# -*- coding: utf-8 -*-
#
# Copyright © Spyder Project Contributors
# Licensed under the terms of the MIT License
# (see spyder/__init__.py for details)

"""
NumPy Array Editor Dialog based on Qt
"""

# pylint: disable=C0103
# pylint: disable=R0903
# pylint: disable=R0911
# pylint: disable=R0201

# Standard library imports
from __future__ import print_function

# Third party imports
import numpy as np
from qtpy.compat import from_qvariant, to_qvariant
from qtpy.QtCore import (QAbstractTableModel, QItemSelection, QLocale,
                         QItemSelectionRange, QModelIndex, Qt, Slot)
from qtpy.QtGui import QColor, QCursor, QDoubleValidator, QKeySequence
from qtpy.QtWidgets import (QAbstractItemDelegate, QApplication, QCheckBox,
                            QComboBox, QDialog, QGridLayout, QHBoxLayout,
                            QInputDialog, QItemDelegate, QLabel, QLineEdit,
                            QMenu, QMessageBox, QPushButton, QSpinBox,
                            QStackedWidget, QTableView, QVBoxLayout,
                            QWidget)
from spyder_kernels.utils.nsview import value_to_display

# Local imports
from spyder.config.base import _
from spyder.config.fonts import DEFAULT_SMALL_DELTA
from spyder.config.gui import get_font
from spyder.config.manager import CONF
from spyder.py3compat import (io, is_binary_string, is_string,
                              is_text_string, PY3, to_binary_string,
                              to_text_string)
from spyder.utils import icon_manager as ima
from spyder.utils.qthelpers import add_actions, create_action, keybinding
from spyder.plugins.variableexplorer.widgets.basedialog import BaseDialog

# Note: string and unicode data types will be formatted with '%s' (see below)
SUPPORTED_FORMATS = {
                     'single': '%.6g',
                     'double': '%.6g',
                     'float_': '%.6g',
                     'longfloat': '%.6g',
                     'float16': '%.6g',
                     'float32': '%.6g',
                     'float64': '%.6g',
                     'float96': '%.6g',
                     'float128': '%.6g',
                     'csingle': '%r',
                     'complex_': '%r',
                     'clongfloat': '%r',
                     'complex64': '%r',
                     'complex128': '%r',
                     'complex192': '%r',
                     'complex256': '%r',
                     'byte': '%d',
                     'bytes8': '%s',
                     'short': '%d',
                     'intc': '%d',
                     'int_': '%d',
                     'longlong': '%d',
                     'intp': '%d',
                     'int8': '%d',
                     'int16': '%d',
                     'int32': '%d',
                     'int64': '%d',
                     'ubyte': '%d',
                     'ushort': '%d',
                     'uintc': '%d',
                     'uint': '%d',
                     'ulonglong': '%d',
                     'uintp': '%d',
                     'uint8': '%d',
                     'uint16': '%d',
                     'uint32': '%d',
                     'uint64': '%d',
                     'bool_': '%r',
                     'bool8': '%r',
                     'bool': '%r',
                     }


LARGE_SIZE = 5e5
LARGE_NROWS = 1e5
LARGE_COLS = 60


#==============================================================================
# Utility functions
#==============================================================================
def is_float(dtype):
    """Return True if datatype dtype is a float kind"""
    return ('float' in dtype.name) or dtype.name in ['single', 'double']


def is_number(dtype):
    """Return True is datatype dtype is a number kind"""
    return is_float(dtype) or ('int' in dtype.name) or ('long' in dtype.name) \
           or ('short' in dtype.name)


def get_idx_rect(index_list):
    """Extract the boundaries from a list of indexes"""
    rows, cols = list(zip(*[(i.row(), i.column()) for i in index_list]))
    return ( min(rows), max(rows), min(cols), max(cols) )


#==============================================================================
# Main classes
#==============================================================================
class ArrayModel(QAbstractTableModel):
    """Array Editor Table Model"""

