"""
Facebook Messenger messages

Uses the output of [[https://github.com/karlicoss/fbmessengerexport][fbmessengerexport]]
"""
REQUIRES = [
    'git+https://github.com/karlicoss/fbmessengerexport',
]

from contextlib import ExitStack, contextmanager
from dataclasses import dataclass
from pathlib import Path
from typing import Iterator

from my.core import PathIsh, Res, stat, Stats
from my.core.warnings import high
from my.config import fbmessenger as user_config

import fbmessengerexport.dal as messenger


###
# support old style config
_new_section = getattr(user_config, 'fbmessengerexport', None)
_old_attr    = getattr(user_config, 'export_db', None)

if _new_section is None and _old_attr is not None:
    high("""DEPRECATED! Please modify your fbmessenger config to look like:

class fbmessenger:
    class fbmessengerexport:
        export_db: PathIsh = '/path/to/fbmessengerexport/database'
            """)
    class fbmessengerexport:
        export_db = _old_attr
    setattr(user_config, 'fbmessengerexport', fbmessengerexport)
###


@dataclass
class config(user_config.fbmessengerexport):
    export_db: PathIsh


@contextmanager
def _dal() -> Iterator[messenger.DAL]:
    model = messenger.DAL(config.export_db)
    with ExitStack() as stack:
        if hasattr(model, '__dal__'):  # defensive to support legacy fbmessengerexport
            stack.enter_context(model)
        yield model


def messages() -> Iterator[Res[messenger.Message]]:
    with _dal() as model:
        for t in model.iter_threads():
            yield from t.iter_messages()


def stats() -> Stats:
    return stat(messages)


### vvv not sure if really belongs here...

def _dump_helper(model: messenger.DAL, tdir: Path) -> None:
    for t in model.iter_threads():
        name = t.name.replace('/', '_') # meh..
        path = tdir / (name + '.txt')
        with path.open('w') as fo:
            for m in t.iter_messages(order_by='-timestamp'):
                # TODO would be nice to have usernames perhaps..
                dts = m.dt.strftime('%Y-%m-%d %a %H:%M')
                msg = f"{dts}: {m.text}"
                print(msg, file=fo)


def dump_chat_history(where: PathIsh) -> None:
    p = Path(where)
    assert not p.exists() or p.is_dir()

    from shutil import rmtree
    from tempfile import TemporaryDirectory
    with TemporaryDirectory() as tdir, _dal() as model:
        td = Path(tdir)
        _dump_helper(model, td)

        if p.exists():
            rmtree(p)
        td.rename(p)
        td.mkdir() # ugh, hacky way of preventing complaints from context manager