move models to commons

2026-01-01 07:26:39 +02:00
parent f3b8589fea
commit eb47c19172
503 changed files with 1675 additions and 888 deletions
@@ -0,0 +1,37 @@
+/**
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.commons.threading
+
+import android.os.Looper
+
+/**
+ * Android implementation of checkNotInMainThread.
+ * Uses Looper to detect if running on main thread.
+ */
+actual fun checkNotInMainThread() {
+    // BuildConfig check removed - commons doesn't have BuildConfig
+    // Enable this check in debug builds at the app level if needed
+    if (isMainThread()) {
+        throw OnMainThreadException("It should not be in the MainThread")
+    }
+}
+
+private fun isMainThread() = Looper.myLooper() == Looper.getMainLooper()
@@ -0,0 +1,29 @@
+/**
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.commons.util
+
+import java.text.NumberFormat
+
+actual class PlatformNumberFormatter {
+    private val formatter = NumberFormat.getInstance()
+
+    actual fun format(value: Long): String = formatter.format(value)
+}
@@ -0,0 +1,89 @@
+/**
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.commons.model
+
+import com.vitorpamplona.quartz.nip47WalletConnect.LnZapPaymentRequestEvent
+import com.vitorpamplona.quartz.nip47WalletConnect.LnZapPaymentResponseEvent
+import com.vitorpamplona.quartz.nip47WalletConnect.Request
+import com.vitorpamplona.quartz.nip47WalletConnect.Response
+import com.vitorpamplona.quartz.nip57Zaps.LnZapPrivateEvent
+import com.vitorpamplona.quartz.nip57Zaps.LnZapRequestEvent
+import com.vitorpamplona.quartz.utils.DualCase
+
+/**
+ * Interface for NIP-47 wallet connect signer state.
+ * Used by Note.kt for checking NWC payment status.
+ */
+interface INwcSignerState {
+    suspend fun decryptResponse(event: LnZapPaymentResponseEvent): Response?
+
+    suspend fun decryptRequest(event: LnZapPaymentRequestEvent): Request?
+
+    fun isNIP47Author(pubKey: String?): Boolean
+}
+
+/**
+ * Interface for private zap decryption cache.
+ * Used by Note.kt for checking private zap status.
+ */
+interface IPrivateZapsDecryptionCache {
+    fun cachedPrivateZap(event: LnZapRequestEvent): LnZapPrivateEvent?
+
+    suspend fun decryptPrivateZap(event: LnZapRequestEvent): LnZapPrivateEvent?
+}
+
+/**
+ * Hidden content settings for filtering notes.
+ * Used by Note.isHiddenFor() to check if content should be hidden.
+ */
+data class LiveHiddenUsers(
+    val showSensitiveContent: Boolean?,
+    val hiddenWordsCase: List<DualCase>,
+    val hiddenUsersHashCodes: Set<Int>,
+    val spammersHashCodes: Set<Int>,
+)
+
+/**
+ * Interface for account operations needed by Note.kt.
+ * Abstracts Android-specific Account class for use in commons.
+ */
+interface IAccount {
+    /** NIP-47 wallet connect state for payment verification */
+    val nip47SignerState: INwcSignerState
+
+    /** Private zaps decryption cache */
+    val privateZapsDecryptionCache: IPrivateZapsDecryptionCache
+
+    /** Current user's profile */
+    fun userProfile(): User
+
+    /** Whether account has write permissions */
+    fun isWriteable(): Boolean
+
+    /** Current user's public key */
+    val pubKey: String
+
+    /** Content filter settings */
+    val showSensitiveContent: Boolean?
+    val hiddenWordsCase: List<DualCase>
+    val hiddenUsersHashCodes: Set<Int>
+    val spammersHashCodes: Set<Int>
+}
@@ -0,0 +1,77 @@
+/**
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.commons.model.cache
+
+import com.vitorpamplona.quartz.nip01Core.core.HexKey
+
+/**
+ * Cache provider interface for accessing cached Notes, Users, and Channels.
+ *
+ * This abstraction allows Note and User models to access the cache without
+ * direct coupling to LocalCache singleton. Platform-specific implementations
+ * (Android LocalCache, Desktop DesktopLocalCache) implement this interface.
+ *
+ * Benefits:
+ * - Dependency injection instead of singleton coupling
+ * - Testable (can mock for unit tests)
+ * - Platform-agnostic model layer
+ */
+interface ICacheProvider {
+    /**
+     * Gets a channel by Note reference.
