import { writeFileSync as writeFile, readFileSync as readFile, existsSync as exists } from 'fs'
import { watch } from 'fs'
import { join } from 'path'
import { parseActions } from './actionParser'
import { normalize } from './action'

const srcDir = join(process.cwd(), 'src')

generateActions()

let timeout: Timer | null = null

const watcher = watch(srcDir, (event, filename) => {
  if (filename === 'game.ts' && event === 'change') {
    if (timeout) clearTimeout(timeout)

    timeout = setTimeout(() => {
      generateActions()
      timeout = null
    }, 1000)
  }
})

import.meta.hot?.dispose(() => {
  watcher.close()
  if (timeout) clearTimeout(timeout)
})

export function generateActions() {
  const actions = parseActions(join(srcDir, 'game.ts'))
  const generated: string[] = []

  generated.push(`// DO NOT MODIFY!\n`)
  generated.push(`// This file is generated by pyre.\n`)
  generated.push(`// Generated: ${new Date().toLocaleString('sv-SE')}.\n`)
  generated.push(`\n`)
  generated.push(`import { send } from 'pyre/client'\n`)

  for (const [name, params] of Object.entries(actions)) {
    generated.push(`
export const ${normalize(name)} = (${paramsToString(params)}) => {
  send({
    type: 'action',
    action: '${name}',
    args: [${argsToString(params)}]
  })
}
`)
  }

  const generatedActions = generated.join('')
  const actionsPath = join(srcDir, 'client', 'actions.ts')

  if (exists(actionsPath)) {
    const existing = readFile(actionsPath, 'utf-8')
    if (stripTimestamp(existing) === stripTimestamp(generatedActions)) return
  }

  writeFile(actionsPath, generatedActions)
  console.log('Wrote', actionsPath)
}

function stripTimestamp(content: string): string {
  return content.replace(/^\/\/ Generated:.*\n/m, '')
}

function paramsToString(params: [string, string][]): string {
  const out: string[] = []

  for (const [param, typeName] of params)
    out.push(`${param}: ${typeName}`)

  return out.join(', ')
}

function argsToString(params: [string, string][]): string {
  const out: string[] = []

  for (const [param] of params)
    out.push(param)

  return out.join(', ')
}