// BrowserAdapter — standalone in-browser waste client.
// Speaks the yaw/2.1 signaling + WebRTC protocol; emits IpcMessage events
// identical to DaemonAdapter so the store and UI need no changes.
//
// No daemon required. Identity is Ed25519, stored as hex seed in localStorage.
// Crypto via libsodium-wrappers.

import sodium from 'libsodium-wrappers'
import type { IpcMessage, PeerInfo } from '../types'

type Listener = (msg: IpcMessage) => void
type Status = 'disconnected' | 'connecting' | 'connected'

const BIND_PREFIX = 'yaw/2 bind'
const EKEY_PREFIX = 'yaw/2.1 ekey'
const FS_TIMEOUT = 2000
const STUN = 'stun:stun.l.google.com:19302'

const enc = (s: string) => new TextEncoder().encode(s)

function concat(...arrs: Uint8Array[]): Uint8Array {
  const n = arrs.reduce((a, b) => a + b.length, 0)
  const out = new Uint8Array(n); let o = 0
  for (const a of arrs) { out.set(a, o); o += a.length }
  return out
}

function toHex(bytes: Uint8Array): string {
  return Array.from(bytes).map(b => b.toString(16).padStart(2, '0')).join('')
}

async function netHash(name: string): Promise<string> {
  const input = enc('yaw2-net:' + name)

  // Use native SHA-256 for protocol-compatible network IDs.
  if (globalThis.crypto?.subtle) {
    const digest = await globalThis.crypto.subtle.digest('SHA-256', input)
    return toHex(new Uint8Array(digest))
  }

  // Fallback for environments where subtle crypto is unavailable.
  const sha256 = (sodium as unknown as { crypto_hash_sha256?: (m: Uint8Array) => Uint8Array }).crypto_hash_sha256
  if (sha256) return sodium.to_hex(sha256(input))

  throw new Error('SHA-256 not available in this browser runtime')
}

// ── Identity ─────────────────────────────────────────────────────────────────

class Identity {
  pub: Uint8Array
  priv: Uint8Array
  id: string
  curvePriv: Uint8Array
  nick: string

  constructor(kp: { publicKey: Uint8Array; privateKey: Uint8Array }) {
    this.pub = kp.publicKey
    this.priv = kp.privateKey
    this.id = sodium.to_hex(this.pub)
    this.curvePriv = sodium.crypto_sign_ed25519_sk_to_curve25519(this.priv)
    this.nick = localStorage.getItem('waste_nick') || ''
  }

  static load(): Identity {
    const seedHex = localStorage.getItem('waste_seed')
    let kp
    if (seedHex) {
      kp = sodium.crypto_sign_seed_keypair(sodium.from_hex(seedHex))
    } else {
      kp = sodium.crypto_sign_keypair()
      localStorage.setItem('waste_seed', sodium.to_hex(kp.privateKey.slice(0, 32)))
    }
    return new Identity(kp)
  }

  setNick(nick: string) {
    this.nick = nick.trim().slice(0, 40)
    localStorage.setItem('waste_nick', this.nick)
  }

  sign(data: Uint8Array): Uint8Array {
    return sodium.crypto_sign_detached(data, this.priv)
  }

  static verify(idHex: string, data: Uint8Array, sig: Uint8Array): boolean {
    try { return sodium.crypto_sign_verify_detached(sig, data, sodium.from_hex(idHex)) }
    catch { return false }
  }

  seal(recipIdHex: string, plaintext: Uint8Array): string {
    const pub = sodium.crypto_sign_ed25519_pk_to_curve25519(sodium.from_hex(recipIdHex))
    const nonce = sodium.randombytes_buf(24)
    const ct = sodium.crypto_box_easy(plaintext, nonce, pub, this.curvePriv)
    return sodium.to_base64(concat(nonce, ct), sodium.base64_variants.ORIGINAL)
  }

  open(senderIdHex: string, boxB64: string): Uint8Array | null {
    const pub = sodium.crypto_sign_ed25519_pk_to_curve25519(sodium.from_hex(senderIdHex))
    const box = sodium.from_base64(boxB64, sodium.base64_variants.ORIGINAL)
    try { return sodium.crypto_box_open_easy(box.slice(24), box.slice(0, 24), pub, this.curvePriv) }
    catch { return null }
  }

