Feat/reworked language codes (#865)

* Reworked language codes to use Steam localization standards

* Reworked language codes tweaks (#864)

* Language code rework tweaks

* Update bg.lua

* Reevaluate whether a language is WIP

* Update bg.lua

* Even better mark for languages as WIP (> 80% translated)

* Update zh_cn.lua

* Update cs.lua

* Fix for game language codes

---------

Co-authored-by: kittenchilly <mario.pikmin.zelda@gmail.com>

features/eid_language_manager.lua

@@ -0,0 +1,138 @@
+-- List of all valid languages
+EID.Languages = {
+    "en", -- English
+    "fr", -- French
+    "pt",   -- Portuguese
+    "pt_br", -- Brazilian Portuguese
+    "ru", -- Russian
+    "es", -- Spanish
+    "it", -- Italian
+    "bg", -- Bulgarian
+    "pl", -- Polish
+    "de", -- German
+    "tr", -- Turkish
+    "ko", -- Korean
+    "zh_cn", -- Simplified Chinese
+    "ja", -- Japanese
+    "cs", -- Czech
+    "nl", -- Dutch
+    "uk", -- Ukrainian
+    "el", -- Greek
+    "ro", -- Romanian
+    "vi" -- Vietnamese
+}
+
+-- List of languages where it is allowed to do line-breaks between UTF-8 characters in a description
+EID.BreakUtf8CharsLanguage = {
+	['zh_cn'] = true
+}
+
+--#region Luadoc definitions
+---@alias EID_LanguageCode
+---| "bg" @Bulgarian
+---| "cs" @Czech
+---| "de" @German
+---| "el" @Greek
+---| "en" @English
+---| "es" @Spanish
+---| "fr" @French
+---| "it" @Italian
+---| "ja" @Japanese
+---| "ko" @Korean
+---| "nl" @Dutch
+---| "pl" @Polish
+---| "pt_br" @Brasilian Portuguese
+---| "pt" @Portuguese
+---| "ro" @Romanian
+---| "ru" @Russian
+---| "tr" @Turkish
+---| "uk" @Ukrainian
+---| "vi" @Vietnamese
+---| "zh_cn" @Simplified Chinese
+--#endregion
+
+---Get the current Language. Defaults to english if none is set.
+---@return EID_LanguageCode
+function EID:getLanguage()
+	local lang = EID.Config["Language"]
+	-- Reset invalid languages (like en_us_detailed)
+	if EID.descriptions[lang] == nil then
+		EID.Config["Language"] = "auto"
+		lang = "auto"
+	end
+	if lang == "auto" then
+		local langToReturn = Options and Options.Language or "en" -- Use game language, if available.
+		-- don't do any updating if on a Repentance version before v1.7.9b
+		if Isaac.RunCallback ~= nil then
+			for _, callbackData in pairs(Isaac.GetCallbacks("EID_EVALUATE_AUTO_LANG")) do
+				local newString = callbackData.Function(callbackData.Mod, langToReturn)
+				if newString and type(newString) == "string" and EID.descriptions[newString] ~= nil then
+					langToReturn = newString
+				end
+			end
+		end
+		return langToReturn
+	end
+	---@cast lang EID_LanguageCode
+	return lang
+end
+
+--- Attempts to load all language packs from a given game version
+function EID:LoadLanguagePacks(gameVersion)
+    --transformation infos
+    local _, _ = pcall(require, "descriptions." .. gameVersion .. ".transformations")
+    --languages
+    for _, languageCode in ipairs(EID.Languages) do
+        local wasSuccessful, err = pcall(require, "descriptions." .. gameVersion .. "." .. languageCode)
+        if not wasSuccessful and not string.find(err, "not found") then
+            EID:WriteErrorMsg("Loading Languagepack '" .. languageCode .. "' (" .. gameVersion .. ") failed: " ..
+                tostring(err))
+        end
+    end
+end
+
+--- Initializes handling of alternative language codes for all languages
+function EID:InitAltLanguageCodes()
+    for _, languageCode in ipairs(EID.Languages) do
+        if EID.descriptions[languageCode] and EID.descriptions[languageCode].alternativeLanguageCodes then
+            for _, altlanguageCode in ipairs(EID.descriptions[languageCode].alternativeLanguageCodes) do
+                EID:AddAlternativeLanguageCode(languageCode, altlanguageCode)
+            end
+        end
+    end
+end
+
+--- Initializes handling of alternative language codes for a specific language using meta-table that redirect table accesses to the original table
+function EID:AddAlternativeLanguageCode(originalLanguageCode, newLanguageCode)
+    EID.descriptions[newLanguageCode] = setmetatable({}, {
+    __index = EID.descriptions[originalLanguageCode],
+    __newindex = function(_, key, value)
+        EID.descriptions[originalLanguageCode][key] = value
+    end,
+    __pairs = function(_) return pairs(EID.descriptions[originalLanguageCode]) end,
+    })
+end
+
+--- Initializes and loads all language packs for the current game version,
+--- including handling for Repentance and Repentance+ expansions,
+--- and sorts the language list after loading.
+function EID:InitializeLanguagePacks()
+    -- load AB+ descriptions
+    EID:LoadLanguagePacks(EID.GameVersion)
+    EID:InitAltLanguageCodes()
+
+    -- load Repentance descriptions
+    if EID.isRepentance then
+        EID.GameVersion = "rep"
+        EID:LoadLanguagePacks(EID.GameVersion)
+
+        -- Load Repentance+ descriptions
+        if EID.isRepentancePlus then
+            EID.GameVersion = "rep+"
+            EID:LoadLanguagePacks(EID.GameVersion)
+        end
+    end
+
+    -- sort table after loading the languages in their specified order
+    table.sort(EID.Languages)
+end