package handler

import (
	"git.noahlan.cn/noahlan/ntool-biz/nmodbus/protocol"
	"git.noahlan.cn/noahlan/ntool-biz/nmodbus/serialize"
	"git.noahlan.cn/noahlan/ntool-biz/nmodbus/util"
)

// ReadInputRegisters 读输入寄存器（AO） 功能码0x04
type ReadInputRegisters struct {
	fnCode uint8
}

func NewReadInputRegisters(fnCode uint8) FunctionHandler {
	return &ReadInputRegisters{fnCode: fnCode}
}

func (r *ReadInputRegisters) FnCode() uint8 {
	return r.fnCode
}

// Function 读输入寄存器（AO） 功能码0x04
func (r *ReadInputRegisters) Function(s *Handler, req protocol.Packet, resp protocol.Packet) *protocol.MError {
	register, numRegs, endRegister := serialize.RegisterAddressAndNumber(req.GetBody())
	if endRegister > 65536 {
		resp.SetBody([]byte{})
		return &protocol.IllegalDataAddress
	}
	dataMgr := s.DataManager(req.GetAddress())
	data := dataMgr.ReadInputRegisters(register, endRegister)
	resp.SetBody(append([]byte{byte(numRegs * 2)}, util.Uint16ToBytes(s.byteOrder, data)...))

	s.HandleLogic(r.fnCode, req, register, numRegs, data)

	return &protocol.Success
}