/**
 * Dockerfile derivation — production image whose CMD is `oke start`.
 */

import { APP_PORT } from "../runtime/types.ts";

/** Options for {@link emitDockerfile}. */
export interface DockerfileOptions {
  /** App listen port. */
  readonly appPort?: number;
  /** Bun base image. */
  readonly baseImage?: string;
}

/**
 * Emit a production Dockerfile. CMD is exactly `oke start`.
 *
 * @param options - Port / base image
 */
export function emitDockerfile(options: DockerfileOptions = {}): string {
  const port = options.appPort ?? APP_PORT;
  const base = options.baseImage ?? "oven/bun:1.4";
  return `# generated by oke docker — do not edit
FROM ${base} AS deps
WORKDIR /app
COPY package.json bun.lock* ./
RUN bun install --frozen-lockfile --production

FROM ${base} AS runner
WORKDIR /app
ENV NODE_ENV=production
ENV PORT=${port}
ENV PATH="/app/node_modules/.bin:\${PATH}"
COPY --from=deps /app/node_modules ./node_modules
COPY . .
EXPOSE ${port}
CMD ["oke", "start"]
`;
}