import { appendFileSync } from "node:fs";
import { execFileSync } from "node:child_process";
import { pathToFileURL } from "node:url";

/** Keep manual test builds out of the production channel. */
export function imagePublication({ event, ref, inputTag, revision }) {
  if (!/^[0-9a-f]{40}$/.test(revision))
    throw new Error("Expected the full SHA-1 of the checked-out commit.");

  let tag, channel;
  if (event === "workflow_dispatch") {
    tag = inputTag || `dev-${revision.slice(0, 7)}`;
    const commit = /^dev-([0-9a-f]{7,40})$/.exec(tag)?.[1];
    if (!commit || tag !== tag.trim())
      throw new Error(
        "Manual image tags must be dev-<commit SHA> (7-40 lowercase hex characters).",
      );
    if (!revision.startsWith(commit))
      throw new Error(
        "The dev tag does not match the checked-out commit. Select the matching source branch or Git tag.",
      );
    channel = "dev";
  } else if (event === "push" && ref?.startsWith("refs/tags/")) {
    tag = ref.slice("refs/tags/".length);
    if (
      !/^v?(0|[1-9]\d*)\.(0|[1-9]\d*)\.(0|[1-9]\d*)$/.test(tag) ||
      tag.length > 128 ||
      tag !== tag.trim()
    )
      throw new Error(
        "Production requires a stable Git version tag: vMAJOR.MINOR.PATCH or MAJOR.MINOR.PATCH.",
      );
    channel = "prod";
  } else {
    throw new Error(
      "Image publication requires a version tag push or a manual dev build.",
    );
  }
  return { tag, channel, revision };
}

if (
  process.argv[1] &&
  import.meta.url === pathToFileURL(process.argv[1]).href
) {
  const env = process.env;
  const revision = execFileSync("git", ["rev-parse", "HEAD"], {
    encoding: "utf8",
  }).trim();
  const publication = imagePublication({
    event: env.EVENT_NAME,
    ref: env.GIT_REF,
    inputTag: env.INPUT_TAG,
    revision,
  });
  const registry = new URL(env.SERVER_URL).host;
  const image = `${registry}/${env.REPOSITORY.toLowerCase()}`;
  const source = `${env.SERVER_URL.replace(/\/$/, "")}/${env.REPOSITORY}`;
  const outputs = { registry, image, source, ...publication };
  appendFileSync(
    env.GITHUB_OUTPUT,
    Object.entries(outputs)
      .map(([key, value]) => `${key}=${value}\n`)
      .join(""),
  );
  console.log(
    `Publishing ${image}:${publication.tag} and :${publication.channel} from ${revision}`,
  );
}