1 files changed, 110 insertions, 0 deletions
diff --git a/internal/i18n/i18n.go b/internal/i18n/i18n.go
new file mode 100644
index 0000000..4f31667
--- /dev/null
+++ b/internal/i18n/i18n.go
@@ -0,0 +1,110 @@
+// Package i18n holds the languages a blog can be in and the translations of
+// the fixed text (dashboard, messages, dates). Keys are the English strings
+// themselves, so an untranslated key renders as English rather than blank.
+package i18n
+
+import (
+	"fmt"
+	"strings"
+	"time"
+)
+
+// Default is what new blogs get and what anything unknown falls back to.
+const Default = "en"
+
+type Language struct {
+	Code, Name string // Name is in the language itself, for the settings menu
+}
+
+var languages = []Language{
+	{Code: "en", Name: "English"},
+	{Code: "el", Name: "Ελληνικά"},
+}
+
+// catalogs maps a language to its translations; English is the identity.
+var catalogs = map[string]map[string]string{
+	"el": el,
+}
+
+func Languages() []Language { return languages }
+
+func Valid(code string) bool {
+	for _, l := range languages {
+		if l.Code == code {
+			return true
+		}
+	}
+	return false
+}
+
+// T translates key into lang, returning the key itself when there is no translation.
+func T(lang, key string) string {
+	if s, ok := catalogs[lang][key]; ok {
+		return s
+	}
+	return key
+}
+
+// Tf is T followed by Sprintf; translations may reorder arguments with %[n]s.
+func Tf(lang, key string, args ...any) string {
+	return fmt.Sprintf(T(lang, key), args...)
+}
+
+// Keys lists what a catalog translates (for the completeness test).
+func Keys(lang string) []string {
+	out := make([]string, 0, len(catalogs[lang]))
+	for k := range catalogs[lang] {
+		out = append(out, k)
+	}
+	return out
+}
+
+// Match picks a supported language from an Accept-Language header: the first
+// tag (in header order) whose primary subtag we have, else Default.
+func Match(acceptLanguage string) string {
+	for _, part := range strings.Split(acceptLanguage, ",") {
+		tag, _, _ := strings.Cut(strings.TrimSpace(part), ";")
+		primary, _, _ := strings.Cut(strings.ToLower(tag), "-")
+		if Valid(primary) {
+			return primary
+		}
+	}
+	return Default
+}
+
+// months are the names a language needs: standalone (archive headings), in a
+// date ("14 September" — Greek uses the genitive there) and abbreviated.
+type months struct {
+	name, inDate, short [12]string
+}
+
+var monthTables = map[string]months{
+	"el": elMonths,
+}
+
+// Month is the standalone month name (archive headings).
+func Month(lang string, m time.Month) string {
+	if t, ok := monthTables[lang]; ok {
+		return t.name[m-1]
+	}
+	return m.String()
+}
+
+// FormatDate renders a post date in the blogger's chosen style (long | short | iso).
+func FormatDate(lang, style string, at time.Time) string {
+	if style == "iso" {
+		return at.Format("2006-01-02")
+	}
+	t, ok := monthTables[lang]
+	if !ok { // English: the Go layouts
+		if style == "short" {
+			return at.Format("2 Jan 2006")
+		}
+		return at.Format("2 January 2006")
+	}
+	m := t.inDate[at.Month()-1]
+	if style == "short" {
+		m = t.short[at.Month()-1]
+	}
+	return fmt.Sprintf("%d %s %d", at.Day(), m, at.Year())
+}