#!/usr/bin/env python3

import argparse
import sys
import re


def get_opts():
    parser = argparse.ArgumentParser(
        description="Counters for markdown.",
        formatter_class=argparse.RawTextHelpFormatter,
    )
    parser.add_argument("-n", help="Number headers", action="store_true")
    parser.add_argument("-e", help="Number enumerated lists", action="store_true")
    parser.add_argument("-c", help="Add counter", action="append", default=[])
    parser.add_argument(
        "markdown",
        help="Filename to read. - for stdin",
        action="store",
        default="-",
        nargs="?",
    )
    args = parser.parse_args()
    return args


def main():
    opts = get_opts()
    if opts.markdown == "-":
        fp = sys.stdin
    else:
        fp = open(opts.markdown, "rt")
    markdown = fp.read().splitlines()

    counters = {"_headers": [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]}
    lastlev = {"_headers": 0}
    number_match = re.compile("[\d\.]+")

    counters["_enumerator"] = [0, 0, 0, 0]
    lastlev["_enumerator"] = 0
    enumerator_match = [re.compile("^" + " " * (4 * x) + "[\d]+\. ") for x in range(4)]
    in_enumerator = False

    for i, row in enumerate(markdown):
        if opts.n:
            if row.startswith("#"):
                headers, title = row.strip().split(" ", 1)
                # remove old numbered title
                if re.match("^\d", title):
                    if number_match.match(title.split(" ", 1)[0]):
                        removed_number, title = title.split(" ", 1)

                depth = headers.count("#") - 1
                if depth < lastlev["_headers"]:
                    counters["_headers"] = [
                        x if i <= depth else 0
                        for i, x in enumerate(counters["_headers"])
                    ]
                counters["_headers"][depth] += 1
                lastlev["_headers"] = depth
                number = "".join(
                    ["{:d}.".format(counters["_headers"][x]) for x in range(depth + 1)]
                )
                row = "{} {} {}".format(headers, number, title)

        if opts.e:
            if not in_enumerator and enumerator_match[0].match(row):
                in_enumerator = True
                counters["_enumerator"] = [0, 0, 0, 0]
                lastlev["_enumerator"] = 0

            if in_enumerator:
                enumerator_depths = [
                    enumerator_match[x].match(row) for x in range(len(enumerator_match))
                ]
                if any(enumerator_depths):
                    enumerator_depth = min(
                        [i for i, x in enumerate(enumerator_depths) if x]
                    )
                leading_spaces = len(row) - len(row.lstrip(" "))

                # if ^spaces = 4x depth
                # if row not empty, and doesnt match to enumerator -> reset
                if (
                    len(row.strip()) > 0
                    and not any(enumerator_depths)
                    and leading_spaces == 0
                ):
                    in_enumerator = False

            if in_enumerator:
                if any(enumerator_depths):
                    if enumerator_depth < lastlev["_enumerator"]:
                        counters["_enumerator"] = [
                            x if i <= enumerator_depth else 0
                            for i, x in enumerate(counters["_enumerator"])
                        ]
                    counters["_enumerator"][enumerator_depth] += 1
                    lastlev["_enumerator"] = enumerator_depth

                    removed_number, content = row.lstrip(" ").split(" ", 1)
                    number = "{:d}.".format(counters["_enumerator"][enumerator_depth])
                    row = "{}{} {}".format(" " * leading_spaces, number, content)

        print(row)


if __name__ == "__main__":
    main()