from datetime import date
from math import ceil
from random import randint

import click
from flask_security.utils import hash_password

from advlabdb import create_app, data_dir, user_datastore
from advlabdb.exceptions import DatabaseException
from advlabdb.models import (
    Admin,
    Appointment,
    Assistant,
    Experiment,
    ExperimentMark,
    Group,
    GroupExperiment,
    Part,
    PartStudent,
    Program,
    Semester,
    SemesterExperiment,
    Student,
    db,
)
from cli.test.generate_test_db.assistant_names import assistant_names
from cli.test.generate_test_db.experiment_titles import experiment_titles
from cli.test.generate_test_db.student_names import student_names


def db_add(obj):
    db.session.add(obj)
    return obj


def _generate_test_db():
    db_file = data_dir / "db/advlabdb.sqlite"
    if db_file.is_file():
        click.echo(
            click.style(
                f"Generating a test database is not allowed because a database already exists at {db_file}.",
                fg="red",
            )
        )
        return

    app = create_app(create_for_server=False)

    with app.app_context(), db.session.begin():
        db.create_all()

        bs_prog = db_add(Program(label="BS"))
        ms_prog = db_add(Program(label="MS"))
        be_prog = db_add(Program(label="BE"))
        programs = (bs_prog, ms_prog, be_prog)

        ss = db_add(Semester(label="SS", year=23))
        ws = db_add(Semester(label="WS", year=23))
        semesters = (ss, ws)

        bs_1_ss_part = db_add(Part(semester=ss, program=bs_prog, number=1))
        bs_2_ss_part = db_add(Part(semester=ss, program=bs_prog, number=2))
        ms_1_ss_part = db_add(Part(semester=ss, program=ms_prog, number=1))
        ms_2_ss_part = db_add(Part(semester=ss, program=ms_prog, number=2))
        be_1_ss_part = db_add(Part(semester=ss, program=be_prog, number=1))
        be_2_ss_part = db_add(Part(semester=ss, program=be_prog, number=2))
        ss_parts = (bs_1_ss_part, bs_2_ss_part, ms_1_ss_part, ms_2_ss_part, be_1_ss_part, be_2_ss_part)

        db_add(Part(semester=ws, program=bs_prog, number=1))
        bs_2_ws_part = db_add(Part(semester=ws, program=bs_prog, number=2))
        ms_1_ws_part = db_add(Part(semester=ws, program=ms_prog, number=1))
        ms_2_ws_part = db_add(Part(semester=ws, program=ms_prog, number=2))
        db_add(Part(semester=ws, program=be_prog, number=1))
        be_2_ws_part = db_add(Part(semester=ws, program=be_prog, number=2))

        semester_program_part_students = {
            ss: {program: [] for program in programs},
            ws: {program: [] for program in programs},
        }

        def add_part_student(student, part):
            part_student = db_add(PartStudent(student=student, part=part))
            semester_program_part_students[part.semester][part.program].append(part_student)

        for ind, name in enumerate(student_names):
            contact_email = f"{name[0]}-{name[1]}@private.de".lower() if ind % 2 == 0 else None

            student = db_add(
                Student(
                    student_number=ind,
                    first_name=name[0],
                    last_name=name[1],
                    uni_email=f"{name[0]}-{name[1]}@uni.de".lower(),
                    contact_email=contact_email,
                )
            )

            part = ss_parts[ind % len(ss_parts)]
            add_part_student(student, part)

            if ind % 10 < 9:
                # Transfer to the next part in the second semester
                if part == bs_1_ss_part:
                    add_part_student(student, bs_2_ws_part)
                elif part == bs_2_ss_part:
                    add_part_student(student, ms_1_ws_part)
                elif part == ms_1_ss_part:
                    add_part_student(student, ms_2_ws_part)
                elif part == be_1_ss_part:
                    add_part_student(student, be_2_ws_part)

        program_groups = {program: [] for program in programs}
        for program_part_students in semester_program_part_students.values():
            for program, part_students in program_part_students.items():
                if len(part_students) % 2 == 1:
                    # Add the first 3 students into a special group for an uneven number of students
                    group_part_students = []
                    for _ in range(3):
                        if len(part_students) == 0:
                            break

