#include "qmlcodecompletion.h"
#include "qmleditor.h"
#include "qmlmodelmanagerinterface.h"
#include "qmlexpressionundercursor.h"
#include "qmllookupcontext.h"
#include "qmlresolveexpression.h"
#include "qmlsymbol.h"

#include <texteditor/basetexteditor.h>
#include <QtDebug>

using namespace QmlEditor::Internal;

QmlCodeCompletion::QmlCodeCompletion(QmlModelManagerInterface *modelManager,QObject *parent)
    : TextEditor::ICompletionCollector(parent),
      m_modelManager(modelManager),
      m_editor(0),
      m_startPosition(0),
      m_caseSensitivity(Qt::CaseSensitive)
{
    Q_ASSERT(modelManager);
}

QmlCodeCompletion::~QmlCodeCompletion()
{ }

Qt::CaseSensitivity QmlCodeCompletion::caseSensitivity() const
{ return m_caseSensitivity; }

void QmlCodeCompletion::setCaseSensitivity(Qt::CaseSensitivity caseSensitivity)
{ m_caseSensitivity = caseSensitivity; }

bool QmlCodeCompletion::supportsEditor(TextEditor::ITextEditable *editor)
{
    if (qobject_cast<ScriptEditor *>(editor->widget()))
        return true;

    return false;
}

bool QmlCodeCompletion::triggersCompletion(TextEditor::ITextEditable *)
{ return false; }

int QmlCodeCompletion::startCompletion(TextEditor::ITextEditable *editor)
{
    m_editor = editor;

    ScriptEditor *edit = qobject_cast<ScriptEditor *>(m_editor->widget());
    if (! edit)
        return -1;

    int pos = editor->position();

    while (editor->characterAt(pos - 1).isLetterOrNumber() || editor->characterAt(pos - 1) == QLatin1Char('_'))
        --pos;

    m_startPosition = pos;
    m_completions.clear();

//    foreach (const QString &word, edit->keywords()) {
//        TextEditor::CompletionItem item(this);
//        item.m_text = word;
//        m_completions.append(item);
//    }
//
//    foreach (const QString &word, edit->words()) {
//        TextEditor::CompletionItem item(this);
//        item.m_text = word;
//        m_completions.append(item);
//    }

    QmlDocument::Ptr qmlDocument = edit->qmlDocument();
    qDebug() << "*** document:" << qmlDocument;
    if (qmlDocument.isNull())
        return pos;

    if (!qmlDocument->program())
        qmlDocument = m_modelManager->snapshot().value(qmlDocument->fileName());

    if (qmlDocument->program()) {
         QmlJS::AST::UiProgram *program = qmlDocument->program();
        qDebug() << "*** program:" << program;
 
         if (program) {
            QmlExpressionUnderCursor expressionUnderCursor;
            QTextCursor cursor(edit->document());
            cursor.setPosition(pos);
            expressionUnderCursor(cursor, qmlDocument);

            QmlLookupContext context(expressionUnderCursor.expressionScopes(), qmlDocument, m_modelManager->snapshot());
            QmlResolveExpression resolver(context);
            QList<QmlSymbol*> symbols = resolver.visibleSymbols(expressionUnderCursor.expressionNode());

            foreach (QmlSymbol *symbol, symbols) {
                QString word;

                if (symbol->isIdSymbol()) {
                    word = symbol->asIdSymbol()->id();
                } else {
                    word = symbol->name();
                }

                if (word.isEmpty())
                    continue;
 
                TextEditor::CompletionItem item(this);
                item.m_text = word;
                m_completions.append(item);
            }
        }
    }

    return pos;
}

void QmlCodeCompletion::completions(QList<TextEditor::CompletionItem> *completions)
{
    // ### FIXME: this code needs to be generalized.

    const int length = m_editor->position() - m_startPosition;

    if (length == 0)
        *completions = m_completions;
    else if (length > 0) {
        const QString key = m_editor->textAt(m_startPosition, length);

        /*
         * This code builds a regular expression in order to more intelligently match
         * camel-case style. This means upper-case characters will be rewritten as follows:
         *
         *   A => [a-z0-9_]*A (for any but the first capital letter)
         *
         * Meaning it allows any sequence of lower-case characters to preceed an
         * upper-case character. So for example gAC matches getActionController.
         */
        QString keyRegExp;
        keyRegExp += QLatin1Char('^');
        bool first = true;
        foreach (const QChar &c, key) {
            if (c.isUpper() && !first) {
                keyRegExp += QLatin1String("[a-z0-9_]*");
                keyRegExp += c;
            } else if (m_caseSensitivity == Qt::CaseInsensitive && c.isLower()) {
                keyRegExp += QLatin1Char('[');
                keyRegExp += c;
                keyRegExp += c.toUpper();
                keyRegExp += QLatin1Char(']');
            } else {
                keyRegExp += QRegExp::escape(c);
            }
            first = false;
        }
        const QRegExp regExp(keyRegExp, Qt::CaseSensitive);

        foreach (TextEditor::CompletionItem item, m_completions) {
            if (regExp.indexIn(item.m_text) == 0) {
                item.m_relevance = (key.length() > 0 &&
                                    item.m_text.startsWith(key, Qt::CaseInsensitive)) ? 1 : 0;
                (*completions) << item;
            }
        }
    }
}

void QmlCodeCompletion::complete(const TextEditor::CompletionItem &item)
{
    const QString toInsert = item.m_text;
    const int length = m_editor->position() - m_startPosition;
    m_editor->setCurPos(m_startPosition);
    m_editor->replace(length, toInsert);
}

bool QmlCodeCompletion::partiallyComplete(const QList<TextEditor::CompletionItem> &completionItems)
{
    if (completionItems.count() == 1) {
        complete(completionItems.first());
        return true;
    } else {
        // Compute common prefix
        QString firstKey = completionItems.first().m_text;
        QString lastKey = completionItems.last().m_text;
        const int length = qMin(firstKey.length(), lastKey.length());
        firstKey.truncate(length);
        lastKey.truncate(length);

        while (firstKey != lastKey) {
            firstKey.chop(1);
            lastKey.chop(1);
        }

        int typedLength = m_editor->position() - m_startPosition;
        if (!firstKey.isEmpty() && firstKey.length() > typedLength) {
            m_editor->setCurPos(m_startPosition);
            m_editor->replace(typedLength, firstKey);
        }
    }
    return false;
}

void QmlCodeCompletion::cleanup()
{
    m_editor = 0;
    m_startPosition = 0;
    m_completions.clear();
}