proxmox-snapshot-service/pvesnap/curses_util.py

"""Gemeinsame curses-Bausteine fuer Konfigurationseditor und Explorer."""

from __future__ import annotations

import curses

C_HEADER, C_FOOTER, C_SEL, C_WARN, C_OK, C_DIM, C_DIR, C_MARK, C_MSG = range(1, 10)


def init_colors():
    try:
        curses.start_color()
        curses.use_default_colors()
        curses.init_pair(C_HEADER, curses.COLOR_WHITE, curses.COLOR_BLUE)
        curses.init_pair(C_FOOTER, curses.COLOR_BLACK, curses.COLOR_WHITE)
        curses.init_pair(C_SEL, curses.COLOR_BLACK, curses.COLOR_CYAN)
        curses.init_pair(C_WARN, curses.COLOR_WHITE, curses.COLOR_RED)
        # Gruen als Schriftfarbe, nicht als Hintergrund. Schwarz auf Gruen sah
        # im Terminal matschig aus - und mit A_BOLD wird aus Schwarz (Farbe 0)
        # Hellschwarz (Farbe 8), also Grau. Grau auf Gruen kann man nicht lesen.
        curses.init_pair(C_OK, curses.COLOR_GREEN, -1)
        curses.init_pair(C_DIM, -1, -1)
        curses.init_pair(C_DIR, curses.COLOR_CYAN, -1)
        curses.init_pair(C_MARK, curses.COLOR_YELLOW, -1)
        # Meldungsleiste: Weiss auf Blau bleibt auch fett gut lesbar, weil die
        # Schrift dabei heller wird statt dunkler.
        curses.init_pair(C_MSG, curses.COLOR_WHITE, curses.COLOR_BLUE)
    except curses.error:
        pass


# ---------------------------------------------------------------------------
# Zeichnen
# ---------------------------------------------------------------------------

def put(win, y, x, text, attr=0):
    """addstr, das bei zu kleinem Terminal nicht abstuerzt."""
    height, width = win.getmaxyx()
    if y < 0 or y >= height or x >= width:
        return
    try:
        win.addstr(y, x, str(text)[: max(0, width - x - 1)], attr)
    except curses.error:
        pass


def fill(win, y, text, attr):
    height, width = win.getmaxyx()
    if y < 0 or y >= height:
        return
    try:
        win.addstr(y, 0, str(text).ljust(width - 1)[: width - 1], attr)
    except curses.error:
        pass


def fill_row(win, y, x, text, width, attr):
    put(win, y, x, str(text).ljust(max(0, width - x - 1))[: max(0, width - x - 1)], attr)


# ---------------------------------------------------------------------------
# Tasten
# ---------------------------------------------------------------------------

def read_key(win):
    try:
        return win.get_wch()
    except curses.error:
        return None
    except KeyboardInterrupt:
        return "\x1b"


def is_enter(key):
    return key in ("\n", "\r", curses.KEY_ENTER)


def is_escape(key):
    return key == "\x1b"


def is_backspace(key):
    return key in ("\x7f", "\b", "\x08", curses.KEY_BACKSPACE)


def keybar(width, items):
    """Tastenleiste als Liste von Zeilen, passend zur Breite des Terminals.

    Reicht der Platz nicht fuer eine Zeile, wird auf zwei Zeilen umgebrochen;
    bei ganz schmalen Terminals bleiben nur noch die Tasten uebrig.
    """
    def join(entries, index):
        return " | ".join("%s %s" % (entry[0], entry[index]) for entry in entries)

    long_text = join(items, 1)
    if len(long_text) + 2 <= width:
        return [long_text]

    half = (len(items) + 1) // 2
    first, second = join(items[:half], 1), join(items[half:], 1)
    if max(len(first), len(second)) + 2 <= width:
        return [first, second]

    short_text = join(items, 2)
    if len(short_text) + 2 <= width:
        return [short_text]

    first, second = join(items[:half], 2), join(items[half:], 2)
    if max(len(first), len(second)) + 2 <= width:
        return [first, second]
    return ["  ".join(entry[0] for entry in items)]


