Tags users during message compose.

2025-04-05 02:20:18 +02:00 · 2023-01-18 08:36:42 -05:00 · 2023-01-18 08:36:42 -05:00 · 3ee39887a8
commit 3ee39887a8
parent 8f45293be9
9 changed files with 434 additions and 54 deletions
--- a/.gitignore
+++ b/.gitignore
@ -7,6 +7,7 @@
 /.idea/workspace.xml
 /.idea/navEditor.xml
 /.idea/assetWizardSettings.xml
+/.idea/androidTestResultsUserPreferences.xml
 .DS_Store
 /build
 /captures
--- a/app/src/androidTest/java/com/vitorpamplona/amethyst/ExampleInstrumentedTest.kt
+++ b/app/src/androidTest/java/com/vitorpamplona/amethyst/ExampleInstrumentedTest.kt
@ -1,22 +0,0 @@
-package com.vitorpamplona.amethyst
-
-import androidx.test.ext.junit.runners.AndroidJUnit4
-import androidx.test.platform.app.InstrumentationRegistry
-import org.junit.Assert.*
-import org.junit.Test
-import org.junit.runner.RunWith
-
-/**
- * Instrumented test, which will execute on an Android device.
- *
- * See [testing documentation](http://d.android.com/tools/testing).
- */
-@RunWith(AndroidJUnit4::class)
-class ExampleInstrumentedTest {
-  @Test
-  fun useAppContext() {
-    // Context of the app under test.
-    val appContext = InstrumentationRegistry.getInstrumentation().targetContext
-    assertEquals("com.vitorpamplona.amethyst", appContext.packageName)
-  }
-}
--- a/app/src/androidTest/java/com/vitorpamplona/amethyst/UrlUserTagTransformationTest.kt
+++ b/app/src/androidTest/java/com/vitorpamplona/amethyst/UrlUserTagTransformationTest.kt
@ -0,0 +1,96 @@
+package com.vitorpamplona.amethyst
+
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.text.AnnotatedString
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import androidx.test.platform.app.InstrumentationRegistry
+import com.vitorpamplona.amethyst.model.LocalCache
+import com.vitorpamplona.amethyst.model.decodePublicKey
+import com.vitorpamplona.amethyst.ui.actions.buildAnnotatedStringWithUrlHighlighting
+import org.junit.Assert.*
+import org.junit.Test
+import org.junit.runner.RunWith
+
+/**
+ * Instrumented test, which will execute on an Android device.
+ *
+ * See [testing documentation](http://d.android.com/tools/testing).
+ */
+@RunWith(AndroidJUnit4::class)
+class EUrlUserTagTransformationTest {
+  @Test
+  fun useAppContext() {
+    // Context of the app under test.
+    val appContext = InstrumentationRegistry.getInstrumentation().targetContext
+    assertEquals("com.vitorpamplona.amethyst", appContext.packageName)
+  }
+
+  @Test
+  fun transformationText() {
+    val user = LocalCache.getOrCreateUser(decodePublicKey("npub1gcxzte5zlkncx26j68ez60fzkvtkm9e0vrwdcvsjakxf9mu9qewqlfnj5z"))
+    user.info.displayName = "Vitor Pamplona"
+
+    var transformedText = buildAnnotatedStringWithUrlHighlighting(
+      AnnotatedString("New Hey @npub1gcxzte5zlkncx26j68ez60fzkvtkm9e0vrwdcvsjakxf9mu9qewqlfnj5z"),
+      Color.Red
+    )
+
+    assertEquals("New Hey @Vitor Pamplona", transformedText.text.text)
+
+    assertEquals(0, transformedText.offsetMapping.originalToTransformed(0)) // Before N
+    assertEquals(4, transformedText.offsetMapping.originalToTransformed(4)) // Before H
+    assertEquals(8, transformedText.offsetMapping.originalToTransformed(8)) // Before @
+    assertEquals(8, transformedText.offsetMapping.originalToTransformed(9)) // Before n
+    assertEquals(8, transformedText.offsetMapping.originalToTransformed(10)) // Before p
+    assertEquals(9, transformedText.offsetMapping.originalToTransformed(11)) // Before u
