/**
 * @fileoverview Reads the generated CLI catalogue for the Docker build.
 *
 * `scripts/build-agent-image.mjs` is a `.mjs` and cannot import the TypeScript registry, so it
 * reads `config/clis.stock.json` (generated by `scripts/generate-cli-catalog.mts`) instead.
 * The pure half lives here so `src/docker-hosts.ts`'s programmatic mirror of the same build
 * command can be pinned against it by a test — those two produce the docker argv independently
 * and must not drift.
 */
import { readFileSync } from 'node:fs';
import { fileURLToPath } from 'node:url';

const CATALOG_PATH = fileURLToPath(new URL('../../config/clis.stock.json', import.meta.url));

/**
 * npm package names the AGENT image installs in its shared `npm install -g` layer.
 *
 * PURE: takes the parsed catalogue, returns a sorted-by-registry-order list.
 *
 * ⚠️ Filters on `enabled`. That is the field the earlier attempt's export omitted, which is
 * how a CLI that ships disabled still had its package baked into every image.
 *
 * ⚠️ An entry carrying `discovery.install.agentImageLayer` is excluded here and installed by
 * its own hand-written Dockerfile layer instead, because the registry cannot express what
 * makes it special — a flag, a companion package, or not being on npm at all. This used to be
 * an id-keyed table duplicated between this file and `src/docker-hosts.ts` (exactly the shape
 * `test/cli-registry-no-id-branching.test.ts` exists to forbid inside `src/`, which is why it
 * was a blind spot rather than a pass — that test scans `src/` only). It is data now: both
 * producers filter on the SAME field from the SAME catalogue entry, `reason` is required by
 * `schema.ts`, and `test/docker-agent-image-coverage.test.ts` requires every one of them to
 * still be present in the Dockerfile, so an exclusion cannot quietly become an omission.
 */
/** Tokens allowed in an npm package name reaching a Dockerfile build arg unquoted. */
const SAFE_PACKAGE = /^[@A-Za-z0-9][@A-Za-z0-9/._-]*$/;

export function agentImageNpmPackages(catalog) {
  const packages = [];
  for (const entry of catalog) {
    if (!entry.enabled) continue;
    if (entry.discovery?.install?.agentImageLayer) continue;
    const pkg = entry.discovery?.install?.npmPackage;
    if (!pkg) continue; // antigravity/grok/omp ship standalone installers, not npm
    if (!SAFE_PACKAGE.test(pkg)) {
      // The value is interpolated into a Dockerfile ARG that is expanded UNQUOTED (word
      // splitting is how the list becomes several arguments), so a token with whitespace or
      // shell metacharacters would change what the RUN line means.
      // ⚠️ This exact regex is duplicated in `agentImageNpmPackages()` in
      // `src/docker-hosts.ts` (that file cannot import this one — it is the TypeScript side of
      // the same two-producers split this whole module exists for). Keep both literal patterns
      // identical; `test/agent-image-build-args-parity.test.ts` pins that they are.
      throw new Error(`Refusing unsafe npm package name for "${entry.id}": ${JSON.stringify(pkg)}`);
    }
    packages.push(pkg);
  }
  return packages;
}

/**
 * Environment variable → agent.Dockerfile ARG for the optional git-host CLIs (gh, az).
 * ⚠️ Mirrored by `GIT_HOST_CLI_BUILD_ARGS` in `src/docker-hosts.ts`; the parity test pins them.
 */
export const GIT_HOST_CLI_BUILD_ARGS = [
  ['CODEMAN_AGENT_IMAGE_INSTALL_GH', 'CODEMAN_INSTALL_GH'],
  ['CODEMAN_AGENT_IMAGE_INSTALL_AZ', 'CODEMAN_INSTALL_AZ'],
];

/** Environment variables passed through to the agent image's system Git configuration. */
export const GIT_IDENTITY_BUILD_ARGS = [
  ['CODEMAN_AGENT_IMAGE_GIT_USER_NAME', 'GIT_USER_NAME'],
  ['CODEMAN_AGENT_IMAGE_GIT_USER_EMAIL', 'GIT_USER_EMAIL'],
];

/**
 * The `--build-arg` pairs for the optional git-host CLIs. PURE. An unset or empty variable
 * contributes NOTHING, so the Dockerfile's own default (off) applies and the argv is the same
 * as before these existed; anything other than 0/1 is refused rather than guessed at.
 */
export function gitHostCliBuildArgPairs(env) {
  const pairs = [];
  for (const [envName, argName] of GIT_HOST_CLI_BUILD_ARGS) {
    const value = env[envName];
    if (value === undefined || value === '') continue;
    if (value !== '0' && value !== '1') {
      throw new Error(`${envName} must be 0 or 1, got ${JSON.stringify(value)}`);
    }
    pairs.push([argName, value]);
  }
  return pairs;
}

/** The `--build-arg` pairs for Git identity, requiring either both values or neither. */
export function gitIdentityBuildArgPairs(env) {
  const pairs = GIT_IDENTITY_BUILD_ARGS.map(([envName, argName]) => [argName, env[envName] ?? '']);
  const configured = pairs.filter(([, value]) => value !== '');
  if (configured.length === 0) return [];
  if (configured.length !== pairs.length) {
    throw new Error('Git user name and email must both be set when configuring Git identity');
  }
  return pairs;
}

/** The `--build-arg` pairs the agent image takes. PURE given `env`. */
export function agentImageBuildArgPairs(catalog, env = process.env) {
  return [
    ['CLI_NPM_PACKAGES', agentImageNpmPackages(catalog).join(' ')],
    ...gitHostCliBuildArgPairs(env),
    ...gitIdentityBuildArgPairs(env),
  ];
}

/** Read the committed catalogue. IO. */
export function readCatalog(path = CATALOG_PATH) {
  return JSON.parse(readFileSync(path, 'utf-8'));
}