Add localization support with plugin-local gettext

_meta.lua

@@ -1,6 +1,7 @@
+local _ = require("highlightsync_gettext")
 return {
     name = "HighlightSync",
-    fullname = "HighlightSync",
-    description = "HighlightSync is a plugin for KOReader that synchronizes and merges your highlights, notes, and bookmarks across multiple devices or cloud backup locations.",
-    version = "0.7.2",  -- ← Add this line!
+    fullname = _("HighlightSync"),
+    description = _("HighlightSync is a plugin for KOReader that synchronizes and merges your highlights, notes, and bookmarks across multiple devices or cloud backup locations."),
+    version = "0.7.2",
 }

highlightsync_gettext.lua

@@ -0,0 +1,294 @@
+-- This module is adapted from assistant.koplugin/assistant_gettext.lua
+-- which is in turn based on koreader frontend/gettext.lua
+--
+--[[--
+A pure Lua implementation of a gettext subset for highlightsync.koplugin.
+--]]
+
+local logger = require("logger")
+
+local GetText = {
+    context = {},
+    translation = {},
+    current_lang = "C",
+    dirname = "l10n",
+    textdomain = "koreader",
+    plural_default = "n != 1",
+}
+
+local GetText_mt = {
+    __index = {}
+}
+
+GetText.wrapUntranslated_nowrap = function(text) return text end
+GetText.wrapUntranslated = GetText.wrapUntranslated_nowrap
+
+function GetText_mt.__call(gettext, msgid)
+    return gettext.translation[msgid] and gettext.translation[msgid][0] or gettext.translation[msgid] or gettext.wrapUntranslated(msgid)
+end
+
+local function c_escape(what_full, what)
+    if what == "\n" then return ""
+    elseif what == "a" then return "\a"
+    elseif what == "b" then return "\b"
+    elseif what == "f" then return "\f"
+    elseif what == "n" then return "\n"
+    elseif what == "r" then return "\r"
+    elseif what == "t" then return "\t"
+    elseif what == "v" then return "\v"
+    elseif what == "0" then return "\0"
+    else
+        return what_full
+    end
+end
+
+local function logicalCtoLua(logical_str)
+    logical_str = logical_str:gsub("&&", "and")
+    logical_str = logical_str:gsub("!=", "~=")
+    logical_str = logical_str:gsub("||", "or")
+    return logical_str
+end
+
+local function getDefaultPlural(n)
+    if n ~= 1 then
+        return 1
+    else
+        return 0
+    end
+end
+
+local function getPluralFunc(pl_tests, nplurals, plural_default)
+    local plural_func_str = "return function(n) if "
+
+    if #pl_tests > 1 then
+        for i = 1, #pl_tests do
+            local pl_test = pl_tests[i]
+            pl_test = logicalCtoLua(pl_test)
+
+            if i > 1 and tonumber(pl_test) == nil then
+                pl_test = " elseif "..pl_test
+            end
+            if tonumber(pl_test) ~= nil then
+                pl_test = " else return "..pl_test
+            end
+            pl_test = pl_test:gsub("?", " then return")
+
+            plural_func_str = plural_func_str..pl_test
+        end
+        plural_func_str = plural_func_str.." end end"
+    else
+        local pl_test = pl_tests[1]
+        if pl_test == plural_default then
+            return getDefaultPlural
+        end
+        if tonumber(pl_test) ~= nil then
+            plural_func_str = "return function(n) return "..pl_test.." end"
+        else
+            pl_test = logicalCtoLua(pl_test)
+            plural_func_str = "return function(n) if "..pl_test.." then return 1 else return 0 end end"
+        end
+    end
+    logger.dbg("gettext: plural function", plural_func_str)
+    return loadstring(plural_func_str)()
+end
+
+local function addTranslation(msgctxt, msgid, msgstr, n)
+    local unescaped_string = string.gsub(msgstr, "(\\(.))", c_escape)
+    if msgctxt and msgctxt ~= "" then
+        if not GetText.context[msgctxt] then
+            GetText.context[msgctxt] = {}
+        end
+        if n then
+            if not GetText.context[msgctxt][msgid] then
+                GetText.context[msgctxt][msgid] = {}
+            end
+            GetText.context[msgctxt][msgid][n] = unescaped_string ~= "" and unescaped_string or nil
+        else
+            GetText.context[msgctxt][msgid] = unescaped_string ~= "" and unescaped_string or nil
+        end
+    else
+        if n then
+            if not GetText.translation[msgid] then
+                GetText.translation[msgid] = {}
+            end
+            GetText.translation[msgid][n] = unescaped_string ~= "" and unescaped_string or nil
+        else
+            GetText.translation[msgid] = unescaped_string ~= "" and unescaped_string or nil
+        end
+    end
+end
+
+function GetText_mt.__index.changeLang(new_lang)
+    GetText.context = {}
+    GetText.translation = {}
+    GetText.current_lang = "C"
+
+    if new_lang == "C" or new_lang == nil or new_lang == ""
+       or new_lang:match("^en_US") == "en_US" then 
+        return 
+    end
+
+    -- Strip encoding suffix if present (e.g., "zh_CN.UTF-8" -> "zh_CN")
+    local dot_pos = new_lang:find("%.")
+    if dot_pos then
+        new_lang = new_lang:sub(1, dot_pos - 1)
+    end
+
+    local file = GetText.dirname .. "/" .. new_lang .. "/" .. GetText.textdomain .. ".po"
+    local po = io.open(file, "r")
+
+    if not po then
+        logger.dbg("highlightsync: cannot open translation file:", file)
+        return false
+    end
+    logger.info("highlightsync: successfully opened translation file:", file)
+    print("highlightsync: successfully opened translation file:", file)
+
+    local data = {}
+    local fuzzy = false
+    local headers
+    local what = nil
+    while true do
+        local line = po:read("*l")
+        if line then
+            line = line:gsub("\r$", "")
+        end
+        if line == nil or line == "" then