+    assertEquals(9, transformedText.offsetMapping.originalToTransformed(12)) // Before b
+    assertEquals(9, transformedText.offsetMapping.originalToTransformed(13)) // Before 1
+
+    assertEquals(23, transformedText.offsetMapping.originalToTransformed(71))
+    assertEquals(23, transformedText.offsetMapping.originalToTransformed(72))
+
+
+    assertEquals(0, transformedText.offsetMapping.transformedToOriginal(0))
+    assertEquals(4, transformedText.offsetMapping.transformedToOriginal(4))
+    assertEquals(8, transformedText.offsetMapping.transformedToOriginal(8))
+    assertEquals(12, transformedText.offsetMapping.transformedToOriginal(9))
+
+    assertEquals(72, transformedText.offsetMapping.transformedToOriginal(23))
+    assertEquals(73, transformedText.offsetMapping.transformedToOriginal(24))
+  }
+
+  @Test
+  fun transformationTextTwoKeys() {
+    val user = LocalCache.getOrCreateUser(decodePublicKey("npub1gcxzte5zlkncx26j68ez60fzkvtkm9e0vrwdcvsjakxf9mu9qewqlfnj5z"))
+    user.info.displayName = "Vitor Pamplona"
+
+    var transformedText = buildAnnotatedStringWithUrlHighlighting(
+      AnnotatedString("New Hey @npub1gcxzte5zlkncx26j68ez60fzkvtkm9e0vrwdcvsjakxf9mu9qewqlfnj5z and @npub1gcxzte5zlkncx26j68ez60fzkvtkm9e0vrwdcvsjakxf9mu9qewqlfnj5z"),
+      Color.Red
+    )
+
+    assertEquals("New Hey @Vitor Pamplona and @Vitor Pamplona", transformedText.text.text)
+
+    assertEquals(9, transformedText.offsetMapping.originalToTransformed(11))
+    assertEquals(9, transformedText.offsetMapping.originalToTransformed(12))
+    assertEquals(9, transformedText.offsetMapping.originalToTransformed(13))
+
+    assertEquals(23, transformedText.offsetMapping.originalToTransformed(70)) // Before 5
+    assertEquals(23, transformedText.offsetMapping.originalToTransformed(71)) // Before z
+    assertEquals(23, transformedText.offsetMapping.originalToTransformed(72)) // Before <space>
+    assertEquals(24, transformedText.offsetMapping.originalToTransformed(73)) // Before a
+    assertEquals(25, transformedText.offsetMapping.originalToTransformed(74)) // Before n
+    assertEquals(26, transformedText.offsetMapping.originalToTransformed(75)) // Before d
+    assertEquals(27, transformedText.offsetMapping.originalToTransformed(76)) // Before <space>
+    assertEquals(28, transformedText.offsetMapping.originalToTransformed(77)) // Before @
+    assertEquals(28, transformedText.offsetMapping.originalToTransformed(78)) // Before n
+
+    assertEquals(68, transformedText.offsetMapping.transformedToOriginal(22)) // Before a
+    assertEquals(72, transformedText.offsetMapping.transformedToOriginal(23)) // Before <space>
+    assertEquals(73, transformedText.offsetMapping.transformedToOriginal(24)) // Before a
+    assertEquals(74, transformedText.offsetMapping.transformedToOriginal(25)) // Before n
+    assertEquals(75, transformedText.offsetMapping.transformedToOriginal(26)) // Before d
+    assertEquals(76, transformedText.offsetMapping.transformedToOriginal(27)) // Before <space>
+    assertEquals(77, transformedText.offsetMapping.transformedToOriginal(28)) // Before @
+  }
+}
--- a/app/src/main/java/com/vitorpamplona/amethyst/model/Account.kt
+++ b/app/src/main/java/com/vitorpamplona/amethyst/model/Account.kt
@ -98,7 +98,7 @@ class Account(val loggedIn: Persona, val followingChannels: MutableSet<String> =
      val modifiedMentionsHex = modifiedMentions?.map { it.pubkeyHex }?.toSet() ?: emptySet()

