import { ref, readonly, computed } from 'vue'
import { generateSecretKey, getPublicKey } from 'nostr-tools'
import { bytesToHex, hexToBytes } from 'nostr-tools/utils'
import { nsecEncode } from 'nostr-tools/nip19'
import { buildNip98Token, setToken, getToken, isTokenExpired, authFetch } from '../lib/nostr-auth'

/** NIP-55: Build a nostrsigner: URI for sign_event (inline since nostr-tools doesn't export nip55) */
function buildSignEventUri(eventJson: Record<string, unknown>, callbackUrl: string): string {
  const params = new URLSearchParams({
    type: 'sign_event',
    callbackUrl,
    returnType: 'event',
    compressionType: 'none',
  })
  return `nostrsigner:${encodeURIComponent(JSON.stringify(eventJson))}?${params.toString()}`
}

interface BotCustomization {
  archetype?: string
  primaryColor?: string
  secondaryColor?: string
  forceVisor?: boolean
  forceMohawk?: boolean
  forceHorns?: boolean
}

interface BotData {
  id: string
  name: string
  avatarSeed: string
  archetype: string
  profilePicUrl: string | null
  customization: BotCustomization | null
  isHuman?: boolean
  eloRating: number
  wins: number
  losses: number
  winStreak: number
  bestStreak: number
  tier: number
  satsWon: number
  satsWagered: number
  hasWallet: boolean
}

interface NostrWindow {
  getPublicKey(): Promise<string>
  signEvent(event: Record<string, unknown>): Promise<Record<string, unknown>>
  getRelays?(): Promise<Record<string, { read: boolean; write: boolean }>>
}

declare global {
  interface Window {
    nostr?: NostrWindow
  }
}

// Persist auth state across page navigations and HMR reloads
function loadStored<T>(key: string): T | null {
  try {
    const raw = localStorage.getItem(key)
    return raw ? JSON.parse(raw) : null
  } catch { return null }
}
function store(key: string, value: unknown) {
  if (value == null) localStorage.removeItem(key)
  else localStorage.setItem(key, JSON.stringify(value))
}

/** Normalize server bot data to fill missing fields */
function normalizeBotData(data: Record<string, unknown>): BotData {
  return {
    satsWon: 0,
    satsWagered: 0,
    hasWallet: false,
    ...data,
  } as BotData
}

/** Clear all auth-related state including JWT and nsec */
function clearAllState() {
  pubkey.value = null
  bot.value = null
  profilePicUrl.value = null
  store('bf_pubkey', null)
  store('bf_bot', null)
  store('bf_pic', null)
  setToken(null)
  sessionNsec = null
  sessionStorage.removeItem('bf_nsec')
}

const pubkey = ref<string | null>(loadStored('bf_pubkey'))
const bot = ref<BotData | null>(loadStored('bf_bot'))
const profilePicUrl = ref<string | null>(loadStored('bf_pic'))
const isLoading = ref(false)

// Guard: only auto-restore once — survives Vite HMR module re-evaluation
let autoRestoreRan = (globalThis as any).__bf_autoRestoreRan ?? false
// Flag: skip relay pic fetch for freshly generated keys (no profile exists)
let freshlyGenerated = false
// In-memory nsec for current session (never auto-persisted to localStorage)
let sessionNsec: string | null = null

// Sync in-memory auth state when tab regains focus (handles external localStorage clearing)
if (typeof document !== 'undefined') {
  document.addEventListener('visibilitychange', () => {
    if (document.visibilityState !== 'visible') return
    const storedPubkey = loadStored<string>('bf_pubkey')
    if (!storedPubkey && pubkey.value) {
      // localStorage was cleared externally — wipe in-memory state to match
      clearAllState()
    }
  })
}

