siftlode/backend/app/routes/admin.py

"""Admin-only onboarding: review access requests (Invites), approve/deny, manual add.
Also the demo-account admin surface: the demo email whitelist + a manual state reset."""

from collections.abc import Iterable
from datetime import datetime, timezone

from fastapi import APIRouter, BackgroundTasks, Depends, HTTPException
from pydantic import BaseModel
from sqlalchemy import or_, select
from sqlalchemy.orm import Session

from app import audit
from app import email as email_mod
from app.audit import AuditAction
from app.auth import (
    admin_user,
    can_activate,
    count_admins,
    get_or_create_demo_user,
    is_allowed,
    operator_contact,
    purge_user,
)
from app.config import settings
from app.db import get_db
from app.demo import reset_demo_state
from app.models import (
    DemoWhitelist,
    Invite,
    User,
)
from app.routes._common import get_or_404
from app.routes.auth import send_verification_link
from app.utils import canonical_email, iso, valid_email

router = APIRouter(prefix="/api/admin", tags=["admin"])


def _accounts_for(db: Session, emails: Iterable[str]) -> set[str]:
    """Which of these addresses already have an account, as a set of CANONICAL forms. Batched, so
    listing the invites costs one extra query. An invite whose address has an account must not be
    deletable: `is_allowed` reads this row, so removing it would silently revoke a live user's access.

    Canonical on both sides, because `is_allowed` matches that way: an invite for `x.y@gmail.com`
    whose account registered as `xy@gmail.com` would otherwise look account-less, offer the admin a
    delete button, and take away a live user's access — precisely the accident this guard exists to
    prevent."""
    wanted = {canonical_email(e) for e in emails if e}
    if not wanted:
        return set()
    rows = db.execute(
        select(User.email_canonical).where(User.email_canonical.in_(wanted))
    ).scalars()
    return {e for e in rows if e}


def _env_allowed(email: str) -> bool:
    """Whether the env bootstrap lists still let this address in. `is_allowed` consults them only
    when no Invite row exists, so this is exactly what deleting the row would fall back to — and the
    admin has to know that BEFORE they confirm, not from a toast afterwards."""
    email = (email or "").lower()
    return email in settings.allowed_email_set or email in settings.admin_email_set


def _serialize(inv: Invite, *, has_account: bool = False) -> dict:
    return {
        "id": inv.id,
        "email": inv.email,
        "status": inv.status,
        "note": inv.note,
        "requested_at": iso(inv.requested_at),
        "decided_at": iso(inv.decided_at),
        "decided_by": inv.decided_by,
        # Drives the delete affordance: an entry backed by an account is not removable here.
        "has_account": has_account,
        # …and whether removing it would actually take access away, or leave the env allow-list
        # granting it anyway (for an ADMIN_EMAILS address, as an admin).
        "still_allowed_by_env": _env_allowed(inv.email),
    }


@router.get("/invites")
def list_invites(
    status: str | None = None,
    _: User = Depends(admin_user),
    db: Session = Depends(get_db),
) -> list[dict]:
    stmt = select(Invite)
    if status:
        stmt = stmt.where(Invite.status == status)
    # Pending first, then most-recently requested.
    rows = db.execute(stmt.order_by(Invite.requested_at.desc())).scalars().all()
    order = {"pending": 0, "approved": 1, "denied": 2}
    rows.sort(key=lambda i: order.get(i.status, 9))
    accounts = _accounts_for(db, (i.email for i in rows))
    return [_serialize(i, has_account=canonical_email(i.email) in accounts) for i in rows]


def _activate_user_by_email(db: Session, email: str) -> None:
    """Approving access activates a matching (e.g. pending password-registration) account so
    it can sign in. No-op if no such user exists yet (a Google user is created at first login).

