// postgres's provisioner — the adapter that makes postgres a provider of the mesh
// `postgres-database` interface. The watching, sealing and grant-file handling are the sdk
// harness's; this writes only the per-service half: how postgres creates and removes a consumer's
// database + owning role (novox/hq ADR 0044/0045).
//
// The `postgres-database` interface: a consumer receives `{ host, port, database, user, password }`
// and connects to a database only it owns.
//
// Identity (the database and role names) is derived from `grant.consumer` alone — never from
// `grant.values` — because on removal the harness hands the adapter a grant carrying only the
// consumer. Deriving from the consumer keeps create and remove naming the same resource.
//
// The credential is composed here and returned; the DDL runs through PostgresClient.query(), which
// is the module's one pending boundary (see client.ts). Until that boundary is backed, create()
// surfaces the TODO honestly rather than sealing a credential for a database that was never made.

import { runProvisioner, type Grant, type Credential } from "@novox/mesh-sdk/provisioner";
import { emit } from "@novox/mesh-sdk/events";
import { PostgresClient, generatePassword } from "../client.js";

const postgres = PostgresClient.fromEnv();

/** A stable postgres identifier for a consumer: lowercase [a-z0-9_], never starting with a digit. */
function identity(consumer: string): string {
  let safe = consumer.toLowerCase().replace(/[^a-z0-9_]/g, "_").replace(/^_+|_+$/g, "");
  if (safe === "" ) safe = "consumer";
  if (/^[0-9]/.test(safe)) safe = "_" + safe;
  return safe.slice(0, 63); // postgres identifier limit
}

/** Emit a lifecycle event without letting a broker hiccup fail the provisioning itself. */
async function announce(type: string, body: Record<string, string>): Promise<void> {
  try {
    await emit(type, body);
  } catch (err) {
    console.error(`[provisioner:postgres-database] emit ${type} failed: ${err}`);
  }
}

runProvisioner("postgres-database", {
  async create(grant: Grant): Promise<Credential> {
    const database = identity(grant.consumer);
    const user = database;
    const password = generatePassword();
    await postgres.createDatabaseAndRole(database, user, password);
    await announce("module.postgres.database.provisioned", { consumer: grant.consumer, database, user });
    return {
      fields: {
        host: postgres.host,
        port: String(postgres.port),
        database,
        user,
        password,
      },
    };
  },

  async remove(grant: Grant): Promise<void> {
    const database = identity(grant.consumer);
    const user = database;
    await postgres.dropDatabaseAndRole(database, user);
    await announce("module.postgres.database.deprovisioned", { consumer: grant.consumer, database });
  },
});