'use strict'

/**
 * Metro 插件：自动发现 .xuqmconfig 配置文件。
 *
 * 宿主只需将平台下载的 .xuqmconfig 文件放入 src/assets/config/，
 * SDK 自动读取并完成初始化，无需重命名或创建 .ts 包装文件。
 *
 * 目录内没有配置时保持 common-only；唯一一个 *.xuqmconfig 自动使用；多个文件
 * 无法判断权威配置，必须在构建期明确失败。
 *
 * @param {import('@react-native/metro-config').MetroConfig} metroConfig
 * @returns {import('@react-native/metro-config').MetroConfig}
 */
const fs = require('fs')
const path = require('path')
const crypto = require('node:crypto')

const VIRTUAL_MODULE_ID = '@xuqm/rn-common/auto-init-config'
const AUTO_INIT_MODULE = path.resolve(__dirname, '../src/internal.ts')
const CONFIG_DIRECTORY_RELATIVE_PATH = 'src/assets/config'
const CONFIG_MAGIC = 'XUQM-CONFIG-V2'
const CONFIG_PASSPHRASE = 'xuqm-config-file-v2.2026.internal'
const PBKDF2_ITERATIONS = 120_000
const TRUSTED_CONFIG_KEYS = require('./trusted-config-keys.json')

function decodeBase64Url(value) {
  return Buffer.from(value, 'base64url')
}

/**
 * 配置文件只在 Node/Metro 构建期解密。移动端运行时直接消费解析后的配置，
 * 避免 Hermes 在应用启动阶段执行 12 万次 PBKDF2 并阻塞 JS 线程。
 */
function canonicalJson(value) {
  if (Array.isArray(value)) return `[${value.map(canonicalJson).join(',')}]`
  if (value && typeof value === 'object') {
    return `{${Object.keys(value)
      .filter(key => value[key] !== null && value[key] !== undefined)
      .sort()
      .map(key => `${JSON.stringify(key)}:${canonicalJson(value[key])}`)
      .join(',')}}`
  }
  return JSON.stringify(value)
}

function assertConfigPayload(config, plaintext) {
  const allowedFields = new Set([
    'schemaVersion',
    'configId',
    'revision',
    'issuedAt',
    'expiresAt',
    'appKey',
    'appName',
    'packageName',
    'iosBundleId',
    'harmonyBundleName',
    'serverUrl',
    'signingKey',
  ])
  const unknownField = Object.keys(config).find(field => !allowedFields.has(field))
  if (unknownField) throw new Error(`配置包含不受支持字段：${unknownField}`)
  if (config.schemaVersion !== 2) throw new Error('配置 schemaVersion 必须为 2')
  if (
    typeof config.configId !== 'string' ||
    !/^[0-9a-f]{8}-[0-9a-f]{4}-[1-8][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i.test(
      config.configId,
    )
  ) {
    throw new Error('配置 configId 不是有效 UUID')
  }
  if (!Number.isInteger(config.revision) || config.revision <= 0) {
    throw new Error('配置 revision 必须为正整数')
  }
  for (const field of ['issuedAt', 'appKey', 'appName', 'serverUrl', 'signingKey']) {
    if (typeof config[field] !== 'string' || !config[field].trim()) {
      throw new Error(`配置 ${field} 不能为空`)
    }
  }
  if (!config.issuedAt.endsWith('Z') || Number.isNaN(Date.parse(config.issuedAt))) {
    throw new Error('配置 issuedAt 必须为 RFC3339 UTC 时间')
  }
  if (config.expiresAt !== undefined) {
    const expiresAt = Date.parse(config.expiresAt)
    if (!config.expiresAt.endsWith('Z') || Number.isNaN(expiresAt)) {
      throw new Error('配置 expiresAt 必须为 RFC3339 UTC 时间')
    }
    if (expiresAt <= Date.now()) throw new Error('配置文件已过期，请从租户平台重新生成')
  }
  if (canonicalJson(config) !== plaintext) {
    throw new Error('配置正文不是规范 canonical JSON')
  }
}

function decryptConfigAtBuildTime(content, trustedKeys = TRUSTED_CONFIG_KEYS) {
  const parts = content.trim().split('.')
  if (parts.length !== 6 || parts[0] !== CONFIG_MAGIC) {
    throw new Error('仅支持 XUQM-CONFIG-V2；请从租户平台重新下载配置文件')
  }

  const keyId = parts[1]
  const publicKeyBase64 = trustedKeys[keyId]
  if (!publicKeyBase64) throw new Error(`配置签名 keyId 不受信任：${keyId}`)
  const unsignedToken = parts.slice(0, 5).join('.')
  const signatureValid = crypto.verify(
    null,
    Buffer.from(unsignedToken, 'ascii'),
    {
      key: Buffer.from(publicKeyBase64, 'base64'),
      format: 'der',
      type: 'spki',
    },
    decodeBase64Url(parts[5]),
  )
  if (!signatureValid) throw new Error('配置文件签名验证失败')

