/**
 * Generic runtime index generator for lexicon packages.
 *
 * Produces the `index.ts` file containing factory constructor exports
 * (`createResource`, `createProperty`) and collision-safe re-exports.
 */

export interface RuntimeIndexConfig {
  /** Lexicon identifier: "aws", "terraform", etc. */
  lexiconName: string;
  /** Optional re-exports of intrinsic functions. */
  intrinsicReExports?: {
    names: string[];
    from: string;
  };
  /** Optional re-exports of pseudo-parameters. */
  pseudoReExports?: {
    names: string[];
    from: string;
  };
}

export interface RuntimeIndexEntry {
  tsName: string;
  resourceType: string;
  attrs: Record<string, string>;
}

export interface RuntimeIndexPropertyEntry {
  tsName: string;
  resourceType: string;
}

/**
 * Generate the runtime index.ts content with factory constructor exports.
 *
 * Phases:
 * 1. Banner + import createResource/createProperty
 * 2. Sort and emit resource exports
 * 3. Sort and emit property exports
 * 4. Collision-safe re-exports of intrinsics and pseudo-parameters
 */
export function generateRuntimeIndex(
  resources: RuntimeIndexEntry[],
  properties: RuntimeIndexPropertyEntry[],
  config: RuntimeIndexConfig,
): string {
  const lines: string[] = [];
  lines.push("// Code generated by chant generate. DO NOT EDIT.");
  lines.push('import { createResource, createProperty } from "./runtime";');
  lines.push("");

  // Sort and emit resource exports
  const sortedResources = [...resources].sort((a, b) => a.tsName.localeCompare(b.tsName));
  for (const { tsName, resourceType, attrs } of sortedResources) {
    const attrsStr = JSON.stringify(attrs);
    lines.push(
      `export const ${tsName} = createResource(${JSON.stringify(resourceType)}, ${JSON.stringify(config.lexiconName)}, ${attrsStr});`,
    );
  }

  lines.push("");

  // Sort and emit property exports
  const sortedProperties = [...properties].sort((a, b) => a.tsName.localeCompare(b.tsName));
  for (const { tsName, resourceType } of sortedProperties) {
    lines.push(
      `export const ${tsName} = createProperty(${JSON.stringify(resourceType)}, ${JSON.stringify(config.lexiconName)});`,
    );
  }

  lines.push("");

  // Collision-safe re-exports
  const allExportNames = new Set([
    ...resources.map((e) => e.tsName),
    ...properties.map((e) => e.tsName),
  ]);

  lines.push("// Re-exports for convenience");

  if (config.intrinsicReExports) {
    const safe = config.intrinsicReExports.names.filter((n) => !allExportNames.has(n));
    if (safe.length > 0) {
      lines.push(`export { ${safe.join(", ")} } from ${JSON.stringify(config.intrinsicReExports.from)};`);
    }
  }

  if (config.pseudoReExports) {
    const safe = config.pseudoReExports.names.filter((n) => !allExportNames.has(n));
    if (safe.length > 0) {
      lines.push(`export { ${safe.join(", ")} } from ${JSON.stringify(config.pseudoReExports.from)};`);
    }
  }

  lines.push("");

  return lines.join("\n");
}