// Copyright 2019 Yang ZhongXi
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//     http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package core

import (
	"errors"
	"net"
	"time"
)

// TCPClient TCP客户端
type TCPClient struct {
	conn          net.Conn
	raddr         string
	laddr         string
	isReconnected bool
	isOpened      bool
	isConnected   bool
	receiver      func(data []byte)
}

// NewTCPClient 实例化TCP客户端, raddr:服务端IP地址及端口(如：192.168.2.12:12001)，laddr:本地端IP地址及端口(如：127.0.0.1:13001)可为空,isReconnected:  是否重连
func NewTCPClient(raddr string, laddr string, isReconnected bool) *TCPClient {
	return &TCPClient{raddr: raddr, laddr: laddr, isReconnected: isReconnected}
}

// Open starts the TCP client
func (c *TCPClient) Open() error {
	if c.isOpened {
		return errors.New("已打开")
	}
	c.isOpened = true
	go c.doWork()
	return nil
}

// Close stops the TCP client
func (c *TCPClient) Close() error {
	if !c.isOpened {
		return errors.New("未打开")
	}
	c.isOpened = false
	c.conn.Close()
	return nil
}

// Write 写入数据
func (c *TCPClient) Write(data []byte) error {
	if !c.isOpened {
		return errors.New("串口未打开")
	}
	_, err := c.conn.Write(data)
	return err
}

// IsOpened 判断是否已打开
func (c *TCPClient) IsOpened() bool {
	return c.isOpened
}

// SetReceiver set receiver of the TCP client
func (c *TCPClient) SetReceiver(receiver func(data []byte)) {
	c.receiver = receiver
}

func (c *TCPClient) doWork() {
	buffer := make([]byte, 512)
	for c.isOpened {
		if c.connect() != nil {
			time.Sleep(1000)
			continue
		}
		rLen, err := c.conn.Read(buffer)
		if err != nil {
			c.isConnected = false
			c.conn.Close()
			if !c.isReconnected {
				c.isOpened = false
			}
		} else {
			c.receiver(buffer[:rLen])
		}
	}
}

func (c *TCPClient) connect() error {
	if c.isConnected {
		return nil
	}
	if len(c.laddr) > 0 {
		laddr, err := net.ResolveTCPAddr("tcp", c.laddr)
		if err != nil {
			return err
		}
		d := net.Dialer{Timeout: time.Second * 5, LocalAddr: laddr}
		c.conn, err = d.Dial("tcp", c.raddr)
		return err
	}
	var err error
	c.conn, err = net.Dial("tcp", c.raddr)
	if err == nil {
		c.isConnected = true
	}
	return err
}