Added refresh by swipe

app/src/main/java/com/paktalin/vocabularynotebook/Vocabulary.kt

+package com.paktalin.vocabularynotebook
+
+import com.google.firebase.Timestamp
+import com.google.firebase.firestore.DocumentSnapshot
+import com.paktalin.vocabularynotebook.firestoreitems.WordItem
+import com.paktalin.vocabularynotebook.utils.FirestoreManager.Companion.vocabularyId
+
+class Vocabulary() {
+    private var words: MutableList<WordItem> = mutableListOf()
+
+    constructor(words: MutableList<WordItem>) : this() {
+        this.words = words
+    }
+
+    companion object {
+        private val TAG = "VN/" + Vocabulary::class.java.simpleName
+
+        private const val SORT_BY_TIME = 0
+        private const val SORT_BY_WORD = 1
+        private const val SORT_BY_TRANSLATION = 2
+    }
+
+    fun sort(sortOrder:Int) {
+        when(sortOrder) {
+            SORT_BY_TIME -> sortByTime()
+            SORT_BY_WORD -> sortByWord()
+            SORT_BY_TRANSLATION -> sortByTranslation()
+        }
+    }
+
+    fun deleteWord(position:Int) {
+        words[position].delete() // delete word from the database
+        words.removeAt(position) // delete word from the list
+    }
+
+    fun addWord(newWord: WordItem) {
+        words.add(0, newWord)
+    }
+
+    fun addWords(newWords:MutableList<WordItem>) {
+        words.addAll(newWords)
+    }
+
+    fun addWordsAsDocuments(documents: MutableList<DocumentSnapshot>) {
+        for (ref in documents) {
+            val word = ref["word"].toString()
+            val translation = ref["translation"].toString()
+            val time = ref["time"] as Timestamp
+            words.add(WordItem(word, translation, time.toDate(), ref.id, vocabularyId!!))
+        }
+    }
+
+    fun addWordsFittingQuery(newWords:MutableList<WordItem>, query:String) {
+        for (newWord in newWords) {
+            if (newWord.contains(query))
+                this.addWord(newWord)
+        }
+    }
+
+    fun updateWord(updatedWord: WordItem) {
+        val updatedItemIndex = words.indexOf(updatedWord)
+        words[updatedItemIndex] = updatedWord
+    }
+
+    fun getAt(position: Int): WordItem {
+        return words[position]
+    }
+
+    fun get():MutableList<WordItem> { return words }
+
+    fun size():Int { return words.size }
+
+    fun clear() { words.clear() }
+
+    private fun sortByTime() {
+        words.sortWith(Comparator { item1, item2 ->
+            -item1.pojo.time!!.compareTo(item2.pojo.time) })
+    }
+    private fun sortByWord() {
+        words.sortWith(Comparator { item1, item2 ->
+            item1.pojo.word.compareTo(item2.pojo.word) })
+    }
+    private fun sortByTranslation() {
+        words.sortWith(Comparator { item1, item2 ->
+            item1.pojo.translation.compareTo(item2.pojo.translation) })
+    }
+}
\ No newline at end of file