+     * Used for resolving relay hints for channel messages.
+     *
+     * @param note The note to look up channel for
+     * @return The channel if found, null otherwise
+     */
+    fun getAnyChannel(note: Any?): IChannel?
+
+    /**
+     * Gets a User by public key hex.
+     * Used for updating follower counts and user relationships.
+     *
+     * @param pubkey The user's public key in hex format
+     * @return The User if exists in cache, null otherwise
+     */
+    fun getUserIfExists(pubkey: HexKey): Any?
+
+    /**
+     * Counts users matching a predicate.
+     * Used for calculating follower counts.
+     *
+     * @param predicate Filter function for counting users
+     * @return Count of users matching the predicate
+     */
+    fun countUsers(predicate: (String, Any) -> Boolean): Int
+}
+
+/**
+ * Minimal channel interface for relay resolution.
+ * Full channel implementations (PublicChatChannel, LiveActivitiesChannel)
+ * implement this interface.
+ */
+interface IChannel {
+    /**
+     * Gets the relay URLs for this channel.
+     * @return List of relay URLs or null if none configured
+     */
+    fun relays(): List<Any>?
+}
@@ -0,0 +1,109 @@
+/**
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.commons.model.nip56Reports
+
+import com.vitorpamplona.amethyst.commons.model.Note
+import com.vitorpamplona.amethyst.commons.model.User
+import com.vitorpamplona.amethyst.commons.model.UserDependencies
+import com.vitorpamplona.quartz.nip01Core.core.HexKey
+import com.vitorpamplona.quartz.nip56Reports.ReportEvent
+import com.vitorpamplona.quartz.nip56Reports.ReportType
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.update
+
+class UserReportCache : UserDependencies {
+    val receivedReportsByAuthor = MutableStateFlow(mapOf<User, Set<Note>>())
+
+    fun addReport(note: Note) {
+        val author = note.author ?: return
+
+        val reportsBy = receivedReportsByAuthor.value[author]
+
+        // if it's already there, quick exit
+        if (reportsBy != null && reportsBy.contains(note)) return
+
+        receivedReportsByAuthor.update {
+            val author = note.author
+            if (author == null) {
+                it
+            } else {
+                val reportsByInner = it[author] ?: emptySet()
+                it + (author to reportsByInner + note)
+            }
+        }
+    }
+
+    fun removeReport(deleteNote: Note) {
+        val author = deleteNote.author ?: return
+        val reportsBy = receivedReportsByAuthor.value[author]
+
+        // if it's not already there, quick exit
+        if (reportsBy == null || !reportsBy.contains(deleteNote)) return
+
+        receivedReportsByAuthor.update {
+            val author = deleteNote.author
+            if (author == null) {
+                it
+            } else {
+                val reportsByInner = it[author]
+                if (reportsByInner == null) {
+                    it
+                } else {
+                    it + (author to reportsByInner - deleteNote)
+                }
+            }
+        }
+    }
+
+    fun reportsBy(user: User): Set<Note> = receivedReportsByAuthor.value[user] ?: emptySet()
+
+    fun count() = receivedReportsByAuthor.value.values.sumOf { it.size }
+
+    fun countFlow() =
+        receivedReportsByAuthor.map { reportPerAuthor ->
+            reportPerAuthor.values.sumOf { it.size }
+        }
+
+    fun countReportAuthorsBy(users: Set<HexKey>): Int = receivedReportsByAuthor.value.count { it.key.pubkeyHex in users }
+
+    fun all() = receivedReportsByAuthor.value.values.flatten()
+
+    fun reportsBy(users: Set<HexKey>): List<Note> =
+        receivedReportsByAuthor.value
+            .flatMap {
+                if (it.key.pubkeyHex in users) {
+                    it.value
+                } else {
+                    emptyList()
+                }
+            }
+
+    fun hasReport(
+        loggedIn: User,
+        type: ReportType,
+    ): Boolean =
+        receivedReportsByAuthor.value[loggedIn]?.firstOrNull {
+            (it.event as? ReportEvent)?.reportedAuthor()?.any { it.type == type } ?: false
+        } != null
+
+    fun hasReportNewerThan(timeInSeconds: Long): Boolean = receivedReportsByAuthor.value.any { pair -> pair.value.firstOrNull { (it.createdAt() ?: 0L) > timeInSeconds } != null }
+}
@@ -0,0 +1,150 @@
+/**
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.commons.model.trustedAssertions
+
+import com.vitorpamplona.amethyst.commons.model.AddressableNote
+import com.vitorpamplona.amethyst.commons.model.User
+import com.vitorpamplona.amethyst.commons.model.UserDependencies
