Implement PlatformLocale and StringDelegate for k/wasm (#561) (#625)

* Implement PlatformLocale and StringDelegate for k/wasm (#561)

* Workaround `isOnUiThread` (ui-test) for k/wasm browser target

* Implement PlatformLocale  and StringDelegate for k/wasm

* Get rid of expect/actuals for jsWasmMain and use js(...) for a common implementation

* use the list of preferred languages - `window.navigator.languages`

* delete unused fun `currentLanguageTag`

* Add a comment

compose/ui/ui-text/src/jsMain/kotlin/androidx/compose/ui/text/intl/Actuals.js.kt

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package androidx.compose.ui.text.intl
+
+internal actual fun userPreferredLanguages(): List<String> {
+    return getUserPreferredLanguagesAsArray().toList()
+}
+
+@Suppress("UnsafeCastFromDynamic")
+private fun getUserPreferredLanguagesAsArray(): Array<String> =
+    js("window.navigator.languages")

compose/ui/ui-text/src/jsWasmMain/kotlin/androidx/compose/ui/text/intl/JsPlatformLocale.js.kt

@@ -16,28 +16,54 @@
 
 package androidx.compose.ui.text.intl
 
-internal class JsLocale(val locale: dynamic) : PlatformLocale {
+internal class JsLocale(val locale: IntlLocale) : PlatformLocale {
+
+    constructor(languageTag: String): this(languageTag.toIntlLocale())
+
     override val language: String
-        get() = locale.languageCode!!
+        get() = locale.language
 
     override val script: String
-        get() = locale.scriptCode!!
+        get() = locale.script ?: ""
 
     override val region: String
-        get() = locale.countryCode!!
+        get() = locale.region ?: ""
 
-    override fun toLanguageTag(): String = TODO("implement native toLanguageTag") // locale.toLanguageTag()
+    override fun toLanguageTag(): String = locale.baseName
 }
 
 internal actual fun createPlatformLocaleDelegate(): PlatformLocaleDelegate =
     object : PlatformLocaleDelegate {
         override val current: LocaleList
-            get() = LocaleList(listOf(Locale(JsLocale(Any()))))
+            get() = LocaleList(
+                userPreferredLanguages().map {
+                    Locale(JsLocale(it))
+                }
+            )
 
 
         override fun parseLanguageTag(languageTag: String): PlatformLocale {
-            return JsLocale(Any())
+            return JsLocale(languageTag)
         }
     }
 
-internal actual fun PlatformLocale.isRtl(): Boolean = false // TODO
+// The list of RTL languages is taken from https://github.com/openjdk/jdk/blob/master/src/java.desktop/share/classes/java/awt/ComponentOrientation.java#L156
+private val rtlLanguagesSet = setOf("ar", "fa", "he", "iw", "ji", "ur", "yi")
+
+// Implemented according to ComponentOrientation.getOrientation (AWT),
+// since there is no js API for this.
+internal actual fun PlatformLocale.isRtl(): Boolean = this.language in rtlLanguagesSet
+
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/Locale
+internal external interface IntlLocale {
+    val language: String
+    val script: String?
+    val region: String?
+    val baseName: String
+}
+
+internal fun parseLanguageTagToIntlLocale(languageTag: String): IntlLocale = js("new Intl.Locale(languageTag)")
+
+internal expect fun userPreferredLanguages(): List<String>
+
+private fun String.toIntlLocale(): IntlLocale = parseLanguageTagToIntlLocale(this)

compose/ui/ui-text/src/jsWasmMain/kotlin/androidx/compose/ui/text/platform/JsStringDelegate.js.kt

@@ -23,21 +23,46 @@ import androidx.compose.ui.text.intl.PlatformLocale
 /**
  * A JS implementation of StringDelegate
  */
-
 internal class JsStringDelegate : PlatformStringDelegate {
     override fun toUpperCase(string: String, locale: PlatformLocale): String =
-        string.toUpperCase()
+        toLocaleUpperCase(string, locale.language)
 
     override fun toLowerCase(string: String, locale: PlatformLocale): String =
-        string.toLowerCase()
+        toLocaleLowerCase(string, locale.language)
+
+    override fun capitalize(string: String, locale: PlatformLocale): String {
+        return string.replaceFirstChar {
+            if (it.isLowerCase()) {
+                it.titlecaseImpl(locale)
+            } else {
+                it.toString()
+            }
+        }
+    }
 
-    override fun capitalize(string: String, locale: PlatformLocale): String =
-        string.capitalize()
+    // Copy-pasted from kotlin _OneToManyTitlecaseMappings.kt (internal in stdlib, but doesn't take locale into account)
+    private fun Char.titlecaseImpl(locale: PlatformLocale): String {
+        val uppercase = toLocaleUpperCase(this.toString(), locale.language)
+        if (uppercase.length > 1) {
+            return if (this == '\u0149') uppercase else uppercase[0] + uppercase.substring(1).lowercase()
+        }
+        return titlecaseChar().toString()
+    }
 
-    override fun decapitalize(string: String, locale: PlatformLocale): String =
-        string.decapitalize()
+    override fun decapitalize(string: String, locale: PlatformLocale): String {
+        return string.replaceFirstChar {
+            toLocaleLowerCase(it.toString(), locale.language)
+        }
+    }
 }
 
 internal actual fun ActualStringDelegate(): PlatformStringDelegate =
-    // TODO("implement JsStringDelegate")
     JsStringDelegate()
+
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/toLocaleUpperCase
+internal fun toLocaleUpperCase(text: String, locale: String): String =
+    js("text.toLocaleUpperCase(locale)")
+
+//https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/toLocaleLowerCase
+internal fun toLocaleLowerCase(text: String, locale: String): String =
+    js("text.toLocaleLowerCase(locale)")

compose/ui/ui-text/src/wasmMain/kotlin/androidx/compose/ui/text/intl/Actuals.wasm.kt

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package androidx.compose.ui.text.intl
+
+internal actual fun userPreferredLanguages(): List<String> {
+    val jsStringArray = getUserPreferredLanguagesAsArray()
+    return buildList<String> {
+        repeat(jsStringArray.length) {
+            add(jsStringArray[it].toString())
+        }
+    }
+}
+
+private fun getUserPreferredLanguagesAsArray(): JsArray<JsString> =
+    js("window.navigator.languages")