#!/usr/bin/env node

const {spawn, execFileSync} = require('child_process')

const RESOLUTION_REGEX = /(\d+) x (\d+)/
const DIGIT_FLAG_REGEX = /^--?(\d+)$/

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()
}
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'
]

// 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}`
]

execFileSync('cargo', ['build'], {stdio: 'inherit'})

setTimeout(() => {
  for (let i = 0; i < instanceCount; i++) {
    spawn('target/debug/Zed', 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}`
      }
    })
  }
}, 0.1)