/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

/*!
 * \brief Sample golang application to demonstrate function register into TVM global functions.
 * \file pack_func_register.go
 */

package main

import (
    "fmt"
    "./gotvm"
    "strings"
)

// sampleCb is a simple golang callback function like C = A + B.
func sampleCb(args ...*gotvm.Value) (retVal interface{}, err error) {
    for _, v := range args {
        fmt.Printf("ARGS:%T : %v\n", v.AsInt64(), v.AsInt64())
    }
    val1 := args[0].AsInt64()
    val2 := args[1].AsInt64()
    retVal = int64(val1+val2)
    return
}

// main
func main() {
    // Register sampleCb with TVM packed function system and call and check Global Function List.
    gotvm.RegisterFunction(sampleCb, "sampleCb");
    // Query global functions available
    funcNames, err := gotvm.FuncListGlobalNames()
    if err != nil {
        fmt.Print(err)
        return
    }

    found := 0
    for ii := range (funcNames) {
        if strings.Compare(funcNames[ii], "sampleCb") == 0 {
            found = 1
        }
    }
    if found == 0 {
        fmt.Printf("Function registerd but, not listed\n")
        return
    }


    // Get "sampleCb" and verify the call.
    funp, err := gotvm.GetGlobalFunction("sampleCb")
    if err != nil {
        fmt.Print(err)
        return
    }

    // Call function
    result, err := funp.Invoke((int64)(10), (int64)(20))
    if err != nil {
        fmt.Print(err)
        return
    }
    fmt.Printf("sampleCb result: %v\n", result.AsInt64())
}