import fs from "node:fs";
import path from "node:path";
import type { BuildContext } from "tsdown";
import { portableRelativePath } from "./build-artifact-cache.mts";
import { createDeclarationInputBoundary } from "./local-check-runtime.mts";
import { readDeclarationBuildInputs } from "./tsdown-declaration-boundary.mts";

const stagePrefix = (root: string) =>
  path.join(fs.realpathSync.native(root), ".artifacts/plugin-sdk-staging-");
const receiptPath = (output: string, name: string) =>
  path.join(output, "..", "compiler-inputs", `${name}.json`);

export function createDeclarationStage(root: string) {
  return fs.mkdtempSync(stagePrefix(root));
}

/** Requests and receipts belong only to the writer's fresh, joined private stage. */
export function requestDeclarationInputs(output: string, name: string, roots: string[]) {
  const file = receiptPath(output, name);
  fs.mkdirSync(path.dirname(file), { recursive: true });
  fs.writeFileSync(file, JSON.stringify({ roots }), { flag: "wx" });
}

export function createDeclarationInputCapture(name: string) {
  return async ({ options }: BuildContext) => {
    const boundary = createDeclarationInputBoundary(options.cwd);
    const stage = path.dirname(boundary.resolve(options.outDir));
    const prefix = stagePrefix(options.cwd);
    // Only the writer's private stage owns receipts. A direct build's sibling
    // compiler-inputs directory is ordinary checkout data, even if names match.
    if (
      path.basename(options.outDir) !== "dist" ||
      path.dirname(stage) !== path.dirname(prefix) ||
      !stage.startsWith(prefix)
    ) {
      return;
    }
    const file = receiptPath(options.outDir, name);
    if (!fs.existsSync(file)) {
      return;
    }
    const request: { roots: string[] } = JSON.parse(fs.readFileSync(file, "utf8"));
    const compilation = readDeclarationBuildInputs(options);
    if (request.roots.some((root) => !compilation.roots.has(boundary.resolve(root)))) {
      throw new Error(`Incomplete compiler membership for ${name}`);
    }
    const inputs = [...compilation.inputs]
      .map((input) => portableRelativePath(boundary.root, boundary.assert(input)))
      .toSorted();
    fs.writeFileSync(file, JSON.stringify({ ...request, inputs }));
  };
}

export function readDeclarationInputs(output: string, name: string) {
  const receipt: { roots: string[]; inputs?: unknown } = JSON.parse(
    fs.readFileSync(receiptPath(output, name), "utf8"),
  );
  if (
    !Array.isArray(receipt.inputs) ||
    // Bounded selections can leave empty partitions; only those requests
    // may finish successfully without creating a compiler Program.
    (!receipt.inputs.length && receipt.roots.length > 0) ||
    !receipt.inputs.every((input): input is string => typeof input === "string")
  ) {
    throw new Error(`Missing successful compiler membership for ${name}`);
  }
  return receipt.inputs;
}