/** Configuration package.
*
* @author Sonja Happ <sonja.happ@eonerc.rwth-aachen.de>
* @copyright 2014-2019, Institute for Automation of Complex Power Systems, EONERC
* @license GNU General Public License (version 3)
*
* VILLASweb-backend-go
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program.  If not, see <http://www.gnu.org/licenses/>.
*********************************************************************************/
package configuration

import (
	"flag"
	"log"
	"os"

	"github.com/zpatrick/go-config"
)

// Global configuration
var GlobalConfig *config.Config = nil

func InitConfig() error {
	if GlobalConfig != nil {
		return nil
	}

	var (
		dbHost          = flag.String("db-host", "/var/run/postgresql", "Host of the PostgreSQL database (default is /var/run/postgresql for localhost DB on Ubuntu systems)")
		dbName          = flag.String("db-name", "villasdb", "Name of the database to use (default is villasdb)")
		dbUser          = flag.String("db-user", "", "Username of database connection (default is <empty>)")
		dbPass          = flag.String("db-pass", "", "Password of database connection (default is <empty>)")
		dbSSLMode       = flag.String("db-ssl-mode", "disable", "SSL mode of DB (default is disable)") // TODO: change default for production
		amqpHost        = flag.String("amqp-host", "", "If set, use this as host for AMQP broker (default is disabled)")
		amqpUser        = flag.String("amqp-user", "", "Username for AMQP broker")
		amqpPass        = flag.String("amqp-pass", "", "Password for AMQP broker")
		configFile      = flag.String("config", "", "Path to YAML configuration file")
		mode            = flag.String("mode", "release", "Select debug/release/test mode (default is release)")
		port            = flag.String("port", "4000", "Port of the backend (default is 4000)")
		baseHost        = flag.String("base-host", "localhost:4000", "The host at which the backend is hosted (default: localhost)")
		basePath        = flag.String("base-path", "/api/v2", "The path at which the API routes are located (default /api/v2)")
		adminUser       = flag.String("admin-user", "", "Initial admin username")
		adminPass       = flag.String("admin-pass", "", "Initial admin password")
		adminMail       = flag.String("admin-mail", "", "Initial admin mail address")
		s3Bucket        = flag.String("s3-bucket", "", "S3 Bucket for uploading files")
		s3Endpoint      = flag.String("s3-endpoint", "", "Endpoint of S3 API for file uploads")
		s3Region        = flag.String("s3-region", "default", "S3 Region for file uploads")
		s3NoSSL         = flag.Bool("s3-nossl", false, "Use encrypted connections to the S3 API")
		s3PathStyle     = flag.Bool("s3-pathstyle", false, "Use path-style S3 API")
		jwtSecret       = flag.String("jwt-secret", "This should NOT be here!!@33$8&", "The JSON Web Token secret")
		jwtExpiresAfter = flag.String("jwt-expires-after", "1w", "The time after which the JSON Web Token expires")
	)
	flag.Parse()

	static := map[string]string{
		"db.host":           *dbHost,
		"db.name":           *dbName,
		"db.user":           *dbUser,
		"db.pass":           *dbPass,
		"db.ssl":            *dbSSLMode,
		"amqp.host":         *amqpHost,
		"amqp.user":         *amqpUser,
		"amqp.pass":         *amqpPass,
		"mode":              *mode,
		"port":              *port,
		"base.host":         *baseHost,
		"base.path":         *basePath,
		"admin.user":        *adminUser,
		"admin.pass":        *adminPass,
		"admin.mail":        *adminMail,
		"s3.bucket":         *s3Bucket,
		"s3.endpoint":       *s3Endpoint,
		"s3.region":         *s3Region,
		"jwt.secret":        *jwtSecret,
		"jwt.expires-after": *jwtExpiresAfter,
	}

	if *s3NoSSL == true {
		static["s3.nossl"] = "true"
	} else {
		static["s3.nossl"] = "false"
	}

	if *s3PathStyle == true {
		static["s3.pathstyle"] = "true"
	} else {
		static["s3.pathstyle"] = "false"
	}

	mappings := map[string]string{
		"DB_HOST":           "db.host",
		"DB_NAME":           "db.name",
		"DB_USER":           "db.user",
		"DB_PASS":           "db.pass",
		"DB_SSLMODE":        "db.ssl",
		"AMQP_HOST":         "amqp.host",
		"AMQP_USER":         "amqp.user",
		"AMQP_PASS":         "amqp.pass",
		"BASE_HOST":         "base.host",
		"BASE_PATH":         "base.path",
		"MODE":              "mode",
		"PORT":              "port",
		"ADMIN_USER":        "admin.user",
		"ADMIN_PASS":        "admin.pass",
		"ADMIN_MAIL":        "admin.mail",
		"S3_BUCKET":         "s3.bucket",
		"S3_ENDPOINT":       "s3.endpoint",
		"S3_REGION":         "s3.region",
		"S3_NOSSL":          "s3.nossl",
		"S3_PATHSTYLE":      "s3.pathstyle",
		"JWT_SECRET":        "jwt.secret",
		"JWT_EXPIRES_AFTER": "jwt.expires-after",
	}

	defaults := config.NewStatic(static)
	env := config.NewEnvironment(mappings)

	if _, err := os.Stat(*configFile); os.IsNotExist(err) {
		GlobalConfig = config.NewConfig([]config.Provider{defaults, env})
	} else {
		yamlFile := config.NewYAMLFile(*configFile)
		GlobalConfig = config.NewConfig([]config.Provider{defaults, yamlFile, env})
	}

	err := GlobalConfig.Load()
	if err != nil {
		log.Fatal("failed to parse config")
		return err
	}

	m, err := GlobalConfig.String("mode")
	if err != nil {
		return err
	}

	if m != "test" {
		settings, _ := GlobalConfig.Settings()
		log.Print("All settings:")
		for key, val := range settings {
			// TODO password settings should be excluded!
			log.Printf("   %s = %s \n", key, val)
		}
	}

	return nil
}

func ConfigureBackend() (string, string, string, string, string, string, string, error) {

	err := InitConfig()
	if err != nil {
		log.Printf("Error during initialization of global configuration: %v, aborting.", err.Error())
		return "", "", "", "", "", "", "", err
	}

	mode, err := GlobalConfig.String("mode")
	if err != nil {
		log.Printf("Error reading mode from global configuration: %v, aborting.", err.Error())
		return "", "", "", "", "", "", "", err
	}

	baseHost, err := GlobalConfig.String("base.host")
	if err != nil {
		log.Printf("Error reading base.host from global configuration: %v, aborting.", err.Error())
		return "", "", "", "", "", "", "", err
	}
	basePath, err := GlobalConfig.String("base.path")
	if err != nil {
		log.Printf("Error reading base.path from global configuration: %v, aborting.", err.Error())
		return "", "", "", "", "", "", "", err
	}
	port, err := GlobalConfig.String("port")
	if err != nil {
		log.Printf("Error reading port from global configuration: %v, aborting.", err.Error())
		return "", "", "", "", "", "", "", err
	}

	AMQPhost, _ := GlobalConfig.String("amqp.host")
	AMQPuser, _ := GlobalConfig.String("amqp.user")
	AMQPpass, _ := GlobalConfig.String("amqp.pass")

	return mode, baseHost, basePath, port, AMQPhost, AMQPuser, AMQPpass, nil
}