import re
from datetime import datetime

from flask import Flask, render_template, request, redirect, url_for, flash
from flask_sqlalchemy import SQLAlchemy

app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///accounting.db'
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
app.config['SECRET_KEY'] = "lab4_secret_key"

db = SQLAlchemy(app)


# ---------------- МОДЕЛЬ ----------------

class Employee(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    fullname = db.Column(db.String(120), nullable=False)
    salary = db.Column(db.Integer, nullable=False)
    created_at = db.Column(db.DateTime, default=datetime.utcnow)

    def __repr__(self):
        return f'<Employee {self.id}>'


# ----------- ВАЛИДАЦИЯ БЭКЕНДА ------------

def validate_employee(fullname: str, salary: str):
    errors = []

    fullname = fullname.strip()

    if not fullname:
        errors.append("ФИО не может быть пустым")
    elif len(fullname) < 5 or len(fullname) > 120:
        errors.append("ФИО должно быть от 5 до 120 символов")
    elif not re.fullmatch(r"[A-Za-zА-Яа-яЁё\s\-\']+", fullname):
        errors.append("ФИО может содержать только буквы, пробелы, дефисы и апострофы")

    if not salary:
        errors.append("Зарплата обязательна")
    else:
        try:
            salary = int(salary)
            if salary <= 0 or salary > 10_000_000:
                errors.append("Зарплата должна быть от 1 до 10 000 000")
        except:
            errors.append("Зарплата должна быть числом")

    return errors


# ---------------- РОУТЫ ----------------

@app.route("/")
def index():
    return render_template("index.html")


@app.route("/employees")
def employees():
    items = Employee.query.order_by(Employee.created_at.desc()).all()
    total_salary = sum(e.salary for e in items)
    return render_template("employees.html", employees=items, total_salary=total_salary)


@app.route("/create", methods=["GET", "POST"])
def create_employee():
    if request.method == "POST":
        fullname = request.form.get("fullname", "")
        salary = request.form.get("salary", "")

        errors = validate_employee(fullname, salary)
        if errors:
            for e in errors:
                flash(e, "error")
            return render_template("create_employee.html", fullname=fullname, salary=salary)

        employee = Employee(fullname=fullname.strip(), salary=int(salary))

        try:
            db.session.add(employee)
            db.session.commit()
            return redirect(url_for("employees"))
        except:
            return render_template("error.html", msg="Ошибка добавления")

    return render_template("create_employee.html")


@app.route("/employees/<int:id>")
def employee_detail(id):
    emp = Employee.query.get_or_404(id)
    return render_template("employee_detail.html", emp=emp)


@app.route("/employees/<int:id>/delete")
def employee_delete(id):
    emp = Employee.query.get_or_404(id)
    try:
        db.session.delete(emp)
        db.session.commit()
        return redirect(url_for("employees"))
    except:
        return render_template("error.html", msg="Ошибка удаления")


@app.route("/employees/<int:id>/update", methods=["GET", "POST"])
def employee_update(id):
    emp = Employee.query.get_or_404(id)

    if request.method == "POST":
        fullname = request.form.get("fullname", "")
        salary = request.form.get("salary", "")

        errors = validate_employee(fullname, salary)
        if errors:
            for e in errors:
                flash(e, "error")
            return render_template("employee_update.html", emp=emp)

        emp.fullname = fullname.strip()
        emp.salary = int(salary)

        try:
            db.session.commit()
            return redirect(url_for("employees"))
        except:
            return render_template("error.html", msg="Ошибка обновления")

    return render_template("employee_update.html", emp=emp)


if __name__ == "__main__":
    with app.app_context():
        db.create_all()
    app.run(debug=True)