package zygo

import (
	"errors"
	"fmt"
)

func (env *Zlisp) ImportMsgpackMap() {
	env.AddMacro("msgpack-map", MsgpackMapMacro)
	env.AddFunction("declare-msgpack-map", DeclareMsgpackMapFunction)
}

// declare a new record type
func MsgpackMapMacro(env *Zlisp, name string,
	args []Sexp) (Sexp, error) {

	if len(args) < 1 {
		return SexpNull, fmt.Errorf("struct-name is missing. use: " +
			"(msgpack-map struct-name)\n")
	}

	return MakeList([]Sexp{
		env.MakeSymbol("def"),
		args[0],
		MakeList([]Sexp{
			env.MakeSymbol("quote"),
			env.MakeSymbol("msgmap"),
			&SexpStr{S: args[0].(*SexpSymbol).name},
		}),
	}), nil
}

func DeclareMsgpackMapFunction(env *Zlisp, name string, args []Sexp) (Sexp, error) {
	if len(args) != 1 {
		return SexpNull, WrongNargs
	}

	switch t := args[0].(type) {
	case *SexpStr:
		return t, nil
	}
	return SexpNull, errors.New("argument must be string: the name of the new msgpack-map constructor function to create")
}