import fs from 'node:fs'
import path from 'node:path'

export const EXPO_APP_CONFIG_NAMES = [
  'app.config.js',
  'app.config.ts',
  'app.config.cjs',
  'app.config.mjs',
  'app.json',
] as const

export const RNX_APP_CONFIG_NAMES = [
  'rnx.config.ts',
  'rnx.config.js',
  'rnx.config.mjs',
  'rnx.config.cjs',
] as const

export interface ResolvedAppProject {
  appDir: string
  configPath: string | null
}

function firstNamedFile(dir: string, names: readonly string[]): string | null {
  for (const name of names) {
    const candidate = path.join(dir, name)
    try {
      if (fs.statSync(candidate).isFile()) return candidate
    } catch {}
  }
  return null
}

export function findExpoAppConfig(dir: string): string | null {
  return firstNamedFile(dir, EXPO_APP_CONFIG_NAMES)
}

export function findRNXAppConfig(dir: string): string | null {
  return firstNamedFile(dir, RNX_APP_CONFIG_NAMES)
}

export function resolveAppProject(projectRoot: string): ResolvedAppProject | null {
  const appDir = path.resolve(projectRoot)
  try {
    if (!fs.statSync(appDir).isDirectory()) return null
  } catch {
    return null
  }

  const configPath = findRNXAppConfig(appDir)
  if (
    !configPath &&
    !findExpoAppConfig(appDir) &&
    !fs.existsSync(path.join(appDir, 'package.json'))
  ) {
    return null
  }
  return { appDir, configPath }
}