import type { EkklesiaUserId } from "@ekklesia/contracts";
import { safeParseEkklesiaUserId } from "@ekklesia/contracts";
import { and, eq, sql } from "drizzle-orm";
import type { BootstrapIdentityCreator } from "../identity/bootstrap-identity.js";
import { BootstrapIdentityError } from "../identity/bootstrap-identity.js";
import type { IdentityDrizzleDatabase } from "../identity/database.js";
import { ekklesiaCoreAccount, ekklesiaCoreUser } from "../identity/schema.js";
import { bootstrapPlatformOwner, PlatformOwnerBootstrapError } from "./bootstrap.js";
import type { AuthorizationDrizzleDatabase } from "./database.js";
import { ekklesiaCorePlatformOwnerBootstrap } from "./schema.js";

export type InitialPlatformOwnerErrorCode =
  | "INITIAL_OWNER_ALREADY_COMPLETED"
  | "INITIAL_OWNER_EMAIL_INVALID"
  | "INITIAL_OWNER_IDENTITY_NOT_CREATED"
  | "INITIAL_OWNER_IDENTITY_UNUSABLE"
  | "INITIAL_OWNER_IDENTITY_NOT_VERIFIED"
  | "INITIAL_OWNER_OWNERSHIP_GRANT_FAILED"
  | "INITIAL_OWNER_PASSWORD_TOO_LONG"
  | "INITIAL_OWNER_PASSWORD_TOO_SHORT"
  | "INITIAL_OWNER_SCHEMA_UNAVAILABLE";

const initialOwnerMessages: Readonly<Record<InitialPlatformOwnerErrorCode, string>> = Object.freeze(
  {
    INITIAL_OWNER_ALREADY_COMPLETED:
      "This installation already has a platform owner. Initial-owner bootstrap runs once and cannot run again.",
    INITIAL_OWNER_EMAIL_INVALID: "The email address is not a valid address.",
    INITIAL_OWNER_IDENTITY_NOT_CREATED:
      "The identity system reported success but no account exists for that address. Nothing was changed; the bootstrap is still available.",
    INITIAL_OWNER_IDENTITY_UNUSABLE:
      "An account already exists for that address but has no password and could never sign in. Choose a different address, or remove that account before retrying.",
    INITIAL_OWNER_IDENTITY_NOT_VERIFIED:
      "The identity exists but could not be marked as a verified address, so it could not sign in. Nothing was granted; the bootstrap is still available.",
    INITIAL_OWNER_OWNERSHIP_GRANT_FAILED:
      "The identity exists but platform ownership was not granted. Bootstrap is still available: run this command again with the same email address to finish it.",
    INITIAL_OWNER_PASSWORD_TOO_LONG: "The password is longer than the identity system allows.",
    INITIAL_OWNER_PASSWORD_TOO_SHORT: "The password is shorter than the identity system allows.",
    INITIAL_OWNER_SCHEMA_UNAVAILABLE:
      "The database is unreachable or has not been migrated. Apply migrations before creating the initial owner.",
  },
);

/**
 * Never carries the password, a hash, a connection string, SQL, a driver error, or a cause. The
 * messages are written to be read by an operator at a terminal, so each one states what happened
 * *and* what is still true about the installation — in particular whether bootstrap remains
 * available, which is the only fact that determines what they should do next.
 */
export class InitialPlatformOwnerError extends Error {
  readonly code: InitialPlatformOwnerErrorCode;

  constructor(code: InitialPlatformOwnerErrorCode) {
    super(initialOwnerMessages[code]);
    this.name = "InitialPlatformOwnerError";
    this.code = code;
    this.stack = `${this.name}: ${this.message}`;
    Object.freeze(this);
  }
}

// A CLI-level advisory key distinct from `bootstrap.ts`'s: taking the same one would deadlock this
// operation against the grant it performs. This serializes whole invocations; that one serializes
// the grant transaction itself, and both remain in force.
const initialOwnerLockNamespace = 1_500_000_003;
const initialOwnerLockKey = 1_500_000_004;

export interface CreateInitialPlatformOwnerDependencies {
  readonly authorizationDb: AuthorizationDrizzleDatabase;
  readonly identityDb: IdentityDrizzleDatabase;
  readonly createIdentity: BootstrapIdentityCreator;
  /** Injected so a partial failure — identity created, ownership not granted — can be exercised.
   * Production composition leaves it unset and the real single-use bootstrap is used. */
  readonly grantOwnership?: (userId: EkklesiaUserId) => Promise<void>;
}

export interface CreateInitialPlatformOwnerInput {
  readonly email: string;
  readonly password: string;
  /** The display name the identity model requires. */
  readonly name: string;
}

export interface InitialPlatformOwnerResult {
  readonly email: string;
  readonly userId: EkklesiaUserId;
  /** `created` when this call made the identity; `adopted` when one already existed for that
   * address and only ownership was granted. Reported so an operator is never told something was
   * created when it was not. */
  readonly identity: "adopted" | "created";
}

interface ExistingIdentity {
  readonly userId: string;
  readonly hasCredential: boolean;
  /** As the identity system actually stored it, which is not necessarily as the operator typed it. */
  readonly storedEmail: string;
}