  exportBackup(passphrase: string): object {
    const BK_OPS = 2, BK_MEM = 67108864
    const b64 = (b: Uint8Array) => sodium.to_base64(b, sodium.base64_variants.ORIGINAL)
    const seed = this.priv.slice(0, 32)
    const salt = sodium.randombytes_buf(sodium.crypto_pwhash_SALTBYTES)
    const key = sodium.crypto_pwhash(
      sodium.crypto_secretbox_KEYBYTES, passphrase, salt,
      BK_OPS, BK_MEM, sodium.crypto_pwhash_ALG_ARGON2ID13
    )
    const nonce = sodium.randombytes_buf(sodium.crypto_secretbox_NONCEBYTES)
    const ct = sodium.crypto_secretbox_easy(seed, nonce, key)
    return {
      yaw: 'yaw-key-backup-1', id: this.id, alg: 'argon2id-secretbox',
      ops: BK_OPS, mem: BK_MEM, salt: b64(salt), nonce: b64(nonce), ct: b64(ct)
    }
  }

  static importBackup(b: Record<string, unknown>, passphrase: string): Identity {
    if (!b || b['yaw'] !== 'yaw-key-backup-1') throw new Error('not a yaw key backup')
    const ub = (s: unknown) => sodium.from_base64(s as string, sodium.base64_variants.ORIGINAL)
    const key = sodium.crypto_pwhash(
      sodium.crypto_secretbox_KEYBYTES, passphrase, ub(b['salt']),
      b['ops'] as number | 0, b['mem'] as number | 0, sodium.crypto_pwhash_ALG_ARGON2ID13
    )
    const seed = sodium.crypto_secretbox_open_easy(ub(b['ct']), ub(b['nonce']), key)
    localStorage.setItem('waste_seed', sodium.to_hex(seed))
    return new Identity(sodium.crypto_sign_seed_keypair(seed))
  }

  get short(): string {
    return this.id.slice(0, 16).replace(/(.{4})/g, '$1 ').trim()
  }

  toPeerInfo(networkId = ''): PeerInfo {
    return {
      id: this.id, alias: this.nick || this.short, public_key: this.id,
      created_at: new Date().toISOString(), network_id: networkId
    } as PeerInfo & { network_id?: string }
  }
}

// ── Signaling ─────────────────────────────────────────────────────────────────

class Signaling {
  private ws: WebSocket | null = null
  private _closed = false
  private _backoff = 1000
  private _cbs: {
    onFrom?: (from: string, box: string) => void
    onJoin?: (id: string) => void
    onLeave?: (id: string) => void
    onReconnect?: (peers: string[]) => void
  } = {}

  private url: string
  private identity: Identity
  private net: string

  constructor(url: string, identity: Identity, net: string) {
    this.url = url
    this.identity = identity
    this.net = net
  }

  connect(
    onFrom: (from: string, box: string) => void,
    onJoin: (id: string) => void,
    onLeave: (id: string) => void,
    onReconnect: (peers: string[]) => void,
  ): Promise<string[]> {
    this._cbs = { onFrom, onJoin, onLeave, onReconnect }
    return this._open(true)
  }

  private _open(initial: boolean): Promise<string[]> {
    return new Promise((resolve, reject) => {
      const ws = new WebSocket(this.url)
      this.ws = ws
      let joined = false

      ws.onerror = () => { if (initial && !joined) reject(new Error('signaling connection failed')) }
      ws.onclose = () => { if (!this._closed) this._scheduleReconnect() }
      ws.onmessage = (ev) => {
        let m: Record<string, unknown>
        try { m = JSON.parse(ev.data) } catch { return }

        if (m['type'] === 'challenge') {
          const nonce = sodium.from_hex(m['nonce'] as string)
          const sig = sodium.to_hex(this.identity.sign(concat(nonce, enc(this.net))))
          ws.send(JSON.stringify({ type: 'join', id: this.identity.id, net: this.net, sig }))
        } else if (m['type'] === 'joined') {
          joined = true; this._backoff = 1000
          const peers = (m['peers'] as string[]) || []
          if (initial) resolve(peers)
          else this._cbs.onReconnect?.(peers)
        } else if (m['type'] === 'from') {
          this._cbs.onFrom?.(m['from'] as string, m['box'] as string)
        } else if (m['type'] === 'peer-join') {
          this._cbs.onJoin?.(m['id'] as string)
        } else if (m['type'] === 'peer-leave') {
          this._cbs.onLeave?.(m['id'] as string)
        }
      }
    })
  }

