using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;

namespace IoTDSProviderSample
{
    public partial class ValueInputControll : UserControl
    {
        private class ValueTypeListItem
        {
            public string VariantType { get; private set; }
            public Type ManagedType { get; private set; }
            public ValueTypeListItem(string variantType, Type managedType)
            {
                VariantType = variantType;
                ManagedType = managedType;
            }
        }

        private readonly ValueTypeListItem[] VALUE_TYPES =
        {
            new ValueTypeListItem("VT_EMPTY", null),
            new ValueTypeListItem("VT_NULL", typeof(DBNull)),
            new ValueTypeListItem("VT_I1", typeof(sbyte)),
            new ValueTypeListItem("VT_UI1", typeof(byte)),
            new ValueTypeListItem("VT_I2", typeof(short)),
            new ValueTypeListItem("VT_UI2", typeof(ushort)),
            new ValueTypeListItem("VT_I4", typeof(int)),
            new ValueTypeListItem("VT_UI4", typeof(uint)),
            new ValueTypeListItem("VT_I8", typeof(long)),
            new ValueTypeListItem("VT_UI8", typeof(ulong)),
            new ValueTypeListItem("VT_R4", typeof(float)),
            new ValueTypeListItem("VT_R8", typeof(double)),
            new ValueTypeListItem("VT_CY", typeof(decimal)),
            new ValueTypeListItem("VT_DATE", typeof(DateTime)),
            new ValueTypeListItem("VT_BSTR", typeof(string)),

            new ValueTypeListItem("VT_I1 | VT_ARRAY", typeof(sbyte[])),
            new ValueTypeListItem("VT_UI1 | VT_ARRAY", typeof(byte[])),
            new ValueTypeListItem("VT_I2 | VT_ARRAY", typeof(short[])),
            new ValueTypeListItem("VT_UI2 | VT_ARRAY", typeof(ushort[])),
            new ValueTypeListItem("VT_I4 | VT_ARRAY", typeof(int[])),
            new ValueTypeListItem("VT_UI4 | VT_ARRAY", typeof(uint[])),
            new ValueTypeListItem("VT_I8 | VT_ARRAY", typeof(long[])),
            new ValueTypeListItem("VT_UI8 | VT_ARRAY", typeof(ulong[])),
            new ValueTypeListItem("VT_R4 | VT_ARRAY", typeof(float[])),
            new ValueTypeListItem("VT_R8 | VT_ARRAY", typeof(double[])),
            new ValueTypeListItem("VT_CY | VT_ARRAY", typeof(decimal[])),
            new ValueTypeListItem("VT_DATE | VT_ARRAY", typeof(DateTime[])),
            new ValueTypeListItem("VT_BSTR | VT_ARRAY", typeof(string[])),
            new ValueTypeListItem("VT_VARIANT | VT_ARRAY", typeof(object[])),
        };

        public ValueInputControll()
        {
            InitializeComponent();

            cmbValueType.DisplayMember = "VariantType";
            cmbValueType.ValueMember = "ManagedType";
            cmbValueType.DataSource = VALUE_TYPES;
            cmbValueType.SelectedIndex = 0;
        }

        public object Value
        {
            get
            {
                var type = cmbValueType.SelectedValue as Type;
                if (type == null)
                {
                    return null;
                }
                else if (type == typeof(DBNull))
                {
                    return DBNull.Value;
                }
                else if (type.IsArray)
                {
                    var elementType = type.GetElementType();
                    var tokens = txtValue.Text.Split(',');
                    var arr = Array.CreateInstance(elementType, tokens.Length);
                    for (int i = 0; i < tokens.Length; i++)
                    {
                        arr.SetValue(Convert.ChangeType(tokens[i], elementType), i);
                    }
                    return arr;
                }
                else
                {
                    return Convert.ChangeType(txtValue.Text, type);
                }
            }
            set
            {
                if (value == null)
                {
                    cmbValueType.SelectedIndex = 0;
                    txtValue.Text = "";
                }
                else
                {
                    var type = value.GetType();
                    cmbValueType.SelectedValue = type;
                    if (value is Array)
                    {
                        var elements = new List<string>();
                        foreach (var val in (Array)value)
                        {
                            elements.Add(Convert.ToString(val));
                        }
                        txtValue.Text = string.Join(",", elements);
                    }
                    else
                    {
                        txtValue.Text = Convert.ToString(value);
                    }
                }
            }
        }
    }
}