src/eric7/EricWidgets/EricModelMenu.py

# -*- coding: utf-8 -*-

# Copyright (c) 2009 - 2022 Detlev Offenbach <detlev@die-offenbachs.de>
#

"""
Module implementing a menu populated from a QAbstractItemModel.
"""

from PyQt6.QtCore import QModelIndex, QPoint, Qt, pyqtSignal
from PyQt6.QtGui import QAction, QDrag, QFontMetrics
from PyQt6.QtWidgets import QApplication, QMenu

from eric7.EricGui import EricPixmapCache


class EricModelMenu(QMenu):
    """
    Class implementing a menu populated from a QAbstractItemModel.

    @signal activated(QModelIndex) emitted when an action has been triggered
    """

    activated = pyqtSignal(QModelIndex)

    def __init__(self, parent=None):
        """
        Constructor

        @param parent reference to the parent widget (QWidget)
        """
        super().__init__(parent)

        self.__maxRows = -1
        self.__firstSeparator = -1
        self.__maxWidth = -1
        self.__statusBarTextRole = 0
        self.__separatorRole = 0
        self.__model = None
        self.__root = QModelIndex()
        self.__dragStartPosition = QPoint()

        self.setAcceptDrops(True)

        self._mouseButton = Qt.MouseButton.NoButton
        self._keyboardModifiers = Qt.KeyboardModifier.NoModifier
        self.__dropRow = -1
        self.__dropIndex = None

        self.menuActions = []

        # This is to ensure it will be shown on Mac OS X
        self.addAction("--not populated--")

        self.aboutToShow.connect(self.__aboutToShow)
        self.triggered.connect(self.__actionTriggered)

    def clear(self):
        """
        Public method to clear the menu.
        """
        super().clear()
        self.menuActions.clear()

    def prePopulated(self):
        """
        Public method to add any actions before the tree.

        @return flag indicating if any actions were added
        """
        return False

    def postPopulated(self):
        """
        Public method to add any actions after the tree.
        """
        pass

    def setModel(self, model):
        """
        Public method to set the model for the menu.

        @param model reference to the model (QAbstractItemModel)
        """
        self.__model = model

    def model(self):
        """
        Public method to get a reference to the model.

        @return reference to the model (QAbstractItemModel)
        """
        return self.__model

    def setMaxRows(self, rows):
        """
        Public method to set the maximum number of entries to show.

        @param rows maximum number of entries to show (integer)
        """
        self.__maxRows = rows

    def maxRows(self):
        """
        Public method to get the maximum number of entries to show.

        @return maximum number of entries to show (integer)
        """
        return self.__maxRows

    def setFirstSeparator(self, offset):
        """
        Public method to set the first separator.

        @param offset row number of the first separator (integer)
        """
        self.__firstSeparator = offset

    def firstSeparator(self):
        """
        Public method to get the first separator.

        @return row number of the first separator (integer)
        """
        return self.__firstSeparator

    def setRootIndex(self, index):
        """
        Public method to set the index of the root item.

        @param index index of the root item (QModelIndex)
        """
        self.__root = index

    def rootIndex(self):
        """
        Public method to get the index of the root item.

        @return index of the root item (QModelIndex)
        """
        return self.__root

    def setStatusBarTextRole(self, role):
        """
        Public method to set the role of the status bar text.

        @param role role of the status bar text (integer)
        """
        self.__statusBarTextRole = role

    def statusBarTextRole(self):
        """
        Public method to get the role of the status bar text.

        @return role of the status bar text (integer)
        """
        return self.__statusBarTextRole

    def setSeparatorRole(self, role):
        """
        Public method to set the role of the separator.

        @param role role of the separator (integer)
        """
        self.__separatorRole = role

    def separatorRole(self):
        """
        Public method to get the role of the separator.

