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

import re

from thonny import get_runner, get_workbench, ui_utils
from thonny.codeview import CodeViewText

cell_regex = re.compile(r"(^|\n)(# ?%%|##|# In\[\d+\]:)[^\n]*", re.MULTILINE)  # @UndefinedVariable


def update_editor_cells(event):
    text = event.widget

    if not getattr(text, "cell_tags_configured", False):
        text.tag_configure("CURRENT_CELL", borderwidth=1, relief="groove", background="LightYellow")
        text.tag_configure("CELL_HEADER", font="BoldEditorFont", foreground="#665843")

        text.tag_lower("CELL_HEADER")
        text.tag_lower("CURRENT_CELL")
        text.cell_tags_configured = True

    text.tag_remove("CURRENT_CELL", "0.1", "end")
    text.tag_remove("CELL_HEADER", "0.1", "end")
    source = text.get("1.0", "end")
    cells = []
    prev_marker = 0
    for match in cell_regex.finditer(source):
        if match.start() == 0:
            this_marker = match.start()
        else:
            this_marker = match.start() + 1

        cell_start_index = text.index("1.0+%dc" % prev_marker)
        header_end_index = text.index("1.0+%dc" % match.end())
        cell_end_index = text.index("1.0+%dc" % this_marker)
        text.tag_add("CELL_HEADER", cell_end_index, header_end_index)
        cells.append((cell_start_index, cell_end_index))

        prev_marker = this_marker

    if prev_marker != 0:
        cells.append((text.index("1.0+%dc" % prev_marker), "end"))

    # if get_workbench().focus_get() == text:
    # It's nice to have cell highlighted even when focus
    # is elsewhere ? This would act as kind of bookmark.

    for start_index, end_index in cells:
        if text.compare(start_index, "<=", "insert") and text.compare(end_index, ">", "insert"):
            text.tag_add("CURRENT_CELL", start_index, end_index)
            break


def _submit_code(code):
    lines = code.splitlines()

    # remove starting comments
    while len(lines) > 0 and lines[0].strip().startswith("#"):
        lines = lines[1:]

    # remove starting empty lines
    while len(lines) > 0 and lines[0].strip() == "":
        lines = lines[1:]

    # remove trailing empty lines
    while len(lines) > 0 and lines[-1].strip() == "":
        lines = lines[:-1]

    if len(lines) > 0:
        code = "\n".join(lines) + "\n"
        # if code is function definition/last line start with whitespace
        # end function definition with a second endline
        if re.match(r"^[ \t].*", lines[-1]) is not None:
            code += "\n"
        shell = get_workbench().show_view("ShellView", False)
        shell.submit_python_code(code)


def _patch_perform_return():
    original_perform_return = CodeViewText.perform_return

    def _patched_perform_return(self, event):
        text = event.widget
        ranges = text.tag_ranges("CURRENT_CELL")

        if len(ranges) == 2 and (
            ui_utils.shift_is_pressed(event.state) or ui_utils.control_is_pressed(event.state)
        ):

            if run_enabled():
                code = text.get(ranges[0], ranges[1]).strip()
                _submit_code(code)

                if ui_utils.shift_is_pressed(event.state):
                    # advance to next cell
                    text.mark_set("insert", ranges[1])

            return "break"
        else:
            return original_perform_return(self, event)

    CodeViewText.perform_return = _patched_perform_return


def _patch_intercept_mark():
    """Need to make cursor wider when in first column. Otherwise
    the border of the cell box makes it hard to notice the cursor.

    NB! Need to be careful with setting text["insertwidth"]!
    My first straightforward solution caused unexplainable
    infinite loop of insertions and deletions in the text
    (insert a line and a word, select that word and then do Ctrl-Z).

    Looks like this solution is safe, but I don't dare to include
    it in the main code.

    UPDATE: not safe. Select and delete a block of lines. Write a new
    line and do Ctrl-Z"""

    original_intercept_mark = CodeViewText.intercept_mark

    def _patched_intercept_mark(self, *args):
        if args[:2] == ("set", "insert") and args[2].endswith(".0"):
            self.set_insertwidth(3)
        else:
            self.set_insertwidth(2)

        original_intercept_mark(self, *args)

    CodeViewText.intercept_mark = _patched_intercept_mark


def dummy(event=None):
    "This is dummy method"


def run_selection(event=None):
    widget = get_workbench().focus_get()
    if isinstance(widget, CodeViewText):
        text = widget

        if text.has_selection():
            code = text.get("sel.first", "sel.last")
        else:
            code = text.get("insert linestart", "insert lineend")

        # move cursor to next row
        row, col = map(int, text.index("insert").split("."))
        text.mark_set("insert", "{}.{}".format(row + 1, col))

        _submit_code(code)


def run_enabled():
    widget = get_workbench().focus_get()
    return isinstance(widget, CodeViewText) and get_runner().is_waiting_toplevel_command()


def _load_plugin():
    wb = get_workbench()
    wb.bind_class("CodeViewText", "<<CursorMove>>", update_editor_cells, True)
    wb.bind_class("CodeViewText", "<<TextChange>>", update_editor_cells, True)
    wb.bind_class("CodeViewText", "<FocusIn>", update_editor_cells, True)
    wb.bind_class("CodeViewText", "<FocusOut>", update_editor_cells, True)

    _patch_perform_return()
    # TODO: try changing insertwidth in keyup/mouseup events
    # _patch_intercept_mark() # Still causes freezes

    wb.add_command(
        "run_cell",
        "run",
        ("Run cell"),
        handler=dummy,  # actual handler is in the patch
        default_sequence="<Control-Return>",
        tester=run_enabled,
        group=11,
    )

    wb.add_command(
        "run_cell_and_advance",
        "run",
        ("Run cell and advance"),
        handler=dummy,  # actual handler is in the patch
        default_sequence="<Shift-Return>",
        tester=run_enabled,
        group=11,
    )

    wb.add_command(
        "run_selection",
        "run",
        ("Run selection or current line"),
        handler=run_selection,
        default_sequence="<F9>",
        tester=run_enabled,
        group=11,
    )
