#!/usr/bin/env node

const { spawn, execFileSync } = require("child_process");

const RESOLUTION_REGEX = /(\d+) x (\d+)/;
const DIGIT_FLAG_REGEX = /^--?(\d+)$/;
const ZED_2_MODE = "--zed2";
const RELEASE_MODE = "--release";

const args = process.argv.slice(2);

// Parse the number of Zed instances to spawn.
let instanceCount = 1;
const digitMatch = args[0]?.match(DIGIT_FLAG_REGEX);
if (digitMatch) {
  instanceCount = parseInt(digitMatch[1]);
  args.shift();
}
const isZed2 = args.some((arg) => arg === ZED_2_MODE);
const isReleaseMode = args.some((arg) => arg === RELEASE_MODE);
if (instanceCount > 4) {
  throw new Error("Cannot spawn more than 4 instances");
}

// Parse the resolution of the main screen
const displayInfo = JSON.parse(
  execFileSync("system_profiler", ["SPDisplaysDataType", "-json"], {
    encoding: "utf8",
  }),
);
const mainDisplayResolution =
  displayInfo?.SPDisplaysDataType[0]?.spdisplays_ndrvs
    ?.find((entry) => entry.spdisplays_main === "spdisplays_yes")
    ?._spdisplays_resolution?.match(RESOLUTION_REGEX);
if (!mainDisplayResolution) {
  throw new Error("Could not parse screen resolution");
}
const screenWidth = parseInt(mainDisplayResolution[1]);
const screenHeight = parseInt(mainDisplayResolution[2]);

// Determine the window size for each instance
let instanceWidth = screenWidth;
let instanceHeight = screenHeight;
if (instanceCount > 1) {
  instanceWidth = Math.floor(screenWidth / 2);
  if (instanceCount > 2) {
    instanceHeight = Math.floor(screenHeight / 2);
  }
}

let users = ["nathansobo", "as-cii", "maxbrunsfeld", "iamnbutler"];

const RUST_LOG = process.env.RUST_LOG || "info";

// If a user is specified, make sure it's first in the list
const user = process.env.ZED_IMPERSONATE;
if (user) {
  users = [user].concat(users.filter((u) => u !== user));
}

const positions = [
  "0,0",
  `${instanceWidth},0`,
  `0,${instanceHeight}`,
  `${instanceWidth},${instanceHeight}`,
];

const buildArgs = (() => {
  const buildArgs = ["build"];
  if (isReleaseMode) {
    buildArgs.push("--release");
  }

  if (isZed2) {
    buildArgs.push("-p", "zed2");
  }

  return buildArgs;
})();
const zedBinary = (() => {
  const target = isReleaseMode ? "release" : "debug";
  const binary = isZed2 ? "Zed2" : "Zed";

  return `target/${target}/${binary}`;
})();

execFileSync("cargo", buildArgs, { stdio: "inherit" });
setTimeout(() => {
  for (let i = 0; i < instanceCount; i++) {
    spawn(zedBinary, i == 0 ? args : [], {
      stdio: "inherit",
      env: {
        ZED_IMPERSONATE: users[i],
        ZED_WINDOW_POSITION: positions[i],
        ZED_STATELESS: "1",
        ZED_ALWAYS_ACTIVE: "1",
        ZED_SERVER_URL: "http://localhost:8080",
        ZED_ADMIN_API_TOKEN: "secret",
        ZED_WINDOW_SIZE: `${instanceWidth},${instanceHeight}`,
        PATH: process.env.PATH,
        RUST_LOG,
      },
    });
  }
}, 0.1);