package handler

import (
	"encoding/binary"
	"git.noahlan.cn/noahlan/nnet/conn"
	"git.noahlan.cn/noahlan/nnet/packet"
	rt "git.noahlan.cn/noahlan/nnet/router"
	"git.noahlan.cn/noahlan/ntool-biz/nmodbus/protocol"
	"git.noahlan.cn/noahlan/ntool/nlog"
	"sync"
)

var _ rt.Handler = (*Handler)(nil)

type (
	Handler struct {
		byteOrder binary.ByteOrder // 字节序

		logics     map[uint8]LogicFunc
		handlerMap map[uint8]FunctionHandler

		dataMap map[uint8]*DataMgr
		mu      sync.RWMutex
	}

	FunctionHandler interface {
		Function(handler *Handler, req protocol.Packet, resp protocol.Packet) *protocol.MError
		FnCode() uint8
	}

	LogicFunc func(pkg protocol.Packet, startAddr, number int, val any)
)

func NewHandler(byteOrder binary.ByteOrder) *Handler {
	p := &Handler{
		byteOrder:  byteOrder,
		logics:     make(map[uint8]LogicFunc),
		handlerMap: make(map[uint8]FunctionHandler),
		dataMap:    make(map[uint8]*DataMgr),
		mu:         sync.RWMutex{},
	}

	// 添加功能码对应功能
	p.RegisterFunction(NewReadCoils(0x01))
	p.RegisterFunction(NewReadDiscreteInputs(0x02))
	p.RegisterFunction(NewReadHoldingRegisters(0x03))
	p.RegisterFunction(NewReadInputRegisters(0x04))
	p.RegisterFunction(NewWriteSingleCoil(0x05))
	p.RegisterFunction(NewWriteHoldingRegister(0x06))
	p.RegisterFunction(NewWriteMultipleCoils(0x0F))
	p.RegisterFunction(NewWriteHoldingRegisters(0x10))

	return p
}

func (p *Handler) RegisterFunction(fn FunctionHandler) {
	p.handlerMap[fn.FnCode()] = fn
}

// RegisterLogic 注册功能码对应的 扩展 处理方法
func (p *Handler) RegisterLogic(fnCode uint8, fn LogicFunc) {
	p.logics[fnCode] = fn
}

// DataManager 数据管理器，基于主机地址（客户端地址）（modbus协议规定的主机号）
func (p *Handler) DataManager(address uint8) *DataMgr {
	p.mu.Lock()
	defer p.mu.Unlock()

	ret, ok := p.dataMap[address]
	if !ok {
		ret = NewDataManager(address)
		p.dataMap[address] = ret
	}
	return ret
}

// Handle 核心处理逻辑（核心路由）
func (p *Handler) Handle(nc *conn.Connection, pkg packet.IPacket) {
	req, ok := pkg.(protocol.Packet)
	if !ok {
		nlog.Error(packet.ErrWrongPacketType)
	}
	var err *protocol.MError

	resp := req.Copy()

	fnCode := req.GetFunction()
	handler, ok := p.handlerMap[fnCode]
	if ok {
		err = handler.Function(p, req, resp)
	} else {
		err = &protocol.IllegalFunction
	}

	if err != &protocol.Success {
		resp.SetError(err)
	}
	_ = nc.Send(resp.GetHeader(), resp.GetBody())
}

// HandleLogic 功能码对应的扩展处理方法
func (p *Handler) HandleLogic(fnCode uint8, pkg protocol.Packet, startAddr, number int, val any) {
	go func() {
		if fn, ok := p.logics[fnCode]; ok {
			fn(pkg, startAddr, number, val)
		}
	}()
}