/**
 * Walks a folder of authored templates and lints each file.
 *
 * The Node adapter for the rules in `@beehexa/hexasync-template-assets`: the walking and YAML parsing
 * live here, the rules live in core, so the editor's Phase 1 diagnostics can apply the same
 * ones without reimplementing them.
 */
import { readFile, readdir } from 'node:fs/promises';
import { join, basename } from 'node:path';
import { parse } from 'yaml';
import {
  lintDocument,
  summariseLint,
  type LintSummary,
} from '@beehexa/hexasync-template-assets';

/** Directories never authored by hand, so never linted. */
const SKIP_DIRS = new Set(['__configs', 'node_modules', '.git', '.hexasync']);

async function* walk(dir: string): AsyncGenerator<string> {
  for (const entry of await readdir(dir, { withFileTypes: true })) {
    if (entry.isDirectory()) {
      if (SKIP_DIRS.has(entry.name)) continue;
      yield* walk(join(dir, entry.name));
    } else if (entry.name.endsWith('.yaml')) {
      // Composed output is generated, so its aggregation is not an authoring mistake.
      if (/^output.*\.yaml$/.test(entry.name)) continue;
      yield join(dir, entry.name);
    }
  }
}

export async function lintTree(root: string): Promise<LintSummary> {
  const results: {
    path: string;
    diagnostics: ReturnType<typeof lintDocument>;
  }[] = [];
  for await (const file of walk(root)) {
    let document: unknown;
    try {
      document = parse(await readFile(file, 'utf8'));
    } catch {
      // A file that does not parse is a different problem, reported by compose rather than by a
      // structural lint. Skipping it here keeps this rule set about structure.
      continue;
    }
    const relative = file.startsWith(root)
      ? file.slice(root.length).replace(/^[/\\]/, '')
      : file;
    results.push({
      path: relative,
      diagnostics: lintDocument(basename(file), document),
    });
  }
  // Re-key the diagnostics onto the relative path, so a report points at the file a developer
  // can open rather than at a bare basename.
  return summariseLint(
    results.map((r) => ({
      path: r.path,
      diagnostics: r.diagnostics.map((d) => ({ ...d, path: r.path })),
    })),
  );
}