Link resolver implementation

src/main/kotlin/org/koitharu/kotatsu/parsers/MangaLoaderContext.kt

@@ -1,12 +1,15 @@
 package org.koitharu.kotatsu.parsers
 
 import okhttp3.CookieJar
+import okhttp3.HttpUrl
+import okhttp3.HttpUrl.Companion.toHttpUrl
 import okhttp3.OkHttpClient
 import okhttp3.Response
 import org.koitharu.kotatsu.parsers.bitmap.Bitmap
 import org.koitharu.kotatsu.parsers.config.MangaSourceConfig
 import org.koitharu.kotatsu.parsers.model.MangaParserSource
 import org.koitharu.kotatsu.parsers.model.MangaSource
+import org.koitharu.kotatsu.parsers.util.LinkResolver
 import java.util.*
 
 public abstract class MangaLoaderContext {
@@ -17,6 +20,10 @@ public abstract class MangaLoaderContext {
 
 	public fun newParserInstance(source: MangaParserSource): MangaParser = source.newParser(this)
 
+	public fun newLinkResolver(link: HttpUrl): LinkResolver = LinkResolver(this, link)
+
+	public fun newLinkResolver(link: String): LinkResolver = newLinkResolver(link.toHttpUrl())
+
 	public open fun encodeBase64(data: ByteArray): String = Base64.getEncoder().encodeToString(data)
 
 	public open fun decodeBase64(data: String): ByteArray = Base64.getDecoder().decode(data)

src/main/kotlin/org/koitharu/kotatsu/parsers/MangaParser.kt

@@ -2,6 +2,7 @@ package org.koitharu.kotatsu.parsers
 
 import androidx.annotation.CallSuper
 import okhttp3.Headers
+import okhttp3.HttpUrl
 import org.koitharu.kotatsu.parsers.config.ConfigKey
 import org.koitharu.kotatsu.parsers.config.MangaSourceConfig
 import org.koitharu.kotatsu.parsers.model.*
@@ -105,4 +106,10 @@ public abstract class MangaParser @InternalParsersApi constructor(
 	public open suspend fun getRelatedManga(seed: Manga): List<Manga> {
 		return RelatedMangaFinder(listOf(this)).invoke(seed)
 	}
+
+	/**
+	 * Return [Manga] object by web link to it
+	 * @see [Manga.publicUrl]
+	 */
+	public open suspend fun resolveLink(link: HttpUrl): Manga? = null
 }

src/main/kotlin/org/koitharu/kotatsu/parsers/site/all/MangaDexParser.kt

@@ -4,6 +4,8 @@ import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.async
 import kotlinx.coroutines.awaitAll
 import kotlinx.coroutines.coroutineScope
+import okhttp3.HttpUrl
+import org.json.JSONArray
 import org.json.JSONObject
 import org.koitharu.kotatsu.parsers.MangaLoaderContext
 import org.koitharu.kotatsu.parsers.MangaParser
@@ -199,73 +201,28 @@ internal class MangaDexParser(context: MangaLoaderContext) : MangaParser(context
 			}
 		}
 		val json = webClient.httpGet(url).parseJson().getJSONArray("data")
-		return json.mapJSON { jo ->
-			val id = jo.getString("id")
-			val attrs = jo.getJSONObject("attributes")
-			val relations = jo.getJSONArray("relationships").associateByKey("type")
-			val cover = relations["cover_art"]
-				?.getJSONObject("attributes")
-				?.getString("fileName")
-				?.let {
-					"https://uploads.$domain/covers/$id/$it"
+		return json.mapJSON { jo -> jo.fetchManga(null) }
 	}
-			Manga(
-				id = generateUid(id),
-				title = requireNotNull(attrs.getJSONObject("title").selectByLocale()) {
-					"Title should not be null"
-				},
-				altTitle = attrs.optJSONObject("altTitles")?.selectByLocale(),
-				url = id,
-				publicUrl = "https://$domain/title/$id",
-				rating = RATING_UNKNOWN,
-				isNsfw = when (attrs.getStringOrNull("contentRating")) {
-					"erotica", "pornographic" -> true
-					else -> false
-				},
-				coverUrl = cover?.plus(".256.jpg").orEmpty(),
-				largeCoverUrl = cover,
-				description = attrs.optJSONObject("description")?.selectByLocale(),
-				tags = attrs.getJSONArray("tags").mapJSONToSet { tag ->
-					MangaTag(
-						title = tag.getJSONObject("attributes")
-							.getJSONObject("name")
-							.firstStringValue()
-							.toTitleCase(),
-						key = tag.getString("id"),
-						source = source,
-					)
-				},
-				state = when (attrs.getStringOrNull("status")) {
-					"ongoing" -> MangaState.ONGOING
-					"completed" -> MangaState.FINISHED
-					"hiatus" -> MangaState.PAUSED
-					"cancelled" -> MangaState.ABANDONED
-					else -> null
-				},
-				author = (relations["author"] ?: relations["artist"])
-					?.getJSONObject("attributes")
-					?.getStringOrNull("name"),
-				source = source,
-			)
+
+	override suspend fun getDetails(manga: Manga): Manga {
+		val mangaId = manga.url.removePrefix("/")
+		return getDetails(mangaId)
 	}
+
+	override suspend fun resolveLink(link: HttpUrl): Manga? {
+		val regex = Regex("[0-9a-f\\-]{10,}", RegexOption.IGNORE_CASE)
+		val mangaId = link.pathSegments.find { regex.matches(it) } ?: return null
+		return getDetails(mangaId)
 	}
 
