"""

An auto-completion window for IDLE, used by the AutoComplete extension

"""

from Tkinter import *

from MultiCall import MC_SHIFT

import AutoComplete

HIDE_VIRTUAL_EVENT_NAME = "<<autocompletewindow-hide>>"

HIDE_SEQUENCES = ("<FocusOut>", "<ButtonPress>")

KEYPRESS_VIRTUAL_EVENT_NAME = "<<autocompletewindow-keypress>>"

# We need to bind event beyond <Key> so that the function will be called

# before the default specific IDLE function

KEYPRESS_SEQUENCES = ("<Key>", "<Key-BackSpace>", "<Key-Return>", "<Key-Tab>",

                      "<Key-Up>", "<Key-Down>", "<Key-Home>", "<Key-End>",

                      "<Key-Prior>", "<Key-Next>")

KEYRELEASE_VIRTUAL_EVENT_NAME = "<<autocompletewindow-keyrelease>>"

KEYRELEASE_SEQUENCE = "<KeyRelease>"

LISTUPDATE_SEQUENCE = "<B1-ButtonRelease>"

WINCONFIG_SEQUENCE = "<Configure>"

DOUBLECLICK_SEQUENCE = "<B1-Double-ButtonRelease>"

class AutoCompleteWindow:

    def __init__(self, widget):

        # The widget (Text) on which we place the AutoCompleteWindow

        self.widget = widget

        # The widgets we create

        self.autocompletewindow = self.listbox = self.scrollbar = None

        # The default foreground and background of a selection. Saved because

        # they are changed to the regular colors of list items when the

        # completion start is not a prefix of the selected completion

        self.origselforeground = self.origselbackground = None

        # The list of completions

        self.completions = None

        # A list with more completions, or None

        self.morecompletions = None

        # The completion mode. Either AutoComplete.COMPLETE_ATTRIBUTES or

        # AutoComplete.COMPLETE_FILES

        self.mode = None

        # The current completion start, on the text box (a string)

        self.start = None

        # The index of the start of the completion

        self.startindex = None

        # The last typed start, used so that when the selection changes,

        # the new start will be as close as possible to the last typed one.

        self.lasttypedstart = None

        # Do we have an indication that the user wants the completion window

        # (for example, he clicked the list)

        self.userwantswindow = None

        # event ids

        self.hideid = self.keypressid = self.listupdateid = self.winconfigid \

        = self.keyreleaseid = self.doubleclickid                         = None

        # Flag set if last keypress was a tab

        self.lastkey_was_tab = False

    def _change_start(self, newstart):

        min_len = min(len(self.start), len(newstart))

        i = 0

        while i < min_len and self.start[i] == newstart[i]:

            i += 1

        if i < len(self.start):

            self.widget.delete("%s+%dc" % (self.startindex, i),

                               "%s+%dc" % (self.startindex, len(self.start)))

        if i < len(newstart):

            self.widget.insert("%s+%dc" % (self.startindex, i),

                               newstart[i:])

        self.start = newstart

    def _binary_search(self, s):

        """Find the first index in self.completions where completions[i] is

        greater or equal to s, or the last index if there is no such

        one."""

        i = 0; j = len(self.completions)

        while j > i:

            m = (i + j) // 2

            if self.completions[m] >= s:

                j = m

            else:

                i = m + 1

        return min(i, len(self.completions)-1)

    def _complete_string(self, s):

        """Assuming that s is the prefix of a string in self.completions,

        return the longest string which is a prefix of all the strings which

        s is a prefix of them. If s is not a prefix of a string, return s."""

        first = self._binary_search(s)

        if self.completions[first][:len(s)] != s:

            # There is not even one completion which s is a prefix of.

            return s

        # Find the end of the range of completions where s is a prefix of.

        i = first + 1

        j = len(self.completions)

        while j > i:

            m = (i + j) // 2

            if self.completions[m][:len(s)] != s:

                j = m

            else:

                i = m + 1

        last = i-1

        if first == last: # only one possible completion

            return self.completions[first]

        # We should return the maximum prefix of first and last

        first_comp = self.completions[first]

        last_comp = self.completions[last]

        min_len = min(len(first_comp), len(last_comp))

        i = len(s)

        while i < min_len and first_comp[i] == last_comp[i]:

            i += 1

        return first_comp[:i]

    def _selection_changed(self):

        """Should be called when the selection of the Listbox has changed.

