"""Excel (.xlsx) → Markdown。每個工作表一節，內容輸出為 Markdown 表格。

可獨立執行：python tools/convert/from_xlsx.py <file.xlsx> [-o out.md] [--dry-run]
"""
import argparse
import pathlib

import openpyxl


def _cell(v):
    return "" if v is None else str(v).replace("|", "\\|").replace("\n", " ").strip()


def convert(src, assets_dir=None, md_dir=None):
    """回傳 (markdown, status)。status 恆為 'ok'。

    ponytail: merged cell 只有左上角有值（openpyxl read_only 行為），不展開；
    升級路徑：非 read_only 模式讀 merged_cells.ranges 補值。
    """
    wb = openpyxl.load_workbook(str(src), data_only=True, read_only=True)
    sections = []
    for ws in wb.worksheets:
        rows = [[_cell(v) for v in row] for row in ws.iter_rows(values_only=True)]
        rows = [r for r in rows if any(r)]  # 去除全空列
        body = f"## 工作表：{ws.title}\n\n"
        if not rows:
            body += "（空白工作表）"
        else:
            width = max(len(r) for r in rows)
            rows = [r + [""] * (width - len(r)) for r in rows]
            lines = ["| " + " | ".join(rows[0]) + " |", "|" + " --- |" * width]
            lines += ["| " + " | ".join(r) + " |" for r in rows[1:]]
            body += "\n".join(lines)
        sections.append(body)
    wb.close()
    return "\n\n".join(sections), "ok"


def main(argv=None):
    ap = argparse.ArgumentParser(description=__doc__)
    ap.add_argument("src")
    ap.add_argument("-o", "--output")
    ap.add_argument("--dry-run", action="store_true")
    a = ap.parse_args(argv)
    md, status = convert(a.src)
    if a.dry_run:
        print(f"[dry-run] {a.src}: status={status}, {len(md)} chars")
        return
    out = pathlib.Path(a.output) if a.output else pathlib.Path(a.src).with_suffix(".md")
    out.write_text(md, encoding="utf-8")
    print(out)


if __name__ == "__main__":
    main()