+import com.vitorpamplona.amethyst.commons.util.PlatformNumberFormatter
+import com.vitorpamplona.quartz.experimental.relationshipStatus.ContactCardEvent
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.combineTransform
+import kotlinx.coroutines.flow.emitAll
+import kotlinx.coroutines.flow.flowOn
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.update
+
+class UserCardsCache : UserDependencies {
+    val receivedCards = MutableStateFlow(mapOf<User, AddressableNote>())
+
+    fun addCard(note: AddressableNote) {
+        val author = note.author ?: return
+
+        val cardBy = receivedCards.value[author]
+
+        // if it's already there, quick exit
+        if (cardBy != null && cardBy == note) return
+
+        receivedCards.update {
+            val author = note.author
+            if (author == null) {
+                it
+            } else {
+                it + (author to note)
+            }
+        }
+    }
+
+    fun removeCard(note: AddressableNote) {
+        val author = note.author ?: return
+        val cardBy = receivedCards.value[author]
+
+        // if it's not already there, quick exit
+        if (cardBy == null || cardBy != note) return
+
+        receivedCards.update {
+            val author = note.author
+            if (author == null) {
+                it
+            } else {
+                val reportsByInner = it[author]
+                if (reportsByInner == null) {
+                    it
+                } else {
+                    it - author
+                }
+            }
+        }
+    }
+
+    fun rankFlow(trustProviderList: TrustProviderListState) =
+        combineTransform(receivedCards, trustProviderList.liveUserRankProvider) { cards, provider ->
+            if (provider != null) {
+                val flow =
+                    cards.firstNotNullOfOrNull {
+                        if (it.key.pubkeyHex == provider.pubkey) {
+                            it.value
+                                .flow()
+                                .metadata.stateFlow
+                        } else {
+                            null
+                        }
+                    }
+
+                if (flow != null) {
+                    emitAll(flow)
+                } else {
+                    emit(null)
+                }
+            } else {
+                emit(null)
+            }
+        }.map {
+            (it?.note?.event as? ContactCardEvent)?.rank()
+        }.flowOn(Dispatchers.IO)
+
+    private val formatter = PlatformNumberFormatter()
+
+    fun followerCountStrFlow(trustProviderList: TrustProviderListState) =
+        combineTransform(receivedCards, trustProviderList.liveUserFollowerCount) { cards, provider ->
+            if (provider != null) {
+                val flow =
+                    cards.firstNotNullOfOrNull {
+                        if (it.key.pubkeyHex == provider.pubkey) {
+                            it.value
+                                .flow()
+                                .metadata.stateFlow
+                        } else {
+                            null
+                        }
+                    }
+
+                if (flow != null) {
+                    emitAll(flow)
+                } else {
+                    emit(null)
+                }
+            } else {
+                emit(null)
+            }
+        }.map {
+            val value = (it?.note?.event as? ContactCardEvent)?.followerCount()
+
+            if (value != null && value > 0) {
+                formatter.format(value.toLong())
+            } else {
+                "--"
+            }
+        }.flowOn(Dispatchers.IO)
+}
+
+// Placeholder for TrustProviderListState - will be properly extracted later
+// For now, this allows UserCardsCache to compile
+interface TrustProviderListState {
+    val liveUserRankProvider: kotlinx.coroutines.flow.StateFlow<ServiceProviderTag?>
+    val liveUserFollowerCount: kotlinx.coroutines.flow.StateFlow<ServiceProviderTag?>
+}
+
+// Placeholder for ServiceProviderTag
+interface ServiceProviderTag {
+    val pubkey: String
+}
@@ -0,0 +1,36 @@
+/**
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.commons.threading
+
+/**
+ * Checks that the current code is not running on the main thread.
+ * Throws an exception in debug builds if called from the main thread.
+ *
+ * Platform-specific: Android uses Looper, Desktop may use different mechanism or no-op.
+ */
+expect fun checkNotInMainThread()
+
+/**
+ * Exception thrown when code expected to run on a background thread is executed on the main thread.
