import { ref, computed, watch, onUnmounted } from 'vue'
import { Accounts } from 'applesauce-accounts'
import { onlyEvents } from 'applesauce-relay'
import { accountManager, AmberClipboardSigner, AmberClipboardAccount } from '../lib/accounts'
import { TEST_PERSONAS, TASTEMAKER_PERSONAS } from '../data/testPersonas'
import { pool, APP_RELAYS, LOOKUP_RELAYS } from '../lib/relay'
import type { Subscription } from 'rxjs'

type Persona = { name: string; nsec: string; pubkey: string }

/** Nostr kind 0 profile metadata */
interface NostrProfileMetadata {
  name?: string
  display_name?: string
  picture?: string
  about?: string
  nip05?: string
  lud16?: string
  banner?: string
}

/**
 * Vue composable for Nostr account management.
 * Wraps applesauce AccountManager observables as Vue reactive refs.
 * Provides login methods for Extension, test personas, and private keys.
 */
export function useAccounts() {
  const activeAccount = ref<any>(null)
  const allAccounts = ref<any[]>([])
  const isLoggingIn = ref(false)
  const loginError = ref<string | null>(null)

  /** Cached kind 0 profile metadata keyed by pubkey */
  const profileCache = ref<Map<string, NostrProfileMetadata>>(new Map())

  const subscriptions: Subscription[] = []

  // Subscribe to active account changes
  const activeSub = accountManager.active$.subscribe((account) => {
    activeAccount.value = account ?? null
  })
  subscriptions.push(activeSub)

  // Subscribe to all accounts changes
  const accountsSub = accountManager.accounts$.subscribe((accounts) => {
    allAccounts.value = [...accounts]
  })
  subscriptions.push(accountsSub)

  const isLoggedIn = computed(() => activeAccount.value !== null)
  const activePubkey = computed(() => activeAccount.value?.pubkey ?? null)

  /** The current user's kind 0 profile metadata (fetched from relays) */
  const activeProfile = computed<NostrProfileMetadata | null>(() => {
    if (!activePubkey.value) return null
    return profileCache.value.get(activePubkey.value) ?? null
  })

  /**
   * Display name: prefer Nostr profile → test persona → npub slice.
   * Skips generic placeholder names like "Nostr" so the user sees
   * a more useful identifier while they set up their profile.
   */
  const activeName = computed(() => {
    if (!activeAccount.value) return null

    // First: check if we have kind 0 profile metadata
    const profile = activeProfile.value
    if (profile?.display_name && !/^nostr$/i.test(profile.display_name.trim())) {
      return profile.display_name
    }
    if (profile?.name && !/^nostr$/i.test(profile.name.trim())) {
      return profile.name
    }

    // Second: check test personas
    const allPersonas: Persona[] = [
      ...(TEST_PERSONAS as unknown as Persona[]),
      ...(TASTEMAKER_PERSONAS as unknown as Persona[]),
    ]
    const match = allPersonas.find(
      (p) => p.pubkey === activeAccount.value?.pubkey,
    )
    if (match?.name) return match.name

    // Fallback: truncated npub for a friendlier display
    const pk = activeAccount.value?.pubkey
    if (!pk) return 'Unknown'
    return `npub...${pk.slice(-6)}`
  })

  /**
   * Profile picture URL: prefer Nostr profile picture → robohash fallback.
   */
  const activeProfilePicture = computed(() => {
    const profile = activeProfile.value
    if (profile?.picture) return profile.picture
    if (activePubkey.value) return `https://robohash.org/${activePubkey.value}.png`
    return null
  })

  /**
   * Fetch kind 0 profile metadata for a pubkey from relays.
   * Queries multiple relays and keeps the MOST RECENT event
   * (highest created_at) to ensure we get the latest profile.
   */
  function fetchProfile(pubkey: string) {
    if (!pubkey || profileCache.value.has(pubkey)) return

    // Track the best (most recent) event seen so far for this fetch
    let bestCreatedAt = 0

    const relays = [...APP_RELAYS, ...LOOKUP_RELAYS]
    try {
      const profileSub = pool
        .subscription(relays, [
          { kinds: [0], authors: [pubkey], limit: 1 },
        ])
        .pipe(onlyEvents())
        .subscribe({
          next: (event: any) => {
            try {
              // Only accept this event if it's newer than what we already have
              const eventTime = event.created_at ?? 0
              if (eventTime < bestCreatedAt) return

              const metadata: NostrProfileMetadata = JSON.parse(event.content)