// Auto-restore session from JWT on first load.
// Identity comes from the token alone — GET /api/auth/me derives the
// pubkey server-side via extractPubkeyFromAuth, so no bare pubkey is
// ever sent to claim a session (D-01/BOT-01).
if (!autoRestoreRan && pubkey.value && !bot.value && getToken() && !isTokenExpired()) {
  autoRestoreRan = true;
  (globalThis as any).__bf_autoRestoreRan = true
  authFetch('/api/auth/me').then(r => r.json()).then(data => {
    if (data.exists) {
      bot.value = normalizeBotData(data.bot)
      store('bf_bot', bot.value)
    }
  }).catch(err => console.warn('[Nostr] auto-restore failed:', err))
} else if (!autoRestoreRan && pubkey.value && !getToken()) {
  // No JWT — clear stale pubkey from before the JWT migration
  autoRestoreRan = true;
  (globalThis as any).__bf_autoRestoreRan = true
  pubkey.value = null
  store('bf_pubkey', null)
}

export function useNostr() {
  const isLoggedIn = computed(() => !!pubkey.value && !!bot.value)
  const hasExtension = computed(() => !!window.nostr)

  /** Wait for window.nostr to appear (mobile signers inject late) */
  async function waitForSigner(timeoutMs = 3000): Promise<boolean> {
    if (window.nostr) return true
    const start = Date.now()
    while (Date.now() - start < timeoutMs) {
      await new Promise(r => setTimeout(r, 200))
      if (window.nostr) return true
    }
    return false
  }

  /**
   * Authenticate with the server using NIP-98 signed request.
   * Works with NIP-07 extension, Amber signer, or local nsec.
   * Returns JWT session token + bot data.
   */
  async function authenticateSession(secretKeyHex?: string | null): Promise<{ pubkey: string; bot: BotData | null }> {
    const sessionUrl = new URL('/api/auth/nostr/session', window.location.origin).toString()
    const nip98Token = await buildNip98Token(sessionUrl, 'POST', secretKeyHex)

    const res = await fetch('/api/auth/nostr/session', {
      method: 'POST',
      headers: {
        'Authorization': `Nostr ${nip98Token}`,
      },
    })

    if (!res.ok) {
      const data = await res.json().catch(() => ({ error: 'Authentication failed' }))
      throw new Error(data.error || 'NIP-98 authentication failed')
    }

    const data = await res.json()

    // Store JWT
    setToken(data.token)

    // Store pubkey
    pubkey.value = data.pubkey
    store('bf_pubkey', data.pubkey)

    if (data.exists && data.bot) {
      bot.value = normalizeBotData(data.bot)
      store('bf_bot', bot.value)
      return { pubkey: data.pubkey, bot: bot.value }
    }

    bot.value = null
    store('bf_bot', null)
    return { pubkey: data.pubkey, bot: null }
  }

  /**
   * Sign in using NIP-07 extension or Amber signer (window.nostr).
   * Authenticates via NIP-98 and receives a JWT session.
   */
  async function login(): Promise<{ pubkey: string; bot: BotData | null }> {
    if (!window.nostr) {
      // Mobile signers (Amber) inject window.nostr late — poll for up to 3s
      const found = await waitForSigner(3000)
      if (!found) {
        // Fall back to session or persisted nsec if available
        const storedNsec = sessionNsec || sessionStorage.getItem('bf_nsec')
        if (storedNsec) {
          return loginWithNsec(storedNsec)
        }
        throw new Error('No Nostr signer found. Install a browser extension or use "Generate New Identity".')
      }
    }

    // Verify extension is responsive
    try {
      await window.nostr!.getPublicKey()
    } catch {
      throw new Error('Nostr signer denied access. Approve the request and try again.')
    }

    isLoading.value = true
    try {
      const result = await authenticateSession()

      // Fetch Nostr profile pic (non-blocking)
      if (!freshlyGenerated) {
        fetchNostrProfilePic(result.pubkey).then(pic => {
          profilePicUrl.value = pic
          store('bf_pic', pic)
        }).catch(err => console.warn('[Nostr] relay profile fetch failed:', err))
      } else {
        freshlyGenerated = false
        profilePicUrl.value = null
        store('bf_pic', null)
      }

      return result
    } finally {
      isLoading.value = false
    }
  }

  /** Generate a fresh Nostr keypair locally — no extension needed */
  function generateLogin(): { pubkey: string; nsec: string } {
    const secretKey = generateSecretKey()
    const pk = getPublicKey(secretKey)
    const nsecHex = bytesToHex(secretKey)
    const nsecBech32 = nsecEncode(secretKey)

