from random import randint
from itertools import islice

from flask import Response, abort
from apiflask import APIBlueprint
from sqlalchemy.exc import IntegrityError
from flask_sqlalchemy import get_debug_queries

from ...students.models import Student, Group, YearGroup, YearGroupStudents
from ...project_supervisor.models import ProjectSupervisor
from ..schemas import StudentSchema, StudentEditSchema, StudentsPaginationSchema, \
    StudentCreateSchema, MessageSchema, FileSchema, StudentQuerySchema, StudentListFileDownloaderSchema
from ...dependencies import db
from ..utils import parse_csv, generate_csv
from ..exceptions import InvalidNameOrTypeHeaderException
from ...base.utils import paginate_models, is_allowed_extensions

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


@bp.get("/<int:year_group_id>/")
@bp.input(StudentQuerySchema, location='query')
@bp.output(StudentsPaginationSchema)
def list_students(year_group_id: int, query: dict) -> dict:
    # add filter by year group
    fullname = query.get('fullname')
    order_by_first_name = query.get('order_by_first_name')
    order_by_last_name = query.get('order_by_last_name')
    page = query.get('page')
    per_page = query.get('per_page')

    student_query = Student.search_by_fullname_and_mode_and_order_by_first_name_or_last_name(
        year_group_id, fullname, order_by_first_name, order_by_last_name)

    data = paginate_models(page, student_query, per_page)
    # print(get_debug_queries()[0])
    return {
        "students": data['items'],
        "max_pages": data['max_pages']
    }


@bp.get("/<int:index>/")
@bp.output(StudentSchema)
def detail_student(index: int) -> Student:
    student = Student.query.filter_by(index=index).first()
    if student is None:
        abort(404, f"Student with {index} index doesn't exist!")
    return student


@bp.delete("/<int:index>/")
@bp.output(MessageSchema, status_code=202)
def delete_student(index: int) -> dict:
    student = Student.query.filter_by(index=index).first()
    if student is None:
        abort(404, f"Student with {index} index doesn't exist!")
    db.session.delete(student)
    db.session.commit()
    return {"message": "Student was deleted!"}


@bp.put("/<int:index>/")
@bp.input(StudentEditSchema)
@bp.output(MessageSchema)
def edit_student(index: int, data: dict) -> dict:
    if not data:
        abort(400, 'You have passed empty data!')

    student_query = Student.query.filter_by(index=index)
    student = student_query.first()

    if student is None:
        abort(404, 'Not found student!')

    student_query.update(data)
    db.session.commit()

    return {"message": "Student was updated!"}


@bp.post("/")
@bp.input(StudentCreateSchema)
@bp.output(MessageSchema)
def create_student(data: dict) -> dict:
    index = data['index']
    yg_id = data['year_group_id']
    del data['year_group_id']
    student = Student.query.filter_by(index=index).first()
    if student is not None:
        abort(400, "Student has already exists!")

    dummy_email = f'student{randint(1, 300_000)}@gmail.com'
    student = Student(**data, email=dummy_email)
    db.session.add(student)

    # add student to the chosen year group
    year_group = YearGroup.query.filter(YearGroup.id == yg_id).first()
    if year_group is None:
        abort(400, "Year group doesn't exist!")
    ygs = YearGroupStudents(student_index=student.index, year_group_id=year_group.id)
    db.session.add(ygs)

    db.session.commit()

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


@bp.post("/upload/")
@bp.input(FileSchema, location='form_and_files')
@bp.output(MessageSchema)
def upload_students(file: dict) -> dict:
    uploaded_file = file.get('file')
    if uploaded_file and is_allowed_extensions(uploaded_file.filename):
        try:
            students = parse_csv(uploaded_file, mode=True)
            while True:
                sliced_students = islice(students, 5)
                list_of_students = list(sliced_students)

                if len(list_of_students) == 0:
                    break
                db.session.add_all(list_of_students)
                db.session.commit()
        except InvalidNameOrTypeHeaderException:
            abort(400, "Invalid format of csv file!")
        except IntegrityError as e:
            # in the future create sql query checks index and add only these students, which didn't exist in db
            abort(400, "These students have already exist!")

    else:
        abort(400, "Invalid extension of file")

    return {"message": "Students was created by uploading csv file!"}


@bp.post("/download/")
@bp.input(StudentListFileDownloaderSchema, location='query')
def download_students(query: dict) -> Response:
    mode = query.get('mode')
    mode = mode if mode is not None else True
    students = db.session.query(Student).join(Group). \
        join(ProjectSupervisor).filter(Student.mode == mode).all()

    if len(students) == 0:
        abort(404, "Not found students, which are assigned to group!")
    csv_file = generate_csv(students)
    response = Response(csv_file, mimetype='text/csv')
    response.headers.set("Content-Disposition", "attachment", filename="students_list.csv")
    return response