"""Simple text browser for IDLE

"""
from tkinter import Toplevel, Text, TclError,\
 HORIZONTAL, VERTICAL, N, S, E, W
from tkinter.ttk import Frame, Scrollbar, Button
from tkinter.messagebox import showerror

from idlelib.colorizer import color_config


class AutoHiddenScrollbar(Scrollbar):
 """A scrollbar that is automatically hidden when not needed.

 Only the grid geometry manager is supported.
 """
 def set(self, lo, hi):
 if float(lo) > 0.0 or float(hi) < 1.0:
 self.grid()
 else:
 self.grid_remove()
 super().set(lo, hi)

 def pack(self, **kwargs):
 raise TclError(f'{self.__class__.__name__} does not support "pack"')

 def place(self, **kwargs):
 raise TclError(f'{self.__class__.__name__} does not support "place"')


class TextFrame(Frame):
 "Display text with scrollbar."

 def __init__(self, parent, rawtext, wrap='word'):
 """Create a frame for Textview.

 parent - parent widget for this frame
 rawtext - text to display
 """
 super().__init__(parent)
 self['relief'] = 'sunken'
 self['height'] = 700

 self.text = text = Text(self, wrap=wrap, highlightthickness=0)
 color_config(text)
 text.grid(row=0, column=0, sticky=N+S+E+W)
 self.grid_rowconfigure(0, weight=1)
 self.grid_columnconfigure(0, weight=1)
 text.insert(0.0, rawtext)
 text['state'] = 'disabled'
 text.focus_set()

 # vertical scrollbar
 self.yscroll = yscroll = AutoHiddenScrollbar(self, orient=VERTICAL,
 takefocus=False,
 command=text.yview)
 text['yscrollcommand'] = yscroll.set
 yscroll.grid(row=0, column=1, sticky=N+S)

 if wrap == 'none':
 # horizontal scrollbar
 self.xscroll = xscroll = AutoHiddenScrollbar(self, orient=HORIZONTAL,
 takefocus=False,
 command=text.xview)
 text['xscrollcommand'] = xscroll.set
 xscroll.grid(row=1, column=0, sticky=E+W)


class ViewFrame(Frame):
 "Display TextFrame and Close button."
 def __init__(self, parent, text, wrap='word'):
 super().__init__(parent)
 self.parent = parent
 self.bind('<Return>', self.ok)
 self.bind('<Escape>', self.ok)
 self.textframe = TextFrame(self, text, wrap=wrap)
 self.button_ok = button_ok = Button(
 self, text='Close', command=self.ok, takefocus=False)
 self.textframe.pack(side='top', expand=True, fill='both')
 button_ok.pack(side='bottom')

 def ok(self, event=None):
 """Dismiss text viewer dialog."""
 self.parent.destroy()


class ViewWindow(Toplevel):
 "A simple text viewer dialog for IDLE."

 def __init__(self, parent, title, text, modal=True, wrap='word',
 *, _htest=False, _utest=False):
 """Show the given text in a scrollable window with a 'close' button.

 If modal is left True, users cannot interact with other windows
 until the textview window is closed.

 parent - parent of this dialog
 title - string which is title of popup dialog
 text - text to display in dialog
 wrap - type of text wrapping to use ('word', 'char' or 'none')
 _htest - bool; change box location when running htest.
 _utest - bool; don't wait_window when running unittest.
 """
 super().__init__(parent)
 self['borderwidth'] = 5
 # Place dialog below parent if running htest.
 x = parent.winfo_rootx() + 10
 y = parent.winfo_rooty() + (10 if not _htest else 100)
 self.geometry(f'=750x500+{x}+{y}')

 self.title(title)
 self.viewframe = ViewFrame(self, text, wrap=wrap)
 self.protocol("WM_DELETE_WINDOW", self.ok)
 self.button_ok = button_ok = Button(self, text='Close',
 command=self.ok, takefocus=False)
 self.viewframe.pack(side='top', expand=True, fill='both')

 self.is_modal = modal
 if self.is_modal:
 self.transient(parent)
 self.grab_set()
 if not _utest:
 self.wait_window()

 def ok(self, event=None):
 """Dismiss text viewer dialog."""
 if self.is_modal:
 self.grab_release()
 self.destroy()


def view_text(parent, title, text, modal=True, wrap='word', _utest=False):
 """Create text viewer for given text.

 parent - parent of this dialog
 title - string which is the title of popup dialog
 text - text to display in this dialog
 wrap - type of text wrapping to use ('word', 'char' or 'none')
 modal - controls if users can interact with other windows while this
 dialog is displayed
 _utest - bool; controls wait_window on unittest
 """
 return ViewWindow(parent, title, text, modal, wrap=wrap, _utest=_utest)


def view_file(parent, title, filename, encoding, modal=True, wrap='word',
 _utest=False):
 """Create text viewer for text in filename.

 Return error message if file cannot be read. Otherwise calls view_text
 with contents of the file.
 """
 try:
 with open(filename, 'r', encoding=encoding) as file:
 contents = file.read()
 except OSError:
 showerror(title='File Load Error',
 message=f'Unable to load file {filename!r} .',
 parent=parent)
 except UnicodeDecodeError as err:
 showerror(title='Unicode Decode Error',
 message=str(err),
 parent=parent)
 else:
 return view_text(parent, title, contents, modal, wrap=wrap,
 _utest=_utest)
 return None


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

 from idlelib.idle_test.htest import run
 run(ViewWindow)