feat(YouTube - Translations): Add compile time option to select custo…

…m language file

src/main/kotlin/app/revanced/patches/youtube/misc/translations/TranslationsPatch.kt

@@ -1,10 +1,19 @@
 package app.revanced.patches.youtube.misc.translations
 
 import app.revanced.patcher.data.ResourceContext
+import app.revanced.patcher.patch.PatchException
+import app.revanced.patcher.patch.options.PatchOption.PatchExtensions.stringPatchOption
 import app.revanced.patches.shared.translations.TranslationsUtils.copyXml
 import app.revanced.patches.youtube.utils.compatibility.Constants.COMPATIBLE_PACKAGE
 import app.revanced.patches.youtube.utils.settings.SettingsPatch
 import app.revanced.util.patch.BaseResourcePatch
+import org.w3c.dom.Node
+import java.io.File
+import javax.xml.parsers.DocumentBuilderFactory
+import javax.xml.transform.OutputKeys
+import javax.xml.transform.TransformerFactory
+import javax.xml.transform.dom.DOMSource
+import javax.xml.transform.stream.StreamResult
 
 val LANGUAGES = arrayOf(
     "ar",
@@ -31,20 +40,111 @@ val LANGUAGES = arrayOf(
     "zh-rTW"
 )
 
-@Suppress("unused")
+@Suppress("DEPRECATION", "unused")
 object TranslationsPatch : BaseResourcePatch(
     name = "Translations",
     description = "Add Crowdin translations for YouTube.",
     dependencies = setOf(SettingsPatch::class),
     compatiblePackages = COMPATIBLE_PACKAGE
 ) {
+    private var CustomLanguage by stringPatchOption(
+        key = "CustomLanguage",
+        default = "",
+        title = "Custom language file",
+        description = """
+            The file path to the strings.xml file. 
+            Please note that applying the strings.xml file will overwrite all existing language translations.
+            """
+            .split("\n")
+            .joinToString("\n") { it.trimIndent() } // Remove the leading whitespace from each line.
+            .trimIndent(), // Remove the leading newline.
+    )
+
     override fun execute(context: ResourceContext) {
+        CustomLanguage?.let { customLang ->
+            if (customLang.isNotEmpty()) {
+                try {
+                    val customLangFile = File(customLang)
+                    if (!customLangFile.exists()) {
+                        throw PatchException("File not found: $customLang")
+                    }
+                    if (!customLangFile.isFile) {
+                        throw PatchException("Provided path is not a file: $customLang")
+                    }
+                    if (customLangFile.name != "strings.xml") {
+                        throw PatchException("Invalid file name: ${customLangFile.name}. Expected: strings.xml")
+                    }
+                    val resourceDirectory = context["res"]
+                    val destinationDirectory = resourceDirectory.resolve("values")
+                    val destinationFile = destinationDirectory.resolve("strings.xml")
 
-        context.copyXml(
-            "youtube",
-            LANGUAGES
-        )
+                    updateStringsXml(customLangFile, destinationFile)
+                } catch (e: Exception) {
+                    throw PatchException("Error copying custom language file: ${e.message}")
+                }
+            }
+            else {
+                context.copyXml(
+                    "youtube",
+                    LANGUAGES
+                )
+            }
+        }
 
         SettingsPatch.updatePatchStatus(this)
     }
+
+    /**
+     * Updates the contents of the destination strings.xml file by merging it with the source strings.xml file.
+     *
+     * This function reads both source and destination XML files, compares each <string> element by their
+     * unique "name" attribute, and if a match is found, it replaces the content in the destination file with
+     * the content from the source file.
+     *
+     * @param sourceFile The source strings.xml file containing new string values.
+     * @param destinationFile The destination strings.xml file to be updated with values from the source file.
+     */
+    private fun updateStringsXml(sourceFile: File, destinationFile: File) {
+        val documentBuilderFactory = DocumentBuilderFactory.newInstance()
+        val documentBuilder = documentBuilderFactory.newDocumentBuilder()
+
+        // Parse the source and destination XML files into Document objects
+        val sourceDoc = documentBuilder.parse(sourceFile)
+        val destinationDoc = documentBuilder.parse(destinationFile)
+
+        val sourceStrings = sourceDoc.getElementsByTagName("string")
+        val destinationStrings = destinationDoc.getElementsByTagName("string")
+
+        // Create a map to store the <string> elements from the source document by their "name" attribute
+        val sourceMap = mutableMapOf<String, Node>()
+
+        // Populate the map with nodes from the source document
+        for (i in 0 until sourceStrings.length) {
+            val node = sourceStrings.item(i)
+            val name = node.attributes.getNamedItem("name").nodeValue
+            sourceMap[name] = node
+        }
+
+        // Update the destination document with values from the source document
+        for (i in 0 until destinationStrings.length) {
+            val node = destinationStrings.item(i)
+            val name = node.attributes.getNamedItem("name").nodeValue
+            if (sourceMap.containsKey(name)) {
+                node.textContent = sourceMap[name]?.textContent
+            }
+        }
+
+        /**
+         * Prepare the transformer for writing the updated document back to the file.
+         * The transformer is configured to indent the output XML for better readability.
+         */
+        val transformerFactory = TransformerFactory.newInstance()
+        val transformer = transformerFactory.newTransformer()
+        transformer.setOutputProperty(OutputKeys.INDENT, "yes")
+        transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "2")
+
+        val domSource = DOMSource(destinationDoc)
+        val streamResult = StreamResult(destinationFile)
+        transformer.transform(domSource, streamResult)
+    }
 }