using Iec61131.Engineering.Prototypes.Common;
using Iec61131.Engineering.Prototypes.Methods;
using Iec61131.Engineering.Prototypes.Pragmas;
using Iec61131.Engineering.Prototypes.Types;
using Iec61131.Engineering.Prototypes.Variables;
using System;
using System.Iec61131Lib;
using System.Runtime.InteropServices;

namespace T255347
{
    // The IecArray must be defined as a struct with a fixed size.
    // The array definition MUST have following Attributes:
    // 1. Array (Actually only one-dimensional arrays are supported by PLCnext Engineer)
    // 2. ArrayDimension
    // 3. DataType to define the data type of the array elements
    [Array(1), ArrayDimension(0, ArrayProperties.LowerBound, ArrayProperties.UpperBound), DataType("STRING")]
    [StructLayout(LayoutKind.Explicit, Size = ArrayProperties.ByteSize)]
    public struct StringArrayFB
    {
        // Helper containing constants to have a
        // clear and maintainable definition for boundaries and size
        private struct ArrayProperties
        {
            public const int LowerBound = -10;     // must not necessarily being zero, it also can be negative
            public const int UpperBound = 9;       // IEC61131 representation is : userArray : ARRAY[-10..9] OF STRING     (* size == 20 *)

            // the size must be changed to the correct size of your elements times the amount of elements
            public const int ByteSize = (UpperBound - LowerBound + 1) * 86;
        }

        public const int ByteSize = ArrayProperties.ByteSize;

        // Fields
        // The field "Anchor" defines the beginning of the array.
        [FieldOffset(0)]
        // The Anchor's data type is the child data type of the array
        public IecString80 Anchor;

        // The constants LB and UB define the upper and lower bound. Boundaries will be checked by using them.
        public const int LB = ArrayProperties.LowerBound;

        public const int UB = ArrayProperties.UpperBound;

        public void Init()
        {
            unsafe
            {
                fixed (IecString80* ptr = &this.Anchor)
                {
                    for (int i = 0; i < UB - LB + 1; i++)
                    {
                        ptr[i].ctor();
                    }
                }
            }
        }

        public IecString80 this[int index]
        {
            get
            {
                if (index >= (LB - ArrayProperties.LowerBound) && index <= (UB - ArrayProperties.LowerBound))
                {
                    unsafe
                    {
                        fixed (IecString80* pValue = &Anchor)
                        {
                            IecString80 result = *(pValue + index);
                            return result;
                        }
                    }
                }
                else
                {
                    throw new IndexOutOfRangeException();
                }
            }
            set
            {
                if (index >= (LB - ArrayProperties.LowerBound) && index <= (UB - ArrayProperties.LowerBound))
                {
                    unsafe
                    {
                        fixed (IecString80* pValue = &Anchor)
                        {
                            *(pValue + index) = value;
                        }
                    }
                }
                else
                {
                    throw new IndexOutOfRangeException();
                }
            }
        }
    }

    [FunctionBlock]
    public class FunctionBlock1
    {
        [Input]
        public short IN1;
        [Input]
        public short IN2;
        [Input]
        public StringArrayFB IN3;
        [Output, DataType("WORD")]
        public ushort OUT;
        [Output, DataType("STRING")]
        public IecString80 OUT1;

        [Initialization]
        public void __Init()
        {
            IN3.Init();
            OUT1.ctor();            
        }

        [Execution]
        public void __Process()
        {
            OUT = (ushort)(IN1 + IN2);
            OUT1 = IN3[0];
        }
    }
}