Internationalization support.

1 files changed, 150 insertions, 0 deletions

diff --git a/src/main/kotlin/pl/treksoft/kvision/i18n/I18n.kt b/src/main/kotlin/pl/treksoft/kvision/i18n/I18n.kt
new file mode 100644
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+++ b/src/main/kotlin/pl/treksoft/kvision/i18n/I18n.kt
@@ -0,0 +1,150 @@
+/*
+ * Copyright (c) 2017-present Robert Jaros
+ *
+ * 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 pl.treksoft.kvision.i18n
+
+import org.w3c.xhr.XMLHttpRequest
+import pl.treksoft.kvision.panel.Root
+import kotlin.browser.window
+import kotlin.js.Promise
+
+external class Jed(json: dynamic) {
+    fun gettext(key: String): String
+    fun ngettext(singularKey: String, pluralKey: String, value: Int): String
+    fun sprintf(format: String, value: Int): String
+}
+
+private const val I18N_SINGLE_DELIMITER = "###KvI18nS###"
+private const val I18N_PLURAL_DELIMITER = "###KvI18nP###"
+
+/**
+ * A singleton object used for translations.
+ */
+object I18n {
+
+    private val defaultLanguage = window.navigator.language.split("-")[0]
+
+    /**
+     * Main language of the application.
+     */
+    var language = defaultLanguage
+        set(value) {
+            field = value
+            Root.roots.forEach { it.reRender() }
+        }
+
+    private val cache = mutableMapOf<String, Jed>()
+
+    /**
+     * I18n initialization function.
+     * Should be called in the main function of the application.
+     * @param languages a list of supported languages.
+     * @param initCallback a code to run after the initialization process is complete.
+     */
+    fun init(vararg languages: String, initCallback: () -> Unit) {
+        val promises = languages.map {
+            I18n.readMessages(it)
+        }.toTypedArray()
+        Promise.all(promises).then { initCallback() }
+    }
+
+    private fun readMessages(language: String): Promise<Jed> {
+        return Promise { resolve, _ ->
+            val xmlHttpRequest = XMLHttpRequest()
+            xmlHttpRequest.overrideMimeType("application/json")
+            xmlHttpRequest.open("GET", "js/messages-$language.json", true)
+            xmlHttpRequest.onreadystatechange = {
+                if (xmlHttpRequest.readyState.toInt() == 4 && (xmlHttpRequest.status.toInt() == 200 ||
+                            xmlHttpRequest.status.toInt() == 0)
+                ) {
+                    val json = JSON.parse<dynamic>(xmlHttpRequest.responseText)
+                    val jed = Jed(json)
+                    cache[language] = jed
+                    resolve(jed)
+                }
+            }
+            xmlHttpRequest.send()
+        }
+    }
+
+    /**
+     * A static translation function for a singular form.
+     * @param key a translation key.
+     * @return translated text.
+     */
+    fun gettext(key: String): String {
+        return cache[language]?.gettext(key) ?: key
+    }
+
+    /**
+     * A static translation function for a plural form.
+     * @param singularKey a translation key for a singular form.
+     * @param pluralKey a translation key for a plural form.
+     * @param value a count value.
+     * @return translated text.
+     */
+    fun ngettext(singularKey: String, pluralKey: String, value: Int): String {
+        return cache[language]?.run {
+            sprintf(ngettext(singularKey, pluralKey, value), value)
+        } ?: if (value == 1) singularKey else pluralKey
+    }
+
+    /**
+     * A dynamic translation function for a singular form.
+     * @param key a translation key.
+     * @return text marked for a dynamic translation.
+     */
+    fun tr(key: String): String {
+        return I18N_SINGLE_DELIMITER + key
+    }
+
+    /**
+     * A dynamic translation function for a plural form.
+     * @param singularKey a translation key for a singular form.
+     * @param pluralKey a translation key for a plural form.
+     * @param value a count value.
+     * @return text marked for a dynamic translation.
+     */
+    fun ntr(singularKey: String, pluralKey: String, value: Int): String {
+        return I18N_PLURAL_DELIMITER + singularKey + I18N_PLURAL_DELIMITER + pluralKey + I18N_PLURAL_DELIMITER + value
+    }
+
+    internal fun trans(text: String): String {
+        return if (text.startsWith(I18N_SINGLE_DELIMITER)) {
+            gettext(text.substring(I18N_SINGLE_DELIMITER.length))
+        } else if (text.startsWith(I18N_PLURAL_DELIMITER)) {
+            val tab = text.substring(I18N_PLURAL_DELIMITER.length).split(I18N_PLURAL_DELIMITER)
+            if (tab.size == 3) {
+                ngettext(tab[0], tab[1], tab[2].toIntOrNull() ?: 1)
+            } else {
+                text
+            }
+        } else {
+            text
+        }
+    }
+
+    internal fun trans(text: String?): String? {
+        return text?.let {
+            trans(it)
+        }
+    }
+}