+            if data.msgid and data.msgid_plural and data["msgstr[0]"] then
+                for k, v in pairs(data) do
+                    local n = tonumber(k:match("msgstr%[([0-9]+)%]"))
+                    local msgstr = v
+
+                    if n and msgstr then
+                        addTranslation(data.msgctxt, data.msgid, msgstr, n)
+                    end
+                end
+            elseif data.msgid and data.msgstr and data.msgstr ~= "" then
+                if not headers and data.msgid == "" then
+                    headers = data.msgstr
+                    local plural_forms = data.msgstr:match("Plural%-Forms: (.*)")
+
+                    -- Guard against missing Plural-Forms header
+                    if not plural_forms then
+                        GetText.getPlural = getDefaultPlural
+                    else
+                        local nplurals = plural_forms:match("nplurals=([0-9]+);") or 2
+                        local plurals = plural_forms:match("plural=%((.*)%);")
+
+                        if plurals == "n == 1) ? 0 : ((n == 2) ? 1 : ((n > 10 && n % 10 == 0) ? 2 : 3)" then
+                            plurals = "n == 1 ? 0 : (n == 2) ? 1 : (n > 10 && n % 10 == 0) ? 2 : 3"
+                        end
+                        if plurals == "n % 10 == 0 || n % 100 >= 11 && n % 100 <= 19) ? 0 : ((n % 10 == 1 && n % 100 != 11) ? 1 : 2" then
+                            plurals = "n % 10 == 0 || n % 100 >= 11 && n % 100 <= 19 ? 0 : (n % 10 == 1 && n % 100 != 11) ? 1 : 2"
+                        end
+                        if plurals == "n == 1) ? 0 : ((n == 0 || n != 1 && n % 100 >= 1 && n % 100 <= 19) ? 1 : 2" then
+                            plurals = "n == 1 ? 0 : (n == 0 || n != 1 && n % 100 >= 1 && n % 100 <= 19) ? 1 : 2"
+                        end
+
+                        if not plurals then
+                            plurals = plural_forms:match("plural=(.*);")
+                        end
+
+                        if plurals and plurals:find("[^n!=%%<>&:()|?0-9 ]") then
+                            plurals = GetText.plural_default
+                        end
+
+                        local pl_tests = {}
+                        if plurals then
+                            for pl_test in plurals:gmatch("[^:]+") do
+                                table.insert(pl_tests, pl_test)
+                            end
+                        end
+
+                        GetText.getPlural = getPluralFunc(pl_tests, nplurals, GetText.plural_default)
+                        if not GetText.getPlural then
+                            GetText.getPlural = getDefaultPlural
+                        end
+                    end
+                end
+
+                addTranslation(data.msgctxt, data.msgid, data.msgstr)
+            end
+            if line == nil then break end
+            data = {}
+            what = nil
+        else
+            if not line:match("^#") then
+                local w, s = line:match("^%s*([%a_%[%]0-9]+)%s+\"(.*)\"%s*$")
+                if w then
+                    what = w
+                else
+                    s = line:match("^%s*\"(.*)\"%s*$")
+                end
+                if what and s and not fuzzy then
+                    -- Single-pass string unescape (more efficient than 3 separate gsub)
+                    s = s:gsub("\\([n\"\\\\])", function(c)
+                        if c == "n" then return "\n"
+                        elseif c == '"' then return '"'
+                        else return "\\"
+                        end
+                    end)
+                    data[what] = (data[what] or "") .. s
+                elseif what and s == "" and fuzzy then
+                    -- Ignore fuzzy entries
+                else
+                    fuzzy = false
+                end
+            elseif line:match("#, fuzzy") then
+                fuzzy = true
+            end
+        end
+    end
+    po:close()
+    GetText.current_lang = new_lang
+end
+
+GetText_mt.__index.getPlural = getDefaultPlural
+
+function GetText_mt.__index.ngettext(msgid, msgid_plural, n)
+    local plural = GetText.getPlural(n)
+
+    if plural == 0 then
+        return GetText.translation[msgid] and GetText.translation[msgid][plural] or GetText.wrapUntranslated(msgid)
+    else
+        return GetText.translation[msgid] and GetText.translation[msgid][plural] or GetText.wrapUntranslated(msgid_plural)
+    end
+end
+
+function GetText_mt.__index.npgettext(msgctxt, msgid, msgid_plural, n)
+    local plural = GetText.getPlural(n)
+
+    if plural == 0 then
+        return GetText.context[msgctxt] and GetText.context[msgctxt][msgid] and GetText.context[msgctxt][msgid][plural] or GetText.wrapUntranslated(msgid)
+    else
+        return GetText.context[msgctxt] and GetText.context[msgctxt][msgid] and GetText.context[msgctxt][msgid][plural] or GetText.wrapUntranslated(msgid_plural)
+    end
+end
+
+function GetText_mt.__index.pgettext(msgctxt, msgid)
+    return GetText.context[msgctxt] and GetText.context[msgctxt][msgid] or GetText.wrapUntranslated(msgid)
+end
+
+setmetatable(GetText, GetText_mt)
+
+-- highlightsync.koplugin specific setup
+GetText.dirname = require("datastorage"):getDataDir() .. "/plugins/highlightsync.koplugin/l10n"
+
+local function loadCurrentLang()
+    local ok, err = pcall(function()
+        local lang = require("gettext").current_lang
+        if lang:match("^zh_Hans") then
+            lang = "zh_CN"
+        elseif lang:match("^zh_Hant") then
+            lang = "zh_TW"
+        end
+        GetText.changeLang(lang)
+    end)
+    if not ok then
+        logger.err("highlightsync: ERROR in loadCurrentLang:", err)
+    end
+end
+
+loadCurrentLang()
+
+return GetText

