/*
© Copyright IBM Corporation 2018, 2019

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 main

import (
	"fmt"
	"io"
	"os"
	"os/exec"
	"os/user"
	"path/filepath"
	"strconv"
	"strings"
	"syscall"

	"github.com/ibm-messaging/mq-container/internal/command"
	"github.com/ibm-messaging/mq-container/internal/keystore"
	"github.com/ibm-messaging/mq-container/internal/mqtemplate"
)

func startWebServer() error {
	_, err := os.Stat("/opt/mqm/bin/strmqweb")
	if err != nil && os.IsNotExist(err) {
		log.Debug("Skipping web server, because it's not installed")
		return nil
	}
	log.Println("Starting web server")
	cmd := exec.Command("strmqweb")
	// Set a default app password for the web server, if one isn't already set
	_, set := os.LookupEnv("MQ_APP_PASSWORD")
	if !set {
		// Take all current environment variables, and add the app password
		cmd.Env = append(os.Environ(), "MQ_APP_PASSWORD=passw0rd")
	}
	uid, gid, err := command.LookupMQM()
	if err != nil {
		return err
	}
	u, err := user.Current()
	if err != nil {
		return err
	}
	currentUID, err := strconv.Atoi(u.Uid)
	if err != nil {
		return fmt.Errorf("Error converting UID to string: %v", err)
	}
	// Add credentials to run as 'mqm', only if we aren't already 'mqm'
	if currentUID != uid {
		cmd.SysProcAttr = &syscall.SysProcAttr{}
		cmd.SysProcAttr.Credential = &syscall.Credential{Uid: uint32(uid), Gid: uint32(gid)}
	}
	out, rc, err := command.RunCmd(cmd)
	if err != nil {
		log.Printf("Error %v starting web server: %v", rc, string(out))
		return err
	}
	log.Println("Started web server")
	return nil
}

// CopyFile copies the specified file
func CopyFile(src, dest string) error {
	log.Debugf("Copying file %v to %v", src, dest)
	in, err := os.Open(src)
	if err != nil {
		return err
	}
	defer in.Close()

	out, err := os.OpenFile(dest, os.O_CREATE|os.O_WRONLY, 0770)
	defer out.Close()

	_, err = io.Copy(out, in)
	if err != nil {
		return err
	}
	err = out.Close()
	return err
}

func configureSSO() error {

	// Ensure all required environment variables are set for SSO
	requiredEnvVars := []string{
		"MQ_WEB_ADMIN_USERS",
		"MQ_OIDC_CLIENT_ID",
		"MQ_OIDC_CLIENT_SECRET",
		"MQ_OIDC_UNIQUE_USER_IDENTIFIER",
		"MQ_OIDC_AUTHORIZATION_ENDPOINT",
		"MQ_OIDC_TOKEN_ENDPOINT",
		"MQ_OIDC_JWK_ENDPOINT",
		"MQ_OIDC_ISSUER_IDENTIFIER",
		"MQ_OIDC_CERTIFICATE",
	}
	for _, envVar := range requiredEnvVars {
		if len(os.Getenv(envVar)) == 0 {
			return fmt.Errorf("%v must be set when MQ_BETA_ENABLE_SSO=true", envVar)
		}
	}

	// Check mqweb directory exists
	const mqwebDir string = "/etc/mqm/web/installations/Installation1/servers/mqweb"
	_, err := os.Stat(mqwebDir)
	if err != nil {
		if os.IsNotExist(err) {
			return nil
		}
		return err
	}

	// Process SSO template for generating file mqwebuser.xml
	adminUsers := strings.Split(os.Getenv("MQ_WEB_ADMIN_USERS"), "\n")
	err = mqtemplate.ProcessTemplateFile(mqwebDir+"/mqwebuser.xml.tpl", mqwebDir+"/mqwebuser.xml", map[string][]string{"AdminUser": adminUsers}, log)
	if err != nil {
		return err
	}

	// Configure SSO TLS
	return configureSSO_TLS()
}

func configureSSO_TLS() error {

	// Create tls directory
	dir := "/run/tls"
	mntdir := "/mnt/tls/"
	_, err := os.Stat(dir)
	if err != nil {
		if os.IsNotExist(err) {
			err = os.MkdirAll(dir, 0770)
			if err != nil {
				return err
			}
			mqmUID, mqmGID, err := command.LookupMQM()
			if err != nil {
				log.Error(err)
				return err
			}
			err = os.Chown(dir, mqmUID, mqmGID)
			if err != nil {
				log.Error(err)
				return err
			}
		} else {
			return err
		}
	}

	// Setup key store & trust store
	ks := keystore.NewJKSKeyStore(filepath.Join(dir, "key.jks"), "password")
	ts := keystore.NewJKSKeyStore(filepath.Join(dir, "trust.jks"), "password")

	log.Debug("Creating key store")
	err = ks.Create(log)
	if err != nil {
		return err
	}
	log.Debug("Creating trust store")
	err = ts.Create(log)
	if err != nil {
		return err
	}
	log.Debug("Generating PKCS12 file")
	err = ks.GeneratePKCS12(filepath.Join(mntdir, "tls.key"), filepath.Join(mntdir, "tls.crt"), filepath.Join(dir, "tls.p12"), "default", "password")
	if err != nil {
		return err
	}
	log.Debug("Importing certificate into key store")
	err = ks.Import(filepath.Join(dir, "tls.p12"), "password")
	if err != nil {
		return err
	}
	log.Debug("Adding OIDC certificate to trust store")
	err = ts.Add(os.Getenv("MQ_OIDC_CERTIFICATE"), "OIDC")
	return err
}

func configureWebServer() error {
	_, err := os.Stat("/opt/mqm/bin/strmqweb")
	if err != nil {
		if os.IsNotExist(err) {
			return nil
		}
		return err
	}
	const webConfigDir string = "/etc/mqm/web"
	_, err = os.Stat(webConfigDir)
	if err != nil {
		if os.IsNotExist(err) {
			return nil
		}
		return err
	}
	uid, gid, err := command.LookupMQM()
	if err != nil {
		return err
	}
	const prefix string = "/etc/mqm/web"
	err = filepath.Walk(prefix, func(from string, info os.FileInfo, err error) error {
		if err != nil {
			return err
		}
		to := fmt.Sprintf("/var/mqm/web%v", from[len(prefix):])
		exists := true
		_, err = os.Stat(to)
		if err != nil {
			if os.IsNotExist(err) {
				exists = false
			} else {
				return err
			}
		}
		if info.IsDir() {
			if !exists {
				err := os.MkdirAll(to, 0770)
				if err != nil {
					return err
				}
			}
		} else {
			if exists {
				err := os.Remove(to)
				if err != nil {
					return err
				}
			}
			err := CopyFile(from, to)
			if err != nil {
				log.Error(err)
				return err
			}
		}
		err = os.Chown(to, uid, gid)
		if err != nil {
			return err
		}
		return nil
	})
	return err
}