    ROWS_TO_LOAD = 500
    COLS_TO_LOAD = 40

    def __init__(self, data, format="%.6g", xlabels=None, ylabels=None,
                 readonly=False, parent=None):
        QAbstractTableModel.__init__(self)

        self.dialog = parent
        self.changes = {}
        self.xlabels = xlabels
        self.ylabels = ylabels
        self.readonly = readonly
        self.test_array = np.array([0], dtype=data.dtype)

        # for complex numbers, shading will be based on absolute value
        # but for all other types it will be the real part
        if data.dtype in (np.complex64, np.complex128):
            self.color_func = np.abs
        else:
            self.color_func = np.real

        # Backgroundcolor settings
        huerange = [.66, .99] # Hue
        self.sat = .7 # Saturation
        self.val = 1. # Value
        self.alp = .6 # Alpha-channel

        self._data = data
        self._format = format

        self.total_rows = self._data.shape[0]
        self.total_cols = self._data.shape[1]
        size = self.total_rows * self.total_cols

        try:
            self.vmin = np.nanmin(self.color_func(data))
            self.vmax = np.nanmax(self.color_func(data))
            if self.vmax == self.vmin:
                self.vmin -= 1
            self.hue0 = huerange[0]
            self.dhue = huerange[1]-huerange[0]
            self.bgcolor_enabled = True
        except (AttributeError, TypeError, ValueError):
            self.vmin = None
            self.vmax = None
            self.hue0 = None
            self.dhue = None
            self.bgcolor_enabled = False

        # Array with infinite values cannot display background colors and
        # crashes. See: spyder-ide/spyder#8093
        self.has_inf = False
        if data.dtype.kind in ['f', 'c']:
            self.has_inf = np.any(np.isinf(data))

        # Deactivate coloring for object arrays or arrays with inf values
        if self._data.dtype.name == 'object' or self.has_inf:
            self.bgcolor_enabled = False

        # Use paging when the total size, number of rows or number of
        # columns is too large
        if size > LARGE_SIZE:
            self.rows_loaded = self.ROWS_TO_LOAD
            self.cols_loaded = self.COLS_TO_LOAD
        else:
            if self.total_rows > LARGE_NROWS:
                self.rows_loaded = self.ROWS_TO_LOAD
            else:
                self.rows_loaded = self.total_rows
            if self.total_cols > LARGE_COLS:
                self.cols_loaded = self.COLS_TO_LOAD
            else:
                self.cols_loaded = self.total_cols

    def get_format(self):
        """Return current format"""
        # Avoid accessing the private attribute _format from outside
        return self._format

    def get_data(self):
        """Return data"""
        return self._data

    def set_format(self, format):
        """Change display format"""
        self._format = format
        self.reset()

    def columnCount(self, qindex=QModelIndex()):
        """Array column number"""
        if self.total_cols <= self.cols_loaded:
            return self.total_cols
        else:
            return self.cols_loaded

    def rowCount(self, qindex=QModelIndex()):
        """Array row number"""
        if self.total_rows <= self.rows_loaded:
            return self.total_rows
        else:
            return self.rows_loaded

    def can_fetch_more(self, rows=False, columns=False):
        if rows:
            if self.total_rows > self.rows_loaded:
                return True
            else:
                return False
        if columns:
            if self.total_cols > self.cols_loaded:
                return True
            else:
                return False

    def fetch_more(self, rows=False, columns=False):
        if self.can_fetch_more(rows=rows):
            reminder = self.total_rows - self.rows_loaded
            items_to_fetch = min(reminder, self.ROWS_TO_LOAD)
            self.beginInsertRows(QModelIndex(), self.rows_loaded,
                                 self.rows_loaded + items_to_fetch - 1)
            self.rows_loaded += items_to_fetch
            self.endInsertRows()
        if self.can_fetch_more(columns=columns):
            reminder = self.total_cols - self.cols_loaded
            items_to_fetch = min(reminder, self.COLS_TO_LOAD)
            self.beginInsertColumns(QModelIndex(), self.cols_loaded,
                                    self.cols_loaded + items_to_fetch - 1)
            self.cols_loaded += items_to_fetch
            self.endInsertColumns()

