llm.js

import * as path from "node:path";
import { exec } from "node:child_process";
import { promisify } from "node:util";
import fs from "node:fs/promises";

const execAsync = promisify(exec);

const bins = await import(
  path.join(import.meta.dirname, "../node_modules/rescript/cli/common/bins.js")
);
const rescriptTools = bins["rescript_tools_exe"];

if (!rescriptTools) {
  throw new Error("rescript-tools not found");
}

async function getDocJson(filePath) {
  try {
    const command = `${rescriptTools} doc "${filePath}"`;
    const options = { maxBuffer: 10 * 1024 * 1024 };
    const { stdout, stderr } = await execAsync(command, options);

    if (stderr) {
      throw new Error(`Error executing command for ${filePath}: ${stderr}`);
    }

    return JSON.parse(stdout);
  } catch (error) {
    throw new Error(`Failed to get documentation JSON for ${filePath}:`, error);
  }
}

async function processFile(filePath) {
  const json = await getDocJson(filePath);
  const relativePath = path.relative(path.join(import.meta.dirname, ".."), filePath);
  const moduleName = moduleNameForFile(relativePath);

  const types = [];
  const functions = [];

  function mkType(item) {
    let description = "";
    if (item.docstrings.length > 0) {
      description = "\n  Description: " + item.docstrings.join("\n");
    }
    let fields = "";
    if (item.detail && item.detail.kind === "record") {
      fields =
        "\n  Fields:\n" +
        item.detail.items
          .map((field) => {
            let fieldDoc = "";
            if (field.docstrings.length > 0) {
              fieldDoc = " - " + field.docstrings.join(" ");
            }
            return `  - ${field.name}: ${field.signature}${fieldDoc}`;
          })
          .join("\n");
    }
    return `- ${item.signature}${description}${fields}`;
  }

  function mkFunction(item) {
    let description = "";
    if (item.docstrings.length > 0) {
      description = "\n  Description: " + item.docstrings.join("\n");
    }
    return `- ${item.signature}${description}`;
  }

  for (const item of json.items) {
    switch (item.kind) {
      case "type":
        types.push(mkType(item));
        break;
      case "value":
        functions.push(mkFunction(item));
        break;
    }
  }

  let typeString = "";
  if (types.length > 0) {
    typeString = "\n\nTypes:\n\n" + types.join("\n\n");
  }

  let functionString = "";
  if (functions.length > 0) {
    functionString = "\n\nFunctions:\n\n" + functions.join("\n\n");
  }

  return `WebApiFile: ${json.source.filepath}
Module: ${moduleName}${typeString}${functionString}
`;
}

const rootDir = path.join(import.meta.dirname, "..");
const rootConfig = JSON.parse(await fs.readFile(path.join(rootDir, "rescript.json"), "utf-8"));
const publicModulesBySourceDir = new Map(
  rootConfig.sources
    .filter((source) => source !== null && typeof source === "object")
    .filter((source) => source.dir?.startsWith("src/") && Array.isArray(source.public))
    .map((source) => [source.dir, new Set(source.public)]),
);

function normalizeRelativePath(filePath) {
  return path.relative(rootDir, filePath).split(path.sep).join("/");
}

function sourceDirForRelativePath(relativePath) {
  for (const sourceDir of publicModulesBySourceDir.keys()) {
    if (relativePath.startsWith(`${sourceDir}/`)) {
      return sourceDir;
    }
  }
}

function isPublicFile(filePath) {
  const relativePath = normalizeRelativePath(filePath);
  const sourceDir = sourceDirForRelativePath(relativePath);

  if (!sourceDir) {
    return false;
  }

  const moduleName = path.basename(relativePath, ".res").replace("$", "");
  return publicModulesBySourceDir.get(sourceDir).has(moduleName);
}

function moduleNameForFile(relativePath) {
  return `WebAPI.${path.basename(relativePath, ".res")}`;
}

const pattern = "../src/*/**/*.res";
const files = [];
for await (const file of fs.glob(pattern, { recursive: true, cwd: import.meta.dirname })) {
  const filePath = path.join(import.meta.dirname, file);

  if (isPublicFile(filePath)) {
    files.push(filePath);
  }
}
files.sort();

const pages = await Promise.all(files.map(processFile));
const packageJson = await fs.readFile(path.join(import.meta.dirname, "../package.json"), "utf-8");
const version = JSON.parse(packageJson).version;
const sha = await execAsync("git rev-parse --short HEAD").then(({ stdout }) => stdout.trim());
const fullVersion = `${version}-alpha-${sha}`;
const header = `Experimental ReScript WebAPI Documentation ${fullVersion}

This is the API documentation for the experimental WebAPI module version ${fullVersion}.
More information can be found on https://rescript-lang.github.io/experimental-rescript-webapi/

`;
const content = pages.join("\n---\n\n");
await fs.writeFile(path.join(import.meta.dirname, "public/llm.txt"), header + content);
console.log("Generated llm.txt");