import { nostrService } from './nostr'
import { keyManagementService } from './keyManagement'
import type { NostrConnectState } from '@/types/nostr'

/**
 * Nostr authentication service using local key management
 * Keys are stored encrypted in IndexedDB and decrypted using recovery phrase
 */
export class NostrAuthService {
  private state: NostrConnectState = {
    connected: false,
    pubkey: null,
    profile: null,
  }

  private listeners: Set<(state: NostrConnectState) => void> = new Set()
  private unlockedPrivateKey: string | null = null

  constructor() {
    if (typeof window !== 'undefined') {
      this.loadStateFromStorage()
      this.setupMessageListener()
    }
  }

  subscribe(callback: (state: NostrConnectState) => void): () => void {
    this.listeners.add(callback)
    callback(this.state)
    return () => {
      this.listeners.delete(callback)
    }
  }

  getState(): NostrConnectState {
    return { ...this.state }
  }

  /**
   * Check if account exists
   */
  async accountExists(): Promise<boolean> {
    return keyManagementService.accountExists()
  }

  /**
   * Create a new account (generate or import key)
   * Returns recovery phrase and npub
   */
  async createAccount(privateKey?: string): Promise<{
    recoveryPhrase: string[]
    npub: string
    publicKey: string
  }> {
    const result = await keyManagementService.createAccount(privateKey)

    // Set public key immediately
    this.state = {
      connected: false,
      pubkey: result.publicKey,
      profile: null,
    }
    nostrService.setPublicKey(result.publicKey)
    this.saveStateToStorage()
    this.notifyListeners()

    return result
  }

  /**
   * Unlock account using recovery phrase
   */
  async unlockAccount(recoveryPhrase: string[]): Promise<void> {
    try {
      const keys = await keyManagementService.unlockAccount(recoveryPhrase)

      this.unlockedPrivateKey = keys.privateKey
      this.state = {
        connected: true,
        pubkey: keys.publicKey,
        profile: null,
      }

      nostrService.setPublicKey(keys.publicKey)
      nostrService.setPrivateKey(keys.privateKey)
      this.saveStateToStorage()
      this.notifyListeners()
      void this.loadProfile()
    } catch (e) {
      console.error('Error unlocking account:', e)
      throw new Error(`Failed to unlock account: ${e instanceof Error ? e.message : 'Unknown error'}`)
    }
  }

  /**
   * Connect using existing stored keys (if already unlocked)
   * This is called when the app loads and keys are already available
   */
  async connect(): Promise<void> {
    // Check if account exists
    const exists = await keyManagementService.accountExists()
    if (!exists) {
      throw new Error('No account found. Please create an account first.')
    }

    // Try to get public keys
    const publicKeys = await keyManagementService.getPublicKeys()
    if (!publicKeys) {
      throw new Error('Account exists but public keys not found')
    }

    // Set public key but don't unlock private key yet
    // Private key will be unlocked when user provides recovery phrase
    this.state = {
      connected: false,
      pubkey: publicKeys.publicKey,
      profile: null,
    }
    nostrService.setPublicKey(publicKeys.publicKey)
    this.saveStateToStorage()
    this.notifyListeners()
    void this.loadProfile()
  }

  /**
   * Get the private key if unlocked
   */
  getPrivateKey(): string | null {
    return this.unlockedPrivateKey
  }

  /**
   * Check if private key is unlocked
   */
  isUnlocked(): boolean {
    return this.unlockedPrivateKey !== null
  }

  disconnect(): void {
    this.unlockedPrivateKey = null
    this.state = {
      connected: false,
      pubkey: null,
      profile: null,
    }
    // Clear keys from nostrService - the service stores keys internally, we just clear our reference
    // The service will continue to work but won't have access to the keys
    nostrService.setPrivateKey('')
    nostrService.setPublicKey('')
    this.saveStateToStorage()
    this.notifyListeners()
  }

  /**
   * Delete account (remove all stored keys)
   */
  async deleteAccount(): Promise<void> {
    await keyManagementService.deleteAccount()
    this.disconnect()
  }

  private async loadProfile(): Promise<void> {
    if (!this.state.pubkey) {
      return
    }

    try {
      const profile = await nostrService.getProfile(this.state.pubkey)
      if (profile) {
        this.state.profile = profile
        this.saveStateToStorage()
        this.notifyListeners()
      }
    } catch (e) {
      console.error('Error loading profile:', e)
    }
  }

  private setupMessageListener(): void {
    window.addEventListener('storage', (e) => {
      if (e.key === 'nostr_auth_state') {
        this.loadStateFromStorage()
      }
    })
  }

  private loadStateFromStorage(): void {
    try {
      const stored = localStorage.getItem('nostr_auth_state')
      if (stored) {
        const parsed = JSON.parse(stored)
        this.state = {
          connected: parsed.connected ?? false,
          pubkey: parsed.pubkey ?? null,
          profile: parsed.profile ?? null,
        }
        if (this.state.pubkey) {
          nostrService.setPublicKey(this.state.pubkey)
        }
        // Note: private key is not stored, it must be unlocked with recovery phrase
      }
    } catch (e) {
      console.error('Error loading state from storage:', e)
    }
  }

  private saveStateToStorage(): void {
    try {
      // Only save public information, never private keys
      const stateToSave = {
        connected: this.state.connected,
        pubkey: this.state.pubkey,
        profile: this.state.profile,
      }
      localStorage.setItem('nostr_auth_state', JSON.stringify(stateToSave))
    } catch (e) {
      console.error('Error saving state to storage:', e)
    }
  }

  private notifyListeners(): void {
    this.listeners.forEach((callback) => callback({ ...this.state }))
  }
}

export const nostrAuthService = new NostrAuthService()