document-a38

#!/usr/bin/python3
import argparse
import logging
import subprocess
import os
import re
import sys


log = logging.getLogger("document-a38")


class Fail(Exception):
    pass


def sample_output(cmd, max_lines=None, max_line_length=None, returncode=0):
    res = subprocess.run("./" + cmd, universal_newlines=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, shell=True)
    if res.returncode != returncode:
        raise RuntimeError(f"{cmd} return code is {res.returncode} instead of {returncode}")
    lines = []
    for idx, line in enumerate(res.stdout.splitlines()):
        if max_lines is not None and idx >= max_lines:
            lines.append("…")
            break
        if max_line_length is not None and len(line) > max_line_length:
            lines.append(line[:max_line_length] + "…")
        else:
            lines.append(line)
    return lines


def generate_output(mo):
    cmd = mo.group("cmd")
    output = mo.group("output")
    returncode = mo.group("result")
    if returncode is not None:
        returncode = int(returncode)
    else:
        returncode = 0

    # Autodetect max_lines and max_line_length
    lines = output.splitlines()

    max_lines = None
    if lines[-1] == "…":
        max_lines = len(lines) - 1

    max_line_length = None
    for l in lines:
        if len(l) > 1 and l[-1] == "…":
            max_line_length = len(l) - 1
            break

    lines = [
        "```text",
        f"$ {cmd}",
    ]
    lines.extend(sample_output(cmd, max_lines, max_line_length, returncode))
    if returncode != 0:
        lines.append("$ echo $?")
        lines.append(str(returncode))
    lines.append("```")

    return "\n".join(lines) + "\n"


def process_md(fname):
    with open(fname, "rt") as fd:
        content = fd.read()

    # print(re.search(
    #     r"```text\s*\n"
    #     r"(?P<output>.+?)"
    #     r"```"
    #     , content, re.S))

    new_content = re.sub(
        r"```text[ \t]*\n"
        r"\$ (?P<cmd>a38tool [^\n]+)\n"
        r"(?P<output>.+?)"
        r"(?:\$ echo \$\?\s*\n(?P<result>\d+)\s*\n)?"
        r"```[ \t]*\n", generate_output, content, flags=re.S)

    if new_content == content:
        return False

    with open(fname, "wt") as fd:
        fd.write(new_content)
    return True


def main():
    parser = argparse.ArgumentParser(description="Update a38tool examples in markdown documentation")
    parser.add_argument("--verbose", "-v", action="store_true", help="verbose output")
    parser.add_argument("--debug", action="store_true", help="debug output")

    args = parser.parse_args()

    log_format = "%(asctime)-15s %(levelname)s %(message)s"
    level = logging.WARN
    if args.debug:
        level = logging.DEBUG
    elif args.verbose:
        level = logging.INFO
    logging.basicConfig(level=level, stream=sys.stderr, format=log_format)

    for fn in os.listdir("."):
        if not fn.endswith(".md"):
            continue
        if process_md(fn):
            log.warning("%s: updated", fn)
        else:
            log.info("%s: unchanged", fn)


if __name__ == "__main__":
    try:
        main()
    except Fail as e:
        print(e, file=sys.stderr)
        sys.exit(1)
    except Exception:
        log.exception("uncaught exception")