        Updates the Listbox display and calls _change_start."""

        cursel = int(self.listbox.curselection()[0])

        self.listbox.see(cursel)

        lts = self.lasttypedstart

        selstart = self.completions[cursel]

        if self._binary_search(lts) == cursel:

            newstart = lts

        else:

            min_len = min(len(lts), len(selstart))

            i = 0

            while i < min_len and lts[i] == selstart[i]:

                i += 1

            newstart = selstart[:i]

        self._change_start(newstart)

        if self.completions[cursel][:len(self.start)] == self.start:

            # start is a prefix of the selected completion

            self.listbox.configure(selectbackground=self.origselbackground,

                                   selectforeground=self.origselforeground)

        else:

            self.listbox.configure(selectbackground=self.listbox.cget("bg"),

                                   selectforeground=self.listbox.cget("fg"))

            # If there are more completions, show them, and call me again.

            if self.morecompletions:

                self.completions = self.morecompletions

                self.morecompletions = None

                self.listbox.delete(0, END)

                for item in self.completions:

                    self.listbox.insert(END, item)

                self.listbox.select_set(self._binary_search(self.start))

                self._selection_changed()

    def show_window(self, comp_lists, index, complete, mode, userWantsWin):

        """Show the autocomplete list, bind events.

        If complete is True, complete the text, and if there is exactly one

        matching completion, don't open a list."""

        # Handle the start we already have

        self.completions, self.morecompletions = comp_lists

        self.mode = mode

        self.startindex = self.widget.index(index)

        self.start = self.widget.get(self.startindex, "insert")

        if complete:

            completed = self._complete_string(self.start)

            self._change_start(completed)

            i = self._binary_search(completed)

            if self.completions[i] == completed and \

               (i == len(self.completions)-1 or

                self.completions[i+1][:len(completed)] != completed):

                # There is exactly one matching completion

                return

        self.userwantswindow = userWantsWin

        self.lasttypedstart = self.start

        # Put widgets in place

        self.autocompletewindow = acw = Toplevel(self.widget)

        # Put it in a position so that it is not seen.

        acw.wm_geometry("+10000+10000")

        # Make it float

        acw.wm_overrideredirect(1)

        try:

            # This command is only needed and available on Tk >= 8.4.0 for OSX

            # Without it, call tips intrude on the typing process by grabbing

            # the focus.

            acw.tk.call("::tk::unsupported::MacWindowStyle", "style", acw._w,

                        "help", "noActivates")

        except TclError:

            pass

        self.scrollbar = scrollbar = Scrollbar(acw, orient=VERTICAL)

        self.listbox = listbox = Listbox(acw, yscrollcommand=scrollbar.set,

                                         exportselection=False, bg="white")

        for item in self.completions:

            listbox.insert(END, item)

        self.origselforeground = listbox.cget("selectforeground")

        self.origselbackground = listbox.cget("selectbackground")

        scrollbar.config(command=listbox.yview)

        scrollbar.pack(side=RIGHT, fill=Y)

        listbox.pack(side=LEFT, fill=BOTH, expand=True)

        # Initialize the listbox selection

        self.listbox.select_set(self._binary_search(self.start))

        self._selection_changed()

