using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using xCommons.Extensions;
using xExceptions.Constants;
using xStringService.Interfaces;
using xStringService.Interfaces.Dtos;
using xStringService.Models.Dtos;

namespace xStringService.Providers
{
    public abstract class XBaseItemResourceProvider : IXItemResourceProvider
    {
        /// <summary>
        /// Item Name for Resource Providing ... 
        /// </summary>
        private readonly string item;

        /// <summary>
        /// an Implementation of Item Resource Provider 
        /// </summary>
        /// <value></value>
        private readonly XBaseResourceProvider provider;

        /// <summary>
        /// String Provider Service ...
        /// </summary>
        private readonly IXStringServiceProvider stringProvider;

        //
        #region Constructor ...
        protected XBaseItemResourceProvider(
            string item,
            IXStringServiceProvider stringProvider
        )
        {
            //
            this.item = item;
            this.stringProvider = stringProvider;
            provider = new XBaseResourceProvider(
                item,
                stringProvider
            );
        }
        #endregion

        //
        #region All Item Actions ...
        /// <summary>
        /// Retrieve a List of Exists Languages for Current Item ...
        /// </summary>
        /// <param name="cancellationToken"></param>
        /// <returns></returns>
        public async Task<IEnumerable<string>> GetLanguages(
            CancellationToken cancellationToken = default
        )
        {
            //
            var result =
                (await GetResourceLocales(cancellationToken))
                .Select(x => x.Language)
                .Distinct()
                .ToList();

            //
            return result;
        }

        /// <summary>
        /// Retrieve all Exists Items of type ...
        /// </summary>
        /// <param name="cancellationToken"></param>
        /// <returns></returns>
        public async Task<IEnumerable<XStringDto>> GetResourceLocales(
            CancellationToken cancellationToken = default
        )
        {
            //
            var identifier = GetResourceTitle();
            var result = await stringProvider
                .FindManyAsync(
                    includeBuilder: null,
                    ignoreSoftDeleteds: true,
                    cancellationToken: cancellationToken,
                    orderBuilder:
                        x => x
                            .OrderBy(y => y.Language)
                            .ThenBy(y => y.ResourceTitle),
                    predicate: x =>
                        x.ResourceTitle.StartsWith(identifier, StringComparison.InvariantCultureIgnoreCase)
                );

            //
            return result;
        }
        #endregion

        //
        #region Single Item Actions ...
        /// <summary>
        /// Retrieve a List of Exists Languages for Current Item ...
        /// </summary>
        /// <param name="identifier"></param>
        /// <param name="cancellationToken"></param>
        /// <returns></returns>
        public async Task<IEnumerable<string>> GetLanguages(
            object identifier,
            CancellationToken cancellationToken = default
        )
        {
            //
            // Validate ...
            var isValid = !identifier.IsNull();
            if (!isValid)
            {
                XException.InvalidArgs.Throw();
            }

            //
            // Set Identifier ...
            SetResourceTitle(identifier);

            //
            var result =
                await provider.GetLanguages(cancellationToken);
            return result;
        }

        /// <summary>
        /// Retrieve all Exists Items of type ...
        /// </summary>
        /// <param name="identifier"></param>
        /// <param name="cancellationToken"></param>
        /// <returns></returns>
        public async Task<IEnumerable<XStringDto>> GetResourceLocales(
            object identifier,
            CancellationToken cancellationToken = default
        )
        {
            //
            // Validate ...
            var isValid = !identifier.IsNull();
            if (!isValid)
            {
                XException.InvalidArgs.Throw();
            }

            //
            // Set Identifier ...
            SetResourceTitle(identifier);

            //
            var result =
                await provider.GetResourceLocales(cancellationToken);
            return result;
        }
        #endregion

        //
        #region Private ...
        private string GetResourceTitle(object identifier = null)
        {
            //
            var result = item;

            //
            if (!identifier.IsNull())
            {
                result = $"{item}_{identifier}";
            }

            //
            return result;
        }

        private void SetResourceTitle(object identifier = null)
        {
            //
            var itemIdentifier = GetResourceTitle(identifier);
            provider.SetField(
                field: "resource",
                value: $"{itemIdentifier}"
            );
        }
        #endregion
    }
}