-	override suspend fun getDetails(manga: Manga): Manga = coroutineScope {
-		val domain = domain
-		val mangaId = manga.url.removePrefix("/")
-		val attrsDeferred = async {
+	private suspend fun getDetails(mangaId: String): Manga = coroutineScope {
+		val jsonDeferred = async {
 			webClient.httpGet(
 				"https://api.$domain/manga/${mangaId}?includes[]=artist&includes[]=author&includes[]=cover_art",
-			).parseJson().getJSONObject("data").getJSONObject("attributes")
+			).parseJson().getJSONObject("data")
 		}
 		val feedDeferred = async { loadChapters(mangaId) }
-		val mangaAttrs = attrsDeferred.await()
-		val feed = feedDeferred.await()
-		manga.copy(
-			description = mangaAttrs.optJSONObject("description")?.selectByLocale()
-				?: manga.description,
-			chapters = mapChapters(feed),
-		)
+		jsonDeferred.await().fetchManga(mapChapters(feedDeferred.await()))
 	}
 
 	override suspend fun getPages(chapter: MangaChapter): List<MangaPage> {
@@ -312,6 +269,57 @@ internal class MangaDexParser(context: MangaLoaderContext) : MangaParser(context
 			}
 	}
 
+	private fun JSONObject.fetchManga(chapters: List<MangaChapter>?): Manga {
+		val id = getString("id")
+		val attrs = getJSONObject("attributes")
+		val relations = getJSONArray("relationships").associateByKey("type")
+		val cover = relations["cover_art"]
+			?.getJSONObject("attributes")
+			?.getString("fileName")
+			?.let {
+				"https://uploads.$domain/covers/$id/$it"
+			}
+		return Manga(
+			id = generateUid(id),
+			title = requireNotNull(attrs.getJSONObject("title").selectByLocale()) {
+				"Title should not be null"
+			},
+			altTitle = attrs.optJSONArray("altTitles")?.flatten()?.selectByLocale(),
+			url = id,
+			publicUrl = "https://$domain/title/$id",
+			rating = RATING_UNKNOWN,
+			isNsfw = when (attrs.getStringOrNull("contentRating")) {
+				"erotica", "pornographic" -> true
+				else -> false
+			},
+			coverUrl = cover?.plus(".256.jpg").orEmpty(),
+			largeCoverUrl = cover,
+			description = attrs.optJSONObject("description")?.selectByLocale(),
+			tags = attrs.getJSONArray("tags").mapJSONToSet { tag ->
+				MangaTag(
+					title = tag.getJSONObject("attributes")
+						.getJSONObject("name")
+						.firstStringValue()
+						.toTitleCase(),
+					key = tag.getString("id"),
+					source = source,
+				)
+			},
+			state = when (attrs.getStringOrNull("status")) {
+				"ongoing" -> MangaState.ONGOING
+				"completed" -> MangaState.FINISHED
+				"hiatus" -> MangaState.PAUSED
+				"cancelled" -> MangaState.ABANDONED
+				else -> null
+			},
+			author = (relations["author"] ?: relations["artist"])
+				?.getJSONObject("attributes")
+				?.getStringOrNull("name"),
+			chapters = chapters,
+			source = source,
+		)
+	}
+
 	private fun JSONObject.firstStringValue() = values().next() as String
 
 	private fun JSONObject.selectByLocale(): String? {
@@ -323,6 +331,19 @@ internal class MangaDexParser(context: MangaLoaderContext) : MangaParser(context
 		return getStringOrNull(LOCALE_FALLBACK) ?: values().nextOrNull() as? String
 	}
 
