#!/usr/bin/env python3

import argparse
import datetime
import zoneinfo

SWEDEN = zoneinfo.ZoneInfo("Europe/Stockholm")

parser = argparse.ArgumentParser(
    prog="nikola_to_zola.py",
    description="Convert Nikola frontmatter to Zola",
)
parser.add_argument("filename")

args = parser.parse_args()

def parse_frontmatter_line(line: str) -> tuple[str, str]:
    """Parse one line from Nikola frontmatter

    Returns a tuple with (key, value).

    Parses dates into ISO8601 format.
    """
    frontmatter = tuple(line.strip()[3:].split(": ", 1))
    key = frontmatter[0]

    if key.strip().endswith(":"):
        key = key[:-1]

    if len(frontmatter) < 2:
        val = ""
    else:
        val = frontmatter[1]

    # Parse dateformat used in our frontmatter
    if key == 'date':
        try:
            time_format = "%Y-%m-%d %H:%M:%S %Z"
            val = datetime.datetime.strptime(val, time_format)
        except ValueError:
            time_format2 = "%Y-%m-%d %H:%M %Z"
            val = datetime.datetime.strptime(val, time_format2)

        val = val.astimezone(SWEDEN).isoformat()

    return key, val


def read_file():
    frontmatter = {}
    text = []
    with open(args.filename, 'r') as file:
        reading_frontmatter = True
        for line in file:
            if line == "<!--\n":
                continue
            if line.startswith("-->"):
                reading_frontmatter = False
                continue

            # Strip out teaser comments
            if line.startswith("<!-- TEASER"):
                continue

            if reading_frontmatter and line.startswith(".. "):
                fkey, fval = parse_frontmatter_line(line)
                frontmatter[fkey] = fval
            else:
                text.append(line)

    print("+++")
    for key, val in frontmatter.items():
        print(f'{key} = "{val}"')
    print("+++")
    print("".join(text).strip())


if __name__ == '__main__':
    read_file()