"""
An auto-completion window for IDLE, used by the autocomplete extension
"""
import platform

from tkinter import *
from tkinter.ttk import Frame, Scrollbar

from idlelib.autocomplete import COMPLETE_FILES, COMPLETE_ATTRIBUTES
from idlelib.multicall import MC_SHIFT

HIDE_VIRTUAL_EVENT_NAME = "<<autocompletewindow-hide>>"
HIDE_FOCUS_OUT_SEQUENCE = "<FocusOut>"
HIDE_SEQUENCES = (HIDE_FOCUS_OUT_SEQUENCE, "<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)
 start = 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 completed == start
 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)
 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)
 acw.lift() # work around bug in Tk 8.5.18+ (issue #24570)

 # Initialize the listbox selection
 self.listbox.select_set(self._binary_search(self.start))
 self._selection_changed()

 # bind events
 self.hideaid = acw.bind(HIDE_VIRTUAL_EVENT_NAME, self.hide_event)
 self.hidewid = self.widget.bind(HIDE_VIRTUAL_EVENT_NAME, self.hide_event)
 acw.event_add(HIDE_VIRTUAL_EVENT_NAME, HIDE_FOCUS_OUT_SEQUENCE)
 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)
 return None

 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))

 if platform.system().startswith('Windows'):
 # See issue 15786. When on Windows platform, Tk will misbehave
 # to call winconfig_event multiple times, we need to prevent this,
 # otherwise mouse button double click will not be able to used.
 acw.unbind(WINCONFIG_SEQUENCE, self.winconfigid)
 self.winconfigid = None

 def _hide_event_check(self):
 if not self.autocompletewindow:
 return

 try:
 if not self.autocompletewindow.focus_get():
 self.hide_window()
 except KeyError:
 # See issue 734176, when user click on menu, acw.focus_get()
 # will get KeyError.
 self.hide_window()

 def hide_event(self, event):
 # Hide autocomplete list if it exists and does not have focus or
 # mouse click on widget / text area.
 if self.is_active():
 if event.type == EventType.FocusOut:
 # On Windows platform, it will need to delay the check for
 # acw.focus_get() when click on acw, otherwise it will return
 # None and close the window
 self.widget.after(1, self._hide_event_check)
 elif event.type == EventType.ButtonPress:
 # ButtonPress event only bind to self.widget
 self.hide_window()

 def listselect_event(self, event):
 if self.is_active():
 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 None
 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 == 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 None
 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.complete()
 self.hide_window()
 return 'break'

 elif (self.mode == COMPLETE_ATTRIBUTES and keysym in
 ("period", "space", "parenleft", "parenright", "bracketleft",
 "bracketright")) or \
 (self.mode == 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 == COMPLETE_ATTRIBUTES or self.start):
 self._change_start(self.completions[cursel])
 self.hide_window()
 return None

 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 None

 elif any(s in keysym for s in ("Shift", "Control", "Alt",
 "Meta", "Command", "Option")):
 # A modifier key, so ignore
 return None

 elif event.char and event.char >= ' ':
 # Regular character with a non-length-1 keycode
 self._change_start(self.start + event.char)
 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"

 else:
 # Unknown event, close the window and let it through.
 self.hide_window()
 return None

 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
 self.autocompletewindow.event_delete(HIDE_VIRTUAL_EVENT_NAME,
 HIDE_FOCUS_OUT_SEQUENCE)
 for seq in HIDE_SEQUENCES:
 self.widget.event_delete(HIDE_VIRTUAL_EVENT_NAME, seq)

 self.autocompletewindow.unbind(HIDE_VIRTUAL_EVENT_NAME, self.hideaid)
 self.widget.unbind(HIDE_VIRTUAL_EVENT_NAME, self.hidewid)
 self.hideaid = None
 self.hidewid = 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
 if self.winconfigid:
 self.autocompletewindow.unbind(WINCONFIG_SEQUENCE, self.winconfigid)
 self.winconfigid = None

 # Re-focusOn frame.text (See issue #15786)
 self.widget.focus_set()

 # destroy widgets
 self.scrollbar.destroy()
 self.scrollbar = None
 self.listbox.destroy()
 self.listbox = None
 self.autocompletewindow.destroy()
 self.autocompletewindow = None


if __name__ == '__main__':
 from unittest import main
 main('idlelib.idle_test.test_autocomplete_w', verbosity=2, exit=False)

# TODO: autocomplete/w htest here