# Author: Miguel Martinez Lopez
# Version: 0.8

import re
from abc import ABC, abstractmethod
try:
    from Tkinter import StringVar, Entry, Frame, Listbox, Scrollbar
    from Tkconstants import *
except ImportError:
    from tkinter import StringVar, Entry, Frame, Listbox, Scrollbar
    from tkinter.constants import *


def autoscroll(sbar, first, last):
    """Hide and show scrollbar as needed."""
    first, last = float(first), float(last)
    if first <= 0 and last >= 1:
        sbar.grid_remove()
    else:
        sbar.grid()
    sbar.set(first, last)


class Combobox_Autocomplete(Entry):
    def __init__(self, master, searchCallback=None,callbackOnSelection=None, listbox_width=None, listbox_height=7, vscrollbar=True, hscrollbar=False, **kwargs):


        if callbackOnSelection is None:
            self.callbackOnSelection = lambda text:None
        else:
            self.callbackOnSelection = callbackOnSelection

        self._listbox_height = int(listbox_height)
        self._listbox_width = listbox_width

        self.searchCallback = searchCallback
        
        self._use_vscrollbar = vscrollbar
        self._use_hscrollbar = hscrollbar

        kwargs.setdefault("background", "white")

        if "textvariable" in kwargs:
            self._entry_var = kwargs["textvariable"]
        else:
            self._entry_var = kwargs["textvariable"] = StringVar()

        Entry.__init__(self, master, **kwargs)

        self._trace_id = self._entry_var.trace('w', self._on_change_entry_var)
        
        self._listbox = None

        self.bind("<Tab>", self._on_tab)
        self.bind("<Up>", self._previous)
        self.bind("<Down>", self._next)
        self.bind('<Control-n>', self._next)
        self.bind('<Control-p>', self._previous)

        self.bind("<Return>", self._update_entry_from_listbox)
        self.bind("<Escape>", lambda event: self.unpost_listbox())
        
    def _on_tab(self, event):
        self.post_listbox()
        return "break"

    def _on_change_entry_var(self, name, index, mode):
        
        entry_data = self._entry_var.get()

        if entry_data == '':
            self.unpost_listbox()
            self.callbackOnSelection('')
            self.focus()
        else:
            values = self.searchCallback(entry_data)
            if values:
                if self._listbox is None:
                    self._build_listbox(values)
                else:
                    self._listbox.delete(0, END)

                    height = min(self._listbox_height, len(values))
                    self._listbox.configure(height=height)

                    for item in values:
                        self._listbox.insert(END, item)              
            else:
                self.unpost_listbox()
                self.focus()

    def _build_listbox(self, values):
        listbox_frame = Frame()

        self._listbox = Listbox(listbox_frame, background="white", selectmode=SINGLE, activestyle="none", exportselection=True)
        self._listbox.grid(row=0, column=0,sticky = N+E+W+S)

        self._listbox.bind("<ButtonRelease-1>", self._update_entry_from_listbox)
        self._listbox.bind("<Return>", self._update_entry_from_listbox)
        self._listbox.bind("<Escape>", lambda event: self.unpost_listbox())
        
        self._listbox.bind('<Control-n>', self._next)
        self._listbox.bind('<Control-p>', self._previous)

        if self._use_vscrollbar:
            vbar = Scrollbar(listbox_frame, orient=VERTICAL, command= self._listbox.yview)
            vbar.grid(row=0, column=1, sticky=N+S)
            
            self._listbox.configure(yscrollcommand= lambda f, l: autoscroll(vbar, f, l))
            
        if self._use_hscrollbar:
            hbar = Scrollbar(listbox_frame, orient=HORIZONTAL, command= self._listbox.xview)
            hbar.grid(row=1, column=0, sticky=E+W)
            
            self._listbox.configure(xscrollcommand= lambda f, l: autoscroll(hbar, f, l))

        listbox_frame.grid_columnconfigure(0, weight= 1)
        listbox_frame.grid_rowconfigure(0, weight= 1)

        x = -self.cget("borderwidth") - self.cget("highlightthickness") 
        y = self.winfo_height()-self.cget("borderwidth") - self.cget("highlightthickness")

        if self._listbox_width:
            width = self._listbox_width
        else:
            width=self.winfo_width()

        listbox_frame.place(in_=self, x=x, y=y, width=width)
        
        height = min(self._listbox_height, len(values))
        self._listbox.configure(height=height)

        for item in values:
            self._listbox.insert(END, item)

    def post_listbox(self):
        if self._listbox is not None: return

        entry_data = self._entry_var.get()
        if entry_data == '': return

        values = self.searchCallback(entry_data)
        if values:
            self._build_listbox(values)

    def unpost_listbox(self):
        if self._listbox is not None:
            self._listbox.master.destroy()
            self._listbox = None

    def get_value(self):
        return self._entry_var.get()

    def GetData(self):
        return self.get_value()

    def set_value(self, text, close_dialog=False):
        self._set_var(text)

        if close_dialog:
            self.unpost_listbox()

        self.icursor(END)
        self.xview_moveto(1.0)
        
    def _set_var(self, text):
        self._entry_var.trace_vdelete("w", self._trace_id)
        self._entry_var.set(text)
        self._trace_id = self._entry_var.trace('w', self._on_change_entry_var)

    def _update_entry_from_listbox(self, event):
        if self._listbox is not None:
            current_selection = self._listbox.curselection()
            
            if current_selection:
                text = self._listbox.get(current_selection)
                self.callbackOnSelection(text)
                self._set_var(text)

            self._listbox.master.destroy()
            self._listbox = None

            self.focus()
            self.icursor(END)
            self.xview_moveto(1.0)
           
        return "break"

    def _previous(self, event):
        if self._listbox is not None:
            current_selection = self._listbox.curselection()

            if len(current_selection)==0:
                self._listbox.selection_set(0)
                self._listbox.activate(0)
            else:
                index = int(current_selection[0])
                self._listbox.selection_clear(index)

                if index == 0:
                    index = END
                else:
                    index -= 1

                self._listbox.see(index)
                self._listbox.selection_set(first=index)
                self._listbox.activate(index)

        return "break"

    def _next(self, event):
        if self._listbox is not None:

            current_selection = self._listbox.curselection()
            if len(current_selection)==0:
                self._listbox.selection_set(0)
                self._listbox.activate(0)
            else:
                index = int(current_selection[0])
                self._listbox.selection_clear(index)
                
                if index == self._listbox.size() - 1:
                    index = 0
                else:
                    index +=1
                    
                self._listbox.see(index)
                self._listbox.selection_set(index)
                self._listbox.activate(index)
        return "break"