    def bgcolor(self, state):
        """Toggle backgroundcolor"""
        self.bgcolor_enabled = state > 0
        self.reset()

    def get_value(self, index):
        i = index.row()
        j = index.column()
        if len(self._data.shape) == 1:
            value = self._data[j]
        else:
            value = self._data[i, j]
        return self.changes.get((i, j), value)

    def data(self, index, role=Qt.DisplayRole):
        """Cell content."""
        if not index.isValid():
            return to_qvariant()
        value = self.get_value(index)
        dtn = self._data.dtype.name

        # Tranform binary string to unicode so they are displayed
        # correctly
        if is_binary_string(value):
            try:
                value = to_text_string(value, 'utf8')
            except Exception:
                pass

        # Handle roles
        if role == Qt.DisplayRole:
            if value is np.ma.masked:
                return ''
            else:
                if dtn == 'object':
                    # We don't know what's inside an object array, so
                    # we can't trust value repr's here.
                    return value_to_display(value)
                else:
                    try:
                        return to_qvariant(self._format % value)
                    except TypeError:
                        self.readonly = True
                        return repr(value)
        elif role == Qt.TextAlignmentRole:
            return to_qvariant(int(Qt.AlignCenter|Qt.AlignVCenter))
        elif (role == Qt.BackgroundColorRole and self.bgcolor_enabled
                and value is not np.ma.masked and not self.has_inf):
            try:
                hue = (self.hue0 +
                       self.dhue * (float(self.vmax) - self.color_func(value))
                       / (float(self.vmax) - self.vmin))
                hue = float(np.abs(hue))
                color = QColor.fromHsvF(hue, self.sat, self.val, self.alp)
                return to_qvariant(color)
            except (TypeError, ValueError):
                return to_qvariant()
        elif role == Qt.FontRole:
            return to_qvariant(get_font(font_size_delta=DEFAULT_SMALL_DELTA))
        return to_qvariant()

    def setData(self, index, value, role=Qt.EditRole):
        """Cell content change"""
        if not index.isValid() or self.readonly:
            return False
        i = index.row()
        j = index.column()
        value = from_qvariant(value, str)
        dtype = self._data.dtype.name
        if dtype == "bool":
            try:
                val = bool(float(value))
            except ValueError:
                val = value.lower() == "true"
        elif dtype.startswith("string") or dtype.startswith("bytes"):
            val = to_binary_string(value, 'utf8')
        elif dtype.startswith("unicode") or dtype.startswith("str"):
            val = to_text_string(value)
        else:
            if value.lower().startswith('e') or value.lower().endswith('e'):
                return False
            try:
                val = complex(value)
                if not val.imag:
                    val = val.real
            except ValueError as e:
                QMessageBox.critical(self.dialog, "Error",
                                     "Value error: %s" % str(e))
                return False
        try:
            self.test_array[0] = val  # will raise an Exception eventually
        except OverflowError as e:
            print("OverflowError: " + str(e))  # spyder: test-skip
            QMessageBox.critical(self.dialog, "Error",
                                 "Overflow error: %s" % str(e))
            return False