  private _scheduleReconnect() {
    if (this._closed) return
    const delay = this._backoff
    this._backoff = Math.min(this._backoff * 2, 30000)
    setTimeout(() => { if (!this._closed) this._open(false).catch(() => { }) }, delay)
  }

  sendTo(toId: string, box: string) {
    try { this.ws?.send(JSON.stringify({ type: 'to', to: toId, box })) } catch { }
  }

  close() { this._closed = true; this.ws?.close() }
}

// ── Peer connection (yaw/2.1) ─────────────────────────────────────────────────

type PeerCallback = (event: string, data: Record<string, unknown>) => void

class PeerConn {
  pc: RTCPeerConnection
  dc: RTCDataChannel | null = null
  verified = false
  peerAuthed = false
  created = Date.now()

  private _esk: Uint8Array | null
  private _epk: Uint8Array | null
  peer_epk: Uint8Array | null = null
  private _ekeySent = false
  private _offerPending = false
  private _offered = false

  private identity: Identity
  private sig: Signaling
  public peerId: string
  private on: PeerCallback
  private nick: string

  constructor(identity: Identity, sig: Signaling, peerId: string, on: PeerCallback, nick: string) {
    this.identity = identity
    this.sig = sig
    this.peerId = peerId
    this.on = on
    this.nick = nick
    this.pc = new RTCPeerConnection({ iceServers: [{ urls: STUN }] })
    const kp = sodium.crypto_box_keypair()
    this._esk = kp.privateKey
    this._epk = kp.publicKey
    this.pc.ondatachannel = (ev) => this._wire(ev.channel)
    this.pc.onconnectionstatechange = () =>
      this.on('status', { peer: this.peerId, state: this.pc.connectionState })
  }

  private _seal(obj: object, preferEph: boolean): [string, boolean] {
    const data = enc(JSON.stringify(obj))
    if (preferEph && this.peer_epk && this._esk) {
      const nonce = sodium.randombytes_buf(24)
      const ct = sodium.crypto_box_easy(data, nonce, this.peer_epk, this._esk)
      return [sodium.to_base64(concat(nonce, ct), sodium.base64_variants.ORIGINAL), true]
    }
    return [this.identity.seal(this.peerId, data), false]
  }

  private _open(box: string): [Uint8Array | null, boolean] {
    if (this.peer_epk && this._esk) {
      try {
        const raw = sodium.from_base64(box, sodium.base64_variants.ORIGINAL)
        return [sodium.crypto_box_open_easy(raw.slice(24), raw.slice(0, 24), this.peer_epk, this._esk), true]
      } catch { }
    }
    return [this.identity.open(this.peerId, box), false]
  }

  private _sendEkey() {
    if (this._ekeySent || !this._epk) return
    this._ekeySent = true
    const signed = concat(enc(EKEY_PREFIX), sodium.from_hex(this.identity.id),
      sodium.from_hex(this.peerId), this._epk)
    const msg = {
      kind: 'ekey', v: 'yaw/2.1', epk: sodium.to_hex(this._epk),
      sig: sodium.to_hex(this.identity.sign(signed))
    }
    const [box] = this._seal(msg, false)
    this.sig.sendTo(this.peerId, box)
  }

  private async _onEkey(obj: Record<string, unknown>) {
    if (this.peer_epk) return
    try {
      const epkRaw = sodium.from_hex(obj['epk'] as string)
      const sig = sodium.from_hex(obj['sig'] as string)
      const signed = concat(enc(EKEY_PREFIX), sodium.from_hex(this.peerId),
        sodium.from_hex(this.identity.id), epkRaw)
      if (epkRaw.length !== 32 || !Identity.verify(this.peerId, signed, sig)) return
      this.peer_epk = epkRaw
    } catch { return }
    this._sendEkey()
    if (this._offerPending) await this._doOffer()
  }

  async startOffer() {
    this._sendEkey()
    this._offerPending = true
    setTimeout(() => { if (this._offerPending) this._doOffer() }, FS_TIMEOUT)
    if (this.peer_epk) await this._doOffer()
  }

