feat: render image in chat message (#36)

Reviewed-on: https://git.reya.su/reya/coop-mobile/pulls/36

shared/src/commonMain/kotlin/su/reya/coop/Extensions.kt

@@ -6,3 +6,21 @@ fun PublicKey.short(): String {
     val bech32 = toBech32()
     return bech32.substring(0, 6) + "..." + bech32.substring(bech32.length - 4)
 }
+
+val URL_REGEX = Regex("(https?://\\S+)", RegexOption.IGNORE_CASE)
+private val imageExtensions = setOf("jpg", "jpeg", "png", "gif", "webp", "bmp")
+
+fun String.extractUrls(): List<String> {
+    return URL_REGEX.findAll(this).map { it.value }.toList()
+}
+
+fun String.removeImageUrls(): String {
+    return URL_REGEX.replace(this) { result ->
+        if (result.value.isImageUrl()) "" else result.value
+    }.replace(Regex("\\s+"), " ").trim()
+}
+
+fun String.isImageUrl(): Boolean {
+    val extension = this.substringAfterLast('.', "").lowercase()
+    return extension in imageExtensions
+}