        # Add change to self.changes
        self.changes[(i, j)] = val
        self.dataChanged.emit(index, index)

        if not is_string(val):
            val = self.color_func(val)

            if val > self.vmax:
                self.vmax = val

            if val < self.vmin:
                self.vmin = val

        return True

    def flags(self, index):
        """Set editable flag"""
        if not index.isValid():
            return Qt.ItemIsEnabled
        return Qt.ItemFlags(int(QAbstractTableModel.flags(self, index) |
                                Qt.ItemIsEditable))

    def headerData(self, section, orientation, role=Qt.DisplayRole):
        """Set header data"""
        if role != Qt.DisplayRole:
            return to_qvariant()
        labels = self.xlabels if orientation == Qt.Horizontal else self.ylabels
        if labels is None:
            return to_qvariant(int(section))
        else:
            return to_qvariant(labels[section])

    def reset(self):
        self.beginResetModel()
        self.endResetModel()


class ArrayDelegate(QItemDelegate):
    """Array Editor Item Delegate"""
    def __init__(self, dtype, parent=None):
        QItemDelegate.__init__(self, parent)
        self.dtype = dtype

    def createEditor(self, parent, option, index):
        """Create editor widget"""
        model = index.model()
        value = model.get_value(index)
        if type(value) == np.ndarray or model.readonly:
            # The editor currently cannot properly handle this case
            return
        elif model._data.dtype.name == "bool":
            value = not value
            model.setData(index, to_qvariant(value))
            return
        elif value is not np.ma.masked:
            editor = QLineEdit(parent)
            editor.setFont(get_font(font_size_delta=DEFAULT_SMALL_DELTA))
            editor.setAlignment(Qt.AlignCenter)
            if is_number(self.dtype):
                validator = QDoubleValidator(editor)
                validator.setLocale(QLocale('C'))
                editor.setValidator(validator)
            editor.returnPressed.connect(self.commitAndCloseEditor)
            return editor

    def commitAndCloseEditor(self):
        """Commit and close editor"""
        editor = self.sender()
        # Avoid a segfault with PyQt5. Variable value won't be changed
        # but at least Spyder won't crash. It seems generated by a bug in sip.
        try:
            self.commitData.emit(editor)
        except AttributeError:
            pass
        self.closeEditor.emit(editor, QAbstractItemDelegate.NoHint)

    def setEditorData(self, editor, index):
        """Set editor widget's data"""
        text = from_qvariant(index.model().data(index, Qt.DisplayRole), str)
        editor.setText(text)


#TODO: Implement "Paste" (from clipboard) feature
class ArrayView(QTableView):
    """Array view class"""
    def __init__(self, parent, model, dtype, shape):
        QTableView.__init__(self, parent)

        self.setModel(model)
        self.setItemDelegate(ArrayDelegate(dtype, self))
        total_width = 0
        for k in range(shape[1]):
            total_width += self.columnWidth(k)
        self.viewport().resize(min(total_width, 1024), self.height())
        self.shape = shape
        self.menu = self.setup_menu()
        CONF.config_shortcut(
            self.copy,
            context='variable_explorer',
            name='copy',
            parent=self)
        self.horizontalScrollBar().valueChanged.connect(
            self._load_more_columns)
        self.verticalScrollBar().valueChanged.connect(self._load_more_rows)

    def _load_more_columns(self, value):
        """Load more columns to display."""
        # Needed to avoid a NameError while fetching data when closing
        # See spyder-ide/spyder#12034.
        try:
            self.load_more_data(value, columns=True)
        except NameError:
            pass

    def _load_more_rows(self, value):
        """Load more rows to display."""
        # Needed to avoid a NameError while fetching data when closing
        # See spyder-ide/spyder#12034.
        try:
            self.load_more_data(value, rows=True)
        except NameError:
            pass

    def load_more_data(self, value, rows=False, columns=False):

        try:
            old_selection = self.selectionModel().selection()
            old_rows_loaded = old_cols_loaded = None

            if rows and value == self.verticalScrollBar().maximum():
                old_rows_loaded = self.model().rows_loaded
                self.model().fetch_more(rows=rows)

            if columns and value == self.horizontalScrollBar().maximum():
                old_cols_loaded = self.model().cols_loaded
                self.model().fetch_more(columns=columns)

