// Copyright (c) HashiCorp, Inc.
// SPDX-License-Identifier: BUSL-1.1

package api

import (
	"os"
	"strings"
)

const (
	// legacyEnvPrefix is the environment variable prefix used by upstream
	// HashiCorp Boundary. It is still honored as a fallback.
	legacyEnvPrefix = "BOUNDARY_"
	// envPrefix is the preferred environment variable prefix for Threshold.
	envPrefix = "THRESHOLD_"
)

// PreferredEnvName returns the Threshold (THRESHOLD_*) form of an environment
// variable name. Names that do not use the legacy BOUNDARY_ prefix are
// returned unchanged.
func PreferredEnvName(name string) string {
	if strings.HasPrefix(name, legacyEnvPrefix) {
		return envPrefix + strings.TrimPrefix(name, legacyEnvPrefix)
	}
	return name
}

// LegacyEnvName returns the legacy (BOUNDARY_*) form of an environment
// variable name. Names that do not use the THRESHOLD_ prefix are returned
// unchanged.
func LegacyEnvName(name string) string {
	if strings.HasPrefix(name, envPrefix) {
		return legacyEnvPrefix + strings.TrimPrefix(name, envPrefix)
	}
	return name
}

// LookupEnv looks up an environment variable, preferring the THRESHOLD_*
// name and falling back to the legacy BOUNDARY_* name. The name may be given
// with either prefix; names with neither prefix are looked up as-is.
func LookupEnv(name string) (string, bool) {
	if v, ok := os.LookupEnv(PreferredEnvName(LegacyEnvName(name))); ok {
		return v, true
	}
	return os.LookupEnv(LegacyEnvName(name))
}

// Getenv is like os.Getenv but follows the LookupEnv precedence. A set but
// empty THRESHOLD_* variable falls through to the legacy BOUNDARY_* variable.
func Getenv(name string) string {
	if v := os.Getenv(PreferredEnvName(LegacyEnvName(name))); v != "" {
		return v
	}
	return os.Getenv(LegacyEnvName(name))
}