from datetime import datetime, timedelta
import json
from typing import List

from apollo_main_db.apollo.models import ApolloVisitLog
from smelog.factory import BoundLogger

from track_visit_events_handling import config
from track_visit_events_handling.main_db import session_scope


def update_legacy_messages(records: List[dict]):
    """Convert legacy messages to new format.

    Args:
        records: Legacy records.

    """
    for item in records:
        if item.get("spotify_id"):
            item.update({"dsp_id": 1, "type_id": 1, "instance_id": item["spotify_id"]})
        if item.get("apple_id"):
            item.update({"dsp_id": 2, "type_id": 1, "instance_id": item["apple_id"]})
        if "spotify_id" in item:
            del item["spotify_id"]
        if "apple_id" in item:
            del item["apple_id"]


def save_track_visits(records: List[dict]):
    """Insert new track visit logs to the database.

    Args:
        records (List[dict]): Track visit records to insert

    """
    update_legacy_messages(records)
    for i in range(0, len(records), config.TRACK_VISITS_BATCH_SIZE):
        current_chunk = records[i:i + config.TRACK_VISITS_BATCH_SIZE]

        with session_scope() as session:
            session.bulk_insert_mappings(ApolloVisitLog, current_chunk, render_nulls=True)


def cleanup_track_visit_logs() -> int:
    """Remove outdated track page visit logs from the database

    Returns:
        int: Affected row count.

    """
    cut_off_time = datetime.utcnow() - timedelta(days=config.TRACK_VISITS_LOG_RETENTION_DAYS)
    with session_scope() as session:
        result = session.query(ApolloVisitLog).filter(ApolloVisitLog.created_at < cut_off_time).delete()
        return result


def process_event(logger: BoundLogger, event: dict):
    """Handler contains business logic

    Args:
        logger (logging.Logger): Logger instance
        event (dict): SQS records.

    """
    records = [json.loads(r["body"]) for r in event["Records"]]

    save_track_visits(records)
    logger.info("{} new records saved.".format(len(records)))

    count = cleanup_track_visit_logs()
    logger.info("{} outdated records were removed.".format(count))