            if old_rows_loaded is not None or old_cols_loaded is not None:
                # if we've changed anything, update selection
                new_selection = QItemSelection()
                for part in old_selection:
                    top = part.top()
                    bottom = part.bottom()
                    if (old_rows_loaded is not None and
                            top == 0 and bottom == (old_rows_loaded-1)):
                        # complete column selected (so expand it to match
                        # updated range)
                        bottom = self.model().rows_loaded-1
                    left = part.left()
                    right = part.right()
                    if (old_cols_loaded is not None
                            and left == 0 and right == (old_cols_loaded-1)):
                        # compete row selected (so expand it to match updated
                        # range)
                        right = self.model().cols_loaded-1
                    top_left = self.model().index(top, left)
                    bottom_right = self.model().index(bottom, right)
                    part = QItemSelectionRange(top_left, bottom_right)
                    new_selection.append(part)
                self.selectionModel().select
                (new_selection, self.selectionModel().ClearAndSelect)
        except NameError:
            # Needed to handle a NameError while fetching data when closing
            # See isue 7880
            pass

    def resize_to_contents(self):
        """Resize cells to contents"""
        QApplication.setOverrideCursor(QCursor(Qt.WaitCursor))
        self.resizeColumnsToContents()
        self.model().fetch_more(columns=True)
        self.resizeColumnsToContents()
        QApplication.restoreOverrideCursor()

    def setup_menu(self):
        """Setup context menu"""
        self.copy_action = create_action(self, _('Copy'),
                                         shortcut=keybinding('Copy'),
                                         icon=ima.icon('editcopy'),
                                         triggered=self.copy,
                                         context=Qt.WidgetShortcut)
        menu = QMenu(self)
        add_actions(menu, [self.copy_action, ])
        return menu

    def contextMenuEvent(self, event):
        """Reimplement Qt method"""
        self.menu.popup(event.globalPos())
        event.accept()

    def keyPressEvent(self, event):
        """Reimplement Qt method"""
        if event == QKeySequence.Copy:
            self.copy()
        else:
            QTableView.keyPressEvent(self, event)

    def _sel_to_text(self, cell_range):
        """Copy an array portion to a unicode string"""
        if not cell_range:
            return
        row_min, row_max, col_min, col_max = get_idx_rect(cell_range)
        if col_min == 0 and col_max == (self.model().cols_loaded-1):
            # we've selected a whole column. It isn't possible to
            # select only the first part of a column without loading more,
            # so we can treat it as intentional and copy the whole thing
            col_max = self.model().total_cols-1
        if row_min == 0 and row_max == (self.model().rows_loaded-1):
            row_max = self.model().total_rows-1

        _data = self.model().get_data()
        if PY3:
            output = io.BytesIO()
        else:
            output = io.StringIO()
        try:
            np.savetxt(output, _data[row_min:row_max+1, col_min:col_max+1],
                       delimiter='\t', fmt=self.model().get_format())
        except:
            QMessageBox.warning(self, _("Warning"),
                                _("It was not possible to copy values for "
                                  "this array"))
            return
        contents = output.getvalue().decode('utf-8')
        output.close()
        return contents

    @Slot()
    def copy(self):
        """Copy text to clipboard"""
        cliptxt = self._sel_to_text( self.selectedIndexes() )
        clipboard = QApplication.clipboard()
        clipboard.setText(cliptxt)


class ArrayEditorWidget(QWidget):

    def __init__(self, parent, data, readonly=False,
                 xlabels=None, ylabels=None):
        QWidget.__init__(self, parent)
        self.data = data
        self.old_data_shape = None
        if len(self.data.shape) == 1:
            self.old_data_shape = self.data.shape
            self.data.shape = (self.data.shape[0], 1)
        elif len(self.data.shape) == 0:
            self.old_data_shape = self.data.shape
            self.data.shape = (1, 1)

