import { dirname } from "path";

import { registerAs } from "@nestjs/config";
import { TypeOrmModuleOptions } from "@nestjs/typeorm";
import { DataSourceOptions } from "typeorm";

/**
 * Finance migrations are recorded in `finance.migrations`, alongside
 * `iam.typeorm_migrations`, `freight.migrations` and `hr.migrations` in the same
 * database. Each app owns exactly one history table; Finance never writes
 * another app's.
 */
export const FINANCE_MIGRATIONS = {
  schema: "finance",
  table: "migrations",
} as const;

/**
 * IAM entity registration.
 *
 * `IamModule` is embedded in this app (the platform pattern: every service takes
 * the IAM package as a dependency and IAM gates each action by the caller's
 * position), so its entities must be on this DataSource.
 *
 * Registered as GLOBS over the two package dists rather than as a hand-written
 * class list — copied from `apps/edr-hr-api/src/config/database.config.ts`,
 * which documents why: freight-api's hand-listed array goes stale on every
 * package bump, and globs cannot.
 *
 * BOTH dists are required. Some IAM entities relate to notification entities
 * that physically live in `@tria-plc/api-common` — the IAM barrel only
 * re-exports them — so registering only the IAM dist throws
 * `Entity metadata for User#sessions was not found` at boot.
 */
function resolvePackageDist(pkg: string): string {
  // Node honours each package's `exports` map at runtime even though TypeScript's
  // resolution does not, so require.resolve on the barrel lands in dist/.
  return dirname(require.resolve(pkg)).replace(/\\/g, "/");
}

const IAM_ENTITY_GLOBS = [
  `${resolvePackageDist("@tria-plc/iamapi-common")}/entities/**/*.entity.{ts,js}`,
  `${resolvePackageDist("@tria-plc/api-common")}/entities/**/*.entity.{ts,js}`,
];

function buildConnectionOptions() {
  return {
    type: "postgres" as const,
    host: process.env.DB_HOST ?? "localhost",
    port: parseInt(process.env.DB_PORT ?? "5432", 10),
    username: process.env.DB_USER ?? "edr",
    password: process.env.DB_PASSWORD ?? "edr_secret",
    database: process.env.DB_NAME ?? "edr_database",
    // Do NOT pass `extra.options: '-c search_path=...'` — the connection pooler
    // fronting the dev database rejects the Postgres `options` startup parameter
    // with `08P01`. search_path is applied per physical connection in a pool
    // `connect` handler instead (see app.module.ts).
    synchronize: false,
    logging:
      process.env.TYPEORM_LOGGING === "true"
        ? true
        : (["error", "warn"] as DataSourceOptions["logging"]),
  };
}

/**
 * Runtime options for the API. Carries no migrations — see `migration:run`.
 *
 * One connection serves both schemas: Finance entities are
 * `@Entity({schema:"finance"})` and IAM's are `schema:"iam"`, so they cannot
 * collide. `autoLoadEntities` is OFF because everything is listed explicitly
 * here — leaving it on lets IamModule's `forFeature` registrations add a PARTIAL
 * entity set, which is the exact configuration that failed at boot in HR.
 */
export function buildDataSourceOptions(): DataSourceOptions {
  return {
    ...buildConnectionOptions(),
    schema: FINANCE_MIGRATIONS.schema,
    entities: [__dirname + "/../**/*.entity.{ts,js}", ...IAM_ENTITY_GLOBS],
    migrations: [],
  };
}

/**
 * Finance migrations only, recorded in `finance.migrations`.
 *
 * Deliberately no entities: this DataSource exists to run Finance's own DDL.
 * Finance never migrates `iam`, `freight`, `passenger`, `hr` or `edr_payment` —
 * it only ever READS those, and each belongs to its own owner.
 */
export function buildFinanceMigrationDataSourceOptions(): DataSourceOptions {
  return {
    ...buildConnectionOptions(),
    schema: FINANCE_MIGRATIONS.schema,
    entities: [],
    migrations: [__dirname + "/../migrations/*.js"],
    migrationsTableName: FINANCE_MIGRATIONS.table,
    migrationsTransactionMode: "each",
  };
}

export default registerAs(
  "database",
  (): TypeOrmModuleOptions => ({
    ...buildDataSourceOptions(),
    autoLoadEntities: false,
    // Migrations run as a separate one-shot step, never on API boot (house rule).
    migrationsRun: false,
  }),
);