        # bind events

        self.hideid = self.widget.bind(HIDE_VIRTUAL_EVENT_NAME,

                                       self.hide_event)

        for seq in HIDE_SEQUENCES:

            self.widget.event_add(HIDE_VIRTUAL_EVENT_NAME, seq)

        self.keypressid = self.widget.bind(KEYPRESS_VIRTUAL_EVENT_NAME,

                                           self.keypress_event)

        for seq in KEYPRESS_SEQUENCES:

            self.widget.event_add(KEYPRESS_VIRTUAL_EVENT_NAME, seq)

        self.keyreleaseid = self.widget.bind(KEYRELEASE_VIRTUAL_EVENT_NAME,

                                             self.keyrelease_event)

        self.widget.event_add(KEYRELEASE_VIRTUAL_EVENT_NAME,KEYRELEASE_SEQUENCE)

        self.listupdateid = listbox.bind(LISTUPDATE_SEQUENCE,

                                         self.listselect_event)

        self.winconfigid = acw.bind(WINCONFIG_SEQUENCE, self.winconfig_event)

        self.doubleclickid = listbox.bind(DOUBLECLICK_SEQUENCE,

                                          self.doubleclick_event)

    def winconfig_event(self, event):

        if not self.is_active():

            return

        # Position the completion list window

        text = self.widget

        text.see(self.startindex)

        x, y, cx, cy = text.bbox(self.startindex)

        acw = self.autocompletewindow

        acw_width, acw_height = acw.winfo_width(), acw.winfo_height()

        text_width, text_height = text.winfo_width(), text.winfo_height()

        new_x = text.winfo_rootx() + min(x, max(0, text_width - acw_width))

        new_y = text.winfo_rooty() + y

        if (text_height - (y + cy) >= acw_height # enough height below

            or y < acw_height): # not enough height above

            # place acw below current line

            new_y += cy

        else:

            # place acw above current line

            new_y -= acw_height

        acw.wm_geometry("+%d+%d" % (new_x, new_y))

    def hide_event(self, event):

        if not self.is_active():

            return

        self.hide_window()

    def listselect_event(self, event):

        if not self.is_active():

            return

        self.userwantswindow = True

        cursel = int(self.listbox.curselection()[0])

        self._change_start(self.completions[cursel])

    def doubleclick_event(self, event):

        # Put the selected completion in the text, and close the list

        cursel = int(self.listbox.curselection()[0])

        self._change_start(self.completions[cursel])

        self.hide_window()

    def keypress_event(self, event):

        if not self.is_active():

            return

        keysym = event.keysym

        if hasattr(event, "mc_state"):

            state = event.mc_state

        else:

            state = 0

        if keysym != "Tab":

            self.lastkey_was_tab = False

        if (len(keysym) == 1 or keysym in ("underscore", "BackSpace")

            or (self.mode==AutoComplete.COMPLETE_FILES and keysym in

                ("period", "minus"))) \

           and not (state & ~MC_SHIFT):

            # Normal editing of text

            if len(keysym) == 1:

                self._change_start(self.start + keysym)

            elif keysym == "underscore":

                self._change_start(self.start + '_')

            elif keysym == "period":

                self._change_start(self.start + '.')

            elif keysym == "minus":

                self._change_start(self.start + '-')

            else:

                # keysym == "BackSpace"

                if len(self.start) == 0:

                    self.hide_window()

                    return

                self._change_start(self.start[:-1])

            self.lasttypedstart = self.start

            self.listbox.select_clear(0, int(self.listbox.curselection()[0]))

            self.listbox.select_set(self._binary_search(self.start))

            self._selection_changed()

            return "break"

        elif keysym == "Return":

            self.hide_window()

            return

        elif (self.mode == AutoComplete.COMPLETE_ATTRIBUTES and keysym in

              ("period", "space", "parenleft", "parenright", "bracketleft",

               "bracketright")) or \

             (self.mode == AutoComplete.COMPLETE_FILES and keysym in

              ("slash", "backslash", "quotedbl", "apostrophe")) \

             and not (state & ~MC_SHIFT):

