import fs from "node:fs/promises";
import path from "node:path";
import { execFileSync } from "node:child_process";
const config = JSON.parse(await fs.readFile(process.argv[2], "utf8"));
const resource = JSON.parse(await fs.readFile(config.interface, "utf8"));
if (resource.kind !== "interface") throw Error("React props belong to an interface resource");
const iface = resource.revision;
const output = process.env.out;
if (!output) throw Error("Missing Nix output");
const work = path.resolve("contracts-source");
const declarations = [];
await fs.cp(config.source, work, { recursive: true });
const writable = async (directory) => {
  await fs.chmod(directory, 0o755);
  for (const entry of await fs.readdir(directory, { withFileTypes: true })) {
    const file = path.join(directory, entry.name);
    if (entry.isSymbolicLink()) throw Error("Contract source cannot contain symlinks");
    if (entry.isDirectory()) await writable(file);
    else {
      await fs.chmod(file, 0o644);
      if (/\.d\.[cm]?ts$/.test(file)) declarations.push(path.relative(work, file));
    }
  }
};
await writable(work);
const packageFile = path.join(work, "package.json");
const metadata = await fs.readFile(packageFile, "utf8").then(JSON.parse, (error) => {
  if (error.code === "ENOENT") return {};
  throw error;
});
await fs.writeFile(packageFile, JSON.stringify({ ...metadata, type: "module" }));
if (config.dependencies) await fs.symlink(config.dependencies, path.join(work, "node_modules"));
const members = Object.create(null);
let index = 0;
for (const [id, entry] of Object.entries(config.members)) {
  const member = (iface.template?.members ?? iface.members).find((member) => member.id === id);
  if (
    member?.kind !== "module" ||
    !["org.quixos.react.component/1", "org.quixos.react.subject-only/1"].includes(member.contract)
  )
    throw Error("Props entry is not a React module member: " + id);
  if (
    !/^[$A-Z_a-z][$\w]*$/.test(entry.export) ||
    path.isAbsolute(entry.entry) ||
    entry.entry.split("/").some((part) => part === ".." || !part)
  )
    throw Error("Invalid props type entry");
  const filename = `props-${index++}.ts`;
  const typeImport = JSON.stringify("./" + entry.entry.replace(/\.[cm]?tsx?$/, ".js"));
  await fs.writeFile(
    path.join(work, filename),
    `import type {${entry.export} as Props} from ${typeImport};
type Assert<T extends true> = T;
type ObjectProps = Assert<Props extends object ? true : false>;
type ReservedSubject = Assert<"subject" extends keyof Props ? false : true>;
${member.contract === "org.quixos.react.subject-only/1" ? "type SubjectOnly = Assert<{} extends Props ? true : false>;" : ""}
export type {Props};\n`,
  );
  members[id] = { path: filename.replace(/\.ts$/, ".d.ts"), export: "Props" };
}
await fs.mkdir(path.join(output, "types"), { recursive: true });
if (!Object.keys(members).length) throw Error("React type companion declares no module members");
execFileSync(
  config.node,
  [
    config.tsc,
    "--declaration",
    "--emitDeclarationOnly",
    "--strict",
    "--target",
    "es2024",
    "--module",
    "nodenext",
    "--moduleResolution",
    "nodenext",
    "--rootDir",
    work,
    "--outDir",
    path.join(output, "types"),
    ...Object.values(members).map((entry) => path.join(work, entry.path.replace(/\.d\.ts$/, ".ts"))),
  ],
  { cwd: work, stdio: "inherit" },
);
// TypeScript emits declarations for implementation sources, but does not copy
// authored declarations which those emitted files may import.
for (const file of declarations) {
  await fs.mkdir(path.dirname(path.join(output, "types", file)), { recursive: true });
  await fs.copyFile(path.join(work, file), path.join(output, "types", file));
}
await fs.writeFile(path.join(output, "package.json"), JSON.stringify({ type: "module" }));
if (config.dependencies) await fs.symlink(config.dependencies, path.join(output, "node_modules"));
await fs.writeFile(
  path.join(output, "react-contracts.json"),
  JSON.stringify({ schemaVersion: 1, interfaceRevisionId: iface.revisionId, members }, null, 2),
);