from datetime import datetime
import logging
from pathlib import Path
import re
from typing import List, Optional

def date2org(t: datetime) -> str:
    return t.strftime("%Y-%m-%d %a")

def datetime2orgtime(t: datetime) -> str:
    return t.strftime("%H:%M")

def datetime2org(t: datetime) -> str:
    return date2org(t) + " " + datetime2orgtime(t)

# TODO priority maybe??
# TODO need to sanitize!
def as_org_entry(
        heading: Optional[str] = None,
        tags: List[str] = [],
        body: Optional[str] = None,
        created: Optional[datetime]=None,
        todo=True,
):
    if heading is None:
        if body is None:
            raise RuntimeError('Both heading and body are empty!!')
        heading = body.splitlines()[0] # TODO ??

    if body is None:
        body = ''

    # TODO FIXME escape everything properly!
    heading = re.sub(r'\s', ' ', heading)
    # TODO remove newlines from body

    NOW = datetime.now() # TODO tz??
    # appended only added if it's different from created
    app = [f':APPENDED: [{datetime2org(NOW)}]'] if created is not None else []
    if created is None:
        created = NOW


    todo_s = ' TODO' if todo else ''
    tag_s = ':'.join(tags)

    sch = [f'  SCHEDULED: <{date2org(NOW)}>'] if todo else []

    if len(tag_s) != 0:
        tag_s = f':{tag_s}:'
    lines = [
        f"""*{todo_s} {heading} {tag_s}""",
        *sch,
        ':PROPERTIES:',
        *app,
        f':CREATED: [{datetime2org(created)}]',
        ':END:',
        body,
        "",
        "",
    ]
    return '\n'.join(lines)

# TODO should we check if it exists first?
def append_org_entry(
        path: Path,
        *args,
        **kwargs,
):
    res = as_org_entry(*args, **kwargs)
    # https://stackoverflow.com/a/13232181
    if len(res.encode('utf8')) > 4096:
        logging.warning("writing out %s might be non-atomic", res)
    with path.open('a') as fo:
        fo.write(res)