      val repliesTo = replyToEvent.replyTos.plus(replyToEvent.id.toHex())
-      val mentions = replyToEvent.mentions.plus(replyToEvent.pubKey.toHex()).filter {
+      val mentions = replyToEvent.mentions.plus(replyToEvent.pubKey.toHex()).plus(modifiedMentionsHex).filter {
        it in modifiedMentionsHex
      }

@ -114,7 +114,7 @@ class Account(val loggedIn: Persona, val followingChannels: MutableSet<String> =
      val signedEvent = TextNoteEvent.create(
        msg = message,
        replyTos = null,
-        mentions = null,
+        mentions = modifiedMentions?.map { it.pubkeyHex } ?: emptyList(),
        privateKey = loggedIn.privKey!!
      )
      Client.send(signedEvent)
--- a/app/src/main/java/com/vitorpamplona/amethyst/model/LocalCache.kt
+++ b/app/src/main/java/com/vitorpamplona/amethyst/model/LocalCache.kt
@ -132,7 +132,7 @@ object LocalCache {
    val user = getOrCreateUser(event.pubKey)

    if (event.createdAt > user.updatedFollowsAt) {
-      Log.d("CL", "AAA ${user.toBestDisplayName()} ${event.follows.size}")
+      //Log.d("CL", "AAA ${user.toBestDisplayName()} ${event.follows.size}")
      user.updateFollows(
        event.follows.map {
          try {
@ -312,6 +312,10 @@ object LocalCache {

  }

+  fun findUsersStartingWith(username: String): List<User> {
+    return users.values.filter { it.info.anyNameStartsWith(username) }
+  }
+
  // Observers line up here.
  val live: LocalCacheLiveData = LocalCacheLiveData(this)

--- a/app/src/main/java/com/vitorpamplona/amethyst/model/User.kt
+++ b/app/src/main/java/com/vitorpamplona/amethyst/model/User.kt
@ -124,6 +124,11 @@ class UserMetadata {
    var iris: String? = null
    var main_relay: String? = null
    var twitter: String? = null
+
+    fun anyNameStartsWith(prefix: String): Boolean {
+        return listOfNotNull(name, username, display_name, displayName, nip05, lud06, lud16)
+              .filter { it.startsWith(prefix, true) }.isNotEmpty()
+    }
 }

 class UserLiveData(val user: User): LiveData<UserState>(UserState(user)) {
--- a/app/src/main/java/com/vitorpamplona/amethyst/ui/actions/NewPostView.kt
+++ b/app/src/main/java/com/vitorpamplona/amethyst/ui/actions/NewPostView.kt
@ -1,16 +1,24 @@
 package com.vitorpamplona.amethyst.ui.actions

 import androidx.compose.foundation.border
+import androidx.compose.foundation.clickable
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.PaddingValues
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.fillMaxHeight
 import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.itemsIndexed
+import androidx.compose.foundation.shape.CircleShape
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.foundation.text.KeyboardOptions
 import androidx.compose.material.Button
 import androidx.compose.material.ButtonDefaults
+import androidx.compose.material.Divider
 import androidx.compose.material.MaterialTheme
 import androidx.compose.material.OutlinedTextField
 import androidx.compose.material.Surface
@ -29,9 +37,12 @@ import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.layout.ContentScale
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.platform.LocalSoftwareKeyboardController
+import androidx.compose.ui.text.AnnotatedString
+import androidx.compose.ui.text.TextRange
 import androidx.compose.ui.text.input.KeyboardCapitalization
+import androidx.compose.ui.text.input.TransformedText
+import androidx.compose.ui.text.input.VisualTransformation
 import androidx.compose.ui.unit.dp
-import androidx.compose.ui.unit.sp
 import androidx.compose.ui.window.Dialog
 import androidx.compose.ui.window.DialogProperties
 import androidx.lifecycle.viewmodel.compose.viewModel
@ -39,9 +50,14 @@ import coil.compose.AsyncImage
 import com.vitorpamplona.amethyst.model.Account
 import com.vitorpamplona.amethyst.model.Note
 import com.vitorpamplona.amethyst.ui.components.UrlPreview
+import com.vitorpamplona.amethyst.ui.components.VideoView
 import com.vitorpamplona.amethyst.ui.components.imageExtension
+import com.vitorpamplona.amethyst.ui.components.isValidURL
+import com.vitorpamplona.amethyst.ui.components.noProtocolUrlValidator
+import com.vitorpamplona.amethyst.ui.components.videoExtension
 import com.vitorpamplona.amethyst.ui.navigation.UploadFromGallery
 import com.vitorpamplona.amethyst.ui.note.ReplyInformation
+import com.vitorpamplona.amethyst.ui.note.UserDisplay
 import kotlinx.coroutines.delay
 import nostr.postr.events.TextNoteEvent

