feat: render image in chat message (#36)

Reviewed-on: #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
+}

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

@@ -153,21 +153,25 @@ fun UnsignedEvent.roomId(): Long {
     return sortedUniqueKeys.hashCode().toLong()
 }
 
-fun Timestamp.ago(): String {
-    val SECONDS_IN_MINUTE = 60L
-    val MINUTES_IN_HOUR = 60L
-    val HOURS_IN_DAY = 24L
-    val DAYS_IN_MONTH = 30L
+fun Timestamp.formatAsTime(): String {
+    val timeZone = TimeZone.currentSystemDefault()
+    val inputInstant = Instant.fromEpochSeconds(this.asSecs().toLong())
+    val inputDateTime = inputInstant.toLocalDateTime(timeZone)
+    val hour = inputDateTime.hour.toString().padStart(2, '0')
+    val minute = inputDateTime.minute.toString().padStart(2, '0')
+    return "$hour:$minute"
+}
 
+fun Timestamp.ago(): String {
     val inputInstant = Instant.fromEpochSeconds(this.asSecs().toLong())
     val now = Clock.System.now()
     val duration = now - inputInstant
 
     return when {
-        duration.inWholeSeconds < SECONDS_IN_MINUTE -> "Now"
-        duration.inWholeMinutes < MINUTES_IN_HOUR -> "${duration.inWholeMinutes}m"
-        duration.inWholeHours < HOURS_IN_DAY -> "${duration.inWholeHours}h"
-        duration.inWholeDays < DAYS_IN_MONTH -> "${duration.inWholeDays}d"
+        duration.inWholeSeconds < 60L -> "Now"
+        duration.inWholeMinutes < 60L -> "${duration.inWholeMinutes}m"
+        duration.inWholeHours < 24L -> "${duration.inWholeHours}h"
+        duration.inWholeDays < 30L -> "${duration.inWholeDays}d"
         else -> {
             val localDateTime = inputInstant.toLocalDateTime(TimeZone.currentSystemDefault())
             val month =