package main

import (
	"flag"
	"context"
	"errors"
	"math"
	"log"
	"net/http"
	"os"	
	
	"github.com/semrush/zenrpc/v2"
	"github.com/semrush/zenrpc/v2/testdata"
)

type ArithService struct{ zenrpc.Service }

// Sum sums two digits and returns error with error code as result and IP from context.
func (as ArithService) Sum(ctx context.Context, a, b int) (bool, *zenrpc.Error) {
	r, _ := zenrpc.RequestFromContext(ctx)

	return true, zenrpc.NewStringError(a+b, r.Host)
}

// Multiply multiples two digits and returns result.
func (as ArithService) Multiply(a, b int) int {
	return a * b
}

type Quotient struct {
	Quo, Rem int
}

func (as ArithService) Divide(a, b int) (quo *Quotient, err error) {
	if b == 0 {
		return nil, errors.New("divide by zero")
	} else if b == 1 {
		return nil, zenrpc.NewError(401, errors.New("we do not serve 1"))
	}

	return &Quotient{
		Quo: a / b,
		Rem: a % b,
	}, nil
}

// Pow returns x**y, the base-x exponential of y. If Exp is not set then default value is 2.
//zenrpc:exp=2
func (as ArithService) Pow(base float64, exp float64) float64 {
	return math.Pow(base, exp)
}

//go:generate zenrpc

func main() {
	addr := flag.String("addr", "localhost:9999", "listen address")
	flag.Parse()

	rpc := zenrpc.NewServer(zenrpc.Options{ExposeSMD: true})
	rpc.Register("arith", testdata.ArithService{})
	rpc.Register("", testdata.ArithService{}) // public
	rpc.Use(zenrpc.Logger(log.New(os.Stderr, "", log.LstdFlags)))

	http.Handle("/", rpc)

	log.Printf("starting arithsrv on %s", *addr)
	log.Fatal(http.ListenAndServe(*addr, nil))
}