              // Skip profiles with no meaningful data (empty or
              // generic placeholder names without a picture)
              const hasName = !!(metadata.display_name || metadata.name)
              const isGeneric = hasName && /^nostr$/i.test((metadata.display_name || metadata.name || '').trim())
              const hasPicture = !!metadata.picture

              // Accept if: has a non-generic name, has a picture, or
              // this is the first event we've received
              if (bestCreatedAt === 0 || !isGeneric || hasPicture) {
                bestCreatedAt = eventTime
                const updated = new Map(profileCache.value)
                updated.set(pubkey, metadata)
                profileCache.value = updated
              }
            } catch {
              // Invalid JSON in profile event
            }
          },
        })

      // Close subscription after 8 seconds (allows slower relays to respond)
      setTimeout(() => profileSub.unsubscribe(), 8000)
      subscriptions.push(profileSub)
    } catch (err) {
      console.error(`[useAccounts] Failed to fetch profile for ${pubkey}:`, err)
    }
  }

  // Auto-fetch profile when active account changes
  watch(activePubkey, (pubkey) => {
    if (pubkey) fetchProfile(pubkey)
  }, { immediate: true })

  /**
   * Login with a browser extension (NIP-07)
   */
  async function loginWithExtension() {
    isLoggingIn.value = true
    loginError.value = null
    try {
      const account = await Accounts.ExtensionAccount.fromExtension()
      accountManager.addAccount(account)
      accountManager.setActive(account)
    } catch (err: any) {
      loginError.value = err.message || 'Extension login failed'
      console.error('Extension login error:', err)
    } finally {
      isLoggingIn.value = false
    }
  }

  /**
   * Login with a test persona (for development)
   */
  async function loginWithPersona(persona: Persona) {
    isLoggingIn.value = true
    loginError.value = null
    try {
      const account = Accounts.PrivateKeyAccount.fromKey(persona.nsec)
      accountManager.addAccount(account)
      accountManager.setActive(account)
    } catch (err: any) {
      loginError.value = err.message || 'Persona login failed'
      console.error('Persona login error:', err)
    } finally {
      isLoggingIn.value = false
    }
  }

  /**
   * Login with a private key (nsec)
   */
  async function loginWithPrivateKey(nsec: string) {
    isLoggingIn.value = true
    loginError.value = null
    try {
      const account = Accounts.PrivateKeyAccount.fromKey(nsec)
      accountManager.addAccount(account)
      accountManager.setActive(account)
    } catch (err: any) {
      loginError.value = err.message || 'Private key login failed'
      console.error('Private key login error:', err)
    } finally {
      isLoggingIn.value = false
    }
  }

  /**
   * Check if Amber signer is supported on this platform (Android + clipboard)
   */
  const isAmberSupported = computed(() => !!AmberClipboardSigner.SUPPORTED)

  /**
   * Login with Amber (NIP-55 Android Signer).
   * Uses the AmberClipboardSigner to request the pubkey via Android intents.
   * The signer is retained for future event signing (comments, reactions, etc.)
   */
  async function loginWithAmber() {
    isLoggingIn.value = true
    loginError.value = null
    try {
      const signer = new AmberClipboardSigner()
      const pubkey = await signer.getPublicKey()
      const account = new AmberClipboardAccount(pubkey, signer)
      accountManager.addAccount(account)
      accountManager.setActive(account)
      return pubkey
    } catch (err: any) {
      loginError.value = err.message || 'Amber login failed'
      console.error('Amber login error:', err)
      throw err
    } finally {
      isLoggingIn.value = false
    }
  }

  /**
   * Logout current account.
   * removeAccount already clears the active account if it's the one being removed.
   */
  function logout() {
    const current = accountManager.active
    if (current) {
      try {
        accountManager.removeAccount(current)
      } catch (err) {
        console.debug('Account removal cleanup:', err)
      }
    }
  }

  /**
   * Get all available test personas
   */
  const testPersonas = computed(() => [
    ...(TEST_PERSONAS as unknown as Persona[]),
  ])

  const tastemakerPersonas = computed(() => [
    ...(TASTEMAKER_PERSONAS as unknown as Persona[]),
  ])

  // Cleanup on unmount
  onUnmounted(() => {
    subscriptions.forEach((sub) => sub.unsubscribe())
  })

  return {
    // State
    activeAccount,
    allAccounts,
    isLoggedIn,
    isLoggingIn,
    loginError,
    activePubkey,
    activeName,
    activeProfile,
    activeProfilePicture,

    // Login methods
    loginWithExtension,
    loginWithPersona,
    loginWithPrivateKey,
    loginWithAmber,
    logout,

    // Platform checks
    isAmberSupported,

    // Personas for dev UI
    testPersonas,
    tastemakerPersonas,
  }
}