// The project file, <root>/.mosaic/project.json. It lives in the project's
// repository and changes by reviewed commits there. The stack only reads it.

import { isAbsolute, join, normalize } from "node:path";
import { refuse } from "./errors.mjs";
import { checkVars } from "./vars.mjs";
import { requireObject, rejectUnknownKeys, requireId, readJsonFile, deepFreeze } from "./util.mjs";

export function projectFilePath(root) {
  return join(root, ".mosaic", "project.json");
}

export function validateProjectDocument(document, file) {
  requireObject(document, "project file");
  rejectUnknownKeys(document, ["projectVersion", "id", "vars", "roles"], "project file");
  if (document.projectVersion !== 1) refuse(`project file "projectVersion" must be 1 (${file})`);
  requireId(document.id, "project id");
  const vars = checkVars(document.vars ?? {}, "project", `${file} vars`);
  const roles = {};
  if (document.roles !== undefined) {
    requireObject(document.roles, `${file} roles`);
    for (const [instance, entry] of Object.entries(document.roles)) {
      requireId(instance, `${file} role instance`);
      requireObject(entry, `${file} roles.${instance}`);
      rejectUnknownKeys(entry, ["vars"], `${file} roles.${instance}`);
      roles[instance] = { vars: checkVars(entry.vars ?? {}, "project", `${file} roles.${instance}.vars`) };
    }
  }
  return deepFreeze({ projectVersion: 1, id: document.id, file, vars, roles });
}

export function loadProject(root) {
  if (typeof root !== "string" || !isAbsolute(root) || normalize(root) !== root) refuse(`project root must be a normalized absolute path (got ${JSON.stringify(root)})`);
  const file = projectFilePath(root);
  return validateProjectDocument(readJsonFile(file, "project file"), file);
}