from flask import abort, current_app
from apiflask import APIBlueprint
from flask_sqlalchemy import get_debug_queries

from ...students.models import Group, Student
from ...project_supervisor.models import ProjectSupervisor
from ..schemas import GroupSchema, GroupEditSchema, GroupsPaginationSchema, \
    GroupCreateSchema, MessageSchema, GroupQuerySchema
from ...dependencies import db
from ...base.utils import paginate_models

bp = APIBlueprint("groups", __name__, url_prefix="/groups")


@bp.route("/", methods=["GET"])
@bp.input(GroupQuerySchema, location='query')
@bp.output(GroupsPaginationSchema)
def list_groups(query: dict) -> dict:
    search_name = query.get('name')
    page = query.get('page')
    per_page = query.get('per_page')

    groups_query = Group.search_by_name(search_name)

    data = paginate_models(page, groups_query, per_page)

    return {
        "groups": data['items'],
        "max_pages": data['max_pages']
    }


@bp.route("/", methods=["POST"])
@bp.input(GroupCreateSchema)
@bp.output(MessageSchema)
def create_group(data: dict) -> dict:
    name = data['name']
    students_indexes = data['students']
    project_supervisor_id = data['project_supervisor_id']

    project_supervisor = ProjectSupervisor.query.filter_by(id=project_supervisor_id).first()

    limit_student_per_group = current_app.config.get('LIMIT_STUDENTS_PER_GROUP')
    if project_supervisor is None:
        abort(400, f"Project Supervisor with id {project_supervisor_id} doesnt exist")
    elif limit_student_per_group is not None and limit_student_per_group < len(students_indexes):
        abort(400, f"Too much students you want add to group, "
                   f"The group can have only {limit_student_per_group} students")

    limit = db.session.query(ProjectSupervisor.limit_group - db.func.count(ProjectSupervisor.id)).join(Group).filter(
        ProjectSupervisor.id == project_supervisor_id).group_by(ProjectSupervisor.id).scalar()

    if limit is not None and limit <= 0:
        abort(400, "Can't create new group, project supervisor achieved a limit of groups")

    group = Group(name=name, project_supervisor_id=project_supervisor_id)

    students_without_groups = db.session.query(Student).join(Group, isouter=True) \
        .filter(Group.id.is_(None)).filter(Student.index.in_(students_indexes)).count()

    if students_without_groups != len(students_indexes):
        abort(400, "One or more students have already belonged to group!")

    db.session.add(group)
    db.session.commit()

    students = db.session.query(Student).filter(Student.index.in_(students_indexes)).all()
    project_supervisor.count_groups += 1
    for student in students:
        student.group_id = group.id

    db.session.commit()

    return {"message": "Project Supervisor was created!"}


@bp.route("/<int:id>/", methods=["GET"])
@bp.output(GroupSchema)
def detail_group(id: int) -> Group:
    group = Group.query.filter_by(id=id).first()
    if group is None:
        abort(400, f"Group with id {id} doesn't exist!")
    return group


@bp.route("/<int:id>/", methods=["DELETE"])
@bp.output(MessageSchema, status_code=202)
def delete_group(id: int) -> dict:
    group = Group.query.filter_by(id=id).first()
    if group is None:
        abort(400, f"Group with id {id} doesn't exist!")

    project_supervisor = ProjectSupervisor.query.filter_by(id=group.project_supervisor_id).first()
    project_supervisor.count_groups -= 1

    students = db.session.query(Student).filter_by(group_id=id).all()
    for student in students:
        student.group_id = None

    db.session.delete(group)
    db.session.commit()
    return {"message": "Group was deleted!"}


@bp.route("/<int:id>", methods=["PUT"])
@bp.input(GroupEditSchema)
@bp.output(MessageSchema)
def edit_group(id: int, data: dict) -> dict:
    if not data:
        abort(400, 'You have passed empty data!')

    group_query = Group.query.filter_by(id=id)
    group = group_query.first()

    if group is None:
        abort(400, f"Group with id {id} doesn't exist!")

    group_query.update(data)
    db.session.commit()
    return {"message": "Group was updated!"}