    E9.5 S1: this path deliberately does NOT revoke a preset password. Approval is not an ownership
    attestation, and it does not need to be one — `password_login` refuses an unverified account
    BEFORE it looks at `is_active`, so a pre-emptor who set a password on someone else's address
    still cannot sign in with it, approved or not. Revoking here only ever destroyed the password a
    legitimate registrant had just chosen, and made "your password was cleared for security" the
    DEFAULT experience, because approve-before-verify is the normal ordering. The revoke stays on
    the Google-adoption path (auth.revoke_preset_password_if_unverified), where the real owner does
    attest ownership and the preset password must not survive."""
    # Canonical, with the literal spelling preferred when both exist: approving
    # `npeter83.temu@gmail.com` must activate the account that registered as `npeter83temu@gmail.com`,
    # since Gmail delivers both to one mailbox and the admin decided about the mailbox.
    email = email.lower()
    candidates = (
        db.execute(
            select(User).where(User.email_canonical == canonical_email(email)).order_by(User.id)
        )
        .scalars()
        .all()
    )
    user = next((u for u in candidates if u.email == email), None) or next(iter(candidates), None)
    if user is not None and not user.is_active:
        user.is_active = True
        db.commit()


def _decide(db: Session, invite_id: int, admin: User, approved: bool) -> Invite:
    inv = db.get(Invite, invite_id)
    if inv is None:
        raise HTTPException(status_code=404, detail="No such invite")
    # Idempotency guard: only a still-pending invite can be decided. Without this a repeat/stale
    # approve or deny re-runs its side effects — re-activating a user, or (now that deny emails)
    # sending a duplicate decision mail, even flipping an already-approved invite to "denied" and
    # mailing a rejection to an already-active account.
    if inv.status != "pending":
        raise HTTPException(status_code=409, detail="Invite already decided")
    inv.status = "approved" if approved else "denied"
    inv.decided_at = datetime.now(timezone.utc)
    inv.decided_by = admin.email
    audit.record(
        db,
        admin.id,
        AuditAction.INVITE_APPROVE if approved else AuditAction.INVITE_DENY,
        target_type="invite",
        target_id=inv.id,
        summary=inv.email,
    )
    db.commit()
    return inv


@router.post("/invites/{invite_id}/approve")
def approve_invite(
    invite_id: int,
    background: BackgroundTasks,
    admin: User = Depends(admin_user),
    db: Session = Depends(get_db),
) -> dict:
    inv = _decide(db, invite_id, admin, approved=True)
    _activate_user_by_email(db, inv.email)
    background.add_task(email_mod.send_access_approved, inv.email)
    return _serialize(inv, has_account=bool(_accounts_for(db, [inv.email])))


@router.post("/invites/{invite_id}/deny")
def deny_invite(
    invite_id: int,
    background: BackgroundTasks,
    admin: User = Depends(admin_user),
    db: Session = Depends(get_db),
) -> dict:
    # Symmetry with approve: the requester hears back either way, instead of a silent limbo. No
    # account is activated, so this is an email only (the requester has no in-app inbox yet).
    inv = _decide(db, invite_id, admin, approved=False)
    background.add_task(email_mod.send_access_denied, inv.email)
    return _serialize(inv, has_account=bool(_accounts_for(db, [inv.email])))


class AddInviteIn(BaseModel):
    email: str = ""


@router.post("/invites")
def add_invite(
    body: AddInviteIn,
    admin: User = Depends(admin_user),
    db: Session = Depends(get_db),
) -> dict:
    """Manually whitelist an email (approved straight away). Convenience for the admin."""
    email = body.email.strip().lower()
    if not valid_email(email):
        raise HTTPException(status_code=400, detail="Enter a valid email address.")
    # Reuse a canonically-equal row instead of adding a second one for the same mailbox. Prod carries
    # exactly that pair for one person from 2026-06-16 (hartmann.peter1986@ / hartmannpeter1986@),
    # which is how an admin ends up approving the same human twice and still seeing them bounce.
    canon = canonical_email(email)
    rows = db.execute(select(Invite).where(Invite.email_canonical == canon)).scalars().all()
    inv = next((r for r in rows if r.email == email), None) or next(iter(rows), None)
    if inv is None:
        inv = Invite(email=email)
        db.add(inv)
    inv.status = "approved"
    inv.decided_at = datetime.now(timezone.utc)
    inv.decided_by = admin.email
    audit.record(
        db, admin.id, AuditAction.INVITE_ADD, target_type="invite", target_id=inv.id, summary=email
    )
    db.commit()
    _activate_user_by_email(db, email)
    return _serialize(inv, has_account=bool(_accounts_for(db, [email])))


