import fs from "node:fs";
import path from "node:path";
import fg from "fast-glob";
import type { CheckError, SyncCheckResult } from "../../lib/sync-check/shared";
import { appE2eCategory } from "./categories";

/**
 * E2E sync check.
 *
 * Each business flow (`docs/business-flow/<flow>/README.md`) must have a matching
 * spec file (`frontend/e2e/tests/<flow>.spec.ts`), and each spec file must match a
 * business flow. Spec content is not inspected — whether the spec holds a journey
 * that covers the flow's `## Flow Diagram` main path is a review concern.
 */
export async function runE2eSyncCheck(appRoot: string, cwd: string): Promise<SyncCheckResult> {
  const errors: CheckError[] = [];
  const config = appE2eCategory(appRoot);

  const flowReadmes = await fg(config.docPattern, { cwd });
  const flowNames = new Set(flowReadmes.map((p) => path.basename(path.dirname(p))));

  for (const readmePath of flowReadmes) {
    const flow = path.basename(path.dirname(readmePath));
    const specPath = `${appRoot}/${config.testDir}/${flow}.spec.ts`;
    if (!fs.existsSync(path.join(cwd, specPath))) {
      errors.push({
        type: "missing-test-file",
        category: config.name,
        docPath: readmePath,
        sourcePath: specPath,
        expectedBasename: `${flow}.spec.ts`,
      });
    }
  }

  // A spec is valid only directly at tests/<flow>.spec.ts. Playwright still runs
  // nested specs, so anything in a subdirectory is an orphan regardless of name.
  const allSpecFiles = await fg(`${appRoot}/${config.testDir}/**/*.spec.ts`, { cwd });
  for (const specFile of allSpecFiles) {
    const rel = path.posix.relative(`${appRoot}/${config.testDir}`, specFile);
    const base = path.basename(specFile, ".spec.ts");
    if (rel.includes("/") || !flowNames.has(base)) {
      errors.push({
        type: "orphaned-spec",
        category: config.name,
        sourcePath: specFile,
        expectedBasename: path.basename(specFile),
      });
    }
  }

  return { errors, filesChecked: flowReadmes.length + allSpecFiles.length };
}