@ -99,7 +115,7 @@ fun NewPostView(onClose: () -> Unit, baseReplyTo: Note? = null, account: Account
                            postViewModel.sendPost()
                            onClose()
                        },
-                        postViewModel.message.isNotBlank()
+                        postViewModel.message.text.isNotBlank()
                    )
                }

@ -112,8 +128,7 @@ fun NewPostView(onClose: () -> Unit, baseReplyTo: Note? = null, account: Account
                OutlinedTextField(
                    value = postViewModel.message,
                    onValueChange = {
-                        postViewModel.message = it
-                        postViewModel.urlPreview = postViewModel.findUrlInMessage()
+                        postViewModel.updateMessage(it)
                    },
                    keyboardOptions = KeyboardOptions.Default.copy(
                        capitalization = KeyboardCapitalization.Sentences
@ -141,30 +156,86 @@ fun NewPostView(onClose: () -> Unit, baseReplyTo: Note? = null, account: Account
                        .outlinedTextFieldColors(
                            unfocusedBorderColor = Color.Transparent,
                            focusedBorderColor = Color.Transparent
-                        )
+                        ),
+                    visualTransformation = UrlUserTagTransformation(MaterialTheme.colors.primary)
                )

+                val userSuggestions = postViewModel.userSuggestions
+                if (userSuggestions.isNotEmpty()) {
+                    LazyColumn(
+                        contentPadding = PaddingValues(
+                            top = 10.dp,
+                            bottom = 10.dp
+                        )
+                    ) {
+                        itemsIndexed(userSuggestions, key = { _, item -> item.pubkeyHex }) { index, item ->
+                            Column(modifier = Modifier.fillMaxWidth().clickable(onClick = {
+                                postViewModel.autocompleteWithUser(item)
+                            })) {
+                                Row(
+                                    modifier = Modifier
+                                        .padding(
+                                            start = 12.dp,
+                                            end = 12.dp,
+                                            top = 10.dp)
+                                ) {
+
+                                    AsyncImage(
+                                        model = item.profilePicture(),
+                                        contentDescription = "Profile Image",
+                                        modifier = Modifier
+                                            .width(55.dp).height(55.dp)
+                                            .clip(shape = CircleShape)
+                                    )
+
+                                    Column(modifier = Modifier.padding(start = 10.dp).weight(1f)) {
+                                        Row(verticalAlignment = Alignment.CenterVertically) {
+                                            UserDisplay(item)
+                                        }
+
+                                        Text(
+                                            item.info.about?.take(100) ?: "",
+                                            color = MaterialTheme.colors.onSurface.copy(alpha = 0.32f)
+                                        )
+                                    }
+                                }
+
+                                Divider(
+                                    modifier = Modifier.padding(top = 10.dp),
+                                    thickness = 0.25.dp
+                                )
+                            }
+                        }
+                    }
+                }
+
                val myUrlPreview = postViewModel.urlPreview
                if (myUrlPreview != null) {
                    Column(modifier = Modifier.padding(top = 5.dp)) {
-                        val removedParamsFromUrl = myUrlPreview.split("?")[0].toLowerCase()
-                        if (imageExtension.matcher(removedParamsFromUrl).matches()) {
-                            AsyncImage(
-                                model = myUrlPreview,
-                                contentDescription = myUrlPreview,
-                                contentScale = ContentScale.FillWidth,
-                                modifier = Modifier
-                                    .padding(top = 4.dp)
-                                    .fillMaxWidth()
-                                    .clip(shape = RoundedCornerShape(15.dp))
-                                    .border(
-                                        1.dp,
-                                        MaterialTheme.colors.onSurface.copy(alpha = 0.12f),
-                                        RoundedCornerShape(15.dp)
-                                    )
-                            )
-                        } else {
