/*
 *  This file is part of CoCalc: Copyright © 2020 Sagemath, Inc.
 *  License: AGPLv3 s.t. "Commons Clause" – see LICENSE.md for details
 */

const { writeFile, readFile, unlink } = require("fs");
const tmp = require("tmp");
const { callback } = require("awaiting");
const { spawn } = require("child_process");
import { Options } from "./index";

function close(proc, cb): void {
  proc.on("close", (code) => cb(undefined, code));
}

// ref: https://clang.llvm.org/docs/ClangFormat.html

function run_clang_format(
  input_path: string,
  indent: number /*, logger: any*/
) {
  const style = `-style={BasedOnStyle: google, IndentWidth: ${indent}}`;
  // See https://github.com/sagemathinc/cocalc/issues/5419 for why we disable sort-includes!
  const args = ["--sort-includes=0", "-i", style, input_path];
  // logger.debug(`run_clang_format args: [${args}]`);
  return spawn("clang-format", args);
}

export async function clang_format(
  input: string,
  ext: string,
  options: Options,
  logger: any
): Promise<string> {
  // create input temp file
  // we have to set the correct filename extension, because clang format uses it
  const input_path: string = await callback(tmp.file, { postfix: `.${ext}` });
  try {
    // logger.debug(`clang_format tmp file: ${input_path}`);
    await callback(writeFile, input_path, input);

    // spawn the c formatter
    let formatter;
    const indent = options.tabWidth || 2;

    switch (options.parser) {
      case "clang-format":
        formatter = run_clang_format(input_path, indent /*, logger*/);
        break;
      default:
        throw Error(
          `Unknown C/C++ code formatting utility '${options.parser}'`
        );
    }
    // stdout/err capture
    let stdout: string = "";
    let stderr: string = "";
    // read data as it is produced.
    formatter.stdout.on("data", (data) => (stdout += data.toString()));
    formatter.stderr.on("data", (data) => (stderr += data.toString()));
    // wait for subprocess to close.
    const code = await callback(close, formatter);

    if (code >= 1) {
      const err_msg = `C/C++ code formatting utility "${options.parser}" exited with code ${code}\nOutput:\n${stdout}\n${stderr}`;
      logger.debug(`clang-format error: ${err_msg}`);
      throw Error(err_msg);
    }

    // all fine, we read from the temp file
    const output: Buffer = await callback(readFile, input_path);

    const s: string = output.toString("utf-8");
    // logger.debug(`clang_format output s ${s}`);

    return s;
  } finally {
    unlink(input_path, () => {});
  }
}