+ */
+class OnMainThreadException(
+    str: String,
+) : RuntimeException(str)
@@ -0,0 +1,134 @@
+/**
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.commons.util
+
+import com.vitorpamplona.amethyst.commons.emojicoder.EmojiCoder
+import com.vitorpamplona.quartz.nip01Core.core.ImmutableListOfLists
+
+fun String.isUTF16Char(pos: Int): Boolean = Character.charCount(this.codePointAt(pos)) == 2
+
+fun String.firstFullCharOld(): String {
+    return when (this.length) {
+        0,
+        1,
+        -> return this
+        2,
+        3,
+        -> return if (isUTF16Char(0)) this.take(2) else this.take(1)
+        else -> {
+            val first = isUTF16Char(0)
+            val second = isUTF16Char(2)
+            if (first && second) {
+                this.take(4)
+            } else if (first) {
+                this.take(2)
+            } else {
+                this.take(1)
+            }
+        }
+    }
+}
+
+fun String.firstFullChar(): String {
+    var isInJoin = false
+    var hasHadSecondChance = false
+    var start = 0
+    var previousCharLength = 0
+    var next: Int
+    var codePoint: Int
+
+    var i = 0
+
+    while (i < this.length) {
+        codePoint = codePointAt(i)
+
+        // Skips if it starts with the join char 0x200D
+        if (codePoint == 0x200D && previousCharLength == 0) {
+            next = offsetByCodePoints(i, 1)
+            start = next
+        } else {
+            // If join, searches for the next char
+            if (codePoint == 0xFE0F) {
+            } else if (codePoint == 0x200D) {
+                isInJoin = true
+            } else {
+                // stops when two chars are not joined together
+                if (previousCharLength > 0 && !isInJoin) {
+                    if (Character.charCount(codePoint) == 1 || hasHadSecondChance) {
+                        break
+                    } else {
+                        hasHadSecondChance = true
+                    }
+                } else {
+                    hasHadSecondChance = false
+                }
+
+                isInJoin = false
+            }
+
+            // next char to evaluate
+            next = offsetByCodePoints(i, 1)
+            previousCharLength += (next - i)
+        }
+
+        i = next
+    }
+
+    // if ends in join, then seachers backwards until a char is found.
+    if (isInJoin) {
+        i = previousCharLength - 1
+        while (i > 0) {
+            if (this[i].code == 0x200D) {
+                previousCharLength -= 1
+            } else {
+                break
+            }
+
+            i -= 1
+        }
+    }
+
+    return substring(start, start + previousCharLength)
+}
+
+fun String.firstFullCharOrEmoji(tags: ImmutableListOfLists<String>): String {
+    if (length <= 2) {
+        return firstFullChar()
+    }
+
+    if (this[0] == ':') {
+        // makes sure an emoji exists
+        val emojiParts = this.split(":", limit = 3)
+        if (emojiParts.size >= 2) {
+            val emojiName = emojiParts[1]
+            val emojiUrl = tags.lists.firstOrNull { it.size > 1 && it[1] == emojiName }?.getOrNull(2)
+            if (emojiUrl != null) {
+                return ":$emojiName:$emojiUrl"
+            }
+        }
+    }
+
+    if (EmojiCoder.isCoded(this)) {
+        return EmojiCoder.cropToFirstMessage(this)
+    }
+
+    return firstFullChar()
+}
@@ -0,0 +1,26 @@
+/**
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.commons.util
+
+fun <T> Iterable<T>.replace(
+    old: T,
+    new: T,
+): List<T> = map { if (it == old) new else it }
@@ -0,0 +1,29 @@
+/**
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.commons.util
+
+/**
+ * Platform-agnostic number formatter.
+ * Uses NumberFormat on JVM platforms, custom formatting elsewhere.
+ */
+expect class PlatformNumberFormatter() {
+    fun format(value: Long): String
+}
@@ -0,0 +1,32 @@
+/**
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.commons.threading
+
+/**
+ * Desktop JVM implementation of checkNotInMainThread.
+ * Currently a no-op as Desktop Compose doesn't have the same main thread restrictions as Android.
+ * Could be enhanced to check Swing EDT if needed.
+ */
+actual fun checkNotInMainThread() {
+    // No-op for Desktop - different threading model
+    // Could check for Swing EDT with: javax.swing.SwingUtilities.isEventDispatchThread()
+    // but Compose Desktop doesn't have the same restrictions as Android
+}
@@ -0,0 +1,29 @@
+/**
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.commons.util
+
+import java.text.NumberFormat
+
+actual class PlatformNumberFormatter {
+    private val formatter = NumberFormat.getInstance()
+
+    actual fun format(value: Long): String = formatter.format(value)
+}