package main

import (
	"crypto/x509"
	"encoding/pem"
	"fmt"
	"io/ioutil"
	"net/http"
	"os"
	"path/filepath"
	"strconv"
	"strings"
	"time"

	"github.com/docopt/docopt-go"
	"github.com/go-ini/ini"
	"github.com/tidwall/gjson"
)

var (
	appVersion                string
	buildTime                 string
	CertBase                  string
	KeyBase                   string
	GroupName                 string
	RedisBaseURL              string
	VaultBaseURL              string
	certificateDestination    string
	fullchainDestination      string
	keyDestination            string
	caDestination             string
	Type                      string
	tmpCertificateDestination = "/tmp/amce_cert.pem"
	tmpFullchainDestination   = "/tmp/amce_fullchain.pem"
	tmpCaDestination          = "/tmp/amce_ca.pem"
	tmpKeyDestination         = "/tmp/amce_key.pem"
	tempCertSlice             = []string{tmpCertificateDestination, tmpFullchainDestination, tmpCaDestination, tmpKeyDestination}
)

// app exit
func appExit(status int) {
	for _, element := range tempCertSlice {
		err := os.Remove(element)
		if err != nil {
		}
	}
	os.Exit(status)
}

// check certificates
func checkCerificates(dnsname string, certificate string, fullchain string, ca string, key string, days int, fail bool) bool {
	for _, element := range tempCertSlice {
		fmt.Printf(element)
	}
	Seconds := days * 86400

	daysNumber := time.Now().Local().Add(time.Second * time.Duration(Seconds))

	//fmt.Printf(daysNumber)
	certPEM, err := ioutil.ReadFile(certificate)
	if err != nil {
		if fail == true {
			fmt.Printf("[ERROR] %v\n", err)
			appExit(255)
		} else {
			return false
		}
	}

	certFullchainPEM, err := ioutil.ReadFile(fullchain)
	if err != nil {
		if fail == true {
			fmt.Printf("[ERROR] %v\n", err)
			appExit(255)
		} else {
			return false
		}
	}

	rootPEM, err := ioutil.ReadFile(ca)
	if err != nil {
		if fail == true {
			fmt.Printf("[ERROR] %v\n", err)
			appExit(255)
		} else {
			return false
		}
	}

	roots := x509.NewCertPool()
	ok := roots.AppendCertsFromPEM([]byte(rootPEM))
	if !ok {
		if fail == true {
			fmt.Printf("[ERROR] failed to parse root certificate\n")
			appExit(255)
		} else {
			return false
		}
	}

	block, _ := pem.Decode([]byte(certPEM))
	if block == nil {
		if fail == true {
			fmt.Printf("[ERROR] failed to parse certificate PEM\n")
			appExit(255)
		} else {
			return false
		}
	}
	cert, err := x509.ParseCertificate(block.Bytes)
	if err != nil {
		if fail == true {
			fmt.Printf("[ERROR] failed to parse certificate %v\n", err)
			appExit(255)
		} else {
			return false
		}
	}

	fullchainBlock, _ := pem.Decode([]byte(certFullchainPEM))
	if fullchainBlock == nil {
		if fail == true {
			fmt.Printf("[ERROR] failed to parse certificate PEM\n")
			appExit(255)
		} else {
			return false
		}
	}
	fullchainCert, fullchainErr := x509.ParseCertificate(fullchainBlock.Bytes)
	if fullchainErr != nil {
		if fail == true {
			fmt.Printf("[ERROR] failed to parse certificate %v\n", fullchainErr)
			appExit(255)
		} else {
			return false
		}
	}

	opts := x509.VerifyOptions{
		Roots:         roots,
		DNSName:       dnsname,
		CurrentTime:   daysNumber,
		Intermediates: x509.NewCertPool(),
	}

	if _, err := cert.Verify(opts); err != nil {
		if fail == true {
			fmt.Printf("[ERROR] failed to parse certificate %v\n", err.Error())
			appExit(255)
		} else {
			return false
		}
	}
	if _, fullchainErr := fullchainCert.Verify(opts); fullchainErr != nil {
		if fail == true {
			fmt.Printf("[ERROR] failed to parse certificate %v\n", err.Error())
		} else {
			return false
		}
	}
	return true