  const salt = decodeBase64Url(parts[2])
  const iv = decodeBase64Url(parts[3])
  const encrypted = decodeBase64Url(parts[4])
  if (salt.length === 0 || iv.length !== 12 || encrypted.length <= 16) {
    throw new Error('配置文件加密参数无效')
  }

  const body = encrypted.subarray(0, -16)
  const authTag = encrypted.subarray(-16)
  const key = crypto.pbkdf2Sync(CONFIG_PASSPHRASE, salt, PBKDF2_ITERATIONS, 32, 'sha256')
  const decipher = crypto.createDecipheriv('aes-256-gcm', key, iv)
  decipher.setAuthTag(authTag)

  try {
    const plaintext = Buffer.concat([decipher.update(body), decipher.final()])
    const text = plaintext.toString('utf8')
    const config = JSON.parse(text)
    assertConfigPayload(config, text)
    return config
  } catch {
    throw new Error('配置文件解密或内容校验失败')
  }
}

function findConfigFile(projectRoot) {
  const configDirectory = path.resolve(projectRoot, CONFIG_DIRECTORY_RELATIVE_PATH)
  if (!fs.existsSync(configDirectory)) return null
  const candidates = fs
    .readdirSync(configDirectory, { withFileTypes: true })
    .filter(entry => entry.isFile() && entry.name.toLowerCase().endsWith('.xuqmconfig'))
    .map(entry => path.join(configDirectory, entry.name))
    .sort()
  if (candidates.length === 0) return null
  if (candidates.length > 1) {
    throw new Error(
      `[XuqmConfig] ${configDirectory}: 只能存在一个 .xuqmconfig 文件，当前发现 ${candidates.length} 个`,
    )
  }
  return candidates[0]
}

function applyBugCollect(metroConfig) {
  // 不再自动链式 withBugCollect：基于 customSerializer 的 sourcemap 上传在 Metro 0.84
  // 下不可靠（exports 限制无法获取默认 serializer，会破坏 dev 打包）。
  // sourcemap 上传改由独立后处理脚本（react-native bundle 后单独上传）实现。
  return metroConfig
}

function withXuqmConfig(metroConfig) {
  const projectRoot = metroConfig.projectRoot ?? process.cwd()
  const configFile = findConfigFile(projectRoot)

  if (!configFile) {
    // 未找到配置文件，返回原配置（autoInit 会静默跳过）
    return applyBugCollect(metroConfig)
  }

  // 读取加密配置内容
  const encryptedContent = fs.readFileSync(configFile, 'utf-8').trim()

  let resolvedConfig
  try {
    resolvedConfig = decryptConfigAtBuildTime(encryptedContent)
  } catch (error) {
    throw new Error(`[XuqmConfig] ${configFile}: ${error.message}`)
  }

  // 生成临时 TS 文件作为虚拟模块。这里只传输已解析对象，移动端不再解密。
  // Metro 0.84+ only hashes files under projectRoot/watchFolders. Keep the
  // generated transport module in the ignored package-manager cache instead
  // of the system temp directory; the .xuqmconfig file remains the sole source.
  const generatedDir = path.join(projectRoot, 'node_modules', '.cache', 'xuqm-sdk')
  fs.mkdirSync(generatedDir, { recursive: true })
  const virtualFile = path.join(generatedDir, 'autoinit-config.ts')
  fs.writeFileSync(
    virtualFile,
    `// Auto-generated by @xuqm/rn-common/metro — do not edit\nexport const RESOLVED_CONFIG = ${JSON.stringify(resolvedConfig)} as const;\nexport const BUILD_OPTIONS = ${JSON.stringify({ bugCollectMode: process.env.XUQM_BUGCOLLECT_MODE ?? 'platform' })} as const;\n`,
    'utf-8',
  )

  // 拦截默认空实现，将 @xuqm/rn-common/auto-init-config 指向虚拟文件
  const existingResolveRequest = metroConfig.resolver?.resolveRequest
  const existingGetModulesRunBeforeMainModule =
    metroConfig.serializer?.getModulesRunBeforeMainModule

  return applyBugCollect({
    ...metroConfig,
    resolver: {
      ...metroConfig.resolver,
      resolveRequest: (context, moduleName, platform) => {
        if (moduleName === VIRTUAL_MODULE_ID) {
          return {
            type: 'sourceFile',
            filePath: virtualFile,
          }
        }

        if (existingResolveRequest) {
          return existingResolveRequest(context, moduleName, platform)
        }

        return context.resolveRequest(context, moduleName, platform)
      },
    },
    serializer: {
      ...metroConfig.serializer,
      getModulesRunBeforeMainModule: entryFilePath => {
        const existingModules = existingGetModulesRunBeforeMainModule
          ? existingGetModulesRunBeforeMainModule(entryFilePath)
          : []
        return [...new Set([...existingModules, AUTO_INIT_MODULE])]
      },
    },
  })
}

module.exports = { decryptConfigAtBuildTime, findConfigFile, withXuqmConfig }