Add a test suite and some basic navigation

babi.py

@@ -4,6 +4,8 @@ import curses
 from typing import Dict
 from typing import Tuple
 
+VERSION_STR = 'babi v0'
+
 
 def _get_color_pair_mapping() -> Dict[Tuple[int, int], int]:
     ret = {}
@@ -63,18 +65,78 @@ def _color_test(stdscr: '_curses._CursesWindow') -> None:
             x += 4
         y += 1
         x = 0
+    stdscr.get_wch()
+
+
+def _write_header(
+        stdscr: '_curses._CursesWindow',
+        filename: str,
+        *,
+        modified: bool,
+) -> None:
+    filename = filename or '<<new file>>'
+    if modified:
+        filename += ' *'
+    centered_filename = filename.center(curses.COLS)[len(VERSION_STR) + 2:]
+    s = f' {VERSION_STR} {centered_filename}'
+    stdscr.addstr(0, 0, s, curses.A_REVERSE)
+
+
+def _write_status(stdscr: '_curses._CursesWindow', status: str) -> None:
+    stdscr.addstr(curses.LINES - 1, 0, ' ' * (curses.COLS - 1))
+    if status:
+        status = f' {status} '
+        offset = (curses.COLS - len(status)) // 2
+        stdscr.addstr(curses.LINES - 1, offset, status, curses.A_REVERSE)
 
 
 def c_main(stdscr: '_curses._CursesWindow', args: argparse.Namespace) -> None:
     _init_colors(stdscr)
+
     if args.color_test:
-        _color_test(stdscr)
-    stdscr.getch()
+        return _color_test(stdscr)
+
+    filename = args.filename
+    status = ''
+    status_action_counter = -1
+    position_y, position_x = 0, 0
+
+    def _set_status(s: str) -> None:
+        nonlocal status, status_action_counter
+        status = s
+        status_action_counter = 25
+
+    while True:
+        if status_action_counter == 0:
+            status = ''
+        status_action_counter -= 1
+
+        _write_header(stdscr, filename, modified=False)
+        _write_status(stdscr, status)
+        stdscr.move(position_y + 1, position_x)
+
+        wch = stdscr.get_wch()
+        key = wch if isinstance(wch, int) else ord(wch)
+        keyname = curses.keyname(key)
+
+        if key == curses.KEY_DOWN:
+            position_y = min(position_y + 1, curses.LINES - 2)
+        elif key == curses.KEY_UP:
+            position_y = max(position_y - 1, 0)
+        elif key == curses.KEY_RIGHT:
+            position_x = min(position_x + 1, curses.COLS - 1)
+        elif key == curses.KEY_LEFT:
+            position_x = max(position_x - 1, 0)
+        elif keyname == b'^X':
+            return
+        else:
+            _set_status(f'unknown key: {keyname} ({key})')
 
 
 def main() -> int:
     parser = argparse.ArgumentParser()
     parser.add_argument('--color-test', action='store_true')
+    parser.add_argument('filename', nargs='?')
     args = parser.parse_args()
     curses.wrapper(c_main, args)
     return 0