add separation of text sources

CHANGELOG.md

@@ -67,6 +67,10 @@
     * New request `CopyMessage`
     * New extension `List<TextSource>#makeString` for more comfortable work with new api with entities
     * Support for Google Places identifiers for venues
+    * New extensions for text sources separating:
+        * `List<TextSource>#separateForMessage`
+        * `List<TextSource>#separateForCaption`
+        * `List<TextSource>#separateForText`
 * `API`:
     * Extensions `TelegramBot#pinChatMessage` now support any `Chat` and `Message`s from any `Chat`
     * New extensions `TelegramBot#unpinAllChatMessages`

tgbotapi.core/src/commonMain/kotlin/dev/inmo/tgbotapi/CommonAbstracts/TextSource.kt

@@ -1,5 +1,8 @@
 package dev.inmo.tgbotapi.CommonAbstracts
 
+import dev.inmo.tgbotapi.types.captionLength
+import dev.inmo.tgbotapi.types.textLength
+
 typealias FullTextSourcesList = List<TextSource>
 typealias FullTextPartsList = List<TextPart>
 
@@ -22,3 +25,47 @@ data class TextPart(
 
 fun List<TextPart>.justTextSources() = map { it.source }
 fun List<TextSource>.makeString() = joinToString("") { it.source }
+fun List<TextSource>.separateForMessage(limit: IntRange, numberOfParts: Int? = null): List<List<TextSource>> {
+    if (isEmpty()) {
+        return emptyList()
+    }
+
+    val resultList = mutableListOf<MutableList<TextSource>>(mutableListOf())
+    var currentPartLength = 0
+    val maxSize = limit.last + 1
+
+    for (current in this) {
+        if (current.source.length > maxSize) {
+            error("Currently unsupported parts with size more than target one-message parts (${current.source.length} > ${maxSize})")
+        }
+
+        if (currentPartLength + current.source.length > maxSize) {
+            if (numberOfParts == null || numberOfParts < resultList.size) {
+                resultList.add(mutableListOf())
+                currentPartLength = 0
+            } else {
+                break
+            }
+        }
+
+        resultList.last().add(current)
+        currentPartLength += current.source.length
+    }
+
+    return resultList
+}
+
+/**
+ * This method will prepare [TextSource]s list for messages. Remember, that first part will be separated with
+ * [captionLength] and all others with
+ */
+fun List<TextSource>.separateForCaption(): List<List<TextSource>> {
+    val captionPart = separateForMessage(captionLength, 1).first()
+    return listOf(captionPart) + minus(captionPart).separateForMessage(textLength)
+}
+
+/**
+ * This method will prepare [TextSource]s list for messages with [textLength]
+ */
+@Suppress("NOTHING_TO_INLINE")
+inline fun List<TextSource>.separateForText(): List<List<TextSource>> = separateForMessage(textLength)