  private async _doOffer() {
    if (this._offered) return
    this._offered = true; this._offerPending = false
    this.dc = this.pc.createDataChannel('yaw')
    this._wire(this.dc)
    await this.pc.setLocalDescription(await this.pc.createOffer())
    await gatherComplete(this.pc)
    const [box] = this._seal({ kind: 'offer', sdp: this.pc.localDescription!.sdp }, true)
    this.sig.sendTo(this.peerId, box)
  }

  async onBox(box: string) {
    const [plain, usedEph] = this._open(box)
    if (!plain) return
    this.peerAuthed = true
    let obj: Record<string, unknown>
    try { obj = JSON.parse(new TextDecoder().decode(plain)) } catch { return }

    if (obj['kind'] === 'ekey') {
      await this._onEkey(obj)
    } else if (obj['kind'] === 'offer') {
      await this.pc.setRemoteDescription({ type: 'offer', sdp: obj['sdp'] as string })
      await this.pc.setLocalDescription(await this.pc.createAnswer())
      await gatherComplete(this.pc)
      const [box2] = this._seal({ kind: 'answer', sdp: this.pc.localDescription!.sdp }, usedEph)
      this.sig.sendTo(this.peerId, box2)
    } else if (obj['kind'] === 'answer') {
      await this.pc.setRemoteDescription({ type: 'answer', sdp: obj['sdp'] as string })
    }
  }

  private _wire(channel: RTCDataChannel) {
    if (channel.label !== 'yaw') return
    this.dc = channel
    channel.onopen = () => this._sendHello()
    channel.onmessage = (ev) => this._onControl(ev.data)
    if (channel.readyState === 'open') this._sendHello()
  }

  private _sendHello() {
    const bind = enc(BIND_PREFIX)
    const caps: string[] = []
    this._dc({
      type: 'hello', id: this.identity.id, nick: this.nick, caps,
      sig: sodium.to_hex(this.identity.sign(bind))
    })
  }

  private _onControl(data: string) {
    let m: Record<string, unknown>
    try { m = JSON.parse(data) } catch { return }

    if (m['type'] === 'hello') {
      let reason = ''
      if (m['id'] !== this.peerId) reason = 'id mismatch'
      else if (!this.peerAuthed) reason = 'unauthenticated signaling'
      this.verified = !reason
      this.on('connected', {
        peer: this.peerId, verified: this.verified,
        nick: m['nick'] as string || '', caps: m['caps'] || []
      })
    } else if (m['type'] === 'chat') {
      this.on('chat', {
        peer: this.peerId, room: m['room'] as string || 'general',
        text: m['text'] as string, ts: m['ts'] as number || Date.now()
      })
    } else if (m['type'] === 'pm') {
      this.on('pm', { peer: this.peerId, text: m['text'] as string, ts: m['ts'] as number || Date.now() })
    }
  }

  sendChat(room: string, text: string) {
    this._dc({ type: 'chat', room, text, ts: Date.now() })
  }

  sendPm(text: string) {
    this._dc({ type: 'pm', text, ts: Date.now() })
  }

  private _dc(obj: object) {
    if (this.dc?.readyState === 'open') this.dc.send(JSON.stringify(obj))
  }

  close() { try { this.pc.close() } catch { } }
}

function gatherComplete(pc: RTCPeerConnection): Promise<void> {
  if (pc.iceGatheringState === 'complete') return Promise.resolve()
  return new Promise((res) => {
    const check = () => {
      if (pc.iceGatheringState === 'complete') {
        pc.removeEventListener('icegatheringstatechange', check)
        res()
      }
    }
    pc.addEventListener('icegatheringstatechange', check)
    setTimeout(res, 6000)
  })
}

// ── BrowserAdapter ────────────────────────────────────────────────────────────

export class BrowserAdapter {
  private listeners: Listener[] = []
  private identity: Identity | null = null
  private sig: Signaling | null = null
  private peers: Map<string, PeerConn> = new Map()
  private present: Set<string> = new Set()
  private networkId = ''
  private networkName = ''

  status: Status = 'disconnected'
  onStatusChange?: (s: Status) => void

  private setStatus(s: Status) {
    this.status = s
    this.onStatusChange?.(s)
  }

  private emit(msg: IpcMessage) {
    this.listeners.forEach(l => l(msg))
  }

  on(listener: Listener) {
    this.listeners.push(listener)
    return () => { this.listeners = this.listeners.filter(l => l !== listener) }
  }

