import { existsSync, readFileSync, readdirSync } from "node:fs";
import { fileURLToPath } from "node:url";
import { dirname, join, resolve } from "node:path";
import { describe, expect, it } from "vitest";

/**
 * GUARD: `@factory/shared/dto` is the browser-safe DTO surface — the web
 * bundle (Next.js/webpack) imports it, so it must never pull a Node builtin
 * (`node:crypto`, `node:fs`, …) into the browser. A Node-only import here
 * fails the web build with `UnhandledSchemeError` (regression: the
 * `webhook.dto.ts → events.ts → node:crypto` edge that broke every page).
 *
 * We scan every `dto/*.ts` file and its (recursive) relative-import closure
 * — the barrel transitively reaches `constants.ts`, `positions.ts`,
 * `webhook-events.ts`, `formula-ast.ts`, … — and assert none of them import
 * a Node builtin. Only REAL import/export-from statements are considered
 * (comments, including JSDoc examples, are stripped first).
 */
describe("@factory/shared/dto browser safety (no Node builtins in the web bundle)", () => {
  const dtoDir = dirname(fileURLToPath(import.meta.url));

  /** Specifiers of every real import/export-from statement in the file. */
  const importSpecifiersOf = (file: string): string[] => {
    const src = readFileSync(file, "utf8");
    // Strip comments so doc examples (e.g. JSDoc quoting an import) are ignored.
    const code = src.replace(/\/\*[\s\S]*?\*\//g, "").replace(/^\s*\/\/.*$/gm, "");
    const specs = new Set<string>();
    for (const m of code.matchAll(/\b(?:import|export)\b[\s\S]*?\bfrom\s*["']([^"']+)["']/g)) {
      const spec = m[1];
      if (spec) specs.add(spec);
    }
    for (const m of code.matchAll(/^\s*import\s*["']([^"']+)["']/gm)) {
      const spec = m[1];
      if (spec) specs.add(spec);
    }
    return [...specs];
  };

  it("contains no file that imports a node: builtin (directly or transitively)", () => {
    const seen = new Set<string>();
    const queue = readdirSync(dtoDir)
      .filter((f) => f.endsWith(".ts") && !f.endsWith(".test.ts"))
      .map((f) => join(dtoDir, f));
    const offenders: string[] = [];
    while (queue.length) {
      const file = queue.pop()!;
      if (seen.has(file)) continue;
      seen.add(file);
      for (const spec of importSpecifiersOf(file)) {
        if (spec.startsWith("node:") || /^(crypto|fs|path|os|stream|buffer)$/.test(spec)) {
          offenders.push(`${file} → "${spec}"`);
          continue;
        }
        if (spec.startsWith(".")) {
          const target = resolve(dirname(file), spec.replace(/\.js$/, ".ts"));
          if (!existsSync(target)) {
            offenders.push(`${file} → "${spec}" (unresolvable relative import)`);
            continue;
          }
          queue.push(target);
        }
      }
    }
    expect(offenders).toEqual([]);
  });
});