// The resolver (REQ-VAR-1 and 2). It joins one role instance's definition,
// the business file, the optional project file and the system config into
// the record a launcher or the broker uses. Plain values: the most specific
// layer wins. Limits: every layer narrows, nothing widens.

import { refuse } from "./errors.mjs";
import { ACTIONS, NETWORKS } from "./vocabulary.mjs";
import { checkVars, mergeVars } from "./vars.mjs";
import { canonicalJson, sha256, deepFreeze } from "./util.mjs";
import { projectFilePath } from "./project.mjs";

// The system layer from `mosaic-config.mjs validate` output.
export function systemVars(config) {
  return checkVars({
    environment: config.environment,
    dataRoot: config.dataRoot,
    "execution.backend": config.execution.backend,
    "execution.provider": config.execution.provider,
    "execution.model": config.execution.model,
    "execution.adapter": config.execution.adapter,
  }, "system", "system config");
}

function narrowerNetwork(a, b) {
  return NETWORKS.indexOf(a) <= NETWORKS.indexOf(b) ? a : b;
}

// resolveInstance({ system, business, project, instance })
//   system    systemVars(...) output
//   business  loadBusiness(...) output
//   project   loadProject(...) output, or null
//   instance  a role instance the business file declares
export function resolveInstance({ system, business, project = null, instance }) {
  const entry = Object.hasOwn(business.roles, instance) ? business.roles[instance] : null;
  if (!entry) refuse(`business ${business.id} declares no role instance ${JSON.stringify(instance)}`);
  const definition = business.definitions[entry.definition];

  const layers = [
    { layer: "system", source: "system", vars: system },
    { layer: "business", source: `business:${business.id}`, vars: business.vars },
  ];
  let projectId = null;
  if (project) {
    const declared = Object.entries(business.projects).find(([, p]) => projectFilePath(p.root) === project.file);
    if (!declared || declared[0] !== project.id) {
      refuse(`project ${project.id} (${project.file}) isn't declared under that id in business ${business.id}`);
    }
    projectId = project.id;
    for (const name of Object.keys(project.roles)) {
      if (!Object.hasOwn(business.roles, name)) refuse(`project ${project.id} sets vars for role instance ${name}, which business ${business.id} doesn't declare`);
    }
    layers.push({ layer: "project", source: `project:${project.id}`, vars: project.vars });
    if (Object.hasOwn(project.roles, instance)) {
      layers.push({ layer: "project", source: `project:${project.id}:roles.${instance}`, vars: project.roles[instance].vars });
    }
  }
  layers.push({ layer: "agent", source: `business:${business.id}:roles.${instance}`, vars: entry.vars });
  const { vars, provenance } = mergeVars(layers);

  let tools = [...definition.tools];
  let network = definition.network;
  let withinRole = [...definition.authority.withinRole];
  let crossRole = [...definition.authority.crossRole];
  if (vars["limits.tools"]) tools = tools.filter((t) => vars["limits.tools"].includes(t));
  if (vars["limits.network"]) network = narrowerNetwork(network, vars["limits.network"]);
  if (vars["limits.authority"]) {
    withinRole = withinRole.filter((a) => vars["limits.authority"].includes(a));
    crossRole = crossRole.filter((a) => vars["limits.authority"].includes(a));
  }
  // role.launch needs the business file's launch block naming this
  // instance (addendum A section 8), and the verb must survive
  // limits.authority. Otherwise the verb is gated and `launch` is null,
  // so the two never disagree.
  const launch = business.launch && business.launch.by === instance && withinRole.includes("role.launch") ? business.launch : null;
  if (!launch) {
    withinRole = withinRole.filter((a) => a !== "role.launch");
    crossRole = crossRole.filter((a) => a !== "role.launch");
  }

  const resolved = {
    business: business.id,
    project: projectId,
    instance,
    definition: definition.name,
    holder: entry.holder,
    contract: definition.contractPath,
    vars,
    provenance,
    limits: { tools, network, authority: { withinRole, crossRole } },
    credentials: entry.credentials,
    tracker: entry.tracker,
    launch,
  };
  return deepFreeze({ ...resolved, digest: sha256(canonicalJson(resolved)) });
}

// Classify one action for a resolved instance: "within", "cross" or
// "gated". An action outside the vocabulary refuses.
export function classify(resolved, action) {
  if (!ACTIONS.includes(action)) refuse(`unknown action: ${JSON.stringify(action)}`);
  if (resolved.limits.authority.withinRole.includes(action)) return "within";
  if (resolved.limits.authority.crossRole.includes(action)) return "cross";
  return "gated";
}