"""Account activation and password recovery by e-mail.

- Invitation: the professor adds an address → a "choose your password" link (INVITE_TTL_DAYS).
- Forgot / first login: the student asks for a link from the sign-in page (RESET_TTL_MINUTES).
Both land on /mot-de-passe?token=… where the password is chosen and the session opened.
"""

from __future__ import annotations

from app.core.config import Settings
from app.models import User
from app.services import mail, users


def password_link(settings: Settings, token: str) -> str:
    return f"{settings.APP_URL}/mot-de-passe?token={token}"


async def invite_users(targets: list[User], settings: Settings) -> dict:
    """Create one invitation token per user, e-mail them (batch) and stamp invited_at."""
    if not targets:
        return {"sent": [], "failed": [], "links": {}}
    mails: list[mail.Mail] = []
    links: dict[str, str] = {}
    for u in targets:
        token = await users.create_magic_link(u.email, ttl_minutes=settings.INVITE_TTL_DAYS * 24 * 60,
                                              purpose="invite")
        link = password_link(settings, token)
        links[u.id] = link
        mails.append(mail.invitation_mail(u.email, link, u.display_name, settings.INVITE_TTL_DAYS,
                                          settings.TERM_LABEL))
    outcome = await mail.send_batch(settings, mails) if settings.mail_enabled else {}
    sent = [u for u in targets if outcome.get(u.email)]
    failed = [u for u in targets if not outcome.get(u.email)]
    await users.mark_invited([u.id for u in sent])
    return {"sent": [u.email for u in sent], "failed": [u.email for u in failed], "links": links}


async def send_password_link(user: User, settings: Settings) -> tuple[bool, str]:
    """Forgot-password / first-login link. Returns (sent, link)."""
    first_time = not user.password_hash
    token = await users.create_magic_link(user.email, ttl_minutes=settings.RESET_TTL_MINUTES,
                                          purpose="reset")
    link = password_link(settings, token)
    sent = await mail.send(settings, mail.reset_mail(user.email, link, settings.RESET_TTL_MINUTES,
                                                     first_time))
    return sent, link