using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using System.Text;

namespace Tensorflow
{
    public static class c_api
    {
        public const string TensorFlowLibName = "tensorflow";

        /// <summary>
        /// For inputs that take a single tensor.
        /// </summary>
        /// <param name="desc"></param>
        /// <param name="input"></param>
        [DllImport(TensorFlowLibName)]
        public static unsafe extern void TF_AddInput(TF_OperationDescription desc, TF_Output input);

        /// <summary>
        /// returns the sizeof() for the underlying type corresponding to the given TF_DataType enum value.
        /// </summary>
        /// <param name="dt"></param>
        /// <returns></returns>
        [DllImport(TensorFlowLibName)]
        public static unsafe extern ulong TF_DataTypeSize(TF_DataType dt);

        [DllImport(TensorFlowLibName)]
        public static unsafe extern void TF_DeleteSessionOptions(IntPtr opts);

        /// <summary>
        /// Destroy a tensor.
        /// </summary>
        /// <param name="tensor"></param>
        [DllImport(TensorFlowLibName)]
        public static unsafe extern void TF_DeleteTensor(IntPtr tensor);

        [DllImport(TensorFlowLibName)]
        public static extern unsafe long TF_Dim(IntPtr tensor, int dim_index);

        [DllImport(TensorFlowLibName)]
        public static unsafe extern IntPtr TF_FinishOperation(TF_OperationDescription desc, IntPtr status);

        [DllImport(TensorFlowLibName)]
        public static extern string TF_GetBuffer(IntPtr buffer);

        [DllImport(TensorFlowLibName)]
        public static extern unsafe TF_Code TF_GetCode(IntPtr s);

        [DllImport(TensorFlowLibName)]
        public static extern void TF_GraphGetOpDef(IntPtr graph, string op_name, IntPtr output_op_def, IntPtr status);

        [DllImport(TensorFlowLibName)]
        public static extern unsafe string TF_Message(IntPtr s);

        [DllImport(TensorFlowLibName)]
        public static unsafe extern IntPtr TF_NewGraph();

        [DllImport(TensorFlowLibName)]
        public static unsafe extern TF_OperationDescription TF_NewOperation(IntPtr graph, string opType, string oper_name);

        [DllImport(TensorFlowLibName)]
        public static unsafe extern IntPtr TF_NewStatus();

        /// <summary>
        /// Return a new tensor that holds the bytes data[0,len-1]
        /// </summary>
        /// <param name="dataType"></param>
        /// <param name="dims"></param>
        /// <param name="num_dims"></param>
        /// <param name="data"></param>
        /// <param name="len">num_bytes, ex: 6 * sizeof(float)</param>
        /// <param name="deallocator"></param>
        /// <param name="deallocator_arg"></param>
        /// <returns></returns>
        [DllImport(TensorFlowLibName, CallingConvention = CallingConvention.StdCall)]
        public static extern unsafe IntPtr TF_NewTensor(TF_DataType dataType, long[] dims, int num_dims, IntPtr data, UIntPtr len, tf.Deallocator deallocator, IntPtr deallocator_arg);

        /// <summary>
        /// Return the number of dimensions that the tensor has.
        /// </summary>
        /// <param name="tensor"></param>
        /// <returns></returns>
        [DllImport(TensorFlowLibName)]
        public static extern unsafe int TF_NumDims(IntPtr tensor);

        [DllImport(TensorFlowLibName)]
        public static extern unsafe int TF_OperationNumOutputs(IntPtr oper);

        [DllImport(TensorFlowLibName)]
        public static extern unsafe void TF_SetAttrValueProto(TF_OperationDescription desc, string attr_name, IntPtr proto, UIntPtr proto_len, IntPtr status);

        [DllImport(TensorFlowLibName)]
        public static extern unsafe void TF_SetAttrTensor(TF_OperationDescription desc, string attr_name, IntPtr value, IntPtr status);

        /// <summary>
        /// 
        /// </summary>
        /// <param name="session"></param>
        /// <param name="run_options"></param>
        /// <param name="inputs"></param>
        /// <param name="input_values"></param>
        /// <param name="ninputs"></param>
        /// <param name="outputs"></param>
        /// <param name="output_values"></param>
        /// <param name="noutputs"></param>
        /// <param name="target_opers"></param>
        /// <param name="ntargets"></param>
        /// <param name="run_metadata"></param>
        /// <param name="status"></param>
        [DllImport(TensorFlowLibName)]
        public static extern unsafe void TF_SessionRun(IntPtr session, IntPtr run_options,
                   TF_Output[] inputs, IntPtr[] input_values, int ninputs, 
                   TF_Output[] outputs, IntPtr[] output_values, int noutputs,
                   IntPtr[] target_opers, int ntargets,
                   IntPtr run_metadata,
                   IntPtr status);

        [DllImport(TensorFlowLibName)]
        public static extern unsafe void TF_SetAttrType(TF_OperationDescription desc, string attr_name, TF_DataType value);

        /// <summary>
        /// Return the size of the underlying data in bytes.
        /// </summary>
        /// <param name="tensor"></param>
        /// <returns></returns>
        [DllImport(TensorFlowLibName)]
        public static extern unsafe ulong TF_TensorByteSize(IntPtr tensor);

        [DllImport(TensorFlowLibName)]
        public static extern unsafe IntPtr TF_TensorData(IntPtr tensor);

        [DllImport(TensorFlowLibName)]
        public static extern unsafe TF_DataType TF_TensorType(IntPtr tensor);

        [DllImport(TensorFlowLibName)]
        public static extern IntPtr TF_NewSession(IntPtr graph, IntPtr opts, IntPtr status);

        [DllImport(TensorFlowLibName)]
        public static extern IntPtr TF_NewSessionOptions();

        [DllImport(TensorFlowLibName)]
        public static unsafe extern IntPtr TF_Version();
    }
}