// Copyright (C) 2023 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0

#include "copilotsuggestion.h"

#include <texteditor/texteditor.h>

#include <utils/stringutils.h>

using namespace Utils;
using namespace TextEditor;
using namespace LanguageServerProtocol;

namespace Copilot::Internal {

CopilotSuggestion::CopilotSuggestion(const QList<Completion> &completions,
                                     QTextDocument *origin,
                                     int currentCompletion)
    : m_completions(completions)
    , m_currentCompletion(currentCompletion)
{
    const Completion completion = completions.value(currentCompletion);
    const Position start = completion.range().start();
    const Position end = completion.range().end();
    QString text = start.toTextCursor(origin).block().text();
    int length = text.length() - start.character();
    if (start.line() == end.line())
        length = end.character() - start.character();
    text.replace(start.character(), length, completion.text());
    document()->setPlainText(text);
    m_start = completion.position().toTextCursor(origin);
    m_start.setKeepPositionOnInsert(true);
}

bool CopilotSuggestion::apply()
{
    reset();
    const Completion completion = m_completions.value(m_currentCompletion);
    QTextCursor cursor = completion.range().toSelection(m_start.document());
    cursor.insertText(completion.text());
    return true;
}

bool CopilotSuggestion::applyWord(TextEditorWidget *widget)
{
    return applyPart(Word, widget);
}

bool CopilotSuggestion::applyLine(TextEditor::TextEditorWidget *widget)
{
    return applyPart(Line, widget);
}

void CopilotSuggestion::reset()
{
    m_start.removeSelectedText();
}

int CopilotSuggestion::position()
{
    return m_start.selectionEnd();
}

bool CopilotSuggestion::applyPart(Part part, TextEditor::TextEditorWidget *widget)
{
    Completion completion = m_completions.value(m_currentCompletion);
    const Range range = completion.range();
    const QTextCursor cursor = range.toSelection(m_start.document());
    QTextCursor currentCursor = widget->textCursor();
    const QString text = completion.text();
    const int startPos = currentCursor.positionInBlock() - cursor.positionInBlock()
                         + (cursor.selectionEnd() - cursor.selectionStart());
    int next = part == Word ? endOfNextWord(text, startPos) : text.indexOf('\n', startPos);

    if (next == -1)
        return apply();

    if (part == Line)
        ++next;
    QString subText = text.mid(startPos, next - startPos);
    if (subText.isEmpty())
        return false;

    currentCursor.insertText(subText);
    if (const int seperatorPos = subText.lastIndexOf('\n'); seperatorPos >= 0) {
        const QString newCompletionText = text.mid(startPos + seperatorPos + 1);
        if (!newCompletionText.isEmpty()) {
            completion.setText(newCompletionText);
            const Position newStart(range.start().line() + subText.count('\n'), 0);
            int nextSeperatorPos = newCompletionText.indexOf('\n');
            if (nextSeperatorPos == -1)
                nextSeperatorPos = newCompletionText.size();
            const Position newEnd(newStart.line(), nextSeperatorPos);
            completion.setRange(Range(newStart, newEnd));
            completion.setPosition(newStart);
            widget->insertSuggestion(std::make_unique<CopilotSuggestion>(
                QList<Completion>{completion}, widget->document(), 0));
        }
    }
    return false;
}

} // namespace Copilot::Internal