Rewrite image validation code into new patterns

Author: NovaFox161

client/src/main/kotlin/org/dreamexposure/discal/client/commands/global/EventCommand.kt

@@ -9,14 +9,14 @@ import kotlinx.coroutines.reactor.awaitSingleOrNull
 import org.dreamexposure.discal.client.commands.SlashCommand
 import org.dreamexposure.discal.core.business.CalendarService
 import org.dreamexposure.discal.core.business.EmbedService
+import org.dreamexposure.discal.core.business.ImageValidationService
 import org.dreamexposure.discal.core.business.PermissionService
 import org.dreamexposure.discal.core.enums.event.EventColor
 import org.dreamexposure.discal.core.enums.event.EventFrequency
 import org.dreamexposure.discal.core.`object`.event.Recurrence
 import org.dreamexposure.discal.core.`object`.new.Event
 import org.dreamexposure.discal.core.`object`.new.EventWizardState
 import org.dreamexposure.discal.core.`object`.new.GuildSettings
-import org.dreamexposure.discal.core.utils.ImageValidator
 import org.dreamexposure.discal.core.utils.getCommonMsg
 import org.springframework.stereotype.Component
 import java.time.*
@@ -28,6 +28,7 @@ class EventCommand(
     private val permissionService: PermissionService,
     private val calendarService: CalendarService,
     private val embedService: EmbedService,
+    private val imageValidationService: ImageValidationService,
 ) : SlashCommand {
     override val name = "event"
     override val hasSubcommands = true
@@ -447,7 +448,7 @@ class EventCommand(
             .awaitSingle()
 
         // Check if provided link is actually an image we can consume
-        val isValidImage = ImageValidator.validate(image, settings.patronGuild || settings.devGuild).awaitSingle()
+        val isValidImage = imageValidationService.validate(image, settings.patronGuild || settings.devGuild)
         if (!isValidImage) return event.createFollowup(getMessage("image.failure", settings))
             .withEphemeral(ephemeral)
             .withEmbeds(embedService.eventWizardEmbed(existingWizard, settings))

core/src/main/kotlin/org/dreamexposure/discal/core/business/ImageValidationService.kt

@@ -0,0 +1,58 @@
+package org.dreamexposure.discal.core.business
+
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+import org.springframework.stereotype.Component
+import java.io.FileNotFoundException
+import java.io.IOException
+import java.io.InputStream
+import java.net.MalformedURLException
+import java.net.URI
+import java.time.Duration
+import javax.imageio.ImageIO
+import javax.imageio.ImageReader
+
+@Component
+class ImageValidationService {
+    suspend fun validate(url: String, allowGif: Boolean): Boolean = withContext(Dispatchers.IO) {
+        return@withContext try {
+            val image = ImageIO.read(URI.create(url).toURL())
+            image != null
+        } catch (_: IOException) {
+            if (allowGif) validateGif(url)
+            else false
+        } catch (_: MalformedURLException) {
+            false
+        } catch (_: FileNotFoundException) {
+            false
+        }
+    }
+
+    private suspend fun validateGif(url: String): Boolean = withContext(Dispatchers.IO) {
+        val connection = URI.create(url).toURL().openConnection()
+        connection.connectTimeout = Duration.ofSeconds(3).toMillis().toInt()
+        connection.readTimeout = Duration.ofSeconds(3).toMillis().toInt()
+
+        readGif(connection.inputStream)?.equals(".gif", true) == true
+    }
+
+    private suspend fun readGif(input: InputStream): String? = withContext(Dispatchers.IO) {
+        val stream = ImageIO.createImageInputStream(input)
+        val iterator = ImageIO.getImageReaders(stream)
+        if (!iterator.hasNext()) return@withContext null
+
+        var reader: ImageReader? = null
+        try {
+            reader = iterator.next()
+
+            reader.setInput(stream, true, true)
+            reader.read(0, reader.defaultReadParam)
+        } catch (_: Exception) {
+
+        } finally {
+            reader?.dispose()
+        }
+
+        reader?.formatName
+    }
+}

core/src/main/kotlin/org/dreamexposure/discal/core/object/GuildSettings.kt

@@ -10,6 +10,7 @@ import org.dreamexposure.discal.core.serializers.SnowflakeAsStringSerializer
 import java.util.*
 
 @Serializable
+@Deprecated("Prefer to use new.GuildSettings impl")
 data class GuildSettings(
     @Serializable(with = SnowflakeAsStringSerializer::class)
         @SerialName("guild_id")