// Generates public/_redirects (Cloudflare Pages) mapping old flat tool URLs
// (/tools/<id>) to the new section-nested URLs (/tools/<section>/<id>/).
// Both slash variants are emitted because Cloudflare matches paths exactly.
//
// buildRedirects() is exported (side-effect-free) so a drift test can assert the
// committed public/_redirects still matches the catalog; the file is only
// written when this script runs directly (the landing prebuild).
import { writeFileSync } from "node:fs";
import { fileURLToPath, pathToFileURL } from "node:url";
import { TOOLS, toolSection } from "@snapotter/shared";

/** Build the full _redirects file contents from the shared TOOLS catalog. */
export function buildRedirects() {
  const lines = ["# Generated by scripts/generate-redirects.mjs -- do not edit by hand"];
  for (const tool of TOOLS) {
    const to = `/tools/${toolSection(tool)}/${tool.id}/`;
    lines.push(`/tools/${tool.id}/ ${to} 301`);
    lines.push(`/tools/${tool.id} ${to} 301`);
  }
  return `${lines.join("\n")}\n`;
}

/** Absolute path to the generated file. */
export const REDIRECTS_PATH = fileURLToPath(new URL("../public/_redirects", import.meta.url));

function writeRedirects() {
  const content = buildRedirects();
  writeFileSync(REDIRECTS_PATH, content);
  const redirectLines = content.trimEnd().split("\n").length - 1;
  console.log(`wrote ${REDIRECTS_PATH} (${TOOLS.length} tools, ${redirectLines} redirect lines)`);
}

// Write only when executed directly (prebuild); importing for the drift test
// stays side-effect-free.
if (process.argv[1] && import.meta.url === pathToFileURL(process.argv[1]).href) {
  writeRedirects();
}