"""Terminal rendering helpers (CJK-aware column widths)."""

import unicodedata


def display_width(text):
    width = 0
    for char in str(text):
        if unicodedata.east_asian_width(char) in ("W", "F"):
            width += 2
        else:
            width += 1
    return width


def clip(text, limit=60):
    text = "" if text is None else str(text)
    text = text.replace("\n", " ").replace("\r", " ").replace("\t", " ")
    if len(text) <= limit:
        return text
    return text[: max(0, limit - 1)] + "…"


def table(headers, rows, align=None):
    """Render a plain-text table. *align* is a list of ``l``/``r`` per column."""
    rows = [["" if cell is None else str(cell) for cell in row] for row in rows]
    if align is None:
        align = ["l"] * len(headers)
    widths = [display_width(header) for header in headers]
    for row in rows:
        for index, cell in enumerate(row[: len(widths)]):
            widths[index] = max(widths[index], display_width(cell))

    def render(cells):
        parts = []
        for index, cell in enumerate(cells):
            padding = widths[index] - display_width(cell)
            if align[index] == "r":
                parts.append(" " * padding + cell)
            else:
                parts.append(cell + " " * padding)
        return "  ".join(parts).rstrip()

    lines = [render(headers), "  ".join("-" * width for width in widths)]
    lines.extend(render(row) for row in rows)
    return "\n".join(lines)


def human_bytes(size):
    if not isinstance(size, (int, float)):
        return str(size)
    value = float(size)
    for unit in ("B", "KiB", "MiB", "GiB", "TiB"):
        if value < 1024 or unit == "TiB":
            if unit == "B":
                return "%d B" % value
            return "%.1f %s" % (value, unit)
        value /= 1024.0
    return str(size)


def percent(part, total):
    if not total:
        return "-"
    return "%.1f%%" % (100.0 * part / total)


def kv_block(pairs):
    """Render aligned ``key: value`` lines."""
    if not pairs:
        return ""
    width = max(display_width(key) for key, _ in pairs)
    lines = []
    for key, value in pairs:
        padding = " " * (width - display_width(key))
        lines.append("%s%s : %s" % (key, padding, "" if value is None else value))
    return "\n".join(lines)