-                            UrlPreview("https://$myUrlPreview", myUrlPreview, false)
+                        if (isValidURL(myUrlPreview)) {
+                            val removedParamsFromUrl = myUrlPreview.split("?")[0].toLowerCase()
+                            if (imageExtension.matcher(removedParamsFromUrl).matches()) {
+                                AsyncImage(
+                                    model = myUrlPreview,
+                                    contentDescription = myUrlPreview,
+                                    contentScale = ContentScale.FillWidth,
+                                    modifier = Modifier
+                                        .padding(top = 4.dp)
+                                        .fillMaxWidth()
+                                        .clip(shape = RoundedCornerShape(15.dp))
+                                        .border(
+                                            1.dp,
+                                            MaterialTheme.colors.onSurface.copy(alpha = 0.12f),
+                                            RoundedCornerShape(15.dp)
+                                        )
+                                )
+                            } else if (videoExtension.matcher(removedParamsFromUrl).matches()) {
+                                VideoView(myUrlPreview)
+                            } else {
+                                UrlPreview(myUrlPreview, myUrlPreview)
+                            }
+                        } else if (noProtocolUrlValidator.matcher(myUrlPreview).matches()) {
+                            UrlPreview("https://$myUrlPreview", myUrlPreview)
                        }
                    }
                }
--- a/app/src/main/java/com/vitorpamplona/amethyst/ui/actions/NewPostViewModel.kt
+++ b/app/src/main/java/com/vitorpamplona/amethyst/ui/actions/NewPostViewModel.kt
@ -8,12 +8,17 @@ import android.provider.MediaStore
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.setValue
+import androidx.compose.ui.text.TextRange
+import androidx.compose.ui.text.input.TextFieldValue
 import androidx.lifecycle.ViewModel
 import com.vitorpamplona.amethyst.model.Account
+import com.vitorpamplona.amethyst.model.LocalCache
 import com.vitorpamplona.amethyst.model.Note
 import com.vitorpamplona.amethyst.model.User
+import com.vitorpamplona.amethyst.model.decodePublicKey
 import com.vitorpamplona.amethyst.ui.components.isValidURL
 import com.vitorpamplona.amethyst.ui.components.noProtocolUrlValidator
+import nostr.postr.toNpub

 class NewPostViewModel: ViewModel() {
    private var account: Account? = null
@ -22,9 +27,12 @@ class NewPostViewModel: ViewModel() {
    var mentions by mutableStateOf<List<User>?>(null)
    var replyTos by mutableStateOf<MutableList<Note>?>(null)

-    var message by mutableStateOf("")
+    var message by mutableStateOf(TextFieldValue(""))
    var urlPreview by mutableStateOf<String?>(null)

+    var userSuggestions by mutableStateOf<List<User>>(emptyList())
+    var userSuggestionAnchor: TextRange? = null
+
    fun load(account: Account, replyingTo: Note?) {
        originalNote = replyingTo
        replyingTo?.let { replyNote ->
@ -36,9 +44,53 @@ class NewPostViewModel: ViewModel() {
        this.account = account
    }

+    fun addUserToMentionsIfNotInAndReturnIndex(user: User): Int {
+        val replyToSize = replyTos?.size ?: 0
+
+        var myMentions = mentions
+        if (myMentions == null) {
+            mentions = listOf(user)
+            return replyToSize + 0 // position of the user
+        }
+
+        val index = myMentions.indexOf(user)
+
+        if (index >= 0) return replyToSize + index
+
+        myMentions = myMentions.plus(user)
+        mentions = myMentions
+        return replyToSize + myMentions.indexOf(user)
+    }
+
    fun sendPost() {
-        account?.sendPost(message, originalNote, mentions)
-        message = ""
+        // Moves @npub to mentions
+        val newMessage = message.text.split('\n').map { paragraph: String ->
+            paragraph.split(' ').map { word: String ->
+                try {
+                    if (word.startsWith("@npub") && word.length >= 64) {
+                        val keyB32 = word.substring(0, 64)
+                        val restOfWord = word.substring(64)
+
+                        val key = decodePublicKey(keyB32.removePrefix("@"))
+                        val user = LocalCache.getOrCreateUser(key)
+
+                        val index = addUserToMentionsIfNotInAndReturnIndex(user)
+
+                        val newWord = "#[${index}]"
+
+                        newWord + restOfWord
+                    } else {
+                        word
+                    }
+                } catch (e: Exception) {
+                    // if it can't parse the key, don't try to change.
+                    word
+                }
+            }.joinToString(" ")
+        }.joinToString("\n")
+
+        account?.sendPost(newMessage, originalNote, mentions)
+        message = TextFieldValue("")
        urlPreview = null
    }

