import datetime
import re
from sqlalchemy import orm
from sqlalchemy.orm.session import Session
from wrpylib.wrorm import Page, WrIntermapsSledrun, WrIntermapsReport, WrIntermapsReportHistory


class UpdateError(RuntimeError):
    pass


def find_intermaps_sledrun(intermaps_sledrun_id: str, json_content: dict):
    """Returns iterator of tuples (region, sledrun) for given sledrun_id"""
    regions = json_content['items']
    for region in regions:
        for sledrun in region['sledruns']['items']:
            if sledrun['id'] == intermaps_sledrun_id:
                yield region, sledrun


def region_to_region_with_sledrun_dict(region: dict):
    region = region.copy()
    region.update({'sledruns': {sledrun['id']: sledrun for sledrun in region['sledruns']['items']}})
    return region


def json_content_to_region_dict(json_content: dict) -> dict:
    return {region['id']: region_to_region_with_sledrun_dict(region) for region in json_content['items']}


def update_wrintermapssledrun(session: Session, json_content: dict):
    """Updates the wrintermapssledrun table from the wiki. By filling in the missing fields of rows as long as
    intermaps_sledrun_id and wr_page_id are set.
    If convert errors occur, an UpdateError exception
    is raised. No other exception type should be raised under normal circumstances.

    >>> import json
    >>> from sqlalchemy.engine import create_engine
    >>> engine = create_engine('mysql://philipp@localhost:3306/philipp_winterrodeln_wiki?charset=utf8mb4')
    >>> Session = orm.sessionmaker(bind=engine)
    >>> with open('2019-12-06_090500.json') as fp:
    >>>     content = json.load(fp)
    >>> update_wrintermapssledrun(Session(), content)
    """
    q = session.query(WrIntermapsSledrun)
    for intermaps_sledrun in q:
        if intermaps_sledrun.intermaps_sledrun_name is None or intermaps_sledrun.intermaps_region_id is None or \
                intermaps_sledrun.intermaps_region_name is None or intermaps_sledrun.intermaps_country is None:
            region_json, sledrun_json = \
                next(find_intermaps_sledrun(intermaps_sledrun.intermaps_sledrun_id, json_content), (None, None))
            if region_json is None:
                raise UpdateError(
                    f'Sledrun with intermaps id {intermaps_sledrun.intermaps_sledrun_id} not found in JSON')
            if intermaps_sledrun.intermaps_sledrun_name is None:
                intermaps_sledrun.intermaps_sledrun_name = sledrun_json['name']
            if intermaps_sledrun.intermaps_region_id is None:
                intermaps_sledrun.intermaps_region_id = region_json['id']
            if intermaps_sledrun.intermaps_region_name is None:
                intermaps_sledrun.intermaps_region_name = region_json['names']['de']
            if intermaps_sledrun.intermaps_country is None:
                intermaps_sledrun.intermaps_country = region_json['countryCode']

        if intermaps_sledrun.wr_page_title is None:
            page = session.query(Page).get(intermaps_sledrun.wr_page_id)
            intermaps_sledrun.wr_page_title = page.page_title

    session.commit()


def update_wrintermapsreporthistory(session: Session):
    """add current content of wrintermapsreport to wrintermapshistory but does not commit session"""
    # the following lines are equivalent to
    # insert into wrintermapsreporthistory (intermaps_sledrun_id, status, last_update, first_check, utc_offset)
    #   select intermaps_sledrun_id, status, last_update, last_check, utc_offset from wrintermapsreport r
    #   where not exists (select 1 from wrintermapsreporthistory h
    #     where h.intermaps_sledrun_id=r.intermaps_sledrun_id and h.status=r.status and
    #     h.last_update=r.last_update and h.utc_offset=r.utc_offset);
    q = session.query(WrIntermapsReportHistory) \
        .filter(WrIntermapsReportHistory.intermaps_sledrun_id == WrIntermapsReport.intermaps_sledrun_id) \
        .filter(WrIntermapsReportHistory.status == WrIntermapsReport.status) \
        .filter(WrIntermapsReportHistory.last_update == WrIntermapsReport.last_update) \
        .filter(WrIntermapsReportHistory.utc_offset == WrIntermapsReport.utc_offset)
    for report in session.query(WrIntermapsReport).filter(~q.exists()):
        report_history = WrIntermapsReportHistory()
        report_history.intermaps_sledrun_id = report.intermaps_sledrun_id
        report_history.status = report.status
        report_history.last_update = report.last_update
        report_history.first_check = report.last_check
        report_history.utc_offset = report.utc_offset
        session.add(report_history)


def insert_json_to_intermapsreport(session: Session, json_content: dict, last_check: datetime.datetime):
    """add JSON content to intermaps_report. Does not commit the session"""
    regions = json_content_to_region_dict(json_content)
    for sledrun in session.query(WrIntermapsSledrun):
        region = regions.get(sledrun.intermaps_region_id)
        if region is None:
            continue
        sledrun_json = region['sledruns'].get(sledrun.intermaps_sledrun_id)
        if sledrun_json is None:
            continue
        report = WrIntermapsReport()
        report.intermaps_sledrun_id = sledrun.intermaps_sledrun_id
        report.status = sledrun_json['status']
        report.last_update = region['lastUpdate']
        report.last_check = last_check
        report.utc_offset = int(re.match(r'UTC([-+]\d\d)\d\d', region['timeZone']).group(1))
        session.add(report)


def update_wrintermapsreport(session: Session, json_content: dict, last_check: datetime.datetime):
    # add current content of wrintermapsreport to wrintermapshistory
    update_wrintermapsreporthistory(session)

    # delete content of intermaps_report
    session.query(WrIntermapsReport).delete()

    # add JSON content to intermaps_report
    insert_json_to_intermapsreport(session, json_content, last_check)