        format = SUPPORTED_FORMATS.get(data.dtype.name, '%s')
        self.model = ArrayModel(self.data, format=format, xlabels=xlabels,
                                ylabels=ylabels, readonly=readonly, parent=self)
        self.view = ArrayView(self, self.model, data.dtype, data.shape)

        btn_layout = QHBoxLayout()
        btn_layout.setAlignment(Qt.AlignLeft)
        btn = QPushButton(_( "Format"))
        # disable format button for int type
        btn.setEnabled(is_float(data.dtype))
        btn_layout.addWidget(btn)
        btn.clicked.connect(self.change_format)
        btn = QPushButton(_( "Resize"))
        btn_layout.addWidget(btn)
        btn.clicked.connect(self.view.resize_to_contents)
        bgcolor = QCheckBox(_( 'Background color'))
        bgcolor.setChecked(self.model.bgcolor_enabled)
        bgcolor.setEnabled(self.model.bgcolor_enabled)
        bgcolor.stateChanged.connect(self.model.bgcolor)
        btn_layout.addWidget(bgcolor)

        layout = QVBoxLayout()
        layout.addWidget(self.view)
        layout.addLayout(btn_layout)
        self.setLayout(layout)

    def accept_changes(self):
        """Accept changes"""
        for (i, j), value in list(self.model.changes.items()):
            self.data[i, j] = value
        if self.old_data_shape is not None:
            self.data.shape = self.old_data_shape

    def reject_changes(self):
        """Reject changes"""
        if self.old_data_shape is not None:
            self.data.shape = self.old_data_shape

    def change_format(self):
        """Change display format"""
        format, valid = QInputDialog.getText(self, _( 'Format'),
                                 _( "Float formatting"),
                                 QLineEdit.Normal, self.model.get_format())
        if valid:
            format = str(format)
            try:
                format % 1.1
            except:
                QMessageBox.critical(self, _("Error"),
                                     _("Format (%s) is incorrect") % format)
                return
            self.model.set_format(format)


class ArrayEditor(BaseDialog):
    """Array Editor Dialog"""
    def __init__(self, parent=None):
        QDialog.__init__(self, parent)

        # Destroying the C++ object right after closing the dialog box,
        # otherwise it may be garbage-collected in another QThread
        # (e.g. the editor's analysis thread in Spyder), thus leading to
        # a segmentation fault on UNIX or an application crash on Windows
        self.setAttribute(Qt.WA_DeleteOnClose)

        self.data = None
        self.arraywidget = None
        self.stack = None
        self.layout = None
        self.btn_save_and_close = None
        self.btn_close = None
        # Values for 3d array editor
        self.dim_indexes = [{}, {}, {}]
        self.last_dim = 0  # Adjust this for changing the startup dimension

    def setup_and_check(self, data, title='', readonly=False,
                        xlabels=None, ylabels=None):
        """
        Setup ArrayEditor:
        return False if data is not supported, True otherwise
        """
        self.data = data
        readonly = readonly or not self.data.flags.writeable
        is_record_array = data.dtype.names is not None
        is_masked_array = isinstance(data, np.ma.MaskedArray)

        if data.ndim > 3:
            self.error(_("Arrays with more than 3 dimensions are not "
                         "supported"))
            return False
        if xlabels is not None and len(xlabels) != self.data.shape[1]:
            self.error(_("The 'xlabels' argument length do no match array "
                         "column number"))
            return False
        if ylabels is not None and len(ylabels) != self.data.shape[0]:
            self.error(_("The 'ylabels' argument length do no match array row "
                         "number"))
            return False
        if not is_record_array:
            dtn = data.dtype.name
            if dtn == 'object':
                # If the array doesn't have shape, we can't display it
                if data.shape == ():
                    self.error(_("Object arrays without shape are not "
                                 "supported"))
                    return False
                # We don't know what's inside these arrays, so we can't handle
                # edits
                self.readonly = readonly = True
            elif (dtn not in SUPPORTED_FORMATS and not dtn.startswith('str')
                    and not dtn.startswith('unicode')):
                arr = _("%s arrays") % data.dtype.name
                self.error(_("%s are currently not supported") % arr)
                return False