  // Call after connect() to set/update the nick shown to peers
  setNick(nick: string) {
    this.identity?.setNick(nick)
    if (this.identity) {
      this.emit({
        type: 'state_snapshot',
        master_alias: this.identity.nick || this.identity.short,
        master_id: this.identity.id,
        rooms: ['general'],
        networks: this.networkId ? [{
          network_id: this.networkId,
          network_name: this.networkName,
          local_peer: this.identity.toPeerInfo(this.networkId),
        }] : [],
      })
    }
  }

  async connect() {
    await sodium.ready
    this.identity = Identity.load()
    this.setStatus('connecting')

    // Emit identity immediately — UI can show alias before network join
    this.emit({
      type: 'state_snapshot',
      master_alias: this.identity.nick || this.identity.short,
      master_id: this.identity.id,
      rooms: ['general'],
      networks: [],
    })
    // Mark connected — onboarding shows join form
    this.setStatus('connected')
  }

  disconnect() {
    this.sig?.close()
    this.sig = null
    this.peers.forEach(p => p.close())
    this.peers.clear()
    this.present.clear()
    this.networkId = ''
    this.networkName = ''
    this.setStatus('disconnected')
  }

  async joinNetwork(anchorUrl: string, nameOrHash: string, isHash = false) {
    if (!this.identity) return

    const hash = isHash ? nameOrHash : await netHash(nameOrHash)
    this.networkId = hash.slice(0, 16)
    this.networkName = isHash ? hash.slice(0, 16) : nameOrHash

    this.sig?.close()
    this.peers.forEach(p => p.close())
    this.peers.clear()
    this.present.clear()

    const sig = new Signaling(anchorUrl, this.identity, hash)
    this.sig = sig

    try {
      const present = await sig.connect(
        (from, box) => this._onFrom(from, box),
        (pid) => { this.present.add(pid); this._tryConnect(pid) },
        (pid) => {
          this.present.delete(pid)
          this.peers.get(pid)?.close()
          this.peers.delete(pid)
          this.emit({ type: 'peer_disconnected', peer_id: pid as unknown as import('../types').PeerID })
        },
        (peers) => {
          this.present = new Set(peers)
          peers.forEach(pid => this._tryConnect(pid))
        },
      )

      for (const pid of present) {
        this.present.add(pid)
        await this._tryConnect(pid)
      }

      const localPeer = this.identity.toPeerInfo(this.networkId)
      this.emit({
        type: 'network_joined',
        network_id: this.networkId,
        network_name: this.networkName,
        local_peer: localPeer,
        networks: [{ network_id: this.networkId, network_name: this.networkName, local_peer: localPeer }],
      })

      setInterval(() => { this.present.forEach(pid => this._tryConnect(pid)) }, 4000)
    } catch (err) {
      this.emit({ type: 'error', error_message: `signaling: ${err}` })
    }
  }

  private async _tryConnect(pid: string) {
    if (!this.identity || pid === this.identity.id) return
    if (this.identity.id >= pid) return // lower ID answers; higher ID offers

    const existing = this.peers.get(pid)
    if (existing) {
      const open = existing.dc?.readyState === 'open'
      const state = existing.pc.connectionState
      const alive = state !== 'failed' && state !== 'closed'
      const fresh = Date.now() - existing.created < 12000
      if (existing.verified || open || (alive && fresh)) return
    }

    const peer = new PeerConn(this.identity, this.sig!, pid,
      (ev, data) => this._onPeerEvent(ev, data), this.identity.nick)
    this.peers.set(pid, peer)
    await peer.startOffer()
  }

  private async _onFrom(from: string, box: string) {
    if (!this.identity || from === this.identity.id) return
    let peer = this.peers.get(from)
    if (!peer || peer.pc.connectionState === 'failed' || peer.pc.connectionState === 'closed') {
      peer = new PeerConn(this.identity, this.sig!, from,
        (ev, data) => this._onPeerEvent(ev, data), this.identity.nick)
      this.peers.set(from, peer)
    }
    await peer.onBox(box)
  }

