// completertextedit.cpp
#include "completertextedit.h"
#include <QCoreApplication>
#include <QAbstractItemView>
#include <QCompleter>
#include <QKeyEvent>
#include <QString>
#include <QTextCursor>

CompleterTextEdit::CompleterTextEdit(QWidget *parent) :
    QTextEdit(parent), m_completer(NULL) {
}
QCompleter * CompleterTextEdit::GetCompleter()
{
	return m_completer;
}
void CompleterTextEdit::setCompleter(QCompleter *completer)
{
    m_completer = completer;
    if (m_completer) {
        m_completer->setWidget(this);
        connect(m_completer, SIGNAL(activated(QString)),
                this, SLOT(onCompleterActivated(QString)));
    }
}
void CompleterTextEdit::keyReleaseEvent(QKeyEvent *e) 
{
	QTextEdit::keyReleaseEvent(e);
	if(e->key()==Qt::Key_Comma) {
//		QCoreApplication::postEvent(this, new QKeyEvent(QEvent::KeyPress, Qt::Key_Space, Qt::NoModifier, 0));
		return;
	};
}
void CompleterTextEdit::mousePressEvent(QMouseEvent *e)
{
	QTextCursor cursor = textCursor();
	QString text1=cursor.selectedText();
	cursor.clearSelection();
	if (e->button() == Qt::MiddleButton) {
//		cursor.setPosition(e->pos());
		QMouseEvent ss(e->type(),e->pos(),Qt::LeftButton,e->buttons(),e->modifiers());
		QTextEdit::mousePressEvent(&ss);
		QTextEdit::mouseReleaseEvent(&ss);
		setTextCursor(textCursor());
		if(text1.lastIndexOf(0x2029)>=0) {
			text1.remove(0x2029);
		}
		textCursor().insertText(text1);
	}
	else QTextEdit::mousePressEvent(e);
}
void CompleterTextEdit::keyPressEvent(QKeyEvent *e) {
    if (m_completer) {
        if (m_completer->popup()->isVisible()) {
            switch(e->key()) {
            case Qt::Key_Escape:
            case Qt::Key_Enter:
            case Qt::Key_Return:
            case Qt::Key_Tab:
                e->ignore();
                return;
            default:
                break;
            }
        }
		QTextEdit::keyPressEvent(e);
		if(e->key()==Qt::Key_Comma) {
			this->insertPlainText(" ");
		}
		if(e->key()!=Qt::Key_Comma&&e->key()!=Qt::Key_Space
			&&e->key()!=Qt::Key_Up
			&&e->key()!=Qt::Key_Down
			&&e->key()!=Qt::Key_Left
			&&e->key()!=Qt::Key_Right
			) {
			QString completerPrefix = this->wordUnderCursor();
			m_completer->setCompletionPrefix(completerPrefix); // 通过设置QCompleter的前缀，来让Completer寻找关键词
			m_completer->complete();
		}
    }
	else {
		QTextEdit::keyPressEvent(e);
	}
}

void CompleterTextEdit::onCompleterActivated(const QString &completion) {
    QString completionPrefix = wordUnderCursor(),
            shouldInertText = completion;
    QTextCursor cursor = this->textCursor();
    if (!completion.contains(completionPrefix)) {// delete the previously typed.
        cursor.movePosition(QTextCursor::Left, QTextCursor::KeepAnchor, completionPrefix.size());
        cursor.clearSelection();
    } else { // 补全相应的字符
        shouldInertText = shouldInertText.replace(
            shouldInertText.indexOf(completionPrefix), completionPrefix.size(), "");
    }
    cursor.insertText(shouldInertText);
}

QString CompleterTextEdit::wordUnderCursor() { //不断向左移动cursor，并选中字符，并查看选中的单词中是否含有空格——空格作为单词的分隔符
    QTextCursor cursor = this->textCursor();
	int pos1=cursor.position();
    while (cursor.movePosition(QTextCursor::Left, QTextCursor::KeepAnchor)) {
		int pos2=cursor.position();
		if(pos2-pos1>1) {
			break;
		}
		pos1=pos2;
        if (cursor.selectedText().contains(" ")||cursor.selectedText().contains("\n")||cursor.selectedText().contains(",")||cursor.selectedText().contains("\r")) {
            break;
        }
    }
	QString cs=cursor.selectedText();
	cs=cs.remove(" ");
	cs=cs.remove(",");
	cs=cs.remove("\r");
	cs=cs.remove("\n");
    return cs;
}