/**
 * The acorn TypeScript parser and the two guards every play-source analyzer
 * needs, in one dependency-free module.
 *
 * Extracted so modules that must not import each other can still share one
 * parser configuration: `docflow-binding` (binding resolution) and
 * `play-exports` (which plays a file exports) both parse the same source, and
 * a second parser config would be a silent divergence rather than a loud one.
 */
import { Parser } from 'acorn';
import { tsPlugin } from 'acorn-typescript';

export type AstNode = {
  type: string;
  [key: string]: unknown;
};

export const TypeScriptParser = Parser.extend(
  tsPlugin({
    allowSatisfies: true,
    jsx: {
      allowNamespaces: true,
      allowNamespacedObjects: true,
    },
  }) as unknown as (BaseParser: typeof Parser) => typeof Parser,
);

export function isAstNode(value: unknown): value is AstNode {
  return value !== null && typeof value === 'object' && 'type' in value;
}

export function astArray(value: unknown): AstNode[] {
  return Array.isArray(value) ? value.filter(isAstNode) : [];
}

/** Parses play source for analysis. `null` when acorn cannot: the caller
 *  abstains, and the TypeScript diagnostics own the syntax error. */
export function parsePlaySourceForAnalysis(sourceCode: string): AstNode | null {
  try {
    return TypeScriptParser.parse(sourceCode, {
      ecmaVersion: 'latest',
      sourceType: 'module',
      allowHashBang: true,
    }) as unknown as AstNode;
  } catch {
    return null;
  }
}