/**
 * Finds an identity by email, case-insensitively.
 *
 * Deliberately not an exact match on the caller's spelling: Better Auth lowercases the address it
 * stores (verified against the pinned release — `MiXeD@Example.ORG` persists as
 * `mixed@example.org`), so an exact comparison would fail to find the very account this operation
 * had just created and would report it missing.
 */
async function findIdentityByEmail(
  db: IdentityDrizzleDatabase,
  email: string,
): Promise<ExistingIdentity | undefined> {
  const rows = await db
    .select({ email: ekklesiaCoreUser.email, id: ekklesiaCoreUser.id })
    .from(ekklesiaCoreUser)
    .where(sql`lower(${ekklesiaCoreUser.email}) = ${email.trim().toLowerCase()}`)
    .limit(1);
  const found = rows[0];
  if (!found) {
    return undefined;
  }
  // A row in `user` alone is not an account anyone can sign in as — the credential lives in
  // `account`. The distinction matters: granting ownership to a passwordless row would consume the
  // one-time bootstrap on an identity nobody can authenticate as, leaving the installation with an
  // owner that cannot log in and no second chance.
  const credentials = await db
    .select({ id: ekklesiaCoreAccount.id })
    .from(ekklesiaCoreAccount)
    .where(
      and(
        eq(ekklesiaCoreAccount.userId, found.id),
        eq(ekklesiaCoreAccount.providerId, "credential"),
      ),
    )
    .limit(1);
  return { hasCredential: credentials.length > 0, storedEmail: found.email, userId: found.id };
}

/**
 * Marks one identity's address verified.
 *
 * A direct column update rather than an identity-system call, because the pinned release exposes no
 * supported way to mark an address verified other than consuming a token it emailed — which is the
 * one thing a pre-mail installation cannot do. The column is Better Auth's own `emailVerified`, the
 * exact value its `/verify-email` endpoint writes, so the resulting row is indistinguishable from
 * one that verified normally; nothing here invents a parallel notion of verification.
 */
async function markIdentityEmailVerified(
  db: IdentityDrizzleDatabase,
  userId: string,
): Promise<void> {
  await db
    .update(ekklesiaCoreUser)
    .set({ emailVerified: true })
    .where(eq(ekklesiaCoreUser.id, userId));
}

function translateIdentityCreationError(error: unknown): InitialPlatformOwnerError {
  if (error instanceof BootstrapIdentityError) {
    if (error.code === "BOOTSTRAP_IDENTITY_PASSWORD_TOO_SHORT") {
      return new InitialPlatformOwnerError("INITIAL_OWNER_PASSWORD_TOO_SHORT");
    }
    if (error.code === "BOOTSTRAP_IDENTITY_PASSWORD_TOO_LONG") {
      return new InitialPlatformOwnerError("INITIAL_OWNER_PASSWORD_TOO_LONG");
    }
    if (error.code === "BOOTSTRAP_IDENTITY_EMAIL_INVALID") {
      return new InitialPlatformOwnerError("INITIAL_OWNER_EMAIL_INVALID");
    }
  }
  return new InitialPlatformOwnerError("INITIAL_OWNER_IDENTITY_NOT_CREATED");
}

/**
 * Creates the first platform owner of a fresh installation: one identity, then the single-use
 * ownership grant.
 *
 * ## Why the identity is verified rather than trusted
 *
 * Better Auth's sign-up returns a **fabricated success** when the address is already registered —
 * a user object carrying an id that was never persisted, with the database left unchanged (verified
 * against the pinned release). On a public endpoint that is correct: it refuses to tell an
 * anonymous caller which addresses exist. Here it is a trap, because a caller that believed the
 * response would report an owner it never created and then grant ownership to an id that does not
 * exist. So the identity is always read back from the database, and that read — not the sign-up
 * response — is what the grant uses.
 *
 * ## Why an existing identity is adopted rather than refused or overwritten
 *
 * If the address already has a usable account and bootstrap is still open, ownership is granted to
 * it and **its password is left completely alone**. This is precisely the recovery path for the one
 * partial failure this operation can have: sign-up commits through Better Auth's own connection and
 * the grant runs in a separate transaction, so a crash between them leaves an identity with no
 * ownership. Refusing would strand a fresh installation with no way forward but manual SQL; a
 * password reset would be a silent takeover of an account the operator may not own. Adoption
 * changes no credential, and it is reported as `adopted` so nobody is told an account was created
 * when it was not.
 *
 * That is safe here specifically because production has **no** other way to create an identity —
 * public signup cannot be enabled at all — so an account present on a fresh installation was put
 * there by someone who already had database access.
 *
 * ## Ordering
 *
 * The bootstrap sentinel is checked before an identity is created, so a closed bootstrap never
 * leaves a stray account behind. That check is an early exit, not the authority: `bootstrapPlatformOwner`
 * re-checks it inside its own locked transaction, which is what actually makes the grant single-use.
 */
export async function createInitialPlatformOwner(
  dependencies: CreateInitialPlatformOwnerDependencies,
  input: CreateInitialPlatformOwnerInput,
): Promise<InitialPlatformOwnerResult> {
  const email = input.email.trim();
  if (email.length === 0) {
    throw new InitialPlatformOwnerError("INITIAL_OWNER_EMAIL_INVALID");
  }

