from django.contrib import messages
from django.contrib.auth import authenticate
from django.contrib.auth import login as auth_login
from django.contrib.auth import logout as auth_logout
from django.contrib.auth.models import User
from django.core.exceptions import ValidationError
from django.core.validators import validate_email
from django.http import HttpRequest, HttpResponse
from django.shortcuts import redirect, render
from django.views.decorators.http import require_http_methods
from django_ratelimit.decorators import ratelimit

from .models import UserProfile


def home(request):
    return render(request, "frontend/home.html")


@ratelimit(key="ip", rate="5/m", method="POST", block=False)
@require_http_methods(["GET", "POST"])
def register(request: HttpRequest) -> HttpResponse:
    user = getattr(request, "user", None)
    if user and user.is_authenticated:
        return redirect("home")

    if getattr(request, "limited", False):
        messages.error(request, "Too many attempts. Try again in a minute.")

    if request.method == "POST" and not getattr(request, "limited", False):
        email = str(request.POST.get("email", "")).strip().lower()
        display_name = str(request.POST.get("display_name", "")).strip()
        password = request.POST.get("password") or ""
        password_confirm = request.POST.get("password_confirm") or ""

        errors: list[str] = []
        if not email:
            errors.append("Email is required.")
        else:
            try:
                validate_email(email)
            except ValidationError:
                errors.append("Enter a valid email address.")

        if not display_name:
            errors.append("Display name is required.")

        if not password:
            errors.append("Password is required.")
        elif password != password_confirm:
            errors.append("Passwords do not match.")

        if email and User.objects.filter(username=email).exists():
            errors.append("An account with that email already exists.")

        if (
            display_name
            and UserProfile.objects.filter(  # type: ignore[attr-defined]
                display_name=display_name
            ).exists()
        ):
            errors.append("That display name is already taken.")

        if errors:
            for error in errors:
                messages.error(request, error)
        else:
            user = User.objects.create_user(
                username=email, email=email, password=password
            )
            UserProfile.objects.filter(user=user).update(  # type: ignore[attr-defined]
                display_name=display_name
            )
            auth_login(request, user)
            return redirect("home")

    return render(request, "frontend/register.html")


@ratelimit(key="ip", rate="10/m", method="POST", block=False)
@require_http_methods(["GET", "POST"])
def login(request: HttpRequest) -> HttpResponse:
    user = getattr(request, "user", None)
    if user and user.is_authenticated:
        return redirect("home")

    if getattr(request, "limited", False):
        messages.error(request, "Too many attempts. Try again in a minute.")

    if request.method == "POST" and not getattr(request, "limited", False):
        email = str(request.POST.get("email", "")).strip().lower()
        password = request.POST.get("password") or ""

        if not email or not password:
            messages.error(request, "Email and password are required.")
        else:
            user = authenticate(request, username=email, password=password)
            if user is None:
                messages.error(request, "Invalid email or password.")
            else:
                auth_login(request, user)
                return redirect("home")

    return render(request, "frontend/login.html")


@require_http_methods(["GET", "POST"])
def logout(request: HttpRequest) -> HttpResponse:
    if request.method == "POST":
        auth_logout(request)
        return redirect("home")

    return render(request, "frontend/logout.html")