        self.layout = QGridLayout()
        self.setLayout(self.layout)
        self.setWindowIcon(ima.icon('arredit'))
        if title:
            title = to_text_string(title) + " - " + _("NumPy object array")
        else:
            title = _("Array editor")
        if readonly:
            title += ' (' + _('read only') + ')'
        self.setWindowTitle(title)

        # Stack widget
        self.stack = QStackedWidget(self)
        if is_record_array:
            for name in data.dtype.names:
                self.stack.addWidget(ArrayEditorWidget(self, data[name],
                                                       readonly, xlabels,
                                                       ylabels))
        elif is_masked_array:
            self.stack.addWidget(ArrayEditorWidget(self, data, readonly,
                                                   xlabels, ylabels))
            self.stack.addWidget(ArrayEditorWidget(self, data.data, readonly,
                                                   xlabels, ylabels))
            self.stack.addWidget(ArrayEditorWidget(self, data.mask, readonly,
                                                   xlabels, ylabels))
        elif data.ndim == 3:
            pass
        else:
            self.stack.addWidget(ArrayEditorWidget(self, data, readonly,
                                                   xlabels, ylabels))
        self.arraywidget = self.stack.currentWidget()
        if self.arraywidget:
            self.arraywidget.model.dataChanged.connect(
                self.save_and_close_enable)
        self.stack.currentChanged.connect(self.current_widget_changed)
        self.layout.addWidget(self.stack, 1, 0)

        # Buttons configuration
        btn_layout = QHBoxLayout()
        if is_record_array or is_masked_array or data.ndim == 3:
            if is_record_array:
                btn_layout.addWidget(QLabel(_("Record array fields:")))
                names = []
                for name in data.dtype.names:
                    field = data.dtype.fields[name]
                    text = name
                    if len(field) >= 3:
                        title = field[2]
                        if not is_text_string(title):
                            title = repr(title)
                        text += ' - '+title
                    names.append(text)
            else:
                names = [_('Masked data'), _('Data'), _('Mask')]
            if data.ndim == 3:
                # QSpinBox
                self.index_spin = QSpinBox(self, keyboardTracking=False)
                self.index_spin.valueChanged.connect(self.change_active_widget)
                # QComboBox
                names = [str(i) for i in range(3)]
                ra_combo = QComboBox(self)
                ra_combo.addItems(names)
                ra_combo.currentIndexChanged.connect(self.current_dim_changed)
                # Adding the widgets to layout
                label = QLabel(_("Axis:"))
                btn_layout.addWidget(label)
                btn_layout.addWidget(ra_combo)
                self.shape_label = QLabel()
                btn_layout.addWidget(self.shape_label)
                label = QLabel(_("Index:"))
                btn_layout.addWidget(label)
                btn_layout.addWidget(self.index_spin)
                self.slicing_label = QLabel()
                btn_layout.addWidget(self.slicing_label)
                # set the widget to display when launched
                self.current_dim_changed(self.last_dim)
            else:
                ra_combo = QComboBox(self)
                ra_combo.currentIndexChanged.connect(self.stack.setCurrentIndex)
                ra_combo.addItems(names)
                btn_layout.addWidget(ra_combo)
            if is_masked_array:
                label = QLabel(_("<u>Warning</u>: changes are applied separately"))
                label.setToolTip(_("For performance reasons, changes applied "\
                                   "to masked array won't be reflected in "\
                                   "array's data (and vice-versa)."))
                btn_layout.addWidget(label)

        btn_layout.addStretch()

        if not readonly:
            self.btn_save_and_close = QPushButton(_('Save and Close'))
            self.btn_save_and_close.setDisabled(True)
            self.btn_save_and_close.clicked.connect(self.accept)
            btn_layout.addWidget(self.btn_save_and_close)

        self.btn_close = QPushButton(_('Close'))
        self.btn_close.setAutoDefault(True)
        self.btn_close.setDefault(True)
        self.btn_close.clicked.connect(self.reject)
        btn_layout.addWidget(self.btn_close)
        self.layout.addLayout(btn_layout, 2, 0)

        self.setMinimumSize(400, 300)

