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

import requests_util

from personal_data.data import DeduplicateMode, Scraper

from .. import secrets

logger = logging.getLogger(__name__)

URL_API_ROOT = 'https://api.wanikani.com/v2'
URL_ASSIGNMENTS = URL_API_ROOT + '/assignments'
URL_SUMMARY = URL_API_ROOT + '/summary'
URL_SUBJECTS = URL_API_ROOT + '/subjects/{subject_id}'


def _setup_cache(session):
    requests_util.setup_limiter(
        session,
        URL_API_ROOT,
        expire_after=datetime.timedelta(days=90),
        per_minute=30,
    )
    requests_util.setup_limiter(
        session,
        URL_ASSIGNMENTS,
        expire_after=datetime.timedelta(days=3),
        per_minute=30,
    )


@dataclasses.dataclass(frozen=True)
class WaniKaniLessonsFetcher(Scraper):
    dataset_name = 'wanikani_lessons'
    deduplicate_mode = DeduplicateMode.BY_ALL_COLUMNS

    def scrape(self) -> Iterator[Mapping[str, object]]:
        """Fetch assignments from the WaniKani API and yield a dict for each assignment with a non-null unlocked_at timestamp."""
        _setup_cache(self.session)
        headers = {
            'Authorization': f'Bearer {secrets.wanikani_api_key()}',
            'Wanikani-Revision': '20170710',
        }
        url = URL_ASSIGNMENTS
        while url:
            logger.warning('Getting: %s', url)
            response = self.session.get(url, headers=headers)
            response.raise_for_status()
            json_resp = response.json()
            for assignment in json_resp.get('data', []):
                data_item = assignment['data']
                subject_id = data_item.get('subject_id')
                if subject_id:
                    subj_url = URL_SUBJECTS.format(subject_id=subject_id)
                    logger.warning('Getting: %s', subj_url)
                    subj_response = self.session.get(subj_url, headers=headers)
                    subj_response.raise_for_status()
                    subj_json = subj_response.json()
                    subject_characters = subj_json.get('data', {}).get('characters')
                    data_item['subject_characters'] = subject_characters
                yield data_item
            url = json_resp.get('pages', {}).get('next_url')


@dataclasses.dataclass(frozen=True)
class WaniKaniSummaryFetcher(Scraper):
    dataset_name: str = 'wanikani_summary'
    deduplicate_mode = DeduplicateMode.BY_ALL_COLUMNS

    @staticmethod
    def deduplicate_mode() -> DeduplicateMode:
        return DeduplicateMode.BY_ALL_COLUMNS

    def scrape(self) -> Iterator[dict]:
        _setup_cache(self.session)
        headers = {
            'Authorization': f'Bearer {secrets.wanikani_api_key()}',
            'Wanikani-Revision': '20170710',
        }
        response = self.session.get(URL_SUMMARY, headers=headers)
        response.raise_for_status()
        data = response.json()

        lessons = data.get('data', {}).get('lessons', [])
        total_lessons = sum(len(lesson.get('subject_ids', [])) for lesson in lessons)

        reviews = data.get('data', {}).get('reviews', [])
        now = datetime.datetime.now(datetime.timezone.utc)
        total_reviews = 0
        for review in reviews:
            available_at_str = review.get('available_at')
            if available_at_str:
                available_at = datetime.datetime.fromisoformat(
                    available_at_str.replace('Z', '+00:00'),
                )
                if available_at <= now:
                    total_reviews += len(review.get('subject_ids', []))
            del review

        yield {
            'time': now,
            'lessons_available': total_lessons,
            'reviews_available': total_reviews,
        }