# (C) Copyright 2008-2021 Enthought, Inc., Austin, TX
# All rights reserved.
#
# This software is provided without warranty under the terms of the BSD
# license included in LICENSE.txt and may be redistributed only under
# the conditions described in the aforementioned license. The license
# is also available online at http://www.enthought.com/licenses/BSD.txt
#
# Thanks for using Enthought open source!

# ------------------------------------------------------------------------------
# Copyright (c) 2007, Riverbank Computing Limited
# All rights reserved.
#
# This software is provided without warranty under the terms of the BSD license.
# However, when used with the GPL version of PyQt the additional terms
# described in the PyQt GPL exception also apply

#
# Author: Riverbank Computing Limited
# ------------------------------------------------------------------------------

""" Defines a source code editor and code editor factory, for the PyQt user
interface toolkit, useful for tools such as debuggers.
"""


from pyface.qt import QtCore, QtGui

from pyface.ui.qt4.code_editor.code_widget import AdvancedCodeWidget
from traits.api import (
    Str,
    List,
    Int,
    Event,
    Bool,
    TraitError,
    observe,
)
from traits.trait_base import SequenceTypes

from pyface.key_pressed_event import KeyPressedEvent

from .constants import OKColor, ErrorColor
from .editor import Editor
from .helper import pixmap_cache



# Marker line constants:
MARK_MARKER = 0  # Marks a marked line
SEARCH_MARKER = 1  # Marks a line matching the current search
SELECTED_MARKER = 2  # Marks the currently selected line


class SourceEditor(Editor):
    """ Editor for source code which uses the advanced code widget.
    """

    # -------------------------------------------------------------------------
    #  Pyface PythonEditor interface:
    # -------------------------------------------------------------------------

    #: Event that is fired on keypresses:
    key_pressed = Event(KeyPressedEvent)

    # -------------------------------------------------------------------------
    #  Editor interface:
    # -------------------------------------------------------------------------

    #: The code editor is scrollable. This value overrides the default.
    scrollable = True

    # -------------------------------------------------------------------------
    #  SoureEditor interface:
    # -------------------------------------------------------------------------

    #: Is the editor read only?
    readonly = Bool(False)

    #: The currently selected line
    selected_line = Int()

    #: The start position of the selected
    selected_start_pos = Int()

    #: The end position of the selected
    selected_end_pos = Int()

    #: The currently selected text
    selected_text = Str()

    #: The list of line numbers to mark
    mark_lines = List(Int)

    #: The current line number
    line = Event()

    #: The current column
    column = Event()

    #: The lines to be dimmed
    dim_lines = List(Int)
    dim_color = Str()
    dim_style_number = Int(16)  # 0-15 are reserved for the python lexer

    #: The lines to have squiggles drawn under them
    squiggle_lines = List(Int)
    squiggle_color = Str()

    #: The lexer to use.
    lexer = Str()

    # -------------------------------------------------------------------------
    #  Finishes initializing the editor by creating the underlying toolkit
    #  widget:
    # -------------------------------------------------------------------------
    def init(self, parent):
        """ Finishes initializing the editor by creating the underlying toolkit
            widget.
        """
        self.control = QtGui.QWidget()
        layout = QtGui.QVBoxLayout(self.control)
        layout.setContentsMargins(0, 0, 0, 0)

        self._widget = control = AdvancedCodeWidget(
            None, lexer=self.factory.lexer
        )
        layout.addWidget(control)

        factory = self.factory

        # Set up listeners for the signals we care about
        code_editor = self._widget.code

        if self.readonly:
            code_editor.setReadOnly(True)
        else:
            if factory.auto_set:
                code_editor.textChanged.connect(self.update_object)
            else:
                code_editor.focus_lost.connect(self.update_object)

        if factory.selected_text != "":
            code_editor.selectionChanged.connect(self._selection_changed)
        if (factory.line != "") or (factory.column != ""):
            code_editor.cursorPositionChanged.connect(self._position_changed)

        code_editor.line_number_widget.setVisible(factory.show_line_numbers)

        # Make sure the editor has been initialized:
        self.update_editor()

        # Set up any event listeners:
        self.sync_value(factory.mark_lines, "mark_lines", "from", is_list=True)
        self.sync_value(factory.selected_line, "selected_line", "from")
        self.sync_value(factory.selected_text, "selected_text", "to")
        self.sync_value(factory.line, "line")
        self.sync_value(factory.column, "column")

        self.sync_value(factory.selected_start_pos, "selected_start_pos", "to")
        self.sync_value(factory.selected_end_pos, "selected_end_pos", "to")

        self.sync_value(factory.dim_lines, "dim_lines", "from", is_list=True)
        if self.factory.dim_color == "":
            self.dim_color = "grey"
        else:
            self.sync_value(factory.dim_color, "dim_color", "from")

        self.sync_value(
            factory.squiggle_lines, "squiggle_lines", "from", is_list=True
        )
        if factory.squiggle_color == "":
            self.squiggle_color = "red"
        else:
            self.sync_value(factory.squiggle_color, "squiggle_color", "from")