        # Make the dialog act as a window
        self.setWindowFlags(Qt.Window)

        return True

    @Slot(QModelIndex, QModelIndex)
    def save_and_close_enable(self, left_top, bottom_right):
        """Handle the data change event to enable the save and close button."""
        if self.btn_save_and_close:
            self.btn_save_and_close.setEnabled(True)
            self.btn_save_and_close.setAutoDefault(True)
            self.btn_save_and_close.setDefault(True)

    def current_widget_changed(self, index):
        self.arraywidget = self.stack.widget(index)
        self.arraywidget.model.dataChanged.connect(self.save_and_close_enable)

    def change_active_widget(self, index):
        """
        This is implemented for handling negative values in index for
        3d arrays, to give the same behavior as slicing
        """
        string_index = [':']*3
        string_index[self.last_dim] = '<font color=red>%i</font>'
        self.slicing_label.setText((r"Slicing: [" + ", ".join(string_index) +
                                "]") % index)
        if index < 0:
            data_index = self.data.shape[self.last_dim] + index
        else:
            data_index = index
        slice_index = [slice(None)]*3
        slice_index[self.last_dim] = data_index

        stack_index = self.dim_indexes[self.last_dim].get(data_index)
        if stack_index is None:
            stack_index = self.stack.count()
            try:
                self.stack.addWidget(ArrayEditorWidget(
                    self, self.data[tuple(slice_index)]))
            except IndexError:  # Handle arrays of size 0 in one axis
                self.stack.addWidget(ArrayEditorWidget(self, self.data))
            self.dim_indexes[self.last_dim][data_index] = stack_index
            self.stack.update()
        self.stack.setCurrentIndex(stack_index)

    def current_dim_changed(self, index):
        """
        This change the active axis the array editor is plotting over
        in 3D
        """
        self.last_dim = index
        string_size = ['%i']*3
        string_size[index] = '<font color=red>%i</font>'
        self.shape_label.setText(('Shape: (' + ', '.join(string_size) +
                                 ')    ') % self.data.shape)
        if self.index_spin.value() != 0:
            self.index_spin.setValue(0)
        else:
            # this is done since if the value is currently 0 it does not emit
            # currentIndexChanged(int)
            self.change_active_widget(0)
        self.index_spin.setRange(-self.data.shape[index],
                                 self.data.shape[index]-1)

    @Slot()
    def accept(self):
        """Reimplement Qt method."""
        try:
            for index in range(self.stack.count()):
                self.stack.widget(index).accept_changes()
            QDialog.accept(self)
        except RuntimeError:
            # Sometimes under CI testing the object the following error appears
            # RuntimeError: wrapped C/C++ object has been deleted
            pass

    def get_value(self):
        """Return modified array -- this is *not* a copy"""
        # It is important to avoid accessing Qt C++ object as it has probably
        # already been destroyed, due to the Qt.WA_DeleteOnClose attribute
        return self.data

    def error(self, message):
        """An error occurred, closing the dialog box"""
        QMessageBox.critical(self, _("Array editor"), message)
        self.setAttribute(Qt.WA_DeleteOnClose)
        self.reject()

    @Slot()
    def reject(self):
        """Reimplement Qt method"""
        if self.arraywidget is not None:
            for index in range(self.stack.count()):
                self.stack.widget(index).reject_changes()
        QDialog.reject(self)
