param name="resource"></param>
        /// <param name="cancellationToken"></param>
        /// <returns></returns>
        public async Task<IEnumerable<XLocaleResourceDto>> GetLocales(
            string resource,
            CancellationToken cancellationToken = default
        )
        {
            //
            var result = (await GetResourceLocales(
                resource: resource,
                cancellationToken: cancellationToken
            ))
            .ToList()
            .Select(x => x.ToXLocaleResourceDto())
            .ToList();

            //
            return result;
        }

        /// <summary>
        /// Retrieve all Locales of Specified Resource and Represent as XResourceDto ...
        /// </summary>
        /// <param name="resource"></param>
        /// <param name="cancellationToken"></param>
        /// <returns></returns>
        public async Task<XResourceDto> GetResource(
            string resource,
            CancellationToken cancellationToken = default
        )
        {
            //
            XResourceDto result = null;

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

            //
            // Extract Locales of Resource ...
            var locales = await GetLocales(
                resource: resource,
                cancellationToken: cancellationToken
            );

            //
            // Prepare Result ...
            result = new XResourceDto
            {
                Locales = locales,
                Resource = resource,
            };

            //
            return result;
        }

        /// <summary>
        /// Add or Update a Resource Model ...
        /// </summary>
        /// <param name="resource">a XResourceDto Model ...</param>
        /// <param name="userInfo">Actor User for Permissions ...</param>
        /// <param name="connectionId"></param>
        /// <param name="cancellationToken"></param>
        /// <returns></returns>
        public async Task<XResourceDto> AddOrUpdateResource(
            XResourceDto resource,
            XUserClaimsInfoDto userInfo = null,
            string connectionId = null,
            CancellationToken cancellationToken = default
        )
        {
            //
            XResourceDto result = null;

            //
            // Validate Args ...
            var isValid =
                !resource.IsNullOrDefault() &&
                !resource.Resource.IsNullOrEmpty();
            if (!isValid)
            {
                XException.InvalidArgs.Throw();
            }

            //
            // Check Permissions ...
            isValid =
                userInfo.IsNullOrDefault() ||
                HasPermision(userInfo);
            if (!isValid)
            {
                XException.NotAllowed.Throw();
            }

            //
            // Remove all Resources if Exists ...
            result = await GetResource(
                resource: resource.Resource,
                cancellationToken: cancellationToken
            );
            var isExists = !result.IsNullOrDefault();
            if (isExists)
            {
                //
                await RemoveResource(
                    resource: result,
                    userInfo: userInfo,
                    cancellationToken: cancellationToken
                );
            }

            //
            // Loop through all Exists Locales and Add them ...
            foreach (var locale in resource.Locales)
            {
                //
                if (cancellationToken.IsCancellationRequested)
                {
                    break;
                }

                //
                var item = new XStringDto
                {
                    Language = locale.Language,
                    TranslatedValue = locale.Value,
                    ResourceTitle = resource.Resource,
                };
                await Add(
                    item: item,
                    userInfo: userInfo,
                    connectionId: connectionId,
                    cancellationToken: cancellationToken
                );
            }

            //
            // Reload Result after Updates ...
            result = await GetResource(
                resource: resource.Resource,
                cancellationToken: cancellationToken
            );

            //
            return result;
        }

        /// <summary>
        /// Remove Specified Resource Model ...
        /// </summary>
        /// <param name="resource">a XResourceDto Model ...</param>
        /// <param name="userInfo">Actor User for Permissions ...</param>
        /// <param name="connectionId"></param>
        /// <param name="cancellationToken"></param>
        /// <returns></returns>
        public async Task RemoveResource(
            XResourceDto resource,
            XUserClaimsInfoDto userInfo = null,
            string connectionId = null,
            CancellationToken cancellationToken = default
        )
        {
            //
            // Validate ...
            var isValid = !resource.IsNullOrDefault();
            if (!isValid)
            {
                return;
            }

            //
            var items = await GetResourceLocales(
                resource: resource.Resource,
                cancellationToken: cancellationToken
            );
            isValid =
                !items.IsNullOrDefault() &&
                items.HasChild();
            if (!isValid)
            {
                return;
            }

            //
            foreach (var item in items)
            {
                //
                if (cancellationToken.IsCancellationRequested)
                {
                    break;
                }

                //
                await Remove(
                    id: item.Id,
                    userInfo: userInfo,
                    connectionId: connectionId,
                    cancellationToken: cancellationToken
                );
            }
        }
        #endregion
    }
}