        # Set the control tooltip:
        self.set_tooltip()

    def dispose(self):
        """ Disposes of the contents of an editor.
        """
        # Make sure that the editor does not try to update as the control is
        # being destroyed:
        if not self.factory.auto_set:
            self._widget.code.focus_lost.disconnect(self.update_object)

        super().dispose()

    def update_object(self):
        """ Handles the user entering input data in the edit control.
        """
        if not self._locked:
            try:
                value = str(self._widget.code.toPlainText())
                if isinstance(self.value, SequenceTypes):
                    value = value.split()
                self.value = value
            except TraitError as excp:
                pass

    def update_editor(self):
        """ Updates the editor when the object trait changes externally to the
            editor.
        """
        self._locked = True
        new_value = self.value
        if isinstance(new_value, SequenceTypes):
            new_value = "\n".join([line.rstrip() for line in new_value])
        control = self._widget
        if control.code.toPlainText() != new_value:
            control.code.setPlainText(new_value)

            if self.factory.selected_line:
                # TODO: update the factory selected line
                pass

            # TODO: put the cursor somewhere

        self._locked = False

    def error(self, excp):
        """ Handles an error that occurs while setting the object's trait value.
        """
        pass

    # -- UI preference save/restore interface ---------------------------------

    def restore_prefs(self, prefs):
        """ Restores any saved user preference information associated with the
            editor.
        """
        if self.factory.key_bindings is not None:
            key_bindings = prefs.get("key_bindings")
            if key_bindings is not None:
                self.factory.key_bindings.merge(key_bindings)

    def save_prefs(self):
        """ Returns any user preference information associated with the editor.
        """
        return {"key_bindings": self.factory.key_bindings}

    def _mark_lines_changed(self):
        """ Handles the set of marked lines being changed.
        """
        # FIXME: Not implemented at this time.
        return

    def _mark_lines_items_changed(self):
        self._mark_lines_changed()

    def _selection_changed(self):
        self.selected_text = str(
            self._widget.code.textCursor().selectedText()
        )
        start = self._widget.code.textCursor().selectionStart()
        end = self._widget.code.textCursor().selectionEnd()

        if start > end:
            start, end = end, start

        self.selected_start_pos = start
        self.selected_end_pos = end

    def _selected_line_changed(self):
        """ Handles a change in which line is currently selected.
        """
        control = self._widget
        line = max(1, min(control.lines(), self.selected_line))
        _, column = control.get_line_column()
        control.set_line_column(line, column)
        if self.factory.auto_scroll:
            control.centerCursor()

    def _line_changed(self, line):
        if not self._locked:
            _, column = self._widget.get_line_column()
            self._widget.set_line_column(line, column)
            if self.factory.auto_scroll:
                self._widget.centerCursor()

    def _column_changed(self, column):
        if not self._locked:
            line, _ = self._widget.get_line_column()
            self._widget.set_line_column(line, column)

    def _position_changed(self):
        """ Handles the cursor position being changed.
        """
        control = self._widget
        self._locked = True
        self.line, self.column = control.get_line_column()
        self._locked = False
        self.selected_text = control.get_selected_text()
        if self.factory.auto_scroll:
            self._widget.centerCursor()

    def _key_pressed_changed(self, event):
        """ Handles a key being pressed within the editor.
        """
        key_bindings = self.factory.key_bindings
        if key_bindings:
            processed = key_bindings.do(
                event.event, self.ui.handler, self.ui.info
            )
        else:
            processed = False
        if not processed and event.event.matches(QtGui.QKeySequence.Find):
            self._find_widget.show()

    def _dim_color_changed(self):
        pass

    def _squiggle_color_changed(self):
        pass

    @observe("dim_lines, squiggle_lines")
    def _style_document(self, event):
        self._widget.set_warn_lines(self.squiggle_lines)


# Define the simple, custom, text and readonly editors, which will be accessed
# by the editor factory for code editors.

CustomEditor = SimpleEditor = TextEditor = SourceEditor


class ReadonlyEditor(SourceEditor):

    # Set the value of the readonly trait.
    readonly = True