  private _onPeerEvent(event: string, data: Record<string, unknown>) {
    if (event === 'connected') {
      const nick = (data['nick'] as string) || (data['peer'] as string).slice(0, 16)
      this.emit({
        type: 'peer_connected',
        peer: {
          id: data['peer'] as string, alias: nick || (data['peer'] as string).slice(0, 8),
          public_key: data['peer'] as string, created_at: new Date().toISOString()
        },
      })
    } else if (event === 'chat') {
      const ts = (data['ts'] as number) || Date.now()
      const mid = `${data['peer']}-${ts}`
      this.emit({
        type: 'message_received',
        network_id: this.networkId,
        message: {
          mid,
          from: data['peer'] as unknown as import('../types').PeerID,
          room: (data['room'] as string) || 'general',
          text: data['text'] as string,
          ts,
        },
      })
    } else if (event === 'pm') {
      const ts = (data['ts'] as number) || Date.now()
      const from = data['peer'] as string
      this.emit({
        type: 'message_received',
        network_id: this.networkId,
        message: {
          mid: `${from}-${ts}`,
          from: from as unknown as import('../types').PeerID,
          room: `dm:${from.slice(0, 8)}`,
          text: data['text'] as string,
          ts,
        },
      })
    }
  }

  send(msg: IpcMessage) {
    if (!this.identity) return

    if (msg.type === 'join_network') {
      const cfg = (window as unknown as { WASTE_CONFIG?: { signalURL?: string } })['WASTE_CONFIG']
      const anchorUrl = cfg?.signalURL
        || localStorage.getItem('waste_anchor_url')
        || ''
      const isHash = !msg.network_name && !!msg.network_hash
      const nameOrHash = msg.network_name || msg.network_hash || ''
      if (nameOrHash) this.joinNetwork(anchorUrl, nameOrHash, isHash)
      return
    }

    if (msg.type === 'send_message') {
      const room = msg.room || 'general'
      const text = msg.body || ''
      if (!text) return
      const ts = Date.now()
      const mid = `local-${ts}`

      if (msg.to) {
        // DM
        const pid = msg.to as string
        this.peers.get(pid)?.sendPm(text)
        this.emit({
          type: 'message_received',
          network_id: this.networkId,
          message: {
            mid, from: this.identity.id as unknown as import('../types').PeerID,
            to: msg.to, room: `dm:${pid.slice(0, 8)}`, text, ts
          },
        })
      } else {
        // Broadcast
        this.peers.forEach(p => p.sendChat(room, text))
        this.emit({
          type: 'message_received',
          network_id: this.networkId,
          message: {
            mid, from: this.identity.id as unknown as import('../types').PeerID,
            room, text, ts
          },
        })
      }
      return
    }

    if (msg.type === 'export_identity') {
      if (!msg.passphrase) return
      try {
        const backup = this.identity.exportBackup(msg.passphrase)
        this.emit({ type: 'identity_exported', backup: JSON.stringify(backup, null, 2) })
      } catch (err) {
        this.emit({ type: 'error', error_message: `export_identity: ${err}` })
      }
      return
    }

    if (msg.type === 'import_identity') {
      if (!msg.passphrase || !msg.backup) return
      try {
        const parsed = JSON.parse(msg.backup)
        const newId = Identity.importBackup(parsed, msg.passphrase)
        this.identity = newId
        this.emit({ type: 'identity_imported' })
        this.emit({
          type: 'state_snapshot',
          master_alias: newId.nick || newId.short,
          master_id: newId.id,
          rooms: ['general'],
          networks: [],
        })
      } catch (err) {
        this.emit({ type: 'error', error_message: `import_identity: ${err}` })
      }
      return
    }

    if (msg.type === 'generate_invite') {
      const anchor = localStorage.getItem('waste_anchor_url') || 'wss://waste.dev.xplwd.com/ws'
      const name = this.networkName
      if (!name || name === this.networkId) {
        this.emit({ type: 'error', error_message: 'generate_invite: joined by hash — no network name available' })
        return
      }
      const h = netHash(name)
      const payload = btoa(JSON.stringify({ anchor, network: name, net: h }))
        .replace(/\+/g, '-').replace(/\//g, '_').replace(/=/g, '')
      this.emit({ type: 'invite_generated', invite: `waste:${payload}`, network_id: this.networkId })
      return
    }
  }
}