@ -51,19 +103,19 @@ class NewPostViewModel: ViewModel() {

        img?.let {
            ImageUploader.uploadImage(img) {
-                message = message + "\n\n" + it
+                message = TextFieldValue(message.text + "\n\n" + it)
                urlPreview = findUrlInMessage()
            }
        }
    }

    fun cancel() {
-        message = ""
+        message = TextFieldValue("")
        urlPreview = null
    }

    fun findUrlInMessage(): String? {
-        return message.split('\n').firstNotNullOfOrNull { paragraph ->
+        return message.text.split('\n').firstNotNullOfOrNull { paragraph ->
            paragraph.split(' ').firstOrNull { word: String ->
                isValidURL(word) || noProtocolUrlValidator.matcher(word).matches()
            }
@ -73,4 +125,34 @@ class NewPostViewModel: ViewModel() {
    fun removeFromReplyList(it: User) {
        mentions = mentions?.minus(it)
    }
+
+    fun updateMessage(it: TextFieldValue) {
+        message = it
+        urlPreview = findUrlInMessage()
+
+        if (it.selection.collapsed) {
+            val lastWord = it.text.substring(0, it.selection.end).substringAfterLast("\n").substringAfterLast(" ")
+            userSuggestionAnchor = it.selection
+            if (lastWord.startsWith("@") && lastWord.length > 2) {
+                userSuggestions = LocalCache.findUsersStartingWith(lastWord.removePrefix("@"))
+            } else {
+                userSuggestions = emptyList()
+            }
+        }
+    }
+
+    fun autocompleteWithUser(item: User) {
+        userSuggestionAnchor?.let {
+            val lastWord = message.text.substring(0, it.end).substringAfterLast("\n").substringAfterLast(" ")
+            val lastWordStart = it.end - lastWord.length
+            val wordToInsert = "@${item.pubkey.toNpub()} "
+
+            message = TextFieldValue(
+                message.text.replaceRange(lastWordStart, it.end, wordToInsert),
+                TextRange(lastWordStart + wordToInsert.length, lastWordStart + wordToInsert.length)
+            )
+            userSuggestionAnchor = null
+            userSuggestions = emptyList()
+        }
+    }
 }
--- a/app/src/main/java/com/vitorpamplona/amethyst/ui/actions/UrlUserTagTransformation.kt
+++ b/app/src/main/java/com/vitorpamplona/amethyst/ui/actions/UrlUserTagTransformation.kt
@ -0,0 +1,143 @@
+package com.vitorpamplona.amethyst.ui.actions
+
+import android.util.Patterns
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.text.AnnotatedString
+import androidx.compose.ui.text.SpanStyle
+import androidx.compose.ui.text.TextRange
+import androidx.compose.ui.text.buildAnnotatedString
+import androidx.compose.ui.text.input.OffsetMapping
+import androidx.compose.ui.text.input.TransformedText
+import androidx.compose.ui.text.input.VisualTransformation
+import androidx.compose.ui.text.style.TextDecoration
+import com.vitorpamplona.amethyst.model.LocalCache
+import com.vitorpamplona.amethyst.model.decodePublicKey
+import kotlin.math.roundToInt
+
+data class RangesChanges(val original: TextRange, val modified: TextRange)
+
+class UrlUserTagTransformation(val color: Color) : VisualTransformation {
+  override fun filter(text: AnnotatedString): TransformedText {
+    return buildAnnotatedStringWithUrlHighlighting(text, color)
+  }
+}
+
+fun buildAnnotatedStringWithUrlHighlighting(text: AnnotatedString, color: Color): TransformedText {
+    val substitutions = mutableListOf<RangesChanges>()
+
+    val newText = buildAnnotatedString {
+      val builderBefore = StringBuilder() // important to correctly measure Tag start and end
+      val builderAfter = StringBuilder() // important to correctly measure Tag start and end
+      append(
+        text.split('\n').map { paragraph: String ->
+          paragraph.split(' ').map { word: String ->
+            try {
+              if (word.startsWith("@npub") && word.length >= 64) {