+	private fun JSONArray.flatten(): JSONObject {
+		val result = JSONObject()
+		repeat(length()) { i ->
+			val jo = optJSONObject(i)
+			if (jo != null) {
+				for (key in jo.keys()) {
+					result.put(key, jo.get(key))
+				}
+			}
+		}
+		return result
+	}
+
 	private suspend fun loadChapters(mangaId: String): List<JSONObject> {
 		val firstPage = loadChapters(mangaId, offset = 0, limit = CHAPTERS_FIRST_PAGE_SIZE)
 		if (firstPage.size >= firstPage.total) {

src/main/kotlin/org/koitharu/kotatsu/parsers/util/LinkResolver.kt

@@ -0,0 +1,80 @@
+package org.koitharu.kotatsu.parsers.util
+
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.runInterruptible
+import okhttp3.HttpUrl
+import okhttp3.HttpUrl.Companion.toHttpUrlOrNull
+import org.koitharu.kotatsu.parsers.MangaLoaderContext
+import org.koitharu.kotatsu.parsers.MangaParser
+import org.koitharu.kotatsu.parsers.model.*
+
+public class LinkResolver internal constructor(
+	private val context: MangaLoaderContext,
+	public val link: HttpUrl,
+) {
+
+	private val source = SuspendLazy(::resolveSource)
+
+	public suspend fun getSource(): MangaParserSource? = source.get()
+
+	public suspend fun getManga(): Manga? {
+		val parser = context.newParserInstance(source.get() ?: return null)
+		return parser.resolveLink(link) ?: parser.resolveLinkLongPath()
+	}
+
+	private suspend fun resolveSource(): MangaParserSource? = runInterruptible(Dispatchers.Default) {
+		val domains = setOfNotNull(link.host, link.topPrivateDomain())
+		for (s in MangaParserSource.entries) {
+			val parser = context.newParserInstance(s)
+			for (d in parser.configKeyDomain.presetValues) {
+				if (d in domains) {
+					return@runInterruptible s
+				}
+			}
+		}
+		null
+	}
+
+	private suspend fun MangaParser.resolveLinkLongPath(): Manga? {
+		val stubTitle = link.pathSegments.lastOrNull().orEmpty()
+		val seed = Manga(
+			id = 0L,
+			title = stubTitle,
+			altTitle = null,
+			url = link.toString().toRelativeUrl(link.host),
+			publicUrl = link.toString(),
+			rating = RATING_UNKNOWN,
+			isNsfw = false,
+			coverUrl = "",
+			tags = emptySet(),
+			state = null,
+			author = null,
+			largeCoverUrl = null,
+			description = null,
+			chapters = null,
+			source = source,
+		).let { manga ->
+			getDetails(manga)
+		}
+		val query = when {
+			seed.title != stubTitle && seed.title.isNotEmpty() -> seed.title
+			!seed.altTitle.isNullOrEmpty() -> seed.altTitle
+			!seed.author.isNullOrEmpty() -> seed.author
+			else -> return seed // unfortunately we do not know a real manga title so unable to find it
+		}
+		return runCatchingCancellable {
+			val order = if (SortOrder.RELEVANCE in availableSortOrders) SortOrder.RELEVANCE else defaultSortOrder
+			val list = getList(0, order, MangaListFilter(query = query))
+			list.single { manga -> isSameUrl(manga.publicUrl) }
+		}.getOrDefault(seed)
+	}
+
+	private fun isSameUrl(publicUrl: String): Boolean {
+		if (publicUrl == link.toString()) {
+			return true
+		}
+		val httpUrl = publicUrl.toHttpUrlOrNull() ?: return false
+		return link.host == httpUrl.host
+			&& link.encodedPath == httpUrl.encodedPath
+	}
+}

src/test/kotlin/org/koitharu/kotatsu/parsers/util/LinkResolverTest.kt

@@ -0,0 +1,29 @@
+package org.koitharu.kotatsu.parsers.util
+
+import kotlinx.coroutines.test.runTest
+import org.junit.jupiter.api.Assertions
+import org.junit.jupiter.api.Test
+import org.koitharu.kotatsu.parsers.MangaLoaderContextMock
+import org.koitharu.kotatsu.parsers.model.MangaParserSource
+import kotlin.time.Duration.Companion.minutes
+
+internal class LinkResolverTest {
+
+	private val context = MangaLoaderContextMock
+
+	@Test
+	fun supportedSource() = runTest(timeout = 2.minutes) {
+		val resolver = context.newLinkResolver("REDACTED" /* do not publish links to manga on GitHub */)
+		Assertions.assertEquals(MangaParserSource.MANGADEX, resolver.getSource())
+		val manga = resolver.getManga()
+		Assertions.assertEquals(resolver.link.toString(), manga?.publicUrl)
+	}
+
+	@Test
+	fun unsupportedSource2() = runTest(timeout = 2.minutes) {
+		val resolver = context.newLinkResolver("REDACTED" /* do not publish links to manga on GitHub */)
+		Assertions.assertEquals(MangaParserSource.BATOTO, resolver.getSource())
+		val manga = resolver.getManga()
+		Assertions.assertEquals(resolver.link.toString(), manga?.publicUrl)
+	}
+}