import { readFile, readdir } from "node:fs/promises";
import path from "node:path";
import { identityShimEnabled } from "@/config/env";
import { EXPECTED_MIGRATIONS, isShimMigration } from "./migration-manifest";
import type { Db } from "./types";

/**
 * Executor de migrations. Lê o diretório `migrations/`, por isso só é usado
 * pelos scripts operacionais e pelo banco local de development — nunca por uma
 * rota. Quem precisa saber o estado do schema em runtime usa
 * `migration-manifest.ts`, que só consulta o banco.
 *
 * O caminho é estaticamente limitado a `<cwd>/migrations`: montar o caminho a
 * partir de uma variável fazia o Next tracear o projeto inteiro para dentro da
 * saída `standalone`, levando docs, testes e fontes para a imagem.
 */

const MIGRATIONS_FOLDER = "migrations";

export type MigrateOptions = {
  /** Aplica o shim de identidade. Padrão: `ADAPTER_APPLY_IDENTITY_SHIM`. */
  applyIdentityShim?: boolean;
};

export function migrationsDir(): string {
  return path.join(process.cwd(), MIGRATIONS_FOLDER);
}

export async function listMigrationFiles(): Promise<string[]> {
  const entries = await readdir(path.join(process.cwd(), MIGRATIONS_FOLDER));
  return entries.filter((file) => file.endsWith(".sql")).sort();
}

/**
 * O manifesto estático e o diretório precisam contar a mesma história. Um
 * arquivo novo sem entrada no manifesto passaria em branco pelo health check.
 */
export function assertManifestMatches(files: string[]): void {
  const expected: string[] = [...EXPECTED_MIGRATIONS];
  const extra = files.filter((file) => !expected.includes(file));
  const missing = expected.filter((file) => !files.includes(file));
  if (extra.length === 0 && missing.length === 0) return;
  const parts = [
    extra.length ? `fora do manifesto: ${extra.join(", ")}` : "",
    missing.length ? `ausentes no diretório: ${missing.join(", ")}` : "",
  ].filter(Boolean);
  throw new Error(
    `migrations/ e EXPECTED_MIGRATIONS divergiram (${parts.join("; ")}). Atualize src/infra/db/migration-manifest.ts.`,
  );
}

export async function migrate(db: Db, options: MigrateOptions = {}): Promise<string[]> {
  const applyShim = options.applyIdentityShim ?? identityShimEnabled();

  await db.exec(`
    create table if not exists public.schema_migrations (
      id text primary key,
      applied_at timestamptz not null default now()
    );
  `);
  const files = await listMigrationFiles();
  assertManifestMatches(files);
  const appliedRows = await db.withService((query) => query.query<{ id: string }>("select id from public.schema_migrations"));
  const applied = new Set(appliedRows.map((row) => row.id));
  const ran: string[] = [];
  for (const file of files) {
    if (applied.has(file)) continue;
    if (isShimMigration(file) && !applyShim) continue;
    const sql = await readFile(path.join(process.cwd(), MIGRATIONS_FOLDER, file), "utf8");
    await db.exec(sql);
    await db.withService((query) => query.query("insert into public.schema_migrations (id) values ($1)", [file]));
    ran.push(file);
  }
  return ran;
}

export { EXPECTED_MIGRATIONS, SHIM_MIGRATIONS, isShimMigration, pendingMigrations } from "./migration-manifest";