        @return role of the separator (integer)
        """
        return self.__separatorRole

    def __aboutToShow(self):
        """
        Private slot to show the menu.
        """
        self.clear()

        if self.prePopulated():
            self.addSeparator()
        max_ = self.__maxRows
        if max_ != -1:
            max_ += self.__firstSeparator
        self.createMenu(self.__root, max_, self, self)
        self.postPopulated()

    def createBaseMenu(self):
        """
        Public method to get the menu that is used to populate sub menu's.

        @return reference to the menu (EricModelMenu)
        """
        return EricModelMenu(self)

    def createMenu(self, parent, max_, parentMenu=None, menu=None):
        """
        Public method to put all the children of a parent into a menu of a
        given length.

        @param parent index of the parent item (QModelIndex)
        @param max_ maximum number of entries (integer)
        @param parentMenu reference to the parent menu (QMenu)
        @param menu reference to the menu to be populated (QMenu)
        """
        if menu is None:
            v = parent

            title = parent.data()
            modelMenu = self.createBaseMenu()
            # triggered goes all the way up the menu structure
            modelMenu.triggered.disconnect(modelMenu.__actionTriggered)
            modelMenu.setTitle(title)

            icon = parent.data(Qt.ItemDataRole.DecorationRole)
            if icon == NotImplemented or icon is None:
                icon = EricPixmapCache.getIcon("defaultIcon")
            modelMenu.setIcon(icon)
            if parentMenu is not None:
                self.menuActions.append(parentMenu.addMenu(modelMenu).setData(v))
            modelMenu.setRootIndex(parent)
            modelMenu.setModel(self.__model)
            return

        if self.__model is None:
            return

        end = self.__model.rowCount(parent)
        if max_ != -1:
            end = min(max_, end)

        for i in range(end):
            idx = self.__model.index(i, 0, parent)
            if self.__model.hasChildren(idx):
                self.createMenu(idx, -1, menu)
            else:
                if self.__separatorRole != 0 and idx.data(self.__separatorRole):
                    self.addSeparator()
                else:
                    menu.addAction(self.__makeAction(idx))

            if menu == self and i == self.__firstSeparator - 1:
                self.addSeparator()

    def __makeAction(self, idx):
        """
        Private method to create an action.

        @param idx index of the item to create an action for (QModelIndex)
        @return reference to the created action (QAction)
        """
        icon = idx.data(Qt.ItemDataRole.DecorationRole)
        if icon == NotImplemented or icon is None:
            icon = EricPixmapCache.getIcon("defaultIcon")
        action = self.makeAction(icon, idx.data(), self)
        action.setStatusTip(idx.data(self.__statusBarTextRole))

        v = idx
        action.setData(v)

        return action

    def makeAction(self, icon, text, parent):
        """
        Public method to create an action.

        @param icon icon of the action (QIcon)
        @param text text of the action (string)
        @param parent reference to the parent object (QObject)
        @return reference to the created action (QAction)
        """
        fm = QFontMetrics(self.font())
        if self.__maxWidth == -1:
            try:
                self.__maxWidth = fm.horizontalAdvance("m") * 30
            except AttributeError:
                self.__maxWidth = fm.width("m") * 30
        smallText = fm.elidedText(text, Qt.TextElideMode.ElideMiddle, self.__maxWidth)

        return QAction(icon, smallText, parent)

    def __actionTriggered(self, action):
        """
        Private slot to handle the triggering of an action.

        @param action reference to the action that was triggered (QAction)
        """
        idx = self.index(action)
        if idx.isValid():
            self._keyboardModifiers = QApplication.keyboardModifiers()
            self.activated[QModelIndex].emit(idx)

    def index(self, action):
        """
        Public method to get the index of an action.

        @param action reference to the action to get the index for (QAction)
        @return index of the action (QModelIndex)
        """
        if action is None:
            return QModelIndex()

        idx = action.data()
        if idx is None:
            return QModelIndex()

        if not isinstance(idx, QModelIndex):
            return QModelIndex()

        return idx

    def dragEnterEvent(self, evt):
        """
        Protected method to handle drag enter events.