}

// get redis key
func GetRedisKey(redisurl string, redistoken string) string {
	client := &http.Client{}
	req, err := http.NewRequest("GET", redisurl, nil)
	req.SetBasicAuth("redis", redistoken)
	resp, err := client.Do(req)
	body, err := ioutil.ReadAll(resp.Body)
	defer resp.Body.Close()
	if err != nil {
		fmt.Printf("[ERROR] Fail to read %v: %v\n", redisurl, err)
		appExit(255)
	}
	return fmt.Sprintf(string(body))
}

// get Vault key
func GetVaultKey(vaulturl string, vaulttoken string) string {
	vaultClient := &http.Client{}
	req, err := http.NewRequest("GET", vaulturl, nil)
	req.Header.Add("X-vault-token", vaulttoken)
	resp, err := vaultClient.Do(req)
	body, err := ioutil.ReadAll(resp.Body)
	defer resp.Body.Close()
	if err != nil {
		fmt.Printf("[ERROR] Fail to read %v: %v\n", vaulturl, err)
		appExit(255)
	}
	return gjson.Get(string(body), "data.value").String()
}

// create directory structure and write certificate to file
func WriteToFile(content string, destination string, groupname string, filemode os.FileMode, dirmode os.FileMode) {
	baseDir := filepath.Dir(destination)
	if _, err := os.Stat(baseDir); os.IsNotExist(err) {
		os.MkdirAll(baseDir, 0755)
	}
	os.Chmod(baseDir, dirmode)

	file, err := os.OpenFile(destination, os.O_WRONLY|os.O_CREATE, filemode)
	if err != nil {
		fmt.Printf("[ERROR] %v cannot be created\n", destination)
		appExit(255)
	}

	fmt.Fprintf(file, "%v\n", content)
	file.Close()
}

// ReadOSRelease from /etc/os-release
func ReadOSRelease(configfile string) map[string]string {
	ConfigParams := make(map[string]string)
	cfg, err := ini.Load(configfile)
	if err != nil {
		ConfigParams["ID"] = "unknown"
	} else {
		ConfigParams["ID"] = cfg.Section("").Key("ID").String()
	}

	return ConfigParams
}

func main() {

	OSInfo := ReadOSRelease("/etc/os-release")
	OSRelease := OSInfo["ID"]
	if OSRelease == "centos" || OSRelease == "rhel" {
		CertBase = "/etc/pki/tls/certs"
		KeyBase = "/etc/pki/tls/private"
		GroupName = "root"
	} else if OSRelease == "ubuntu" || OSRelease == "debian" {
		CertBase = "/etc/ssl/certs"
		KeyBase = "/etc/ssl/private"
		GroupName = "ssl-cert"
	} else if OSRelease == "arch" {
		CertBase = "/etc/ssl/certs"
		KeyBase = "/etc/ssl/private"
		GroupName = "root"
	} else if OSRelease == "unknown" {
		CertBase = "/PATH/TO/CERTIFICATE"
		KeyBase = "/PATH/TO/PRIV/KEY"
		GroupName = "root"
	}

	usage := fmt.Sprintf(`ACME Downloader:
  - fetches and stores a given Certificate, Full Chain, CA and Private Key

Usage:
  acme-downloader --redis-token=REDISTOKEN --vault-token=VAULTTOKEN --cert-name=CERTNAME --team-name=TEAMNAME [--days=DAYS] [--type=TYPE] [--cert-destination=CERTDESTINATION] [--fullchain-destination=FULLCHAINDESTINATION] [--key-destination=KEYDESTINATION] [--ca-destination=CADESTINATION]
  acme-downloader -v | --version
  acme-downloader -b | --build
  acme-downloader -h | --help

Options:
  -h --help                                     Show this screen
  -v --version                                  Print version exit
  -b --build                                    Print version and build information and exit
  --redis-token=REDISTOKEN                      Redis access token
  --vault-token=VAULTTOKEN                      Vault access token
  --cert-name=CERTNAME                          Certificate name
  --team-name=TEAMNAME                          Team name: swd, dream_team, it, ne, ti...
  --days=DAYS                                   Days before expiration [default: 30]
  --type=TYPE                                   Type, EV or OV [default: EV]
  --cert-destination=CERTDESTINATION            Cert Destination [default: %v/<cert-name>.crt]
  --fullchain-destination=FULLCHAINDESTINATION  Full Chain Destination[default: %v/<cert-name>_fullchain.crt]
  --key-destination=KEYDESTINATION              Key Destination [default: %v/<cert-name>.key]
  --ca-destination=CADESTINATION                CA Destination [default: %v/COMODO_<type>.crt]
`, CertBase, CertBase, KeyBase, CertBase)

	arguments, _ := docopt.Parse(usage, nil, true, appVersion, false)

