import { and, eq, isNotNull } from "drizzle-orm";
import { userEmailIdentities } from "@tasks/database/schema";
import { db } from "@tasks/database";

/**
 * Identity helpers built on top of the `user_email_identities` table.
 *
 * Why this module exists: invite acceptance (and any future feature that
 * binds an action to "the human who owns this email address") needs to
 * answer the question *"does this `users.id` actually control this email?"*
 * without leaking the wrong answer when the user signed in via a different
 * provider than the invite was sent to.
 *
 * The answer is: *yes* iff the user has a row in `user_email_identities`
 * with the lowercased email and `verified_at IS NOT NULL`. Both the
 * `source='primary'` mirror of `users.email` and any OAuth-claimed or
 * manually-verified identity counts.
 */

/**
 * Returns `true` iff the given user owns the given (lowercased) email
 * as a verified identity. Case-insensitive — callers may pass any case
 * and this function normalizes.
 *
 * This is the single source of truth for "is this email under this
 * user's control?" — invite acceptance, profile-bound API access, and
 * any future per-email permission check should funnel through here.
 */
export async function userOwnsEmail(
  userId: string,
  email: string,
): Promise<boolean> {
  const emailLower = email.trim().toLowerCase();
  if (!userId || !emailLower) return false;

  const rows = await db
    .select({ id: userEmailIdentities.id })
    .from(userEmailIdentities)
    .where(
      and(
        eq(userEmailIdentities.userId, userId),
        eq(userEmailIdentities.email, emailLower),
        isNotNull(userEmailIdentities.verifiedAt),
      ),
    )
    .limit(1);

  return rows.length > 0;
}

/**
 * Look up the `users.id` that owns a verified email, or `null` if no
 * verified identity matches. Used by the sign-in callback to resolve
 * an OAuth provider's email claim to the canonical user — replacing
 * the old `ensureUserIdByEmail` lookup against `users.email`.
 *
 * Note: this only returns matches where `verified_at IS NOT NULL`.
 * The (future) "pending manual verification" rows from
 * `Task-manual-email-verification` are correctly invisible here.
 */
export async function findUserIdByVerifiedEmail(
  email: string,
): Promise<string | null> {
  const emailLower = email.trim().toLowerCase();
  if (!emailLower) return null;

  const rows = await db
    .select({ userId: userEmailIdentities.userId })
    .from(userEmailIdentities)
    .where(
      and(
        eq(userEmailIdentities.email, emailLower),
        isNotNull(userEmailIdentities.verifiedAt),
      ),
    )
    .limit(1);

  return rows[0]?.userId ?? null;
}