go-urlsh/internal/config/config.go

package config

import (
	"net/netip"
	"slices"
	"strconv"

	"github.com/rs/zerolog"
	"github.com/spf13/viper"
)

type Config struct {
	DatabaseDSN string

	// panic = 5,
	// fatal = 4,
	// error = 3,
	// warn = 2,
	// info = 1,
	// debug = 0,
	// trace = -1
	LogLevel    int
	HostIP      netip.Addr
	HostPort    int
	HostURL     string
	ProxyHeader string
	AccessLog   bool
}

func NewConfig(configPath string) *Config {
	logger := NewLogger(zerolog.InfoLevel)

	loadConfigFile(configPath, logger)

	cfg := new(Config)
	exit := false

	// handle Database DSN
	if viper.GetString("database.url") != "" {
		cfg.DatabaseDSN = viper.GetString("database.url")
	} else {
		dsn := "postgres://"
		if viper.GetString("database.username") == "" {
			exit = true
			logger.Error().Msg("If database.url is not set, database.username must not be empty!")
		} else {
			dsn = dsn + viper.GetString("database.username")
		}

		if viper.GetString("database.password") == "" {
			exit = true
			logger.Error().Msg("If database.url is not set, database.password must not be empty!")
		} else {
			dsn = dsn + ":" + viper.GetString("database.password")
		}

		if viper.GetString("database.address") == "" {
			exit = true
			logger.Error().Msg("If database.url is not set, database.address must not be empty!")
		} else {
			dsn = dsn + "@" + viper.GetString("database.address")
		}

		if viper.GetString("database.port") != "" {
			dsn = dsn + ":" + strconv.Itoa(viper.GetInt("database.port"))
		}

		if viper.GetString("database.database") == "" {
			exit = true
			logger.Error().Msg("If database.url is not set, database.database must not be empty!")
		} else {
			dsn = dsn + "/" + viper.GetString("database.database")
		}

		if slices.Contains([]string{"disable", "require", "verify-full", ""}, viper.GetString("database.ssl-mode")) {
			if viper.GetString("database.ssl-mode") == "" {
				cfg.DatabaseDSN = dsn + "?sslmode=disable"
			} else {
				cfg.DatabaseDSN = dsn + "?sslmode=" + viper.GetString("database.ssl-mode")
			}
		} else {
			logger.Error().Msg(`If database.url is not set, database.ssl-mode must be either "disable", "require", "verify-full" or empty!`)
		}
	}

	// Handle Logging
	switch logLevel := viper.GetString("logging.level"); logLevel {
	case "panic":
		cfg.LogLevel = 5
	case "fatal":
		cfg.LogLevel = 4
	case "error":
		cfg.LogLevel = 3
	case "warn":
		cfg.LogLevel = 2
	case "info":
		cfg.LogLevel = 1
	case "debug":
		cfg.LogLevel = 0
	case "trace":
		cfg.LogLevel = -1

	default:
		exit = true
		logger.Error().Str("value", logLevel).Msg(`Value of logging.level is invalid!`)
	}

	cfg.HostURL = viper.GetString("application.base-url")

	if viper.GetString("application.listen") != "" {
		ip, err := netip.ParseAddr(viper.GetString("application.listen"))
		if err != nil {
			exit = true
			logger.Error().Str("value", viper.GetString("application.listen")).Msg(`Value of application.listen is not a valid IP address!`)
		} else {
			cfg.HostIP = ip
		}
	} else {
		cfg.HostIP = netip.MustParseAddr("127.0.0.1")
	}

	if viper.GetInt("application.port") != 0 {
		// if port is a valid port number
		if viper.GetInt("application.port") <= 65535 && viper.GetInt("application.port") > 0 {
			cfg.HostPort = viper.GetInt("application.port")
		} else {
			logger.Error().Str("value", viper.GetString("application.port")).Msg(`Value of application.port is not a valid port number!`)
		}
	} else {
		cfg.HostPort = 3000
	}

	if viper.GetString("application.proxy-header") == "" {
		cfg.ProxyHeader = "X-Forwarded-For"
	} else {
		cfg.ProxyHeader = viper.GetString("application.proxy-header")
	}

	if exit {
		logger.Fatal().Msg("There were errors reading the config file. See errors above!")
	}

	return cfg
}