    // Clear all stale state from previous identity
    clearAllState()

    // Mark as freshly generated so login() skips relay pic fetch
    freshlyGenerated = true

    // Hold key in session memory only — user must opt in to persist
    sessionNsec = nsecHex
    pubkey.value = pk
    store('bf_pubkey', pk)

    return { pubkey: pk, nsec: nsecBech32 }
  }

  /** Login with an existing nsec (hex). Signs NIP-98 locally. If persist=true, saves to localStorage. */
  async function loginWithNsec(nsecHex: string, persist = false): Promise<{ pubkey: string; bot: BotData | null }> {
    let secretKey: Uint8Array
    try {
      secretKey = hexToBytes(nsecHex)
    } catch {
      throw new Error('Invalid secret key format.')
    }
    getPublicKey(secretKey) // validate key

    // Clear stale state before switching identity
    bot.value = null
    profilePicUrl.value = null
    store('bf_bot', null)
    store('bf_pic', null)

    sessionNsec = nsecHex
    if (persist) sessionStorage.setItem('bf_nsec', nsecHex)

    isLoading.value = true
    try {
      const result = await authenticateSession(nsecHex)

      // Fetch Nostr profile pic (non-blocking)
      fetchNostrProfilePic(result.pubkey).then(pic => {
        profilePicUrl.value = pic
        store('bf_pic', pic)
      }).catch(err => console.warn('[Nostr] profile pic fetch failed:', err))

      return result
    } finally {
      isLoading.value = false
    }
  }

  async function registerBot(name: string, webhookUrl: string, archetype: string): Promise<{ bot: BotData; secret: string; mode: string }> {
    if (!pubkey.value) throw new Error('Not logged in')

    const res = await authFetch('/api/auth/register', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        pubkey: pubkey.value,
        name,
        webhookUrl,
        archetype,
        profilePicUrl: profilePicUrl.value,
      }),
    })

    const data = await res.json()
    if (!res.ok) {
      let msg = data.details ? `${data.error} ${data.details}` : (data.error || 'Registration failed')
      if (res.status === 429 && data.retryAfterSec) msg += ` (${data.retryAfterSec}s)`
      throw new Error(msg)
    }

    bot.value = {
      id: data.id,
      name: data.name,
      avatarSeed: data.name,
      archetype: data.archetype,
      profilePicUrl: profilePicUrl.value,
      customization: data.customization || null,
      eloRating: 1200,
      wins: 0,
      losses: 0,
      winStreak: 0,
      bestStreak: 0,
      tier: 0,
      satsWon: 0,
      satsWagered: 0,
      hasWallet: false,
    }
    store('bf_bot', bot.value)

    // Re-authenticate to get fresh JWT with botId
    try {
      await authenticateSession(sessionNsec)
    } catch {
      // Non-critical: existing JWT still works, just missing botId
    }

    return { bot: bot.value, secret: data.secret, mode: data.mode || 'webhook' }
  }

  async function updateCustomization(customization: BotCustomization): Promise<void> {
    if (!pubkey.value) throw new Error('Not logged in')

    const res = await authFetch('/api/auth/update', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ pubkey: pubkey.value, customization }),
    })

    if (!res.ok) {
      const data = await res.json()
      throw new Error(data.error || 'Update failed')
    }

    if (bot.value) {
      bot.value = {
        ...bot.value,
        customization: { ...(bot.value.customization || {}), ...customization },
        archetype: customization.archetype || bot.value.archetype,
      }
      store('bf_bot', bot.value)
    }
  }

  async function updateWebhook(newUrl: string): Promise<{ latencyMs: number }> {
    if (!pubkey.value) throw new Error('Not logged in')

    const res = await authFetch('/api/auth/update', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ pubkey: pubkey.value, webhookUrl: newUrl }),
    })

    const data = await res.json()
    if (!res.ok) {
      const msg = data.details ? `${data.error} ${data.details}` : (data.error || 'Update failed')
      throw new Error(msg)
    }

    return { latencyMs: data.latencyMs || 0 }
  }

  async function regenerateSecret(): Promise<{ botId: string; secret: string }> {
    if (!pubkey.value) throw new Error('Not logged in')