@router.delete("/invites/{invite_id}")
def delete_invite(
    invite_id: int,
    admin: User = Depends(admin_user),
    db: Session = Depends(get_db),
) -> dict:
    """Remove a whitelist/request entry outright — the counterpart to add_invite, for an address that
    never became an account (an approval added by mistake, or one that is no longer wanted). Deny
    records a decision and keeps the row for the audit trail; delete forgets the address. Neither
    stops the person asking again: `upsert_pending_invite` reopens a denied row, and a deleted one
    simply comes back as a fresh pending request.

    Refused once an account exists for the address, whatever its state: this row is the account's
    approval gate, and orphaning the account from it would leave a person who can neither sign in nor
    be approved. Delete the USER instead — purge_user removes the invite along with it.

    Reports `still_allowed_by_env`, because deleting the row is NOT always a revoke: `is_allowed`
    falls back to the env ALLOWED_EMAILS / ADMIN_EMAILS bootstrap lists once no invite exists, so for
    an address on those the deletion leaves access intact (and an ADMIN_EMAILS address is still
    promoted to admin on its next Google sign-in). The admin has to hear that, not guess it."""
    inv = db.get(Invite, invite_id)
    if inv is None:
        raise HTTPException(status_code=404, detail="No such invite")
    if _accounts_for(db, [inv.email]):
        raise HTTPException(
            status_code=409,
            detail="That address already has an account — delete the account instead.",
        )
    still_allowed_by_env = _env_allowed(inv.email)
    audit.record(
        db,
        admin.id,
        AuditAction.INVITE_DELETE,
        target_type="invite",
        target_id=inv.id,
        summary=inv.email,
    )
    db.delete(inv)
    db.commit()
    return {"deleted": invite_id, "still_allowed_by_env": still_allowed_by_env}


# --- Users & roles --------------------------------------------------------------------


def _serialize_user(u: User) -> dict:
    return {
        "id": u.id,
        "email": u.email,
        "display_name": u.display_name,
        "role": u.role,
        "is_active": u.is_active,
        "is_suspended": u.is_suspended,
        "email_verified": u.email_verified,
        "is_demo": u.is_demo,
        "has_password": u.password_hash is not None,
        "has_google": u.google_sub is not None,
        "created_at": iso(u.created_at),
    }


@router.get("/users")
def list_users(_: User = Depends(admin_user), db: Session = Depends(get_db)) -> list[dict]:
    rows = db.execute(select(User).order_by(User.created_at.desc())).scalars().all()
    return [_serialize_user(u) for u in rows]


class SetRoleIn(BaseModel):
    role: str


@router.patch("/users/{user_id}/role")
def set_user_role(
    user_id: int,
    body: SetRoleIn,
    background: BackgroundTasks,
    admin: User = Depends(admin_user),
    db: Session = Depends(get_db),
) -> dict:
    """Promote/demote a user. Guards: can't change your own role, can't touch the demo
    account, and can't remove the last remaining admin. Emails the user when it actually changes."""
    role = body.role
    if role not in ("user", "admin"):
        raise HTTPException(status_code=400, detail="role must be 'user' or 'admin'")
    target = db.get(User, user_id)
    if target is None:
        raise HTTPException(status_code=404, detail="No such user")
    if target.is_demo:
        raise HTTPException(status_code=400, detail="The demo account's role can't be changed.")
    if target.id == admin.id:
        raise HTTPException(status_code=400, detail="You can't change your own role.")
    if (
        target.role == "admin"
        and role == "user"
        and not target.is_suspended
        and count_admins(db, active_only=True) <= 1
    ):
        raise HTTPException(status_code=400, detail="Can't remove the last admin.")
    changed = target.role != role
    if changed:
        audit.record(
            db,
            admin.id,
            AuditAction.USER_ROLE_CHANGE,
            target_type="user",
            target_id=target.id,
            summary=target.email,
            before={"role": target.role},
            after={"role": role},
        )
    target.role = role
    db.commit()
    if changed:
        background.add_task(email_mod.send_role_changed, target.email, role, operator_contact())
    return _serialize_user(target)


