import datetime
import json
from decimal import Decimal
from logging import getLogger
from pathlib import Path
from typing import Any

import frontmatter

logger = getLogger(__name__)

StatisticKey = str


class ObsidianVault:
    def __init__(self, vault_path: Path, read_only: bool = 'silent'):
        self.vault_path = vault_path

        assert (self.vault_path / '.obsidian').exists(), 'Not an Obsidian Vault'

        with open(self.vault_path / '.obsidian' / 'daily-notes.json') as f:
            daily_notes_config = json.load(f)
        self.daily_folder = daily_notes_config['folder']
        self.path_format = daily_notes_config['format']
        self.template_file_path = daily_notes_config['template']
        self.read_only = read_only

    def get_statistic(
        self, date: datetime.date, statistic_key: StatisticKey,
    ) -> Any | None:
        try:
            with open(self._date_file_path(date)) as f:
                data = frontmatter.load(f)
        except FileNotFoundError:
            return None

        return data.metadata.get(statistic_key)

    def add_statistic(
        self, date: datetime.date, statistic_key: StatisticKey, amount: Any,
    ) -> bool:
        if self.read_only == 'silent':
            logger.info(
                'Real only ObsidianVault ignoring add_statistic(%s, "%s", %s)',
                date,
                statistic_key,
                amount,
            )
            return False

        self._create_date_if_not_present(date)

        with open(self._date_file_path(date)) as f:
            data = frontmatter.load(f)

        if isinstance(amount, Decimal):
            amount = float(amount)

        if data.metadata.get(statistic_key) == amount:
            return False

        data.metadata[statistic_key] = amount
        if amount is None:
            del data.metadata[statistic_key]

        with open(self._date_file_path(date), 'wb') as f:
            frontmatter.dump(data, f)

        return True

    def add_event(self, date: datetime.date, verb: str, subject: str) -> None:
        if self.read_only == 'silent':
            logger.info(
                'Real only ObsidianVault ignoring add_event(%s, "%s", ?)', date, verb,
            )
            return

        self._create_date_if_not_present(date)
        # TODO

    def _create_date_if_not_present(self, date: datetime.date):
        date_file = self._date_file_path(date)
        if date_file.exists():
            return
        logger.info('File "%s" doesn\'t exist, creating...', date)
        with open(self._daily_template_path()) as f:
            template_text = f.read()
        with open(date_file, 'w') as f:
            f.write(template_text)

    def _date_file_path(self, date: datetime.date):
        path = (
            self.path_format.replace('YYYY', str(date.year))
            .replace('MM', f'{date.month:02d}')
            .replace('DD', f'{date.day:02d}')
        )
        return (self.vault_path / self.daily_folder / path).with_suffix('.md')

    def _daily_template_path(self):
        return (self.vault_path / self.template_file_path).with_suffix('.md')