using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using ln.collections;
using ln.ethercat.controller;
using ln.logging;
using ln.type;

namespace ln.ethercat
{

    public class ECSlave
    {
        internal ECMaster ECMaster;
        public UInt16 Id { get; }

        MappingBTree<UInt16, SDODescriptor> sdoCache = new MappingBTree<UInt16, SDODescriptor>((sdo)=>sdo.Index);

        public ECSlave(ECMaster ecMaster,UInt16 slave_id)
        {
            ECMaster = ecMaster;
            Id = slave_id;

            ECMBind.ecmbind_enumerate_servicedescriptors(Id, (int slave, int index)=>{
                sdoCache.Add(new SDODescriptor(this, (UInt16)index));
            });

            foreach (SDODescriptor sdo in sdoCache)
                sdo.Update();
        }

        public IEnumerable<SDODescriptor> GetSDODescriptors() => sdoCache.Values;
        
        public bool GetDescriptor(UInt16 index, out SDODescriptor descriptor) => sdoCache.TryGet(index, out descriptor);


    }

    public class SDODescriptor
    {
        internal ECSlave Slave;
        public UInt16 SlaveId => Slave.Id;
        public UInt16 Index { get; }

        public string Name { get; private set; }
        public ECDataTypes DataType { get; set; }
        public ECObjectCodes ObjectCode { get; set; }
        public int MaxSubIndex { get; set; }

        MappingBTree<byte, SDOValue> valueCache;

        public SDODescriptor(ECSlave slave, UInt16 index)
        {
            Slave = slave;
            Index = index;
        }

        public void Update()
        {
                if (ECMBind.ecmbind_read_objectdescription(Slave.Id, Index, (int slave, int index, ECDataTypes dataType, ECObjectCodes objectCode, int maxsub, ushort bitlength, String name)=>{
                    Name = name;
                    DataType = dataType;
                    ObjectCode = objectCode;
                    MaxSubIndex = maxsub;
                }) <= 0)
                {
                    Logging.Log(LogLevel.WARNING, "cannot create SDO instance for {0}:{1:X4} not found.", Slave.Id, Index);
                }
        }

        void EnsureValueCache()
        {
            if (valueCache == null)
            {
                valueCache = new MappingBTree<byte, SDOValue>((v)=>v.SubIndex);
                for (byte subIndex = 0; subIndex <= MaxSubIndex; subIndex++)
                    valueCache.Add(new SDOValue(this, subIndex));
            }
        }

        public IEnumerable<SDOValue> GetValues()
        {
            EnsureValueCache();
            return valueCache.Values;
        }

        public SDOValue GetValue(byte subIndex)
        {
            EnsureValueCache();
            return valueCache[subIndex];
        }

        public bool GetValue(byte subIndex, out SDOValue sdoValue)
        {
            EnsureValueCache();
            return valueCache.TryGet(subIndex, out sdoValue);
        }


        public override string ToString() => String.Format("[SDODescriptor Slave={0} Index=0x{1:X4} ObjectCode={2} DataType={3}]", Slave.Id, Index, ObjectCode, DataType);
    }

    public class SDOValue
    {
        public SDODescriptor Descriptor;
        public byte SubIndex { get; }
        public ushort BitLength { get; private set; }

        public string Name { get; private set; }
        public ECDataTypes DataType { get; private set; }

        public SDOValue(SDODescriptor descriptor,byte subIndex)
        {
            Descriptor = descriptor;
            SubIndex = subIndex;

            if ((Descriptor.MaxSubIndex > 0) && (SubIndex == 0))
            {
                DataType = descriptor.DataType;
                Name = descriptor.Name;
            } else {
                if (ECMBind.ecmbind_read_objectdescription_entry(Descriptor.SlaveId, descriptor.Index, SubIndex, (int slave, int index, ECDataTypes dataType, ECObjectCodes objectCode, int si, ushort bitlength, String name)=>{
                    Name = (SubIndex == 0) ? descriptor.Name : name;
                    BitLength = bitlength;
                    DataType = dataType;
                }) <= 0)
                {
                    Logging.Log(LogLevel.WARNING, "SDOValue: could not read object description entry {0}:{1:X4}.{2}", descriptor.SlaveId, descriptor.Index, SubIndex);
                }
            }
        }


        public T GetValue<T>() => (T)GetValue();
        public object GetValue(){
            if (GetValue(out object value))
                return value;
            throw new IOException();
        }
        public bool GetValue(out object value)
        {
            if (GetRawValue(out byte[] data))
                return ECDataTypeConverter.FromEthercat(DataType, data, out value);
            value = null;
            return false;
        }

        public bool GetRawValue(out byte[] rawValue)
        {
            if (Descriptor.Slave.ECMaster.GetPDOItem(this, out PDO pdo))
            {
                return Descriptor.Slave.ECMaster.GetIOmapData(pdo.AddressOffset, pdo.ByteLength, out rawValue);
            } else {
                return Descriptor.Slave.ECMaster.ReadSDO(Descriptor.SlaveId, Descriptor.Index, SubIndex, out rawValue);
            }
        }

        public void SetValue<T>(T value)
        {
            if (ECDataTypeConverter.ToEthercat(DataType, value, out byte[] rawValue))
            {
                SetRawValue(rawValue);
            } else {
                Logging.Log(LogLevel.ERROR, "SDOValue: SetValue<>({0}): could not convert to ethercat", value);
            }
        }

        public void SetRawValue(byte[] rawValue)
        {
            if (Descriptor.Slave.ECMaster.GetPDOItem(this, out PDO pdo))
            {
                Descriptor.Slave.ECMaster.SetIOmapData(pdo.AddressOffset, pdo.ByteLength, rawValue);
            } else {
                Descriptor.Slave.ECMaster.WriteSDO(Descriptor.SlaveId, Descriptor.Index, SubIndex, rawValue);
            }
        }

    }

}