        @param evt reference to the event (QDragEnterEvent)
        """
        if self.__model is not None:
            mimeTypes = self.__model.mimeTypes()
            for mimeType in mimeTypes:
                if evt.mimeData().hasFormat(mimeType):
                    evt.acceptProposedAction()

        super().dragEnterEvent(evt)

    def dropEvent(self, evt):
        """
        Protected method to handle drop events.

        @param evt reference to the event (QDropEvent)
        """
        if self.__model is not None:
            act = self.actionAt(evt.position().toPoint())
            parentIndex = self.__root
            if act is None:
                row = self.__model.rowCount(self.__root)
            else:
                idx = self.index(act)
                if not idx.isValid():
                    super().dropEvent(evt)
                    return

                row = idx.row()
                if self.__model.hasChildren(idx):
                    parentIndex = idx
                    row = self.__model.rowCount(idx)

            self.__dropRow = row
            self.__dropIndex = parentIndex
            evt.acceptProposedAction()
            self.__model.dropMimeData(
                evt.mimeData(), evt.dropAction(), row, 0, parentIndex
            )
            self.close()

        super().dropEvent(evt)

    def mousePressEvent(self, evt):
        """
        Protected method handling mouse press events.

        @param evt reference to the event object (QMouseEvent)
        """
        if evt.button() == Qt.MouseButton.LeftButton:
            self.__dragStartPosition = evt.position().toPoint()
        super().mousePressEvent(evt)

    def mouseMoveEvent(self, evt):
        """
        Protected method to handle mouse move events.

        @param evt reference to the event (QMouseEvent)
        """
        if self.__model is None:
            super().mouseMoveEvent(evt)
            return

        if not (evt.buttons() & Qt.MouseButton.LeftButton):
            super().mouseMoveEvent(evt)
            return

        if self.__dragStartPosition.isNull():
            super().mouseMoveEvent(evt)
            return

        manhattanLength = (
            evt.position().toPoint() - self.__dragStartPosition
        ).manhattanLength()
        if manhattanLength <= QApplication.startDragDistance():
            super().mouseMoveEvent(evt)
            return

        act = self.actionAt(self.__dragStartPosition)
        if act is None:
            super().mouseMoveEvent(evt)
            return

        idx = self.index(act)
        if not idx.isValid():
            super().mouseMoveEvent(evt)
            return

        drag = QDrag(self)
        drag.setMimeData(self.__model.mimeData([idx]))
        actionRect = self.actionGeometry(act)
        drag.setPixmap(self.grab(actionRect))

        if drag.exec() == Qt.DropAction.MoveAction:
            row = idx.row()
            if self.__dropIndex == idx.parent() and self.__dropRow <= row:
                row += 1
            self.__model.removeRow(row, self.__root)

            if not self.isAncestorOf(drag.target()):
                self.close()
            else:
                self.aboutToShow.emit()

    def mouseReleaseEvent(self, evt):
        """
        Protected method handling mouse release events.

        @param evt reference to the event object (QMouseEvent)
        """
        self._mouseButton = evt.button()
        self._keyboardModifiers = evt.modifiers()

        if evt.button() == Qt.MouseButton.LeftButton:
            self.__dragStartPosition = QPoint()

        super().mouseReleaseEvent(evt)

    def resetFlags(self):
        """
        Public method to reset the saved internal state.
        """
        self._mouseButton = Qt.MouseButton.NoButton
        self._keyboardModifiers = Qt.KeyboardModifier.NoModifier

    def removeEntry(self, idx):
        """
        Public method to remove a menu entry.

        @param idx index of the entry to be removed (QModelIndex)
        """
        row = idx.row()
        self.__model.removeRow(row, self.__root)
        self.aboutToShow.emit()