  // Serializes entire invocations against each other. Without it two operators racing on a fresh
  // installation would both pass the sentinel check and both create an identity, and only then
  // would one lose the grant — leaving a stray account that can sign in and owns nothing. The grant
  // alone was already safe; this makes the whole command safe.
  return dependencies.authorizationDb.transaction(async (lockTx) => {
    await lockTx.execute(
      sql`select pg_advisory_xact_lock(${initialOwnerLockNamespace}, ${initialOwnerLockKey})`,
    );

    let alreadyConsumed: boolean;
    try {
      const consumed = await lockTx
        .select({ id: ekklesiaCorePlatformOwnerBootstrap.id })
        .from(ekklesiaCorePlatformOwnerBootstrap)
        .limit(1);
      alreadyConsumed = consumed.length > 0;
    } catch {
      // An unreachable database and a database without the authorization tables are the same
      // situation to an operator running this on a fresh server: the deployment step before this
      // one has not happened. Never migrated implicitly — see ADR 0035.
      throw new InitialPlatformOwnerError("INITIAL_OWNER_SCHEMA_UNAVAILABLE");
    }
    if (alreadyConsumed) {
      throw new InitialPlatformOwnerError("INITIAL_OWNER_ALREADY_COMPLETED");
    }

    let existing: ExistingIdentity | undefined;
    try {
      existing = await findIdentityByEmail(dependencies.identityDb, email);
    } catch {
      throw new InitialPlatformOwnerError("INITIAL_OWNER_SCHEMA_UNAVAILABLE");
    }
    if (existing && !existing.hasCredential) {
      throw new InitialPlatformOwnerError("INITIAL_OWNER_IDENTITY_UNUSABLE");
    }

    // Captured before the read-back below, which cannot distinguish the two: an identity this call
    // just created and one it adopted both come back with a credential.
    const identity: "adopted" | "created" = existing ? "adopted" : "created";

    if (!existing) {
      try {
        await dependencies.createIdentity({
          email,
          name: input.name,
          password: input.password,
        });
      } catch (error) {
        throw translateIdentityCreationError(error);
      }
      existing = await findIdentityByEmail(dependencies.identityDb, email).catch(() => undefined);
      if (!existing) {
        // Reached when sign-up reported success without persisting anything.
        throw new InitialPlatformOwnerError("INITIAL_OWNER_IDENTITY_NOT_CREATED");
      }
    }

    const parsedUserId = safeParseEkklesiaUserId(existing.userId);
    if (!parsedUserId.success) {
      throw new InitialPlatformOwnerError("INITIAL_OWNER_IDENTITY_NOT_CREATED");
    }

    /**
     * The trusted-bootstrap verification exception (ADR 0038).
     *
     * Every other human account must verify its address by email before it may hold a session.
     * This one cannot: it is created on a freshly provisioned server by an operator who already
     * holds the database credentials, at a moment when SMTP may not be configured, may not be
     * reachable, or may not yet have a DNS record to send from. Requiring an email round trip here
     * would mean a working installation whose administrator can never get in — the platform's
     * outbound mail would have to be configured and correct before anyone could sign in to
     * configure anything.
     *
     * The exception is narrow and its authority is the same authority that already makes this
     * command safe: possession of the database, not possession of the mailbox. It marks exactly one
     * address, exactly once per installation, and it is deliberately performed **before** ownership
     * is granted — if it fails, the sentinel and the grant roll back together and re-running the
     * command adopts the identity and finishes, rather than leaving an owner who cannot sign in.
     */
    try {
      await markIdentityEmailVerified(dependencies.identityDb, parsedUserId.data);
    } catch {
      throw new InitialPlatformOwnerError("INITIAL_OWNER_IDENTITY_NOT_VERIFIED");
    }

    try {
      const grant =
        dependencies.grantOwnership ??
        ((userId: EkklesiaUserId) =>
          bootstrapPlatformOwner(dependencies.authorizationDb, { userId }));
      await grant(parsedUserId.data);
    } catch (error) {
      if (
        error instanceof PlatformOwnerBootstrapError &&
        error.code === "PLATFORM_OWNER_BOOTSTRAP_ALREADY_CONSUMED"
      ) {
        throw new InitialPlatformOwnerError("INITIAL_OWNER_ALREADY_COMPLETED");
      }
      // The identity is real and remains usable; the sentinel rolled back with the grant, so
      // re-running this command with the same address adopts it and finishes.
      throw new InitialPlatformOwnerError("INITIAL_OWNER_OWNERSHIP_GRANT_FAILED");
    }

    // The stored address, never the operator's spelling: the identity system lowercases what it
    // persists, and telling someone to sign in as `Owner@Example.ORG` when the account is
    // `owner@example.org` invites them to conclude the command failed.
    return Object.freeze({ email: existing.storedEmail, identity, userId: parsedUserId.data });
  });
}