class SetSuspendedIn(BaseModel):
    suspended: bool = False


@router.patch("/users/{user_id}/suspend")
def set_user_suspended(
    user_id: int,
    body: SetSuspendedIn,
    background: BackgroundTasks,
    admin: User = Depends(admin_user),
    db: Session = Depends(get_db),
) -> dict:
    """Suspend or un-suspend an account. A suspended user can't sign in by any method and any
    live session is dropped on its next request. Guards: can't suspend the demo account, can't
    suspend yourself, and can't suspend the last active admin (that would lock admin out). On
    un-suspend the user is emailed they can return (suspend is announced reactively, on a blocked
    sign-in)."""
    suspended = body.suspended
    target = db.get(User, user_id)
    if target is None:
        raise HTTPException(status_code=404, detail="No such user")
    if target.is_demo:
        raise HTTPException(status_code=400, detail="The demo account can't be suspended.")
    if target.id == admin.id:
        raise HTTPException(status_code=400, detail="You can't suspend your own account.")
    if (
        suspended
        and target.role == "admin"
        and not target.is_suspended
        and count_admins(db, active_only=True) <= 1
    ):
        raise HTTPException(status_code=400, detail="Can't suspend the last active admin.")
    was_suspended = target.is_suspended
    if was_suspended != suspended:
        audit.record(
            db,
            admin.id,
            AuditAction.USER_SUSPEND if suspended else AuditAction.USER_UNSUSPEND,
            target_type="user",
            target_id=target.id,
            summary=target.email,
        )
    target.is_suspended = suspended
    db.commit()
    if was_suspended and not suspended:
        background.add_task(email_mod.send_account_unsuspended, target.email, operator_contact())
    return _serialize_user(target)


@router.delete("/users/{user_id}")
def admin_delete_user(
    user_id: int,
    background: BackgroundTasks,
    admin: User = Depends(admin_user),
    db: Session = Depends(get_db),
) -> dict:
    """Admin-triggered account deletion — the same full erasure a user can perform on themselves
    (cascade delete of all personal data + access-request cleanup + Google-grant revoke). Guards:
    not the demo account, not yourself (use Settings → Account), and not the last admin."""
    target = db.get(User, user_id)
    if target is None:
        raise HTTPException(status_code=404, detail="No such user")
    if target.is_demo:
        raise HTTPException(status_code=400, detail="The demo account can't be deleted.")
    if target.id == admin.id:
        raise HTTPException(
            status_code=400, detail="Delete your own account from Settings → Account."
        )
    if (
        target.role == "admin"
        and not target.is_suspended
        and count_admins(db, active_only=True) <= 1
    ):
        raise HTTPException(status_code=400, detail="Can't delete the last admin.")
    # Record BEFORE the purge — the target row (and its email) is gone afterwards.
    audit.record(
        db,
        admin.id,
        AuditAction.USER_DELETE,
        target_type="user",
        target_id=target.id,
        summary=target.email,
    )
    purge_user(db, target, background)
    return {"deleted": user_id}


# --- Demo account: email whitelist + state reset -------------------------------------


# --- Stuck sign-ups: the admin lifeline (E9.5 S5, roadmap UX-25) ---------------------------------


def _pending_access_rows(db: Session) -> list[User]:
    """Accounts that have signed up but still cannot sign in, newest first.

