# Functions dependent on advlabdb.models

from flask import flash, url_for
from flask_admin.menu import MenuLink
from flask_security import current_user
from sqlalchemy import select

from . import app, db
from .models import Semester


def sortedSemestersStartingWithNewest(limit=0):
    # Inserting an older semester is not allowed!
    # Therefore, the id is enough.
    stmt = select(Semester).order_by(Semester.id.desc())

    if limit > 0:
        stmt = stmt.limit(limit)

    return db.session.execute(stmt).scalars()


def lastSemester():
    return sortedSemestersStartingWithNewest(limit=1).first()


def setUserActiveSemester(semester):
    if semester is None:
        flash(f"Can not change the active semester to None!", "error")
        return

    if current_user.active_semester != semester:
        try:
            current_user.active_semester = semester
            db.session.commit()
        except Exception as ex:
            flash(str(ex), "error")

            db.session.rollback()
        else:
            flash(f"Active semester changed to {semester.repr()}!", "warning")


def initActiveSemesterMenuLinks(space):
    with app.app_context():
        try:
            semesters = sortedSemestersStartingWithNewest()
            for semester in semesters:
                space.add_link(
                    MenuLink(
                        name=semester.repr(),
                        url=url_for("set_semester") + "?semester_id=" + str(semester.id),
                        category="Active semester",
                    )
                )
        except Exception as ex:
            print(
                "ERROR: The Semester table does not exist yet! Therefore, menu links could not be generated. You can ignore this error if you are just initializing the database."
            )
        else:
            space.add_link(MenuLink(name="Logout", url=url_for("security.logout")))


def reportBadAttempt(message):
    print("BAD ATTEMPT:", message)  # TODO: Log


def get_count(table):
    return db.session.scalar(select(func.count()).select_from(table))


def active_semester_repr():
    active_semester = current_user.active_semester
    repr = active_semester.repr()
    if active_semester != lastSemester():
        flash(f"You are in the old semester {repr}!", "warning")

    return repr