/* SPDX-License-Identifier: MIT
 *
 * Copyright (C) 2019-2026 WireGuard LLC. All Rights Reserved.
 */

package l18n

import (
	"sync"

	"golang.org/x/text/message"
)

var (
	printer     *message.Printer
	printerLock sync.Mutex
)

// prn returns the printer for user preferred UI language.
func prn() *message.Printer {
	if printer != nil {
		return printer
	}
	printerLock.Lock()
	if printer != nil {
		printerLock.Unlock()
		return printer
	}
	printer = message.NewPrinter(lang())
	printerLock.Unlock()
	return printer
}

// Sprintf is like fmt.Sprintf, but using language-specific formatting.
func Sprintf(key message.Reference, a ...any) string {
	return prn().Sprintf(key, a...)
}

// EnumerationSeparator returns enumeration separator. For English and western languages,
// enumeration separator is a comma followed by a space (i.e. ", "). For Chinese, it returns
// "\u3001".
func EnumerationSeparator() string {
	// BUG: We could just use `Sprintf(", " /* ...translator instructions... */)` and let the
	// individual locale catalog handle its translation. Unfortunately, the gotext utility tries to
	// be nice to translators and skips all strings without letters when updating catalogs.
	sep := Sprintf("[EnumerationSeparator]" /* Text to insert between items when listing - most western languages will translate ‘[EnumerationSeparator]’ into ‘, ’ to produce lists like ‘apple, orange, strawberry’. Eastern languages might translate into ‘、’ to produce lists like ‘リンゴ、オレンジ、イチゴ’. */)
	if sep == "[EnumerationSeparator]" {
		return ", "
	}
	return sep
}

// UnitSeparator returns the separator to use when concatenating multiple units of the same metric
// (e.g. "1 minute, 32 seconds", "6 feet, 1 inch"). For English and western languages, unit
// separator is a comma followed by a space (i.e. ", "). For Slovenian and Japanese, it returns
// just space.
func UnitSeparator() string {
	// BUG: We could just use `Sprintf(", " /* ...translator instructions... */)` and let the
	// individual locale catalog handle its translation. Unfortunately, the gotext utility tries to
	// be nice to translators and skips all strings without letters when updating catalogs.
	sep := Sprintf("[UnitSeparator]" /* Text to insert when combining units of a measure - most languages will translate ‘[UnitSeparator]’ into ‘ ’ (space) to produce lists like ‘2 minuti 30 sekund’, or empty string ‘’ to produce ‘2分30秒’. */)
	if sep == "[UnitSeparator]" {
		return ", "
	}
	return sep
}