	// Annoyingly docopt tries to use 'version' the way he wants and I am using build
	if arguments["--build"] == true {
		fmt.Printf("acme-downloader version: %v, built on: %v\n", appVersion, buildTime)
		appExit(0)
	}

	VaultToken := arguments["--vault-token"].(string)
	CertName := arguments["--cert-name"].(string)
	CertNameUndercored := strings.Replace(CertName, ".", "_", -1)
	TeamName := arguments["--team-name"].(string)
	RedisToken := arguments["--redis-token"].(string)
	Type = arguments["--type"].(string)
	DayString := arguments["--days"].(string)
	Days, daysErr := strconv.Atoi(DayString)
	if daysErr != nil {
		fmt.Printf("Days mut be an integer\n")
		appExit(255)
	}
	RedisBaseURL = "https://redis.geant.org/GET"
	VaultBaseURL = "https://vault.geant.org/v1"
	VaultURL := fmt.Sprintf("%v/%v/%v/vault_%v_key", VaultBaseURL, TeamName, CertName, CertNameUndercored)
	RedisCertURL := fmt.Sprintf("%v/%v:%v:redis_%v_pem.txt", RedisBaseURL, TeamName, CertName, CertNameUndercored)
	RedisCAURL := fmt.Sprintf("%v/%v:%v:redis_%v_chain_pem.txt", RedisBaseURL, TeamName, CertName, CertNameUndercored)
	RedisFullChainURL := fmt.Sprintf("%v/%v:%v:redis_%v_fullchain_pem.txt", RedisBaseURL, TeamName, CertName, CertNameUndercored)

	if arguments["--cert-destination"] == fmt.Sprintf("%v/<cert-name>.crt", CertBase) {
		certificateDestination = fmt.Sprintf("%v/%v.crt", CertBase, CertName)
	} else {
		certificateDestination = arguments["--cert-destination"].(string)
	}
	if arguments["--fullchain-destination"] == fmt.Sprintf("%v/<cert-name>_fullchain.crt", CertBase) {
		fullchainDestination = fmt.Sprintf("%v/%v_fullchain.crt", CertBase, CertName)
	} else {
		fullchainDestination = arguments["--fullchain-destination"].(string)
	}
	if arguments["--ca-destination"] == fmt.Sprintf("%v/COMODO_<type>.crt", CertBase) {
		caDestination = fmt.Sprintf("%v/COMODO_%v.crt", CertBase, Type)
	} else {
		caDestination = arguments["--ca-destination"].(string)
	}
	if arguments["--key-destination"] == fmt.Sprintf("%v/<cert-name>.key", KeyBase) {
		keyDestination = fmt.Sprintf("%v/%v.key", KeyBase, CertName)
	} else {
		keyDestination = arguments["--key-destination"].(string)
	}

	// check if there is a certificate installed and it is valid
	existingCert := checkCerificates(CertName, certificateDestination, fullchainDestination, caDestination, keyDestination, Days, false)
	if existingCert == true {
		fmt.Printf("the certificates are still valid\n")
		appExit(0)
	}
	certificate := GetRedisKey(RedisCertURL, RedisToken)
	ca := GetRedisKey(RedisCAURL, RedisToken)
	fullChain := GetRedisKey(RedisFullChainURL, RedisToken)
	privKey := GetVaultKey(VaultURL, VaultToken)

	WriteToFile(certificate, tmpCertificateDestination, GroupName, 0644, 0755)
	WriteToFile(fullChain, tmpFullchainDestination, GroupName, 0644, 0755)
	WriteToFile(ca, tmpCaDestination, GroupName, 0644, 0755)
	WriteToFile(privKey, tmpKeyDestination, GroupName, 0640, 0750)

	checkCerificates(CertName, tmpCertificateDestination, tmpFullchainDestination, tmpCaDestination, tmpKeyDestination, Days, true)

	WriteToFile(certificate, certificateDestination, GroupName, 0644, 0755)
	WriteToFile(fullChain, fullchainDestination, GroupName, 0644, 0755)
	WriteToFile(ca, caDestination, GroupName, 0644, 0755)
	WriteToFile(privKey, keyDestination, GroupName, 0640, 0750)

	fmt.Printf("installed: %v\n", certificateDestination)
	fmt.Printf("installed: %v\n", caDestination)
	fmt.Printf("installed: %v\n", fullchainDestination)
	fmt.Printf("installed: %v\n", keyDestination)

	// Exit 100, means application reload
	appExit(1)

}