import logging
from .database import Database
from .jform import JForm
from .admin_log import AdminLog
from .config import *
from .utils import local_now
from .exceptions import *

"""A set of routine methods, run at an interval (somewhere from ten minutes to one hour), to:
- sync JImbrella's databse against data pulled from jForm
- check if any umbrella is now overdue
- send an SMS where applicable, to a user or an admin
"""


def chronological_merge(*sheet_lists) -> list:
    """Merges all lists answer sheets passed in, in chronological order, into a single list.

    All lists of sheets in sheet_lists MUST be already in chronological order.
    By "chronological", we mean sorting by the value under key "date".
    """
    chronicle = []
    while any(sheet_lists):  # at least one list in `sheet_lists` is non-empty
        # for each list of sheets, read date from its first element, then find the earliest
        # is an instance of datetime.datetime
        # only pass non-empty lists to min():
        earliest_date = min(
            [sheet_list[0]["date"] for sheet_list in filter(None, sheet_lists)]
        )
        for idx, sheet_list in enumerate(sheet_lists):
            if not sheet_list:  # is empty
                continue
            if sheet_list[0]["date"] == earliest_date:
                # remove the first element and append it to `chronicle`, if it is the earliest
                chronicle.append(sheet_lists[idx].pop(0))
                # we do not directly break here because there exists a tiny chance
                # two answer sheets were submitted at the exact same millisecond
    return chronicle


def sync_database(takeaway: JForm, giveback: JForm, db: Database, admin: AdminLog):
    takeaway_unread = takeaway.get_unread()
    giveback_unread = giveback.get_unread()
    logging.info(
        "Sync database: found %d unread takeaway sheet(s) and %d unread giveback sheet(s)",
        len(takeaway_unread),
        len(giveback_unread),
    )
    unread = chronological_merge(takeaway_unread, giveback_unread)
    # NOTE: beyond this point `takeaway_unread` and `giveback_unread` are empty
    #       because chronological_merge popped all their elements
    for sheet in unread:
        sheet["date"] = sheet["date"].replace(tzinfo=None)  # it's UTC+8 anyway
        sheet["date_str"] = sheet["date"].isoformat(timespec="seconds")
        tenant_identity = "{name} (ID: {id}, phone: {phone})".format(**sheet)
        if sheet["jform_name"] == "takeaway":
            try:
                db.take_away(
                    sheet["key"],
                    sheet["date"],
                    sheet["name"],
                    sheet["id"],
                    sheet["phone"],
                )
                logging.info(
                    tenant_identity
                    + " borrowed umbrella #{key} at {date_str}".format(**sheet)
                )
                admin.log("TAKEAWAY", sheet, date=sheet["date"])
            except UmbrellaStatusError:
                logging.warning(
                    tenant_identity
                    + " attempted to borrow inavailable umbrella #{key} at {date_str}".format(
                        **sheet
                    )
                )
            except UmbrellaNotFoundError:
                logging.warning(
                    tenant_identity
                    + " attempted to borrow non-existent umbrella #{key} at {date_str}".format(
                        **sheet
                    )
                )
        elif sheet["jform_name"] == "giveback":
            try:
                db.give_back(sheet["key"], sheet["name"], sheet["id"])
                logging.info(
                    tenant_identity
                    + " returned umbrella #{key} at {date_str}".format(**sheet)
                )
                admin.log("GIVEBACK", sheet, date=sheet["date"])
            except UmbrellaStatusError:
                logging.warning(
                    tenant_identity
                    + " attempted to return available umbrella #{key} at {date_str}".format(
                        **sheet
                    )
                )
            except UmbrellaNotFoundError:
                logging.warning(
                    tenant_identity
                    + " attempted to return non-existent umbrella #{key} at {date_str}".format(
                        **sheet
                    ),
                )
            except TenantIdentityError as e:
                logging.warning(
                    tenant_identity
                    + " attempted to return umbrella #{key} whose actual tenant is {expected}".format(
                        expected=e.expected, **sheet
                    )
                )


def process_overdue(db: Database):
    overdue = Database.find_overdue(db.read())
    # mark and log umbrellas that were not, but just became overdue
    for umb in filter(lambda u: u["status"] == "lent", overdue):
        db.mark_overdue(umb["serial"])
        logging.warning(
            "Umbrella #%d is now overdue, tenant: %s (ID: %s, phone: %s)",
            umb["serial"],
            umb["tenant_name"],
            umb["tenant_id"],
            umb["tenant_phone"],
        )


if __name__ == "__main__":
    takeaway = JForm("takeaway", JFORM_TAKEAWAY_URL, JFORM_BOOKMARK_DIR)
    giveback = JForm("giveback", JFORM_GIVEBACK_URL, JFORM_BOOKMARK_DIR)
    db = Database(DATABASE_PATH)
    admin_log = AdminLog(ADMIN_LOG_PATH)
    sync_database(takeaway, giveback, db, admin_log)