import secrets
from datetime import datetime, timezone, timedelta

from fastapi import APIRouter, Depends, Request
from fastapi.responses import HTMLResponse, RedirectResponse
from sqlalchemy.orm import Session

from web.auth.password import hash_password
from web.config import settings
from web.database import get_db
from web.models.user import User
from web.notifications.tasks import send_email_task
from web.templates_env import templates

router = APIRouter()


def _render(request: Request, template: str, ctx: dict) -> HTMLResponse:
    ctx["request"] = request
    ctx.setdefault("jivosite_widget_id", settings.JIVOSITE_WIDGET_ID)
    return templates.TemplateResponse(ctx.pop("request"), template, ctx)


@router.get("/forgot-password")
async def forgot_get(request: Request):
    return _render(request, "forgot_password.html", {"user": None})


@router.post("/forgot-password")
async def forgot_post(request: Request, db: Session = Depends(get_db)):
    form = await request.form()
    email = str(form.get("email", "")).strip()
    user = db.query(User).filter(User.email == email).first()
    if user:
        token = secrets.token_urlsafe(32)
        user.password_reset_token = token
        user.password_reset_expires = datetime.now(timezone.utc).replace(tzinfo=None) + timedelta(
            minutes=settings.PASSWORD_RESET_EXPIRE_MINUTES
        )
        db.commit()
        reset_url = f"{settings.BASE_URL}/reset-password?token={token}"
        html = f'<p>Сброс пароля: <a href="{reset_url}">{reset_url}</a></p>'
        send_email_task.delay(user.email, "Сброс пароля — ЭВОСИНК", html)
    # Always show same message to prevent user enumeration
    return _render(request, "message.html", {
        "user": None,
        "title": "Ссылка отправлена",
        "message": "Если указанный email зарегистрирован, вы получите ссылку для сброса пароля.",
        "link": "/login", "link_text": "Войти",
    })


@router.get("/reset-password")
async def reset_get(request: Request, db: Session = Depends(get_db)):
    token = request.query_params.get("token", "")
    user = db.query(User).filter(User.password_reset_token == token).first()
    if not user or not user.password_reset_expires or user.password_reset_expires < datetime.now(timezone.utc).replace(tzinfo=None):
        return _render(request, "message.html", {
            "user": None, "title": "Ссылка недействительна",
            "message": "Ссылка для сброса пароля устарела или недействительна.",
            "link": "/forgot-password", "link_text": "Запросить новую ссылку",
        })
    return _render(request, "reset_password.html", {"user": None, "token": token})


@router.post("/reset-password")
async def reset_post(request: Request, db: Session = Depends(get_db)):
    token = request.query_params.get("token", "")
    form = await request.form()
    password = str(form.get("password", ""))
    password_confirm = str(form.get("password_confirm", ""))
    errors = []

    user = db.query(User).filter(User.password_reset_token == token).first()
    if not user or not user.password_reset_expires or user.password_reset_expires < datetime.now(timezone.utc).replace(tzinfo=None):
        return _render(request, "message.html", {
            "user": None, "title": "Ссылка недействительна",
            "message": "Ссылка для сброса пароля устарела.",
            "link": "/forgot-password", "link_text": "Запросить новую ссылку",
        })

    if len(password) < 8:
        errors.append("Пароль должен содержать минимум 8 символов")
    if password != password_confirm:
        errors.append("Пароли не совпадают")

    if errors:
        return _render(request, "reset_password.html", {
            "user": None, "token": token, "errors": errors,
        })

    user.password_hash = hash_password(password)
    user.password_reset_token = None
    user.password_reset_expires = None
    db.commit()

    return _render(request, "message.html", {
        "user": None, "title": "Пароль изменён",
        "message": "Ваш пароль успешно изменён.",
        "link": "/login", "link_text": "Войти",
    })