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

from ...students.models import Group, Student, YearGroup, ProjectGradeSheet
from ...project_supervisor.models import ProjectSupervisor, YearGroupProjectSupervisors
from ..schemas import GroupSchema, GroupEditSchema, GroupsPaginationSchema, \
    GroupCreateSchema, MessageSchema, GroupQuerySchema, DetailGroupSchema
from ...dependencies import db
from ...base.utils import paginate_models
from ..utils import load_weight_for_project_grade_sheet, calculate_points_for_one_term

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


@bp.get("/<int:year_group_id>/")
@bp.input(GroupQuerySchema, location='query')
@bp.output(GroupsPaginationSchema)
def list_groups(year_group_id: int, query: dict) -> dict:
    search_name = query.get('name')
    page = query.get('page')
    per_page = query.get('per_page')

    weights = load_weight_for_project_grade_sheet()

    groups_query = Group.search_by_name(year_group_id, search_name)
    data = paginate_models(page, groups_query, per_page)

    items = data['items']
    pgs = []
    for g in items:
        if len(g.project_grade_sheet)==0:
            pgs.append(None)
        else:
            pgs.append(g.project_grade_sheet[0])
    calculated_points = calculate_points_for_one_term(weights, pgs)

    for group, points in zip(items, calculated_points):
        group.points_for_first_term = points[0]
        group.points_for_second_term = points[1]

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


@bp.post("/<int:year_group_id>/")
@bp.input(GroupCreateSchema)
@bp.output(MessageSchema)
def create_group(year_group_id: int, data: dict) -> dict:
    name = data['name']
    students_indexes = data['students']
    project_supervisor_id = data['project_supervisor_id']

    yg = YearGroup.query.filter(YearGroup.id == year_group_id).first()
    if yg is None:
        abort(404, "YearGroup doesn't exist!")

    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(db.func.count(ProjectSupervisor.id)). \
        join(Group).filter(ProjectSupervisor.id == project_supervisor_id).group_by(ProjectSupervisor.id).scalar()

    ygps = YearGroupProjectSupervisors.query. \
        filter(YearGroupProjectSupervisors.year_group_id == year_group_id,
               YearGroupProjectSupervisors.project_supervisor_id == project_supervisor_id).first()
    if limit is not None and ygps is not None and limit >= ygps.limit_group:
        abort(400, "Can't create new group, project supervisor achieved a limit of groups")

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

    students_without_groups = db.session.query(Student, Group). \
        join(Group, Student.groups). \
        filter(Group.year_group_id == year_group_id). \
        filter(db.or_(*[Student.index == idx for idx in students_indexes])).all()
    if len(students_without_groups) > 0:
        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()
    for student in students:
        group.students.append(student)

    db.session.commit()

    pgs = ProjectGradeSheet(group_id=group.id)
    db.session.add(pgs)
    db.session.commit()

    return {"message": "Group was created!"}


@bp.get("/<int:id>/detail/")
@bp.output(DetailGroupSchema)
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.delete("/<int:id>/")
@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!")

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


@bp.put("/<int:id>/")
@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!")

    students = db.session.query(Student).filter(Student.index.in_(data['students'])).all()
    group.students = students
    group.name = data['name']
    group.project_supervisor_id = data['project_supervisor_id']

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