+                val keyB32 = word.substring(0, 64)
+                val restOfWord = word.substring(64)
+
+                val startIndex = builderBefore.toString().length
+
+                builderBefore.append("$keyB32$restOfWord ") // accounts for the \n at the end of each paragraph
+
+                val endIndex = startIndex + keyB32.length
+
+                val key = decodePublicKey(keyB32.removePrefix("@"))
+                val user = LocalCache.getOrCreateUser(key)
+
+                val newWord = "@${user.toBestDisplayName()}"
+                val startNew = builderAfter.toString().length
+
+                builderAfter.append("$newWord$restOfWord ") // accounts for the \n at the end of each paragraph
+
+                substitutions.add(
+                  RangesChanges(
+                    TextRange(startIndex, endIndex),
+                    TextRange(startNew, startNew + newWord.length)
+                  )
+                )
+                newWord + restOfWord
+              } else {
+                builderBefore.append(word + " ")
+                builderAfter.append(word + " ")
+                word
+              }
+            } catch (e: Exception) {
+              // if it can't parse the key, don't try to change.
+              builderBefore.append(word + " ")
+              builderAfter.append(word + " ")
+              word
+            }
+          }.joinToString(" ")
+        }.joinToString("\n")
+      )
+
+      val newText = toAnnotatedString()
+
+      newText.split("\\s+".toRegex()).filter { word ->
+        Patterns.WEB_URL.matcher(word).matches()
+      }.forEach {
+        val startIndex = text.indexOf(it)
+        val endIndex = startIndex + it.length
+        addStyle(
+          style = SpanStyle(
+            color = color,
+            textDecoration = TextDecoration.None
+          ),
+          start = startIndex, end = endIndex
+        )
+      }
+
+      substitutions.forEach {
+        addStyle(
+          style = SpanStyle(
+            color = color,
+            textDecoration = TextDecoration.None
+          ),
+          start = it.modified.start, end = it.modified.end
+        )
+      }
+    }
+
+    val numberOffsetTranslator = object : OffsetMapping {
+        override fun originalToTransformed(offset: Int): Int {
+          val inInsideRange = substitutions.filter { offset > it.original.start && offset < it.original.end }.firstOrNull()
+
+          if (inInsideRange != null) {
+            val percentInRange = (offset - inInsideRange.original.start) / (inInsideRange.original.length.toFloat())
+            return (inInsideRange.modified.start + inInsideRange.modified.length * percentInRange).roundToInt()
+          }
+
+          val lastRangeThrough = substitutions.lastOrNull { offset >= it.original.end }
+
+          if (lastRangeThrough != null) {
+            return lastRangeThrough.modified.end + (offset - lastRangeThrough.original.end)
+          } else {
+            return offset
+          }
+        }
+
+        override fun transformedToOriginal(offset: Int): Int {
+          val inInsideRange = substitutions.filter { offset > it.modified.start && offset < it.modified.end }.firstOrNull()
+
+          if (inInsideRange != null) {
+            val percentInRange = (offset - inInsideRange.modified.start) / (inInsideRange.modified.length.toFloat())
+            return (inInsideRange.original.start + inInsideRange.original.length * percentInRange).roundToInt()
+          }
+
+          val lastRangeThrough = substitutions.lastOrNull { offset >= it.modified.end }
+
+          if (lastRangeThrough != null) {
+            return lastRangeThrough.original.end + (offset - lastRangeThrough.modified.end)
+          } else {
+            return offset
+          }
+        }
+    }
+
+    return TransformedText(
+      newText,
+      numberOffsetTranslator
+    )
+
+}