#!/usr/bin/env python
# vim:fileencoding=utf-8
# License: GPL v3 Copyright: 2018, Kovid Goyal <kovid at kovidgoyal.net>

import os
import sys
from functools import partial
from gettext import gettext as _

from kitty.cli import parse_args
from kitty.key_encoding import ESCAPE

from ..tui.handler import Handler
from ..tui.loop import Loop
from ..tui.operations import clear_screen, set_line_wrapping, set_window_title
from .collect import create_collection

INITIALIZING, READY, RENDERED = range(3)


class DiffHandler(Handler):

    def __init__(self, left, right):
        self.state = INITIALIZING
        self.left, self.right = left, right
        self.report_traceback_on_exit = None

    def create_collection(self):
        self.start_job('diff', create_collection, self.left, self.right)

    def init_terminal_state(self):
        self.write(set_line_wrapping(False))
        self.write(set_window_title('kitty +diff'))

    def initialize(self, *args):
        Handler.initialize(self, *args)
        self.init_terminal_state()
        self.draw_screen()
        self.create_collection()

    def draw_screen(self):
        if self.state is INITIALIZING:
            self.write(clear_screen())
            self.write(_('Calculating diff, please wait...'))
            return
        if self.state is READY:
            self.write(clear_screen())
            self.state = RENDERED
            return

    def on_key(self, key_event):
        if self.state is INITIALIZING:
            if key_event.key is ESCAPE:
                self.quit_loop(0)
            return

    def on_job_done(self, job_id, job_result):
        if 'tb' in job_result:
            self.report_traceback_on_exit = job_result['tb']
            self.quit_loop(1)
            return
        if job_id == 'diff':
            self.collection = job_result['result']
            self.state = READY
            self.write(clear_screen())

    def on_interrupt(self):
        self.quit_loop(1)

    def on_eot(self):
        self.quit_loop(1)


OPTIONS = partial('''\
'''.format, )


def main(args):
    msg = 'Show a side-by-side diff of the specified files/directories'
    args, items = parse_args(args[1:], OPTIONS, 'file_or_directory file_or_directory', msg, 'kitty +kitten diff')
    if len(items) != 2:
        raise SystemExit('You must specify exactly two files/directories to compare')
    left, right = items
    if os.path.isdir(left) != os.path.isdir(right):
        raise SystemExit('The items to be diffed should both be either directories or files. Comparing a directory to a file is not valid.')

    loop = Loop()
    handler = DiffHandler(left, right)
    loop.loop(handler)
    if loop.return_code != 0:
        if handler.report_traceback_on_exit:
            print(handler.report_traceback_on_exit, file=sys.stderr)
        raise SystemExit(loop.return_code)


def handle_result(args, current_char, target_window_id, boss):
    pass


if __name__ == '__main__':
    main(sys.argv)