"""# Markdown Message Conversion.

Conversion script from various messaging formats to markdown.

Supported input formats:

- [Pidgin/Libpurple](https://pidgin.im/) chat program HTML-based logs. **This
  backend is not actively maintained.**
- [SyncTech Backup & Restore](https://www.synctech.com.au/sms-backup-restore/)
  XML-based backup format.

## Motivation

Messaging applications are mostly good at sending real-time messages to other
people, but they generally do not possess any useful archival features. Most
messages are write-once read-once, and the apps where built for this use case.
More and more through, I am attracted to the prospect of archival; of
understanding who I am and who I _were_ when I wrote those messages.

I recently discovered [Obsidian](https://obsidian.md) and liked the prospect of
cross-referencing my notes with my old chat logs. Libpurple uses HTML logs if
you haven't configured it to something else (which I haden't).

I no longer use IRC or Pidgin as my entire friend group have switched to using
Matrix.

## Usage

From the repository root:

```bash
python -m libpurple_to_markdown LOG_DIRECTORY --output OUTPUT_FOLDER
```

It was made specifically for import into Obsidian, so it might not suite your
purposes, but it shouldn't be too difficult to adjust the formatting code.

## TODO

- [ ] Decode MMS parts and reconstruct image attachments.
"""

import dataclasses
import datetime
import logging
from collections.abc import Iterable, Iterator

from ._version import __version__
from .data import Message

__all__ = ['__version__']

logger = logging.getLogger(__name__)


def datetime_sent(
    chat_start: datetime.datetime,
    message_sent: datetime.time,
) -> datetime.datetime:
    naive = datetime.datetime.combine(
        chat_start.date(),
        message_sent,
        chat_start.tzinfo,
    )
    if chat_start.time() > message_sent:
        naive = naive + datetime.timedelta(days=1)
    return naive


MSG_ADJACENTCY_DIST = datetime.timedelta(minutes=2)


def is_useless_message(msg: Message) -> bool:
    return msg.sender.endswith('<AUTO-REPLY>') or msg.sender == ''


def filter_useless_messages(messages: Iterable[Message]) -> Iterator[Message]:
    for msg in messages:
        if not is_useless_message(msg):
            yield msg
        else:
            print(msg.text)


def is_adjacent_messages(first: Message, second: Message) -> bool:
    return (
        first.sender == second.sender
        and second.sent_at - first.sent_at <= MSG_ADJACENTCY_DIST
    )


PUNCTUATION = ('.', '?', '!', ',', ':', ';')


def merge_texts(text1: str, text2: str) -> str:
    punctuated = text1.endswith(PUNCTUATION)
    return text1 + ('' if punctuated else '.') + '\n' + text2


def merge_adjacent_messages(messages: Iterable[Message]) -> list[Message]:
    out: list[Message] = []
    for msg in messages:
        if out and is_adjacent_messages(out[-1], msg):
            out[-1] = dataclasses.replace(
                out[-1],
                text=merge_texts(out[-1].text, msg.text),
            )
        else:
            out.append(msg)
    return out