# ---------------------------------------------------------------------------
# Dialoge
# ---------------------------------------------------------------------------

def message(win, text, error=False):
    height, _ = win.getmaxyx()
    attr = curses.color_pair(C_WARN if error else C_MSG) | curses.A_BOLD
    fill(win, height - 2, " " + str(text) + "   [Taste druecken]", attr)
    win.refresh()
    read_key(win)


def confirm(win, question):
    height, _ = win.getmaxyx()
    fill(win, height - 2, " %s  [j/n]" % question,
         curses.color_pair(C_WARN) | curses.A_BOLD)
    win.refresh()
    while True:
        key = read_key(win)
        if key in ("j", "J", "y", "Y"):
            return True
        if key in ("n", "N") or is_escape(key):
            return False


def ask(win, question, answers, default=None):
    """Mehrfachauswahl in einer Zeile. `answers` ist z.B. 'jnak'."""
    height, _ = win.getmaxyx()
    fill(win, height - 2, " %s" % question, curses.color_pair(C_WARN) | curses.A_BOLD)
    win.refresh()
    while True:
        key = read_key(win)
        if isinstance(key, str) and key.lower() in answers:
            return key.lower()
        if is_escape(key):
            return default


def prompt(win, label, initial=""):
    """Einzeilige Eingabe am unteren Rand. None = abgebrochen."""
    height, width = win.getmaxyx()
    buffer = list(str(initial))
    curses.curs_set(1)
    try:
        while True:
            text = "".join(buffer)
            label_text = " %s: " % label
            visible = width - len(label_text) - 2
            shown = text[-visible:] if visible > 0 and len(text) > visible else text
            fill(win, height - 2, label_text + shown, curses.color_pair(C_SEL))
            try:
                win.move(height - 2, min(width - 2, len(label_text) + len(shown)))
            except curses.error:
                pass
            win.refresh()

            key = read_key(win)
            if key is None:
                continue
            if is_enter(key):
                return "".join(buffer).strip()
            if is_escape(key):
                return None
            if is_backspace(key):
                if buffer:
                    buffer.pop()
                continue
            if key == "\x15":            # Strg-U
                buffer = []
                continue
            if isinstance(key, str) and key.isprintable():
                buffer.append(key)
    finally:
        curses.curs_set(0)


def choose(win, title, entries, current=0):
    """Kleines Auswahlfenster. entries: Liste von (wert, beschriftung)."""
    if not entries:
        return None
    height, width = win.getmaxyx()
    box_h = min(len(entries) + 4, height - 2)
    box_w = min(max([len(title)] + [len(e[1]) for e in entries]) + 8, width - 2)
    top = max(0, (height - box_h) // 2)
    left = max(0, (width - box_w) // 2)
    box = curses.newwin(box_h, box_w, top, left)
    box.keypad(True)
    index = max(0, min(current, len(entries) - 1))
    scroll = 0
    rows = max(1, box_h - 4)

    while True:
        if index < scroll:
            scroll = index
        if index >= scroll + rows:
            scroll = index - rows + 1
        box.erase()
        box.box()
        put(box, 0, 2, " %s " % title, curses.A_BOLD)
        for row in range(rows):
            position = scroll + row
            if position >= len(entries):
                break
            attr = curses.color_pair(C_SEL) if position == index else 0
            put(box, row + 2, 2, " " + entries[position][1].ljust(box_w - 5), attr)
        box.refresh()

        key = read_key(box)
        if key in (curses.KEY_UP, "k"):
            index = (index - 1) % len(entries)
        elif key in (curses.KEY_DOWN, "j"):
            index = (index + 1) % len(entries)
        elif key == curses.KEY_NPAGE:
            index = min(len(entries) - 1, index + rows)
        elif key == curses.KEY_PPAGE:
            index = max(0, index - rows)
        elif is_enter(key):
            return entries[index][0]
        elif is_escape(key) or key == "q":
            return None