l10n/zh_CN/koreader.po

@@ -0,0 +1,61 @@
+# Highlight Sync 插件简体中文翻译
+# Copyright (C) 2025 THE PACKAGE'S COPYRIGHT HOLDER
+# 本文件与 PACKAGE 包使用相同许可证。
+#
+msgid   ""
+msgstr  "Project-Id-Version: highlightsync.koplugin\n"
+        "Report-Msgid-Bugs-To: \n"
+        "POT-Creation-Date: 2025-01-01 12:00+0800\n"
+        "PO-Revision-Date: 2025-01-01 12:00+0800\n"
+        "Last-Translator: \n"
+        "Language-Team: \n"
+        "Language: 简体中文 (zh_CN)\n"
+        "MIME-Version: 1.0\n"
+        "Content-Type: text/plain; charset=UTF-8\n"
+        "Content-Transfer-Encoding: 8bit\n"
+        "Plural-Forms: nplurals=1; plural=0;\n"
+
+#: ../_meta.lua:5
+msgid   "Synchronize book highlights across devices using cloud storage (WebDAV/Dropbox)."
+msgstr  "使用云存储（WebDAV/Dropbox）跨设备同步书籍高亮。"
+
+#: ../main.lua:69
+msgid   "Highlight Sync"
+msgstr  "高亮同步"
+
+#: ../main.lua:119
+msgid   "Syncing book highlights. This may take a while."
+msgstr  "正在同步书籍高亮，请稍候。"
+
+#: ../main.lua:142
+msgid   "Sync Cloud"
+msgstr  "云端设置"
+
+#: ../main.lua:162
+msgid   "Delete"
+msgstr  "删除"
+
+#: ../main.lua:166
+msgid   "Delete server info?"
+msgstr  "删除服务器信息？"
+
+#: ../main.lua:167
+msgid   "Cancel"
+msgstr  "取消"
+
+#: ../main.lua:179
+msgid   "Edit"
+msgstr  "编辑"
+
+#: ../main.lua:186
+msgid   "Close"
+msgstr  "关闭"
+
+#: ../main.lua:193
+#, lua-format
+msgid   "Cloud storage:\n%1\n\nFolder path:\n%2\n\nSet up the same cloud folder on each device to sync across your devices."
+msgstr  "云存储：\n%1\n\n文件夹路径：\n%2\n\n在每台设备上设置相同的云文件夹以实现跨设备同步。"
+
+#: ../main.lua:205
+msgid   "Sync Highlights"
+msgstr  "同步"