                        group_part_students.append(part_students.pop(0))

                    group = db_add(Group.customInit(group_part_students))
                    program_groups[program].append(group)

                while len(part_students) >= 2:
                    # Add the rest of the students into groups of 2
                    group = db_add(Group.customInit([part_students.pop(0) for i in range(2)]))
                    program_groups[program].append(group)

        program_semester_experiments = {program: [] for program in programs}
        all_semester_experiments = []
        for ind, title in enumerate(experiment_titles):
            program = programs[ind % len(programs)]

            experiment = db_add(
                Experiment(
                    number=ind + 1,
                    program=program,
                    title=title,
                    building="Not assigned",
                    room="Not assigned",
                    duration_in_days=2,
                )
            )

            for semester in semesters:
                semester_experiment = db_add(SemesterExperiment(experiment=experiment, semester=semester))
                program_semester_experiments[program].append(semester_experiment)
                all_semester_experiments.append(semester_experiment)

        all_group_experiments = []
        for program in programs:
            semester_experiments = program_semester_experiments[program]
            num_semester_experiments = len(semester_experiments)

            for ind, group in enumerate(program_groups[program]):
                num_tries = 0
                while True:
                    try:
                        semester_experiment = semester_experiments[ind % num_semester_experiments]
                        group_experiment = db_add(GroupExperiment(semester_experiment=semester_experiment, group=group))
                        for part_student in group.part_students:
                            db.session.add(ExperimentMark(part_student=part_student, group_experiment=group_experiment))
                    except DatabaseException as ex:
                        # Catch an error when a student becomes the same experiment for the second time.
                        # Try the next experiment!
                        ind += 1
                        num_tries += 1
                        if num_tries == num_semester_experiments:
                            raise ex
                    else:
                        break

                all_group_experiments.append(group_experiment)

        adminRole = user_datastore.create_role(name="admin")
        assistantRole = user_datastore.create_role(name="assistant")

        admin_names = (
            ("Aileen", "Grant"),
            ("Ben", "Huber"),
        )
        for name in admin_names:
            user = user_datastore.create_user(
                email=f"{name[0]}-{name[1]}@uni.de".lower(),
                password=hash_password("admin"),
                roles=[adminRole],
                first_name=name[0],
                last_name=name[1],
                active_semester=ws,
            )

            db_add(Admin(user=user))

        num_assistants = len(assistant_names)
        num_assistant_experiments = ceil(len(all_semester_experiments) / num_assistants)

        for name in assistant_names:
            user = user_datastore.create_user(
                email=f"{name[0]}-{name[1]}@uni.de".lower(),
                password=hash_password("assistant"),
                roles=[assistantRole],
                first_name=name[0],
                last_name=name[1],
                mobile_phone_number="01" + "".join(str(randint(0, 9)) for i in range(10)),
                active_semester=ws,
            )

            semester_experiments = []
            for _ in range(num_assistant_experiments):
                if len(all_semester_experiments) == 0:
                    break

                semester_experiments.append(all_semester_experiments.pop(0))

            db_add(Assistant(user=user, semester_experiments=semester_experiments))

        for group_experiment in all_group_experiments:
            semester_experiment = group_experiment.semester_experiment
            special = False
            semester = semester_experiment.semester
            if semester.label == "SS":
                month = randint(3, 8)
                if month <= 4:
                    special = True
            else:
                month = randint(9, 12)
                if month <= 10:
                    special = True

            year = 2000 + semester.year
            day = randint(1, 28)
            for appointment_date in (date(year, month, day), date(year, month, day + 1)):
                db_add(
                    Appointment(
                        date=appointment_date,
                        special=special,
                        group_experiment=group_experiment,
                        assistant=semester_experiment.assistants[0],
                    )
                )