#!/usr/bin/env node
// Regenerates the TypeScript attachment text-preview whitelist from the JSON
// source embedded by the Go handler.

import { readFileSync, writeFileSync } from "node:fs";
import { dirname, resolve } from "node:path";
import { fileURLToPath } from "node:url";

const repoRoot = resolve(dirname(fileURLToPath(import.meta.url)), "..");
const jsonPath = resolve(
  repoRoot,
  "server/internal/handler/attachment_text_preview.json",
);
const tsPath = resolve(
  repoRoot,
  "packages/views/editor/utils/text-preview-whitelist.generated.ts",
);

const data = JSON.parse(readFileSync(jsonPath, "utf8"));
const fields = [
  ["content_type_prefixes", "TEXT_PREVIEW_CONTENT_TYPE_PREFIXES"],
  ["content_types", "TEXT_PREVIEW_CONTENT_TYPES"],
  ["extensions", "TEXT_PREVIEW_EXTENSIONS"],
  ["basenames", "TEXT_PREVIEW_BASENAMES"],
];

for (const [jsonName] of fields) {
  validateStringList(jsonName, data[jsonName]);
}

const lines = [
  "// AUTO-GENERATED by scripts/generate-attachment-text-preview.mjs.",
  "// Do not edit by hand — edit",
  "// server/internal/handler/attachment_text_preview.json and run",
  "// `pnpm generate:attachment-text-preview`.",
  "",
];

for (const [jsonName, exportName] of fields) {
  lines.push(`export const ${exportName}: ReadonlySet<string> = new Set([`);
  for (const value of data[jsonName]) {
    lines.push(`  ${JSON.stringify(value)},`);
  }
  lines.push("]);");
  lines.push("");
}

writeFileSync(tsPath, lines.join("\n"));

function validateStringList(name, value) {
  if (!Array.isArray(value) || value.length === 0) {
    throw new Error(
      `attachment_text_preview.json: "${name}" must be a non-empty array`,
    );
  }

  const seen = new Set();
  for (const entry of value) {
    if (
      typeof entry !== "string" ||
      entry.length === 0 ||
      entry !== entry.trim() ||
      entry !== entry.toLowerCase()
    ) {
      throw new Error(
        `attachment_text_preview.json: "${name}" entries must be non-empty, trimmed lowercase strings`,
      );
    }
    if (seen.has(entry)) {
      throw new Error(
        `attachment_text_preview.json: duplicate ${name} entry ${JSON.stringify(entry)}`,
      );
    }
    seen.add(entry);
  }
}