1 files changed, 163 insertions, 0 deletions
diff --git a/src/study/WordDrillModel.cpp b/src/study/WordDrillModel.cpp
new file mode 100644
index 0000000..403535a
--- /dev/null
+++ b/src/study/WordDrillModel.cpp
@@ -0,0 +1,163 @@
+#include "WordDrillModel.h"
+#include "../dictionary/Card.h"
+#include "../dictionary/CardPack.h"
+#include "StudySettings.h"
+
+#include <stdlib.h>
+#include <time.h>
+
+WordDrillModel::WordDrillModel( CardPack* aCardPack ):
+    IStudyModel( aCardPack ), m_historyCurPackStart(0)
+    {
+    curCardNum = NoCardIndex;
+    srand( time(NULL) );
+    connect( aCardPack, SIGNAL(cardsGenerated()), SLOT(updateStudyState()) );
+
+    generateFreshPack();
+    pickNextCard();
+    }
+
+/** Get current card.
+  * If the current card doesn't exist any more, find the next valid card.
+  */
+
+Card* WordDrillModel::getCurCard() const
+    {
+    if( m_cardHistory.isEmpty() || curCardNum < 0 )   // No cards in the pack
+        return NULL;
+    if( curCardNum >= m_cardHistory.size() )
+        return NULL;
+    QString cardName = m_cardHistory.at(curCardNum);
+    return cardPack->getCard( cardName );
+    }
+
+void WordDrillModel::updateStudyState()
+    {
+    generateFreshPack();
+    cleanHistoryFromRemovedCards();
+    if( getCurCard() )
+        emit curCardUpdated();
+    else
+        pickNextCard();
+    }
+
+void WordDrillModel::generateFreshPack()
+    {
+    m_freshPack = cardPack->getCardQuestions();
+    // Remove already reviewed cards
+    if( m_historyCurPackStart >= m_cardHistory.size() )
+        return;
+    foreach( QString reviewedCard, m_cardHistory.mid( m_historyCurPackStart ) )
+        m_freshPack.removeAll( reviewedCard );
+    }
+
+void WordDrillModel::cleanHistoryFromRemovedCards()
+    {
+    if( m_cardHistory.isEmpty() )
+        return;
+    bool cardsRemoved = false;
+    QMutableStringListIterator it( m_cardHistory );
+    int i = 0;
+    while( it.hasNext() )
+        {
+        QString cardName = it.next();
+        if( !cardPack->containsQuestion( cardName ) )
+            {
+            it.remove();
+            cardsRemoved = true;
+            if( i < curCardNum )
+                curCardNum--;
+            }
+        i++;
+        }
+    if( cardsRemoved )
+        {
+        if( curCardNum >= m_cardHistory.size() )
+            curCardNum = m_cardHistory.size() - 1;
+        emit nextCardSelected();
+        }
+    }
+
+
+/** Picks a random card. Removes the selected card from the fresh pack and adds it to the history.
+ * Thus, the new card is the last entry in the history.
+ * This function guarantees that the new card's question will be different from the previous one, unless there is no choice.
+ *
+ * Updates #m_curCardNum.
+ */
+void WordDrillModel::pickNextCard()
+    {
+    QString selectedCardName;
+    const Card* selectedCard = NULL;
+    do
+        {
+        if( m_freshPack.isEmpty() )  // No fresh cards
+            {
+            m_historyCurPackStart = m_cardHistory.size(); // Refers beyond the history pack
+            generateFreshPack();
+            if( m_freshPack.isEmpty() )  // Still no any cards available - no useful cards in the dictionary or it's empty
+                {
+                curCardNum = NoCardIndex;
+                emit nextCardSelected();
+                return;
+                }
+            }
+        if( m_freshPack.size() == 1 )    // Only 1 fresh card, no choice
+            selectedCardName = m_freshPack.takeFirst();
+        else
+            {
+            int selectedCardNum;
+            if( StudySettings::inst()->showRandomly )
+                selectedCardNum = rand() % m_freshPack.size();
+            else
+                selectedCardNum = 0;
+            if( !m_cardHistory.isEmpty() )
+                while( m_freshPack[ selectedCardNum ] == m_cardHistory.last() ) // The new question must be different from the current one
+                    {
+                    selectedCardNum++;
+                    selectedCardNum %= m_freshPack.size();
+                    }
+            selectedCardName = m_freshPack.takeAt( selectedCardNum );
+            }
+        selectedCard = cardPack->getCard( selectedCardName );
+        }
+    while( !selectedCard );
+    m_cardHistory << selectedCardName;
+    curCardNum = m_cardHistory.size() - 1;
+    emit nextCardSelected();
+    }
+
+/** Go back along the history line.
+ * @return true, if the transition was successful
+ */
+bool WordDrillModel::goBack()
+    {
+    if( !canGoBack() )
+        return false;
+    curCardNum--;
+    emit nextCardSelected();
+    return true;
+    }
+
+/** Go forward along the history line.
+ * @return true, if the transition was successful
+ */
+bool WordDrillModel::goForward()
+    {
+    if( !canGoForward() )
+        return false;
+    curCardNum++;
+    emit nextCardSelected();
+    return true;
+    }
+
+bool WordDrillModel::canGoBack()
+    {
+    return curCardNum > 0;
+    }
+
+bool WordDrillModel::canGoForward()
+    {
+    return curCardNum < m_cardHistory.size() - 1;
+    }
+