import { logger } from '@nx/devkit';

/**
 * A place the migration deliberately left untouched because there is no safe
 * mechanical rewrite. Surfaced to the user at the end of the run so they can fix it
 * by hand.
 */
export interface ManualReviewItem {
  /** Workspace-relative path of the file. */
  file: string;
  /** 1-based line number within that file. */
  line: number;
  /** The offending source snippet, trimmed to a single line. */
  snippet: string;
  /** Why it could not be migrated automatically. */
  reason: string;
}

/**
 * Prints the collected manual-review items, grouped by file, via the Nx logger.
 * No-op when there is nothing to report. `migrationLabel` identifies the calling
 * migration in the header (e.g. "Building Block `id`", "signal-queries").
 */
export function reportManualReviewItems(items: ManualReviewItem[], migrationLabel: string): void {
  if (items.length === 0) return;

  // De-duplicate items that resolve to the same file+line+reason.
  const seen = new Set<string>();
  const byFile = new Map<string, ManualReviewItem[]>();
  for (const item of items) {
    const key = `${item.file}:${item.line}:${item.reason}`;
    if (seen.has(key)) continue;
    seen.add(key);
    const bucket = byFile.get(item.file) ?? [];
    bucket.push(item);
    byFile.set(item.file, bucket);
  }

  const lines: string[] = [
    '',
    `The ${migrationLabel} migration left ${seen.size} location(s) unchanged because`,
    'they cannot be migrated automatically. Please review and update them manually:',
    ''
  ];

  for (const [file, fileItems] of byFile) {
    lines.push(`  ${file}`);
    for (const item of fileItems.sort((a, b) => a.line - b.line)) {
      lines.push(`    L${item.line}  ${item.snippet}`);
      lines.push(`          ↳ ${item.reason}`);
    }
    lines.push('');
  }

  logger.warn(lines.join('\n'));
}

/** Collapses a multi-line snippet to a single trimmed line for display. */
export function toSnippet(text: string): string {
  return text.replace(/\s+/g, ' ').trim();
}