using System;
using System.Collections.Generic;
using System.Linq;
using NPoco;
using Umbraco.Core.Cache;
using Umbraco.Core.Logging;
using Umbraco.Core.Models;
using Umbraco.Core.Persistence;
using Umbraco.Core.Persistence.Dtos;
using Umbraco.Core.Persistence.Querying;
using Umbraco.Core.Scoping;

namespace Umbraco.Core.Persistence.Repositories.Implement
{
    internal class KeyValueRepository : NPocoRepositoryBase<string, IKeyValue>, IKeyValueRepository
    {
        public KeyValueRepository(IScopeAccessor scopeAccessor, ILogger logger)
            : base(scopeAccessor, AppCaches.NoCache, logger)
        { }

        /// <summary>
        /// Gets a value directly from the database, no scope, nothing.
        /// </summary>
        /// <remarks>Used by <see cref="Runtime.CoreRuntime"/> to determine the runtime state.</remarks>
        internal static string GetValue(IUmbracoDatabase database, string key)
        {
            if (database is null) return null;

            var sql = database.SqlContext.Sql()
                .Select<KeyValueDto>()
                .From<KeyValueDto>()
                .Where<KeyValueDto>(x => x.Key == key);
            return database.FirstOrDefault<KeyValueDto>(sql)?.Value;
        }

        #region Overrides of IReadWriteQueryRepository<string, IKeyValue>

        public override void Save(IKeyValue entity)
        {
            if (Get(entity.Identifier) == null)
                PersistNewItem(entity);
            else
                PersistUpdatedItem(entity);
        }

        #endregion

        #region Overrides of NPocoRepositoryBase<string, IKeyValue>

        protected override Guid NodeObjectTypeId => throw new NotImplementedException();

        protected override Sql<ISqlContext> GetBaseQuery(bool isCount)
        {
            var sql = SqlContext.Sql();

            sql = isCount
                ? sql.SelectCount()
                : sql.Select<KeyValueDto>();

            sql
                .From<KeyValueDto>();

            return sql;
        }

        protected override string GetBaseWhereClause()
        {
            return Constants.DatabaseSchema.Tables.KeyValue + ".key = @id";
        }

        protected override IEnumerable<string> GetDeleteClauses()
        {
            return new List<string>();
        }

        protected override IKeyValue PerformGet(string id)
        {
            var sql = GetBaseQuery(false).Where<KeyValueDto>(x => x.Key == id);
            var dto = Database.Fetch<KeyValueDto>(sql).FirstOrDefault();
            return dto == null ? null : Map(dto);
        }

        protected override IEnumerable<IKeyValue> PerformGetAll(params string[] ids)
        {
            var sql = GetBaseQuery(false).WhereIn<KeyValueDto>(x => x.Key, ids);
            var dtos = Database.Fetch<KeyValueDto>(sql);
            return dtos.WhereNotNull().Select(Map);
        }

        protected override IEnumerable<IKeyValue> PerformGetByQuery(IQuery<IKeyValue> query)
        {
            throw new NotImplementedException();
        }

        protected override void PersistNewItem(IKeyValue entity)
        {
            var dto = Map(entity);
            Database.Insert(dto);
        }

        protected override void PersistUpdatedItem(IKeyValue entity)
        {
            var dto = Map(entity);
            Database.Update(dto);
        }

        private static KeyValueDto Map(IKeyValue keyValue)
        {
            if (keyValue == null) return null;

            return new KeyValueDto
            {
                Key = keyValue.Identifier,
                Value = keyValue.Value,
                UpdateDate = keyValue.UpdateDate,
            };
        }

        private static IKeyValue Map(KeyValueDto dto)
        {
            if (dto == null) return null;

            return new KeyValue
            {
                Identifier = dto.Key,
                Value = dto.Value,
                UpdateDate = dto.UpdateDate,
            };
        }        

        #endregion        
    }
}