from flask import (Blueprint, render_template, request, redirect, url_for, flash, session, current_app)

from app.services.user_service import UserService
from app.constants.messages import SuccessMessage, ErrorMessage
from app.constants.http_status import HTTPStatus

auth_bp = Blueprint("auth", __name__)


# ==========================
# LOGIN
# ==========================
@auth_bp.route("/login", methods=["GET", "POST"])
def login():

    if session.get("user_id"):
        current_app.logger.info("User already logged in.")
        return redirect(url_for("dashboard.dashboard"))

    if request.method == "POST":

        try:
            email = request.form.get("email", "").strip()
            password = request.form.get("password", "")

            if not email or not password:
                flash(ErrorMessage.INVALID_REQUEST, "danger")
                current_app.logger.warning("Login failed. Email or password missing.")
                return render_template("login.html", title="Login")

            user = UserService.validate_login(email, password)

            if user:
                session.clear()
                session["user_id"] = user.id
                session["user_name"] = user.name
                session["email"] = user.email
                session.permanent = True
                
                current_app.logger.info(f"Login successful. User={user.name}")
                flash(SuccessMessage.LOGIN, "success")
                return redirect(url_for("dashboard.dashboard"))

            current_app.logger.warning(f"Invalid login attempt. Email={email}")
            flash(ErrorMessage.LOGIN_FAILED,"danger")

        except Exception as e:
            current_app.logger.exception("Login Error" )
            flash(ErrorMessage.INTERNAL_SERVER_ERROR,"danger")

    return render_template("login.html", title="Login")


# ==========================
# LOGOUT
# ==========================
@auth_bp.route("/logout")
def logout():
    username = session.get("user_name", "Unknown")
    session.clear()
    current_app.logger.info(f"Logout successful. User={username}")
    flash(SuccessMessage.LOGOUT,"info")

    return redirect(url_for("auth.login"))


# ==========================
# REGISTER
# ==========================
@auth_bp.route("/register", methods=["GET", "POST"])
def register():

    if request.method == "POST":
        try:
            name = request.form.get("name", "").strip()
            email = request.form.get("email", "").strip()
            password = request.form.get("password", "")

            if not name or not email or not password:
                flash(ErrorMessage.INVALID_REQUEST,"danger")
                return redirect(url_for("auth.register"))

            user = UserService.register_user(name, email, password)

            if not user:
                current_app.logger.warning(f"Duplicate Registration: {email}")
                flash(ErrorMessage.DUPLICATE_ENTRY,"danger")
                return redirect(url_for("auth.register"))

            current_app.logger.info(f"New user registered: {email}")
            flash(SuccessMessage.CREATED,"success")
            return redirect(url_for("auth.login"))

        except Exception:
            current_app.logger.exception("User Registration Failed" )
            flash(ErrorMessage.INTERNAL_SERVER_ERROR,"danger")

    return render_template("register.html",title="Register")