Start work on the diff kitten

kittens/diff/main.py

@@ -0,0 +1,57 @@
+#!/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 kitty.cli import parse_args
+
+from ..tui.handler import Handler
+from ..tui.loop import Loop
+from ..tui.operations import set_line_wrapping, set_window_title
+from .collect import create_collection
+
+
+class DiffHandler(Handler):
+
+    def __init__(self, collection):
+        self.collection = collection
+
+    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()
+
+
+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.')
+    collection = create_collection(left, right)
+
+    loop = Loop()
+    handler = DiffHandler(collection)
+    loop.loop(handler)
+    if loop.return_code != 0:
+        raise SystemExit(loop.return_code)
+
+
+def handle_result(args, current_char, target_window_id, boss):
+    pass
+
+
+if __name__ == '__main__':
+    main(sys.argv)