feat(text-format): shared chat text-format parser

.github/workflows/shared-core-tests.yml

@@ -13,6 +13,7 @@ on:
       - 'libs/encryption/**'
       - 'libs/reporting/**'
       - 'libs/analytics-events/**'
+      - 'libs/text-format/**'
       - 'build-logic/convention/src/main/kotlin/AnalyticsCatalogueConventionPlugin.kt'
       - 'build-logic/convention/src/main/kotlin/com/getcode/buildlogic/analytics/**'
       - 'gradle/libs.versions.toml'
@@ -78,7 +79,8 @@ jobs:
             :libs:encryption:mnemonic:iosSimulatorArm64Test \
             :libs:encryption:sha256:iosSimulatorArm64Test \
             :libs:encryption:sha512:iosSimulatorArm64Test \
-            :libs:reporting:iosSimulatorArm64Test
+            :libs:reporting:iosSimulatorArm64Test \
+            :libs:text-format:iosSimulatorArm64Test
 
       # The facade suite has to run against the Kotlin in this checkout, not against the last
       # published release, or a facade written for an unreleased Kotlin change is untested until

kmp/shared-core/build.gradle.kts

@@ -39,6 +39,7 @@ kotlin {
             isStatic = true
             export(project(":libs:codes:kikcode"))
             export(project(":libs:encryption:base58"))
+            export(project(":libs:text-format"))
             export(project(":libs:encryption:sha256"))
             export(project(":libs:encryption:sha512"))
             export(project(":libs:encryption:hmac"))
@@ -56,6 +57,7 @@ kotlin {
             dependencies {
                 api(project(":libs:codes:kikcode"))
                 api(project(":libs:encryption:base58"))
+                api(project(":libs:text-format"))
                 api(project(":libs:encryption:sha256"))
                 api(project(":libs:encryption:sha512"))
                 api(project(":libs:encryption:hmac"))

libs/text-format/build.gradle.kts

@@ -0,0 +1,43 @@
+plugins {
+    alias(libs.plugins.flipcash.kmp.library)
+    alias(libs.plugins.flipcash.kmp.test.fixtures)
+}
+
+// Compiles `src/commonTest/resources` into a generated `TestFixtures.kt` on `commonTest`, readable
+// from every target -- see the `flipcash.kmp.test.fixtures` convention plugin.
+testFixtures {
+    packageName = "com.flipcash.libs.textformat"
+}
+
+kotlin {
+    android {
+        namespace = "com.flipcash.libs.textformat"
+        compileSdk {
+            version = release(libs.versions.android.compileSdk.get().toInt()) {
+                minorApiLevel = libs.versions.android.compileSdkMinor.get().toInt()
+            }
+        }
+        minSdk = 29
+        withHostTest {}
+    }
+
+    iosArm64()
+    iosSimulatorArm64()
+    iosX64()
+    macosArm64()
+    macosX64()
+
+    sourceSets {
+        commonMain {
+            // Pure Kotlin -- no external dependencies needed.
+        }
+        commonTest {
+            dependencies {
+                implementation(kotlin("test"))
+                implementation(libs.kotlinx.serialization.json)
+                // Hashes the copied fixture so a stale copy fails loudly.
+                implementation(libs.kotlincrypto.hash.sha2)
+            }
+        }
+    }
+}

libs/text-format/src/commonMain/kotlin/com/flipcash/libs/textformat/TextFormat.kt

@@ -0,0 +1,48 @@
+package com.flipcash.libs.textformat
+
+/** What a detected range is. The parser never detects these itself; callers pass them in. */
+enum class RangeKind { Link, Mention }
+
+/**
+ * A link or mention that detection found in the raw text. [start] and [end] are UTF-16 code unit
+ * offsets (Kotlin `String` indices), half-open. A marker inside a range is part of it and never
+ * opens or closes a style.
+ */
+data class ProtectedRange(
+    val start: Int,
+    val end: Int,
+    val kind: RangeKind,
+)
+
+/** The styles the parser produces. */
+enum class FormatStyle { Bold, Italic, Strike, Code, CodeBlock, Quote, Bullet, Numbered }
+
+/** A [style] over [FormattedText.display], UTF-16 code unit offsets, half-open. */
+data class StyledSpan(
+    val start: Int,
+    val end: Int,
+    val style: FormatStyle,
+)
+
+/**
+ * An input range moved to [FormattedText.display] offsets. A masked link `[text](url)` becomes a
+ * [RangeKind.Link] over `text` with the URL as [target]. A range without a [target] opens its own
+ * text.
+ */
+data class DisplayRange(
+    val start: Int,
+    val end: Int,
+    val kind: RangeKind,
+    val target: String? = null,
+)
+
+/**
+ * The parser's result. [display] is the raw text minus the consumed markers. [spans] are
+ * normalized per style (touching or overlapping runs merged) and ordered by start, then longest
+ * first, then style name. [displayRanges] are ordered by start, end, kind, then target.
+ */
+data class FormattedText(
+    val display: String,
+    val spans: List<StyledSpan>,
+    val displayRanges: List<DisplayRange>,
+)