package main

import (
	"os"
	"gopkg.in/yaml.v2"
	"io/ioutil"
	"regexp"
	"errors"
)

type Config struct {
	Scripts []Scripts
}

type Scripts struct {
	Name       string
	Recurrence string
	Commands   []string
}

func main() {
	var config Config
	err := yaml.Unmarshal(readFile(os.Args[1]), &config)
	check(err)
	timeFolders := []string{"15min", "hourly", "daily", "weekly", "monthly"}

	//Check whether recurrence entries are valid
	for i := 0; i < len(config.Scripts); i++ {
		match, err := regexp.MatchString("15min|hourly|daily|weekly|monthly", config.Scripts[i].Recurrence)
		check(err)
		if !match {
			panic(errors.New("Invalid recurrence."))
		}
	}
	//Remove old scripts
	for j := 0; j < len(config.Scripts); j++ {
		for i := 0; i < len(timeFolders); i++ {
			path := "/etc/periodic/" + timeFolders[i] + "/" + config.Scripts[j].Name
			exists, err := existsFile(path)
			check(err)
			if exists {
				os.Remove(path)
			}
		}
	}

	for i := 0; i < len(config.Scripts); i++ {
		fileContent := "#!/bin/sh\n"
		for j := 0; j < len(config.Scripts[i].Commands); j++ {
			fileContent += config.Scripts[i].Commands[j] + "\n"
		}
		path := "/etc/periodic/" + config.Scripts[i].Recurrence + "/" + config.Scripts[i].Name
		file, err := os.Create(path)
		check(err)
		file.WriteString(fileContent)
		file.Sync()
		os.Chmod(file.Name(), 0755)
	}

}

func existsFile(path string) (bool, error) {
	_, err := os.Stat(path)
	if err == nil {
		return true, nil
	}
	if os.IsNotExist(err) {
		return false, nil
	}
	return true, err
}

func readFile(path string) []byte {
	data, err := ioutil.ReadFile(path)
	check(err)
	return data
}

func check(e error) {
	if e != nil {
		panic(e)
	}
}