import { runCpuProfile } from './cpu-profile'
import { runInspect } from './inspect'
import { runReact } from './react'

interface PerfOptions {
  port?: number
  verbose?: boolean
}

const VALUE_FLAGS = new Set(['--sim', '--port', '-p'])
const SUBCOMMANDS = new Set(['cpu', 'react', 'shell', 'scroll'])

function findSubcommand(args: string[]): { name: string; index: number } | null {
  for (let i = 0; i < args.length; i++) {
    const arg = args[i]
    if (arg.startsWith('-')) {
      if (VALUE_FLAGS.has(arg)) i++
      continue
    }
    return SUBCOMMANDS.has(arg) ? { name: arg, index: i } : null
  }
  return null
}

function withoutSubcommand(args: string[], index: number): string[] {
  return [...args.slice(0, index), ...args.slice(index + 1)]
}

function printHelp(): void {
  console.log(`
rnx perf — performance profiling tools

usage:
  rnx perf cpu [options]
  rnx perf react <subcommand> [options]
  rnx perf shell <start|stop|transition> [options]
  rnx perf scroll <start|stop> [options]

examples:
  rnx perf cpu --duration 5 --output /tmp/trace.cpuprofile
    # writes page + every worker profile and a role-labelled manifest
  rnx perf react summary --limit 10
  rnx perf shell start
  rnx perf shell stop --json
  rnx perf scroll start
  rnx perf scroll stop --json
`)
}

export async function runPerf(args: string[], opts: PerfOptions): Promise<number> {
  const sub = findSubcommand(args)
  if (!sub) {
    printHelp()
    return args.includes('--help') || args.includes('-h') ? 0 : 1
  }

  const rest = withoutSubcommand(args, sub.index)
  if (sub.name === 'cpu') return runCpuProfile(rest, opts)
  if (sub.name === 'react') return runReact(rest, opts)

  const inspectArgs = rest.includes('--help') || rest.includes('-h') ? [] : rest
  await runInspect(['debug', 'perf', ...inspectArgs], {
    ...opts,
    internalPerfCommand: sub.name === 'scroll' ? 'scroll' : 'shell',
  })
  return typeof process.exitCode === 'number' ? process.exitCode : 0
}