Actualized work with pre type of text - now it is possible to use language for formatting of text

CHANGELOG.md

@@ -14,6 +14,7 @@
 * Now will not be thrown exception when there is income unknown type of `MessageEntity`. Instead of this will be
 created `RegularTextMessageEntity` with the same text
 * Fixed problem that usually string formatting did not trigger escaping of control characters
+* Actualized work with `pre` type of text - now it is possible to use `language` for formatting of text
 * Removed constructor of `TextMentionMessageEntity`, which was deprecated previously
 * Removed constructor of `TextMentionTextSource`, which was deprecated previously
 * All `TelegramMediaFile` instances now have field `fileUniqueId`, which represents `file_unique_id` field from API

src/commonMain/kotlin/com/github/insanusmokrassar/TelegramBotAPI/utils/StringFormatting.kt

@@ -17,8 +17,14 @@ const val htmlPreControl = "pre"
 const val htmlUnderlineControl = "u"
 const val htmlStrikethroughControl = "s"
 
-private fun String.markdownDefault(controlSymbol: String) = "$controlSymbol${toMarkdown()}$controlSymbol"
-private fun String.htmlDefault(controlSymbol: String) = "<$controlSymbol>${toHtml()}</$controlSymbol>"
+private fun String.markdownDefault(
+    openControlSymbol: String,
+    closeControlSymbol: String = openControlSymbol
+) = "$openControlSymbol${toMarkdown()}$closeControlSymbol"
+private fun String.htmlDefault(
+    openControlSymbol: String,
+    closeControlSymbol: String = openControlSymbol
+) = "<$openControlSymbol>${toHtml()}</$closeControlSymbol>"
 
 fun String.linkMarkdown(link: String): String = "[${toMarkdown()}]($link)"
 fun String.linkHTML(link: String): String = "<a href=\"$link\">${toHtml()}</a>"
@@ -36,8 +42,18 @@ fun String.codeMarkdown(): String = markdownDefault(markdownCodeControl)
 fun String.codeHTML(): String = htmlDefault(htmlCodeControl)
 
 
-fun String.preMarkdown(): String = markdownDefault(markdownPreControl)
-fun String.preHTML(): String = htmlDefault(htmlPreControl)
+fun String.preMarkdown(language: String? = null): String = markdownDefault(
+    "$markdownPreControl${language ?.let { "$it\n" } ?: "\n"}",
+    "\n$markdownPreControl"
+)
+fun String.preHTML(language: String? = null): String = htmlDefault(
+    language ?.let { _ ->
+        "$htmlPreControl><$htmlCodeControl class=\"language-$language\""
+    } ?: htmlPreControl,
+    language ?.let { _ ->
+        "$htmlCodeControl></$htmlPreControl"
+    } ?: htmlPreControl
+)
 
 
 fun String.emailMarkdown(): String = linkMarkdown("mailto://$${toMarkdown()}")
@@ -127,6 +143,11 @@ infix fun String.pre(parseMode: ParseMode): String = when (parseMode) {
     is Markdown -> preMarkdown()
 }
 
+fun String.pre(parseMode: ParseMode, language: String? = null): String = when (parseMode) {
+    is HTML -> preHTML(language)
+    is Markdown -> preMarkdown(language)
+}
+
 infix fun String.email(parseMode: ParseMode): String = when (parseMode) {
     is HTML -> emailHTML()
     is Markdown -> emailMarkdown()

src/commonTest/kotlin/com/github/insanusmokrassar/TelegramBotAPI/utils/StringFormattingTests.kt

@@ -0,0 +1,36 @@
+package com.github.insanusmokrassar.TelegramBotAPI.utils
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class StringFormattingTests {
+    @Test
+    fun testThatPreEscapingWorksCorrectly() {
+        val originalHelloWorld = """
+                fun main() {
+                    println("Hello world")
+                }
+            """.replace("                ", "")
+        val helloWorldLanguage = "kotlin"
+        assertEquals(
+            "<pre><code class=\"language-$helloWorldLanguage\">$originalHelloWorld</code></pre>",
+            originalHelloWorld.preHTML(
+                helloWorldLanguage
+            )
+        )
+        assertEquals(
+            "<pre>$originalHelloWorld</pre>",
+            originalHelloWorld.preHTML()
+        )
+        assertEquals(
+            "```$helloWorldLanguage\n$originalHelloWorld\n```",
+            originalHelloWorld.preMarkdown(
+                helloWorldLanguage
+            )
+        )
+        assertEquals(
+            "```\n$originalHelloWorld\n```",
+            originalHelloWorld.preMarkdown()
+        )
+    }
+}