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"
)

type ReadCoils struct {
	fnCode uint8
}

func NewReadCoils(fnCode uint8) FunctionHandler {
	return &ReadCoils{fnCode: fnCode}
}

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

// Function 读线圈寄存器（DO） 功能码0x01
func (r *ReadCoils) Function(s *Handler, req protocol.Packet, resp protocol.Packet) *protocol.MError {
	register, numRegs, endRegister := serialize.RegisterAddressAndNumber(req.GetBody())
	if endRegister > 65535 {
		resp.SetBody([]byte{})
		return &protocol.IllegalDataAddress
	}
	// 一个寄存器2字节
	dataSize := numRegs / 8
	if (numRegs % 8) != 0 {
		dataSize++
	}
	data := make([]byte, 1+dataSize)
	data[0] = byte(dataSize)

	dataMgr := s.DataManager(req.GetAddress())
	coils := dataMgr.ReadCoils(register, endRegister)
	for i, value := range coils {
		if value != 0 {
			shift := uint(i) % 8
			data[1+i/8] |= byte(1 << shift)
		}
	}

	s.HandleLogic(r.fnCode, register, numRegs, coils)

	resp.SetBody(data)
	return &protocol.Success
}

////////////////////////////////////////////// write-single

type WriteSingleCoil struct {
	fnCode uint8
}

func NewWriteSingleCoil(fnCode uint8) FunctionHandler {
	return &WriteSingleCoil{fnCode: fnCode}
}

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

// Function 写单个线圈寄存器 功能码0x05
func (r *WriteSingleCoil) Function(s *Handler, req protocol.Packet, resp protocol.Packet) *protocol.MError {
	data := req.GetBody()
	register, value := serialize.RegisterAddressAndValue(data)
	// TODO Should we use 0 for off and 65,280 (0xFF00) for on?
	if value != 0 {
		value = 1
	}
	dataMgr := s.DataManager(req.GetAddress())
	dataMgr.WriteSingleCoil(register, byte(value))

	s.HandleLogic(r.fnCode, register, 1, value)

	resp.SetBody(data[0:4])

	return &protocol.Success
}

////////////////////////////////////////////// write-multiple

type WriteMultipleCoils struct {
	fnCode uint8
}

func NewWriteMultipleCoils(fnCode uint8) FunctionHandler {
	return &WriteMultipleCoils{fnCode: fnCode}
}

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

// Function 写多个线圈寄存器 功能码 0x0F=15
func (r *WriteMultipleCoils) Function(s *Handler, req protocol.Packet, resp protocol.Packet) *protocol.MError {
	data := req.GetBody()
	register, numRegs, endRegister := serialize.RegisterAddressAndNumber(data)
	valueBytes := data[5:]

	if endRegister > 65536 {
		resp.SetBody([]byte{})
		return &protocol.IllegalDataAddress
	}

	// TODO This is not correct, bits and bytes do not always align
	//if len(valueBytes)/2 != numRegs {
	//	return []byte{}, &IllegalDataAddress
	//}

	idxList := make([]int, 0)
	values := make([]byte, 0)
	bitCount := 0
	for i, value := range valueBytes {
		for bitPos := uint(0); bitPos < 8; bitPos++ {
			idxList = append(idxList, register+(i*8)+int(bitPos))
			values = append(values, util.BitAtPosition(value, bitPos))

			bitCount++
			if bitCount >= numRegs {
				break
			}
		}
		if bitCount >= numRegs {
			break
		}
	}

	dataMgr := s.DataManager(req.GetAddress())
	dataMgr.WriteCoils(idxList, values)

	s.HandleLogic(r.fnCode, register, numRegs, values)

	resp.SetBody(data[0:4])

	return &protocol.Success
}