#!/usr/bin/env zx
$.verbose = false;

/**
 * * helmReleaseDiff.mjs
 * * Runs `helm template` with your Helm values and then runs `dyff` across Flux HelmRelease manifests
 * @param --current-release   The source Flux HelmRelease to compare against the target
 * @param --incoming-release  The target Flux HelmRelease to compare against the source
 * @param --kubernetes-dir    The directory containing your Flux manifests including the HelmRepository manifests
 * * Limitations:
 * * Does not work with multiple HelmRelease maninfests in the same YAML document
 */
const CurrentRelease = argv["current-release"];
const IncomingRelease = argv["incoming-release"];
const KubernetesDir = argv["kubernetes-dir"];

const dyff = await which("dyff");
const helm = await which("helm");
const kustomize = await which("kustomize");

async function helmRelease(releaseFile) {
  const helmRelease = await fs.readFile(releaseFile, "utf8");
  const doc = YAML.parseAllDocuments(helmRelease).map((item) => item.toJS());
  const release = doc.filter(
    (item) =>
      item.apiVersion === "helm.toolkit.fluxcd.io/v2beta1" &&
      item.kind === "HelmRelease"
  );
  return release[0];
}

async function helmRepositoryUrl(kubernetesDir, releaseName) {
  const files = await globby([`${kubernetesDir}/**/*.yaml`]);
  for await (const file of files) {
    const contents = await fs.readFile(file, "utf8");
    const doc = YAML.parseAllDocuments(contents).map((item) => item.toJS());
    if (
      "apiVersion" in doc[0] &&
      doc[0].apiVersion === "source.toolkit.fluxcd.io/v1beta2" &&
      "kind" in doc[0] &&
      doc[0].kind === "HelmRepository" &&
      "metadata" in doc[0] &&
      "name" in doc[0].metadata &&
      doc[0].metadata.name === releaseName
    ) {
      return doc[0].spec.url;
    }
  }
}

async function kustomizeBuild(releaseBaseDir, releaseName) {
  const build =
    await $`${kustomize} build --load-restrictor=LoadRestrictionsNone ${releaseBaseDir}`;
  const docs = YAML.parseAllDocuments(build.stdout).map((item) => item.toJS());
  const release = docs.filter(
    (item) =>
      item.apiVersion === "helm.toolkit.fluxcd.io/v2beta1" &&
      item.kind === "HelmRelease" &&
      item.metadata.name === releaseName
  );
  return release[0];
}

async function helmRepoAdd(registryName, registryUrl) {
  await $`${helm} repo add ${registryName} ${registryUrl}`;
}

async function helmTemplate(
  releaseName,
  registryName,
  chartName,
  chartVersion,
  chartValues
) {
  const values = new YAML.Document();
  values.contents = chartValues;
  const valuesFile = await $`mktemp`;
  await fs.writeFile(valuesFile.stdout.trim(), values.toString());

  const manifestsFile = await $`mktemp`;
  const manifests =
    await $`${helm} template --kube-version 1.26.0 --release-name ${releaseName} --include-crds=false ${registryName}/${chartName} --version ${chartVersion} --values ${valuesFile.stdout.trim()}`;

  // Remove docs that are CustomResourceDefinition and keys which contain generated fields
  let documents = YAML.parseAllDocuments(manifests.stdout.trim());
  documents = documents.filter(
    (doc) => doc.get("kind") !== "CustomResourceDefinition"
  );
  documents.forEach((doc) => {
    const del = (path) => (doc.hasIn(path) ? doc.deleteIn(path) : false);
    del(["metadata", "labels", "app.kubernetes.io/version"]);
    del(["metadata", "labels", "chart"]);
    del(["metadata", "labels", "helm.sh/chart"]);
    del([
      "spec",
      "template",
      "metadata",
      "labels",
      "app.kubernetes.io/version",
    ]);
    del(["spec", "template", "metadata", "labels", "chart"]);
    del(["spec", "template", "metadata", "labels", "helm.sh/chart"]);
  });

  await fs.writeFile(
    manifestsFile.stdout.trim(),
    documents.map((doc) => doc.toString({ directives: true })).join("\n")
  );
  return manifestsFile.stdout.trim();
}

// Generate current template from Helm values
const currentRelease = await helmRelease(CurrentRelease);
const currentBuild = await kustomizeBuild(
  path.dirname(CurrentRelease),
  currentRelease.metadata.name
);
const currentRepositoryUrl = await helmRepositoryUrl(
  KubernetesDir,
  currentBuild.spec.chart.spec.sourceRef.name
);
await helmRepoAdd(
  currentBuild.spec.chart.spec.sourceRef.name,
  currentRepositoryUrl
);
const currentManifests = await helmTemplate(
  currentBuild.metadata.name,
  currentBuild.spec.chart.spec.sourceRef.name,
  currentBuild.spec.chart.spec.chart,
  currentBuild.spec.chart.spec.version,
  currentBuild.spec.values
);

// Generate incoming template from Helm values
const incomingRelease = await helmRelease(IncomingRelease);
const incomingBuild = await kustomizeBuild(
  path.dirname(IncomingRelease),
  incomingRelease.metadata.name
);
const incomingRepositoryUrl = await helmRepositoryUrl(
  KubernetesDir,
  incomingBuild.spec.chart.spec.sourceRef.name
);
await helmRepoAdd(
  incomingBuild.spec.chart.spec.sourceRef.name,
  incomingRepositoryUrl
);
const incomingManifests = await helmTemplate(
  incomingBuild.metadata.name,
  incomingBuild.spec.chart.spec.sourceRef.name,
  incomingBuild.spec.chart.spec.chart,
  incomingBuild.spec.chart.spec.version,
  incomingBuild.spec.values
);

// Print diff using dyff
const diff =
  await $`${dyff} --color=off --truecolor=off between --omit-header --ignore-order-changes --detect-kubernetes=true --output=human ${currentManifests} ${incomingManifests}`;
echo(diff.stdout.trim());