go_blog/i18n/i18n.go

package i18n

import (
	"strings"
)

// Lang represents a supported language code.
type Lang string

const (
	EN Lang = "en"
	ZH Lang = "zh"
)

// translations holds all UI strings keyed by language then translation key.
var translations = map[Lang]map[string]string{
	EN: {
		// Nav
		"site_title": "Go Blog",
		"home":       "Home",
		"login":      "Login",
		"dashboard":  "Dashboard",
		"logout":     "Logout",

		// Home page
		"home_welcome":   "Welcome to Go Blog",
		"home_subtitle":  "A simple, fast blog engine built with Go, Gin, and Tailwind CSS.",
		"home_sign_in":   "Sign In",
		"home_to_dash":   "Dashboard",
		"home_latest":    "Latest Posts",
		"home_post1_tit": "Getting Started",
		"home_post1_dsc": "Welcome to your new blog! This is a placeholder post. Start writing to see your content here.",
		"home_post2_tit": "Hello World",
		"home_post2_dsc": "Blog posts will appear here once you start publishing from the admin dashboard.",
		"home_post3_tit": "Built with Go",
		"home_post3_dsc": "This blog engine uses Go, Gin web framework, GORM, and Tailwind CSS for a modern experience.",

		// Login page
		"login_title":    "Sign In",
		"login_username": "Username",
		"login_password": "Password",
		"login_ph_user":  "Enter your username",
		"login_ph_pass":  "Enter your password",
		"login_submit":   "Sign In",
		"login_error":    "Invalid username or password.",

		// Dashboard
		"dash_title":      "Dashboard",
		"dash_welcome":    "Welcome back,",
		"dash_posts":      "Posts",
		"dash_pages":      "Pages",
		"dash_users":      "Users",
		"dash_mgmt_title": "Blog Management",
		"dash_mgmt_desc":  "Post management, categories, and settings will appear here in future updates.",
		"dash_page_title": "Dashboard",

		// Footer
		"footer_text": "© 2026 Go Blog. Powered by Go & Gin.",

		// Page titles
		"page_home":  "Home",
		"page_login": "Login",

		// Language switcher
		"lang_switch": "中文",

		// Profile dropdown & page
		"profile":                "Profile",
		"admin_panel":            "Admin Panel",
		"profile_title":          "Edit Profile",
		"profile_avatar":         "Avatar",
		"profile_change_avatar":  "Change Avatar",
		"profile_display_name":   "Display Name",
		"profile_gender":         "Gender",
		"profile_birthday":       "Birthday",
		"profile_email":          "Email",
		"profile_change_password": "Change Password",
		"profile_current_password": "Current Password",
		"profile_new_password":   "New Password",
		"profile_save":           "Save Changes",
		"profile_saved":          "Profile updated.",
		"profile_wrong_password": "Current password is incorrect.",
		"gender_male":            "Male",
		"gender_female":          "Female",
		"gender_other":           "Other",
	},
	ZH: {
		// 导航
		"site_title": "Go 博客",
		"home":       "首页",
		"login":      "登录",
		"dashboard":  "后台",
		"logout":     "退出",

		// 首页
		"home_welcome":   "欢迎来到 Go Blog",
		"home_subtitle":  "一个使用 Go、Gin 和 Tailwind CSS 构建的简洁快速的博客引擎。",
		"home_sign_in":   "登录",
		"home_to_dash":   "后台管理",
		"home_latest":    "最新文章",
		"home_post1_tit": "入门指南",
		"home_post1_dsc": "欢迎来到你的新博客！这是一篇占位文章。开始写作后，你的内容将显示在这里。",
		"home_post2_tit": "你好，世界",
		"home_post2_dsc": "当你从后台管理面板发布文章后，博客文章将显示在这里。",
		"home_post3_tit": "使用 Go 构建",
		"home_post3_dsc": "此博客引擎使用 Go、Gin Web 框架、GORM 和 Tailwind CSS 构建，提供现代化的体验。",

		// 登录页
		"login_title":    "登录",
		"login_username": "用户名",
		"login_password": "密码",
		"login_ph_user":  "请输入用户名",
		"login_ph_pass":  "请输入密码",
		"login_submit":   "登录",
		"login_error":    "用户名或密码错误。",

		// 后台
		"dash_title":      "后台管理",
		"dash_welcome":    "欢迎回来，",
		"dash_posts":      "文章",
		"dash_pages":      "页面",
		"dash_users":      "用户",
		"dash_mgmt_title": "博客管理",
		"dash_mgmt_desc":  "文章管理、分类和设置将在后续版本中添加。",
		"dash_page_title": "后台管理",

		// 页脚
		"footer_text": "© 2026 Go Blog。由 Go & Gin 驱动。",

		// 页面标题
		"page_home":  "首页",
		"page_login": "登录",

		// 语言切换
		"lang_switch": "English",

		// 个人中心下拉菜单 & 页面
		"profile":                "个人信息",
		"admin_panel":            "后台管理",
		"profile_title":          "编辑个人信息",
		"profile_avatar":         "头像",
		"profile_change_avatar":  "更换头像",
		"profile_display_name":   "显示名称",
		"profile_gender":         "性别",
		"profile_birthday":       "生日",
		"profile_email":          "邮箱",
		"profile_change_password": "修改密码",
		"profile_current_password": "当前密码",
		"profile_new_password":   "新密码",
		"profile_save":           "保存修改",
		"profile_saved":          "个人信息已更新。",
		"profile_wrong_password": "当前密码错误。",
		"gender_male":            "男",
		"gender_female":          "女",
		"gender_other":           "其他",
	},
}

// T returns a copy of the translation map for the given language.
// Falls back to English if the language is not supported.
func T(l Lang) map[string]string {
	t, ok := translations[l]
	if !ok {
		t = translations[EN]
	}
	// Return a shallow copy so callers cannot mutate the original map values.
	out := make(map[string]string, len(t))
	for k, v := range t {
		out[k] = v
	}
	return out
}

// DetectLang parses the Accept-Language header and returns the best matching
// supported language. Returns EN for unsupported languages.
func DetectLang(acceptHeader string) Lang {
	if acceptHeader == "" {
		return EN
	}

	// Accept-Language format: "zh-CN,zh;q=0.9,en;q=0.8,en-US;q=0.7"
	// Split by comma, then extract primary language from each entry.
	entries := strings.Split(acceptHeader, ",")
	for _, entry := range entries {
		// Trim spaces and remove quality values.
		entry = strings.TrimSpace(entry)
		if idx := strings.Index(entry, ";"); idx != -1 {
			entry = entry[:idx]
		}
		// Extract primary language (before any "-" subtag).
		primary := strings.ToLower(entry)
		if idx := strings.Index(primary, "-"); idx != -1 {
			primary = primary[:idx]
		}
		switch primary {
		case "zh":
			return ZH
		case "en":
			return EN
		}
	}

	return EN
}