using System;
using BLToolkit.Common;
using BLToolkit.Properties;

namespace BLToolkit.Mapping
{
    public class MapIndex
    {
        public MapIndex(string[] names)
        {
            if (null == names)
                throw new ArgumentNullException("names");

            if (names.Length == 0)
                throw new ArgumentException(Resources.MapIndex_EmptyNames, "names");

            _fields = NameOrIndexParameter.FromStringArray(names);
        }

        public MapIndex(int[] indices)
        {
            if (null == indices)
                throw new ArgumentNullException("indices");

            if (indices.Length == 0)
                throw new ArgumentException(Resources.MapIndex_EmptyIndices, "indices");

            _fields = NameOrIndexParameter.FromIndexArray(indices);
        }
        
        public MapIndex(params NameOrIndexParameter[] fields)
        {
            if (null == fields)
                throw new ArgumentNullException("fields");

            if (fields.Length == 0)
                throw new ArgumentException(Resources.MapIndex_EmptyFields, "fields");
            
            _fields = fields;
        }

        private readonly NameOrIndexParameter[] _fields;
        public           NameOrIndexParameter[]  Fields
        {
            get { return _fields; }
        }

        private string _id;
        public  string  ID
        {
            get
            {
                if (_id == null)
                {
                    _id = string.Join(".", Array.ConvertAll<NameOrIndexParameter, string>(_fields,
                        delegate(NameOrIndexParameter nameOrIndex)
                        {
                            return nameOrIndex.ToString();
                        }));
                }

                return _id;
            }
        }

        [CLSCompliant(false)]
        public object GetValue(IMapDataSource source, object obj, int index)
        {
            if (source == null)
                throw new ArgumentNullException("source");

            object value = _fields[index].ByName?
                source.GetValue(obj, _fields[index].Name):
                source.GetValue(obj, _fields[index].Index);

            if (value == null)
            {
                ObjectMapper objectMapper = source as ObjectMapper;

                if (objectMapper != null)
                {
                    MemberMapper mm = _fields[index].ByName?
                        objectMapper[_fields[index].Name]: objectMapper[_fields[index].Index];

                    if (mm == null)
                        throw new MappingException(string.Format(Resources.MapIndex_BadField,
                            objectMapper.TypeAccessor.OriginalType.Name, Fields[index]));
                }
            }

            return value;
        }

        [CLSCompliant(false)]
        public object GetValueOrIndex(IMapDataSource source, object obj)
        {
            return Fields.Length == 1?
                GetValue(source, obj, 0):
                GetIndexValue(source, obj);
        }

        [CLSCompliant(false)]
        public CompoundValue GetIndexValue(IMapDataSource source, object obj)
        {
            object[] values = new object[Fields.Length];

            for (int i = 0; i < values.Length; i++)
                values[i] = GetValue(source, obj, i);

            return new CompoundValue(values);
        }
    }
}