    Two different dead ends share this list, because from the admin's chair they look the same — a
    person who registered and is still outside:
      · `is_active=False` — approved BEFORE they signed up, so nothing ever landed in the
        Access-requests queue and its Approve button doesn't apply (`_decide` only takes a pending
        row). This is roadmap UX-25, and it is why the list exists.
      · `email_verified=False` — the confirmation mail hasn't been acted on. Not the admin's to
        decide, but theirs to help with: on 2026-09-03 the first mail to a fresh Gmail landed in
        Spam, so "send it again" is a real move.
    A suspended account is deliberately excluded: it cannot sign in either, but that is a decision
    already made, not a person stuck waiting on one.
    """
    return list(
        db.execute(
            select(User)
            .where(
                User.is_demo.is_(False),
                User.is_suspended.is_(False),
                or_(User.is_active.is_(False), User.email_verified.is_(False)),
            )
            .order_by(User.created_at.desc())
        )
        .scalars()
        .all()
    )


@router.get("/pending-access")
def list_pending_access(_: User = Depends(admin_user), db: Session = Depends(get_db)) -> list[dict]:
    """The sign-ups that are still outside, with which gate is shut for each. `can_activate` cannot
    be derived on the client — it needs the invite/allow-list lookup — so it is answered here.

    One `is_allowed` query per row rather than a batched re-implementation of it: the row count is
    the admin's own backlog of stuck sign-ups (single digits on any real instance), and a second,
    subtly different copy of the "may this address sign in" rule is exactly the drift this codebase
    keeps getting bitten by."""
    rows = [(u, can_activate(db, u)) for u in _pending_access_rows(db)]
    # An account that is inactive, confirmed and merely waiting on a still-pending invite is ALREADY
    # an actionable row in the Access-requests queue above, with Approve on it. Listing it here too
    # would make the admin choose between two buttons for one person.
    return [
        _serialize_user(u) | {"can_activate": ca} for u, ca in rows if ca or not u.email_verified
    ]


@router.post("/users/{user_id}/activate")
def activate_user(
    user_id: int,
    admin: User = Depends(admin_user),
    db: Session = Depends(get_db),
) -> dict:
    """Let in a registrant whose address was approved before they signed up (roadmap UX-25).

    Admin-side ONLY, and that is the whole design. Two earlier attempts at this were reverted after
    review, and both moved authority rather than visibility: auto-activating on registration turns a
    standing whitelist entry into a bearer grant for whoever registers the address first, and
    reopening the approved invite to `pending` lets an anonymous sign-up REVOKE a standing approval.
    This endpoint changes nothing about what an unauthenticated caller can cause — the admin could
    already do exactly this by re-entering the address in the whitelist box (`add_invite` →
    `_activate_user_by_email`). What was missing was any way to know they had to."""
    target = get_or_404(db, User, user_id, detail="No such user")
    if target.is_demo:
        raise HTTPException(status_code=400, detail="The demo account can't be activated.")
    if target.is_active:
        return _serialize_user(target)  # idempotent: a double click is not an error
    if not is_allowed(db, target.email):
        raise HTTPException(
            status_code=409,
            detail={"code": "activate", "reason": "not_allowed", "email": target.email},
        )
    audit.record(
        db,
        admin.id,
        AuditAction.USER_ACTIVATE,
        target_type="user",
        target_id=target.id,
        summary=target.email,
        before={"is_active": False},
        after={"is_active": True},
    )
    target.is_active = True
    db.commit()
    return _serialize_user(target)


@router.post("/users/{user_id}/resend-verification")
def resend_user_verification(
    user_id: int,
    admin: User = Depends(admin_user),
    db: Session = Depends(get_db),
) -> dict:
    """Re-send an account's confirmation link from the admin side.

    The public /auth/verify/resend answers uniformly and reveals nothing, which is right for an
    anonymous caller but leaves the admin unable to tell a delivered mail from a dropped one. Here
    the caller is already authenticated as an admin, so this one says plainly what happened.

