// 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 (
	"bufio"
	"bytes"
	"io"
	"os/exec"
	"regexp"
)

func init() {

}

// SingleCmdRunner 单条指令执行器
type SingleCmdRunner struct {
	cmd     string
	param   string
	strtool *regexp.Regexp
}

// CmdRunner 操作系统指令执行器，支持多条
type CmdRunner struct {
	cmds []*SingleCmdRunner
}

// NewSingleCmdRunner 实例化单指令执行器。cmd - 指令， param - 参数
func NewSingleCmdRunner(cmd string, param string) *SingleCmdRunner {
	strtool, _ := regexp.Compile(`\s+`)
	return &SingleCmdRunner{cmd: cmd, param: param, strtool: strtool}
}

// NewCmdRunner 实例化
func NewCmdRunner(cmd []string, params []string) *CmdRunner {
	var cmds []*SingleCmdRunner
	for i, c := range cmd {
		cmds = append(cmds, NewSingleCmdRunner(c, params[i]))
	}
	return &CmdRunner{cmds: cmds}
}

// Run 执行指令。
// 返回参数1-标准输出，返回参数2-标准错误输出，参数3-错误信息
func (runner *SingleCmdRunner) Run() (string, string, error) {
	var stdout bytes.Buffer
	var stderr bytes.Buffer
	// 使用正则分割参数字符串
	cmd := exec.Command(runner.cmd, runner.strtool.Split(runner.param, -1)...)
	cmd.Stdout = &stdout
	cmd.Stderr = &stderr
	err := cmd.Run()

	return stdout.String(), stderr.String(), err
}

// RealRun 执行指令，实时输出,执行完之后，函数返回
// receiver - 执行指令回调:参数1-标准输出，参数2-错误输出，参数3-执行错误
func (runner *SingleCmdRunner) RealRun(receiver func(string, string, error)) error {
	var cmd *exec.Cmd

	if len(runner.param) != 0 {
		cmd = exec.Command(runner.cmd, runner.strtool.Split(runner.param, -1)...)
	} else {
		cmd = exec.Command(runner.cmd)
	}

	stdout, err := cmd.StdoutPipe()
	if err != nil {
		receiver("", "", err)
		return err
	}
	defer stdout.Close()
	stderr, err := cmd.StderrPipe()
	if err != nil {
		receiver("", "", err)
		return err
	}
	defer stderr.Close()
	err = cmd.Start()
	if err != nil {
		receiver("", "", err)
		return err
	}
	// 在线程中处理标准错误输出
	go func() {
		reader := bufio.NewReader(stderr)
		for {
			line, err := reader.ReadString('\n')
			if err != nil {
				if io.EOF != err {
					// 如果不是执行完毕，返回错误信息
					receiver("", "", err)
				}
				break
			}
			receiver("", line, nil)
		}
	}()

	reader := bufio.NewReader(stdout)

	for {
		line, err := reader.ReadString('\n')
		if err != nil {
			if io.EOF != err {
				// 如果不是执行完毕，返回错误信息
				receiver("", "", err)
			}
			break
		}
		receiver(line, "", nil)
	}
	return err
}

// Run 同步方式执行，只有执行完毕之后才会返回结果
// 返回参数1-标准输出，返回参数2-标准错误输出，参数3-错误信息
func (runner *CmdRunner) Run() ([]string, []string, []error) {
	var stdouts []string
	var stderrs []string
	var errs []error
	for _, cmd := range runner.cmds {
		stdout, stderr, err := cmd.Run()
		stdouts = append(stdouts, stdout)
		stderrs = append(stderrs, stderr)
		errs = append(errs, err)
	}
	return stdouts, stderrs, errs
}

// RealRun 执行指令，实时输出，执行完之后，函数返回
// receiver - 执行指令回调:参数1-指令序号，从0开始，参数2-标准输出，参数3-错误输出，参数4-执行错误
func (runner *CmdRunner) RealRun(receiver func(int, string, string, error)) {
	for i, cmd := range runner.cmds {
		cmd.RealRun(func(stdout string, stderr string, err error) {
			receiver(i, stdout, stderr, err)
		})
	}
}