Parse LeetCode slugs

Author: madhead

leetcode/src/main/kotlin/by/jprof/telegram/bot/leetcode/LeetCodeUpdateProcessor.kt

@@ -1,9 +1,40 @@
 package by.jprof.telegram.bot.leetcode
 
 import by.jprof.telegram.bot.core.UpdateProcessor
+import dev.inmo.tgbotapi.types.MessageEntity.textsources.TextLinkTextSource
+import dev.inmo.tgbotapi.types.MessageEntity.textsources.URLTextSource
+import dev.inmo.tgbotapi.types.message.abstracts.ContentMessage
+import dev.inmo.tgbotapi.types.message.abstracts.Message
+import dev.inmo.tgbotapi.types.message.content.TextContent
+import dev.inmo.tgbotapi.types.update.MessageUpdate
 import dev.inmo.tgbotapi.types.update.abstracts.Update
+import org.apache.logging.log4j.LogManager
 
 class LeetCodeUpdateProcessor : UpdateProcessor {
+    companion object {
+        private val logger = LogManager.getLogger(LeetCodeUpdateProcessor::class.java)!!
+        private val slugExtractor: SlugExtractor = ::NaiveRegexSlugExtractor
+    }
+
     override suspend fun process(update: Update) {
+        @Suppress("NAME_SHADOWING") val update = update as? MessageUpdate ?: return
+
+        val slugs = extractSlugs(update.data) ?: return
+
+        logger.debug("LeetCode slugs: {}", slugs)
     }
+
+    private fun extractSlugs(message: Message): List<String>? =
+        (message as? ContentMessage<*>)?.let { contentMessage ->
+            (contentMessage.content as? TextContent)?.let { content ->
+                content
+                    .textSources
+                    .mapNotNull {
+                        (it as? URLTextSource)?.source ?: (it as? TextLinkTextSource)?.url
+                    }
+                    .mapNotNull {
+                        slugExtractor(it)
+                    }
+            }
+        }
 }

leetcode/src/main/kotlin/by/jprof/telegram/bot/leetcode/NaiveRegexSlugExtractor.kt

@@ -0,0 +1,8 @@
+package by.jprof.telegram.bot.leetcode
+
+private val slugRegex = "https?://leetcode\\.com/problems/(?<slug>.+?)/?".toRegex()
+
+@Suppress("FunctionName")
+fun NaiveRegexSlugExtractor(message: String): String? {
+    return slugRegex.matchEntire(message)?.groups?.get("slug")?.value
+}

leetcode/src/main/kotlin/by/jprof/telegram/bot/leetcode/SlugExtractor.kt

@@ -0,0 +1,3 @@
+package by.jprof.telegram.bot.leetcode
+
+typealias SlugExtractor = (String) -> String?

leetcode/src/test/kotlin/by/jprof/telegram/bot/leetcode/NaiveRegexSlugExtractorTest.kt

@@ -0,0 +1,27 @@
+package by.jprof.telegram.bot.leetcode
+
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.TestInstance
+import org.junit.jupiter.params.ParameterizedTest
+import org.junit.jupiter.params.provider.Arguments
+import org.junit.jupiter.params.provider.MethodSource
+import java.util.stream.Stream
+import kotlin.streams.asStream
+
+@TestInstance(TestInstance.Lifecycle.PER_CLASS)
+internal class NaiveRegexSlugExtractorTest {
+    @ParameterizedTest
+    @MethodSource
+    fun extract(text: String, slug: String?) {
+        assertEquals(slug, NaiveRegexSlugExtractor(text))
+    }
+
+    private fun extract(): Stream<Arguments> = sequence {
+        yield(Arguments.of("", null))
+        yield(Arguments.of("  ", null))
+        yield(Arguments.of("test", null))
+        yield(Arguments.of("https://google.com", null))
+        yield(Arguments.of("https://leetcode.com/problems/two-sum/", "two-sum"))
+        yield(Arguments.of("https://leetcode.com/problems/3sum", "3sum"))
+    }.asStream()
+}