    const res = await authFetch('/api/auth/regenerate-secret', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
    })

    const data = await res.json()
    if (!res.ok) {
      throw new Error(data.error || 'Failed to regenerate secret')
    }

    return { botId: data.botId, secret: data.secret }
  }

  async function registerHuman(name: string, avatarSeed?: string): Promise<BotData> {
    if (!pubkey.value) throw new Error('Not logged in')

    const res = await authFetch('/api/auth/register-human', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        pubkey: pubkey.value,
        name,
        avatarSeed,
        profilePicUrl: profilePicUrl.value,
      }),
    })

    const data = await res.json()
    if (!res.ok) {
      let msg = data.error || 'Registration failed'
      if (res.status === 429 && data.retryAfterSec) msg += ` (${data.retryAfterSec}s)`
      throw new Error(msg)
    }

    bot.value = {
      id: data.id,
      name: data.name,
      avatarSeed: avatarSeed || data.name,
      archetype: 'human',
      profilePicUrl: profilePicUrl.value,
      customization: null,
      isHuman: true,
      eloRating: 1200,
      wins: 0,
      losses: 0,
      winStreak: 0,
      bestStreak: 0,
      tier: 0,
      satsWon: 0,
      satsWagered: 0,
      hasWallet: false,
    }
    store('bf_bot', bot.value)

    // Re-authenticate to get fresh JWT with botId
    try {
      await authenticateSession(sessionNsec)
    } catch {
      // Non-critical
    }

    return bot.value
  }

  /** Sign out — clears everything including JWT, nsec, and all stored state */
  function logout() {
    clearAllState()
  }

  /** Check if user has a locally stored key (no extension needed) */
  const hasStoredKey = computed(() => !!sessionStorage.getItem('bf_nsec'))

  /** Get the current nsec hex (session memory first, then localStorage) */
  function getStoredNsec(): string | null {
    return sessionNsec || sessionStorage.getItem('bf_nsec')
  }

  /** Persist the current session key to localStorage (opt-in) */
  function persistKey(): void {
    if (sessionNsec) sessionStorage.setItem('bf_nsec', sessionNsec)
  }

  /**
   * NIP-55: Initiate login via Android signer app (Amber/Primal).
   * Builds an unsigned NIP-98 event and navigates to a nostrsigner: URI.
   * The signer app signs the event and redirects back to callbackUrl.
   */
  function initiateNip55Login() {
    const sessionUrl = new URL('/api/auth/nostr/session', window.location.origin).toString()
    const unsignedEvent = {
      kind: 27235,
      tags: [['u', sessionUrl], ['method', 'POST']],
      content: '',
      created_at: Math.floor(Date.now() / 1000),
    }

    const callbackUrl = new URL('/join-bout', window.location.origin).toString()

    const uri = buildSignEventUri(unsignedEvent, callbackUrl)

    window.location.href = uri
  }

  /**
   * NIP-55: Process the callback after returning from an Android signer.
   * Parses the signed event from the URL and authenticates with the server.
   * Returns null if no NIP-55 callback params are present.
   */
  async function processNip55Return(): Promise<{ pubkey: string; bot: BotData | null } | null> {
    const params = new URLSearchParams(window.location.search)

    // Look for the signed event in common NIP-55 callback param names
    const eventStr = params.get('event') || params.get('result') || params.get('signed_event')
    if (!eventStr) return null

    // Clean the URL so the params don't persist
    window.history.replaceState({}, '', window.location.pathname)

    try {
      const signedEvent = JSON.parse(decodeURIComponent(eventStr))
      const nip98Token = btoa(JSON.stringify(signedEvent))

      const res = await fetch('/api/auth/nostr/session', {
        method: 'POST',
        headers: { 'Authorization': `Nostr ${nip98Token}` },
      })

      if (!res.ok) {
        const data = await res.json().catch(() => ({ error: 'Authentication failed' }))
        throw new Error(data.error || 'NIP-98 authentication failed')
      }

      const data = await res.json()

      setToken(data.token)
      pubkey.value = data.pubkey
      store('bf_pubkey', data.pubkey)

      if (data.exists && data.bot) {
        bot.value = normalizeBotData(data.bot)
        store('bf_bot', bot.value)
        return { pubkey: data.pubkey, bot: bot.value }
      }

      bot.value = null
      store('bf_bot', null)
      return { pubkey: data.pubkey, bot: null }
    } catch (e) {
      console.error('[NIP-55] Failed to process signer callback:', e)
      throw e
    }
  }

