Files
tuir/rtv/utils.py

271 lines
7.5 KiB
Python

import os
import sys
import curses
import time
import threading
from curses import textpad, ascii
from contextlib import contextmanager
from six.moves import configparser
from .errors import EscapePressed
ESCAPE = 27
HELP = """
Global Commands
`UP/DOWN` or `j/k` : Scroll to the prev/next item
`r` or `F5` : Refresh the current page
`q` : Quit the program
`o` : Open the selected item in the default web browser
`?` : Show this help message
Subreddit Mode
`RIGHT` or `l` : View comments for the selected submission
`/` : Open a prompt to switch subreddits
Submission Mode
`LEFT` or `h` : Return to subreddit mode
`RIGHT` or `l` : Fold the selected comment, or load additional comments
"""
class Color(object):
COLORS = {
'RED': (curses.COLOR_RED, -1),
'GREEN': (curses.COLOR_GREEN, -1),
'YELLOW': (curses.COLOR_YELLOW, -1),
'BLUE': (curses.COLOR_BLUE, -1),
'MAGENTA': (curses.COLOR_MAGENTA, -1),
'CYAN': (curses.COLOR_CYAN, -1),
'WHITE': (curses.COLOR_WHITE, -1),
}
@classmethod
def get_level(cls, level):
levels = [cls.MAGENTA, cls.CYAN, cls.GREEN, cls.YELLOW]
return levels[level % len(levels)]
@classmethod
def init(cls):
"""
Initialize color pairs inside of curses using the default background.
This should be called once during the curses initial setup. Afterwards,
curses color pairs can be accessed directly through class attributes.
"""
# Assign the terminal's default (background) color to code -1
curses.use_default_colors()
for index, (attr, code) in enumerate(cls.COLORS.items(), start=1):
curses.init_pair(index, code[0], code[1])
setattr(cls, attr, curses.color_pair(index))
def load_config():
"""
Search for a configuration file at the location ~/.rtv and attempt to load
saved settings for things like the username and password.
"""
config_path = os.path.join(os.path.expanduser('~'), '.rtv')
config = configparser.ConfigParser()
config.read(config_path)
defaults = {}
if config.has_section('rtv'):
defaults = dict(config.items('rtv'))
return defaults
def text_input(window):
"""
Transform a window into a text box that will accept user input and loop
until an escape sequence is entered.
If enter is pressed, return the input text as a string.
If escape is pressed, return None.
"""
window.clear()
curses.curs_set(2)
textbox = textpad.Textbox(window, insert_mode=True)
def validate(ch):
"Filters characters for special key sequences"
if ch == ESCAPE:
raise EscapePressed
# Fix backspace for iterm
if ch == ascii.DEL:
ch = curses.KEY_BACKSPACE
return ch
# Wrapping in an exception block so that we can distinguish when the user
# hits the return character from when the user tries to back out of the
# input.
try:
out = textbox.edit(validate=validate)
out = out.strip()
except EscapePressed:
out = None
curses.curs_set(0)
return out
def display_message(stdscr, message):
"Display a message box at the center of the screen and wait for a keypress"
n_rows, n_cols = stdscr.getmaxyx()
box_width = max(map(len, message)) + 2
box_height = len(message) + 2
# Make sure the window is large enough to fit the message
# TODO: Should find a better way to display the message in this situation
if (box_width > n_cols) or (box_height > n_rows):
curses.flash()
return
s_row = (n_rows - box_height) // 2
s_col = (n_cols - box_width) // 2
window = stdscr.derwin(box_height, box_width, s_row, s_col)
window.erase()
window.border()
for index, line in enumerate(message, start=1):
window.addstr(index, 1, line)
window.refresh()
stdscr.getch()
window.clear()
window = None
stdscr.refresh()
def display_help(stdscr):
"""Display a help message box at the center of the screen and wait for a
keypress"""
help_msgs = HELP.split("\n")
display_message(stdscr, help_msgs)
class LoadScreen(object):
def __init__(self, stdscr):
self._stdscr = stdscr
self._args = None
self._animator = None
self._is_running = None
def __call__(
self,
delay=0.5,
interval=0.4,
message='Downloading',
trail='...'):
self._args = (delay, interval, message, trail)
return self
def __enter__(self):
self._animator = threading.Thread(target=self.animate, args=self._args)
self._animator.daemon = True
self._is_running = True
self._animator.start()
def __exit__(self, exc_type, exc_val, exc_tb):
self._is_running = False
self._animator.join()
def animate(self, delay, interval, message, trail):
# Delay before starting animation to avoid wasting resources if the
# wait time is very short
start = time.time()
while (time.time() - start) < delay:
if not self._is_running:
return
message_len = len(message) + len(trail)
n_rows, n_cols = self._stdscr.getmaxyx()
s_row = (n_rows - 3) // 2
s_col = (n_cols - message_len - 1) // 2
window = self._stdscr.derwin(3, message_len+2, s_row, s_col)
while True:
for i in range(len(trail)+1):
if not self._is_running:
window.clear()
window = None
self._stdscr.refresh()
return
window.erase()
window.border()
window.addstr(1, 1, message + trail[:i])
window.refresh()
time.sleep(interval)
@contextmanager
def curses_session():
try:
# Curses must wait for some time after the Escape key is pressed to
# check if it is the beginning of an escape sequence indicating a
# special key. The default wait time is 1 second, which means that
# getch() will not return the escape key (27) until a full second
# after it has been pressed.
# Turn this down to 25 ms, which is close to what VIM uses.
# http://stackoverflow.com/questions/27372068
os.environ['ESCDELAY'] = '25'
# Initialize curses
stdscr = curses.initscr()
# Turn off echoing of keys, and enter cbreak mode,
# where no buffering is performed on keyboard input
curses.noecho()
curses.cbreak()
# In keypad mode, escape sequences for special keys
# (like the cursor keys) will be interpreted and
# a special value like curses.KEY_LEFT will be returned
stdscr.keypad(1)
# Start color, too. Harmless if the terminal doesn't have
# color; user can test with has_color() later on. The try/catch
# works around a minor bit of over-conscientiousness in the curses
# module -- the error return from C start_color() is ignorable.
try:
curses.start_color()
except:
pass
Color.init()
# Hide blinking cursor
curses.curs_set(0)
yield stdscr
finally:
if stdscr is not None:
stdscr.keypad(0)
curses.echo()
curses.nocbreak()
curses.endwin()