namespace LaaProductionWeb.Data
{
    using LaaProductionWeb.Data.Interfaces;

    using System;
    using System.Collections.Generic;
    using System.Data.SqlClient;
    using System.Linq;
    using System.Threading.Tasks;

    public class SqlReader : ISqlReader, IDisposable
    {
        private readonly SqlDataReader sqlDataReader;
        private readonly IDictionary<string, int> columns;

        private int column;

        private SqlReader(SqlDataReader sqlDataReader)
        {
            this.sqlDataReader = sqlDataReader;
            this.columns = new Dictionary<string, int>();

            var columnsCount = this.sqlDataReader.FieldCount;
            var columns = new string[columnsCount];

            for (int i = 0; i < columnsCount; i++)
            {
                var columnName = this.sqlDataReader.GetName(i);
                this.columns[columnName] = i;
            }
        }

        public void Dispose()
        {
            this.sqlDataReader.Close();
            this.sqlDataReader.Dispose();
        }

        public byte[] GetBytes(int index = -1)
        {
            var bytes = default(byte[]);

            if (index < 0)
            {
                index = this.column++;
            }

            if (!this.sqlDataReader.IsDBNull(index))
            {
                bytes = this.sqlDataReader.GetFieldValue<byte[]>(0);
            }

            return bytes ?? Array.Empty<byte>();
        }

        internal string[] GetColumns()
            => this.columns.Keys.ToArray();

        public string GetString(int index = -1)
        {
            if (index < 0)
            {
                index = this.column++;
            }

            if (!this.sqlDataReader.IsDBNull(index))
            {
                return $"{this.sqlDataReader.GetValue(index)}";
            }

            return default(string);
        }

        public T GetValue<T>(int index = -1)
        {
            if (index < 0)
            {
                index = this.column++;
            }

            if (!this.sqlDataReader.IsDBNull(index))
            {
                if (this.sqlDataReader.GetValue(index) is T value)
                {
                    return value;
                }
            }

            return default(T);
        }

        internal bool Read()
        {
            this.column = 0;

            return this.sqlDataReader.Read();
        }

        internal Task<bool> ReadAsync()
        {
            this.column = 0;

            return this.sqlDataReader.ReadAsync();
        }

        public object GetValue(string field)
        {
            if (this.columns.TryGetValue($"{field}", out int index))
            {
                if (!this.sqlDataReader.IsDBNull(index))
                {
                    return this.sqlDataReader.GetValue(index);
                }
            }

            return default(object);
        }

        public int GetInt(int index = -1)
        {
            if (index < 0)
            {
                index = this.column++;
            }

            if (!this.sqlDataReader.IsDBNull(index))
            {
                return this.sqlDataReader.GetInt32(index);
            }

            return default(int);
        }

        public short GetSmallint(int index = -1)
        {
            if (index < 0)
            {
                index = this.column++;
            }

            if (!this.sqlDataReader.IsDBNull(index))
            {
                return this.sqlDataReader.GetInt16(index);
            }

            return default(short);
        }

        public static implicit operator SqlReader(SqlDataReader sqlDataReader)
            => new SqlReader(sqlDataReader);
    }
}