import { app, safeStorage } from 'electron'
import { promises as fs } from 'node:fs'
import path from 'node:path'

export interface StoredLicense {
  token: string
  licenseCodeMask: string
  deviceMask: string
  expiresAt?: string
  maxDevices: number
  lastVerifiedAt: string
}

interface StoredLicenseFile {
  encryptedToken: string
  licenseCodeMask: string
  deviceMask: string
  expiresAt?: string
  maxDevices: number
  lastVerifiedAt: string
}

export class LicenseStore {
  private get filePath(): string {
    return path.join(app.getPath('userData'), 'license.json')
  }

  async load(): Promise<StoredLicense | null> {
    try {
      const raw = await fs.readFile(this.filePath, 'utf8')
      const stored = JSON.parse(raw) as StoredLicenseFile
      const decrypted = await safeStorage.decryptStringAsync(
        Buffer.from(stored.encryptedToken, 'base64'),
      )
      return {
        token: decrypted.result,
        licenseCodeMask: stored.licenseCodeMask,
        deviceMask: stored.deviceMask,
        expiresAt: stored.expiresAt,
        maxDevices: stored.maxDevices,
        lastVerifiedAt: stored.lastVerifiedAt,
      }
    } catch {
      return null
    }
  }

  async save(license: StoredLicense): Promise<void> {
    if (!(await safeStorage.isAsyncEncryptionAvailable())) {
      throw new Error('系统安全凭据存储不可用')
    }
    const encryptedToken = await safeStorage.encryptStringAsync(license.token)
    const stored: StoredLicenseFile = {
      encryptedToken: encryptedToken.toString('base64'),
      licenseCodeMask: license.licenseCodeMask,
      deviceMask: license.deviceMask,
      expiresAt: license.expiresAt,
      maxDevices: license.maxDevices,
      lastVerifiedAt: license.lastVerifiedAt,
    }
    await fs.mkdir(path.dirname(this.filePath), { recursive: true })
    const temporaryPath = `${this.filePath}.tmp`
    await fs.writeFile(temporaryPath, JSON.stringify(stored), { mode: 0o600 })
    await fs.rename(temporaryPath, this.filePath)
  }

  async clear(): Promise<void> {
    await fs.rm(this.filePath, { force: true })
  }
}