  /** Detect if Android signer apps (Amber/Primal) might be available */
  const hasAndroidSigner = computed(() => /android/i.test(navigator.userAgent))

  return {
    pubkey: readonly(pubkey),
    bot: readonly(bot),
    profilePicUrl: readonly(profilePicUrl),
    isLoggedIn,
    isLoading: readonly(isLoading),
    hasExtension,
    hasStoredKey,
    login,
    waitForSigner,
    generateLogin,
    loginWithNsec,
    registerBot,
    registerHuman,
    updateCustomization,
    updateWebhook,
    regenerateSecret,
    getStoredNsec,
    persistKey,
    logout,
    fetchNostrProfile,
    initiateNip55Login,
    processNip55Return,
    hasAndroidSigner,
  }
}

export interface NostrProfile {
  displayName: string | null
  about: string | null
  picture: string | null
  banner: string | null
  nip05: string | null
}

// Profile cache with 5-min TTL
const profileCache = new Map<string, { data: NostrProfile; ts: number }>()
const PROFILE_TTL = 5 * 60 * 1000

const RELAYS = [
  'wss://relay.damus.io',
  'wss://relay.nostr.band',
  'wss://nos.lol',
]

// Fetch profile picture from a Nostr relay
async function fetchNostrProfilePic(pk: string): Promise<string | null> {
  const profile = await fetchNostrProfile(pk)
  return profile?.picture || null
}

/** Fetch full Nostr profile (kind:0 metadata) with caching.
 *  Queries all relays in parallel, picks result with latest created_at. */
async function fetchNostrProfile(pk: string): Promise<NostrProfile | null> {
  const cached = profileCache.get(pk)
  if (cached && Date.now() - cached.ts < PROFILE_TTL) return cached.data

  const results = await Promise.allSettled(
    RELAYS.map(relay => queryRelayProfile(relay, pk))
  )

  // Pick the profile with the latest created_at (newest wins)
  let best: { profile: NostrProfile; createdAt: number } | null = null
  for (const r of results) {
    if (r.status !== 'fulfilled' || !r.value) continue
    if (!best || r.value.createdAt > best.createdAt) {
      best = r.value
    }
  }

  if (best) {
    profileCache.set(pk, { data: best.profile, ts: Date.now() })
    return best.profile
  }
  return null
}

function queryRelayProfile(url: string, pk: string): Promise<{ profile: NostrProfile; createdAt: number } | null> {
  return new Promise((resolve) => {
    let timedOut = false
    const timeout = setTimeout(() => {
      timedOut = true
      if (ws.readyState === WebSocket.OPEN) ws.close()
      resolve(null)
    }, 3000)

    const ws = new WebSocket(url)
    const subId = Math.random().toString(36).slice(2, 10)

    ws.onopen = () => {
      if (timedOut) { ws.close(); return }
      ws.send(JSON.stringify(['REQ', subId, { kinds: [0], authors: [pk], limit: 1 }]))
    }

    ws.onmessage = (msg) => {
      try {
        const data = JSON.parse(msg.data)
        if (data[0] === 'EVENT' && data[2]?.kind === 0) {
          const meta = JSON.parse(data[2].content)
          clearTimeout(timeout)
          ws.close()
          resolve({
            profile: {
              displayName: meta.display_name || meta.name || null,
              about: meta.about || null,
              picture: meta.picture || null,
              banner: meta.banner || null,
              nip05: meta.nip05 || null,
            },
            createdAt: data[2].created_at || 0,
          })
        } else if (data[0] === 'EOSE') {
          clearTimeout(timeout)
          ws.close()
          resolve(null)
        }
      } catch {
        // ignore parse errors
      }
    }

    ws.onerror = () => {
      clearTimeout(timeout)
      resolve(null)
    }
  })
}