from typing import Tuple
from random import randint
from itertools import islice

from flask import Blueprint, request, Response
from marshmallow import ValidationError
from sqlalchemy.exc import IntegrityError
from flask_sqlalchemy import get_debug_queries

from ...students.models import Student
from ..schemas import StudentSchema, StudentEditSchema, StudentCreateSchema
from ...dependencies import db
from ..utils import parse_csv
from ..exceptions import InvalidNameOrTypeHeaderException
from ...base.utils import paginate_models, is_allowed_extensions

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


@bp.route("/", methods=["GET"])
def list_students() -> Tuple[dict, int]:
    students_schema = StudentSchema(many=True)

    fullname = request.args.get('fullname')
    order_by_first_name = request.args.get('order_by_first_name')
    order_by_last_name = request.args.get('order_by_last_name')
    page = request.args.get('page')

    student_query = Student.search_by_fullname_and_order_by_first_name_or_last_name(fullname, order_by_first_name,
                                                                                    order_by_last_name)

    response = paginate_models(page, student_query)
    if isinstance(response, tuple):
        return response
    # print(get_debug_queries()[0])
    return {"students": students_schema.dump(response['items']), "max_pages": response['max_pages']}, 200


@bp.route("/<int:index>/", methods=["GET"])
def detail_student(index: int) -> Tuple[dict, int]:
    student_schema = StudentSchema()
    student = Student.query.filter_by(index=index).first()
    if student is not None:
        return student_schema.dump(student), 200
    return {"error": f"Student with {index} index doesn't exist!"}, 404


@bp.route("/<int:index>/", methods=["DELETE"])
def delete_student(index: int) -> Tuple[dict, int]:
    student = Student.query.filter_by(index=index).first()
    if student is not None:
        db.session.delete(student)
        db.session.commit()
        return {"message": "Student was deleted!"}, 202
    return {"error": f"Student with {index} index doesn't exist!"}, 404


@bp.route("/<int:index>/", methods=["PUT"])
def edit_student(index: int) -> Tuple[dict, int]:
    request_data = request.get_json()
    student_schema = StudentEditSchema()

    try:
        data = student_schema.load(request_data)
        if not data:
            return {"error": "You have passed empty data!"}, 400

        student_query = Student.query.filter_by(index=index)
        student = student_query.first()
        if student is None:
            return {"error": "Not Found student!"}, 404

        student_query.update(data)
        db.session.commit()
    except ValidationError as e:
        return {"error": e.messages}, 422
    return {"message": "Student was updated!"}, 200


@bp.route("/", methods=["POST"])
def create_student() -> Tuple[dict, int] or Response:
    request_data = request.get_json()
    student_schema = StudentCreateSchema()

    try:
        data = student_schema.load(request_data)

        index = data['index']
        student = Student.query.filter_by(index=index).first()
        if student is not None:
            return {"error": "Student has already exists!"}, 400

        dummy_email = f'student{randint(1, 300_000)}@gmail.com'
        student = Student(**data, email=dummy_email)
        db.session.add(student)
        db.session.commit()
    except ValidationError as e:
        return {'error': e.messages}, 422
    return {"message": "Student was created!"}, 200


@bp.route("/upload/", methods=["POST"])
def upload_students() -> Tuple[dict, int]:
    """Maybe in the future move to celery workers"""
    if (uploaded_file := request.files.get('file')) is None or uploaded_file.filename == '':
        return {"error": "You didn't attach a csv file!"}, 400

    if uploaded_file and is_allowed_extensions(uploaded_file.filename):
        try:
            students = parse_csv(uploaded_file)
        except InvalidNameOrTypeHeaderException:
            return {"error": "Invalid format of csv file!"}, 400

        try:
            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 IntegrityError as e:
            # print(e)
            # in the future create sql query checks index and add only these students, which didn't exist in db
            return {"error": "These students have already exist!"}, 400
    else:
        return {"error": "Invalid extension of file"}, 400

    return {"message": "Students was created by uploading csv file!"}, 200