    Not rate-limited: an admin is not a threat model to enumerate against, and the deliberate silence
    of the public endpoint is exactly what this exists to escape."""
    target = get_or_404(db, User, user_id, detail="No such user")
    if target.is_demo or target.email_verified:
        raise HTTPException(
            status_code=409,
            detail={"code": "resend", "reason": "not_applicable", "email": target.email},
        )
    if not email_mod.email_enabled(db):
        # Mail is fail-soft everywhere else, which is what left the 0.78.5 sign-ups with nothing to
        # fall back on. An admin pressing a button deserves the failure, not a success toast.
        raise HTTPException(status_code=409, detail={"code": "resend", "reason": "email_off"})
    send_verification_link(db, target)
    audit.record(
        db,
        admin.id,
        AuditAction.USER_VERIFY_RESEND,
        target_type="user",
        target_id=target.id,
        summary=target.email,
    )
    db.commit()
    return {"ok": True, "email": target.email}


def _serialize_demo(row: DemoWhitelist) -> dict:
    return {
        "id": row.id,
        "email": row.email,
        "note": row.note,
        "added_by": row.added_by,
        "created_at": iso(row.created_at),
    }


@router.get("/demo/whitelist")
def list_demo_whitelist(_: User = Depends(admin_user), db: Session = Depends(get_db)) -> list[dict]:
    rows = (
        db.execute(select(DemoWhitelist).order_by(DemoWhitelist.created_at.desc())).scalars().all()
    )
    return [_serialize_demo(r) for r in rows]


class AddDemoWhitelistIn(BaseModel):
    email: str = ""
    note: str | None = None


@router.post("/demo/whitelist")
def add_demo_whitelist(
    body: AddDemoWhitelistIn,
    admin: User = Depends(admin_user),
    db: Session = Depends(get_db),
) -> dict:
    """Add an email that may enter the shared demo account from the login page (no Google
    sign-in). Idempotent — re-adding an existing email just returns it."""
    email = body.email.strip().lower()
    if not valid_email(email):
        raise HTTPException(status_code=400, detail="Enter a valid email address.")
    row = db.execute(select(DemoWhitelist).where(DemoWhitelist.email == email)).scalar_one_or_none()
    if row is None:
        row = DemoWhitelist(
            email=email,
            note=(body.note or "").strip() or None,
            added_by=admin.email,
        )
        db.add(row)
        audit.record(
            db, admin.id, AuditAction.DEMO_ADD, target_type="demo", target_id=email, summary=email
        )
        db.commit()
    return _serialize_demo(row)


@router.delete("/demo/whitelist/{entry_id}")
def remove_demo_whitelist(
    entry_id: int,
    admin: User = Depends(admin_user),
    db: Session = Depends(get_db),
) -> dict:
    row = db.get(DemoWhitelist, entry_id)
    if row is not None:
        audit.record(
            db,
            admin.id,
            AuditAction.DEMO_REMOVE,
            target_type="demo",
            target_id=row.email,
            summary=row.email,
        )
        db.delete(row)
        db.commit()
    return {"deleted": entry_id}


@router.post("/demo/reset")
def reset_demo(admin: User = Depends(admin_user), db: Session = Depends(get_db)) -> dict:
    """Manually clean up the shared demo sandbox back to a baseline. A scheduled job does the
    same automatically (admin-tunable interval); this is the admin's on-demand button."""
    demo = get_or_create_demo_user(db)
    seeded = reset_demo_state(db, demo)
    audit.record(
        db, admin.id, AuditAction.DEMO_RESET, summary=f"{seeded} sample playlists re-seeded"
    )
    db.commit()
    return {"reset": True, "playlists_seeded": seeded}


@router.post("/purge-discovery")
def purge_discovery(admin: User = Depends(admin_user), db: Session = Depends(get_db)) -> dict:
    """Reclaim all un-kept discovery content NOW (ignoring the grace period): live-search result
    videos nobody watched/saved/subscribed to, plus explored-but-unsubscribed channels. The
    scheduled discovery-cleanup job does the same on its interval; this is the on-demand button."""
    from app.sync.explore import purge_unkept_explored, purge_unkept_search

    result = {**purge_unkept_search(db, grace_days=0), **purge_unkept_explored(db)}
    audit.record(
        db,
        admin.id,
        AuditAction.DISCOVERY_PURGE,
        summary=", ".join(f"{k}: {v}" for k, v in result.items()) or None,
        after=result,
    )
    db.commit()
    return result