            # If start is a prefix of the selection, but is not '' when

            # completing file names, put the whole

            # selected completion. Anyway, close the list.

            cursel = int(self.listbox.curselection()[0])

            if self.completions[cursel][:len(self.start)] == self.start \

               and (self.mode==AutoComplete.COMPLETE_ATTRIBUTES or self.start):

                self._change_start(self.completions[cursel])

            self.hide_window()

            return

        elif keysym in ("Home", "End", "Prior", "Next", "Up", "Down") and \

             not state:

            # Move the selection in the listbox

            self.userwantswindow = True

            cursel = int(self.listbox.curselection()[0])

            if keysym == "Home":

                newsel = 0

            elif keysym == "End":

                newsel = len(self.completions)-1

            elif keysym in ("Prior", "Next"):

                jump = self.listbox.nearest(self.listbox.winfo_height()) - \

                       self.listbox.nearest(0)

                if keysym == "Prior":

                    newsel = max(0, cursel-jump)

                else:

                    assert keysym == "Next"

                    newsel = min(len(self.completions)-1, cursel+jump)

            elif keysym == "Up":

                newsel = max(0, cursel-1)

            else:

                assert keysym == "Down"

                newsel = min(len(self.completions)-1, cursel+1)

            self.listbox.select_clear(cursel)

            self.listbox.select_set(newsel)

            self._selection_changed()

            self._change_start(self.completions[newsel])

            return "break"

        elif (keysym == "Tab" and not state):

            if self.lastkey_was_tab:

                # two tabs in a row; insert current selection and close acw

                cursel = int(self.listbox.curselection()[0])

                self._change_start(self.completions[cursel])

                self.hide_window()

                return "break"

            else:

                # first tab; let AutoComplete handle the completion

                self.userwantswindow = True

                self.lastkey_was_tab = True

                return

        elif reduce(lambda x, y: x or y,

                    [keysym.find(s) != -1 for s in ("Shift", "Control", "Alt",

                                                    "Meta", "Command", "Option")

                     ]):

            # A modifier key, so ignore

            return

        else:

            # Unknown event, close the window and let it through.

            self.hide_window()

            return

    def keyrelease_event(self, event):

        if not self.is_active():

            return

        if self.widget.index("insert") != \

           self.widget.index("%s+%dc" % (self.startindex, len(self.start))):

            # If we didn't catch an event which moved the insert, close window

            self.hide_window()

    def is_active(self):

        return self.autocompletewindow is not None

    def complete(self):

        self._change_start(self._complete_string(self.start))

        # The selection doesn't change.

    def hide_window(self):

        if not self.is_active():

            return

        # unbind events

        for seq in HIDE_SEQUENCES:

            self.widget.event_delete(HIDE_VIRTUAL_EVENT_NAME, seq)

        self.widget.unbind(HIDE_VIRTUAL_EVENT_NAME, self.hideid)

        self.hideid = None

        for seq in KEYPRESS_SEQUENCES:

            self.widget.event_delete(KEYPRESS_VIRTUAL_EVENT_NAME, seq)

        self.widget.unbind(KEYPRESS_VIRTUAL_EVENT_NAME, self.keypressid)

        self.keypressid = None

        self.widget.event_delete(KEYRELEASE_VIRTUAL_EVENT_NAME,

                                 KEYRELEASE_SEQUENCE)

        self.widget.unbind(KEYRELEASE_VIRTUAL_EVENT_NAME, self.keyreleaseid)

        self.keyreleaseid = None

        self.listbox.unbind(LISTUPDATE_SEQUENCE, self.listupdateid)

        self.listupdateid = None

        self.autocompletewindow.unbind(WINCONFIG_SEQUENCE, self.winconfigid)

        self.winconfigid = None

        # destroy widgets

        self.scrollbar.destroy()

        self.scrollbar = None

        self.listbox.destroy()

        self.listbox = None

        self.autocompletewindow.destroy()

        self.autocompletewindow = None