#!/usr/bin/env node
// Igneum devnet observer. Connects to a node's wRPC JSON endpoint, subscribes to new blocks and
// writes what it sees to Neon so /api/live and /live can show it.
//
//   node tools/observer/observer.mjs
//
// Environment (every value has a default):
//   IGNEUM_RPC    wRPC JSON url of the node        default ws://127.0.0.1:28610 (igneum-devnet wRPC JSON port)
//   DATABASE_URL  Neon connection string           default: read from ~/.config/igneum/env
//   LIVE_RETAIN_HOURS  hours of blocks to keep     default 24
//
// Tables (created on start if missing): live_blocks, live_state, live_events. See README.md.
// Zero dependencies: Node 22 WebSocket and fetch, Neon's HTTP SQL endpoint.

import { readFileSync } from 'node:fs';
import { homedir } from 'node:os';

const RPC = process.env.IGNEUM_RPC || 'ws://127.0.0.1:28610';
const RETAIN_HOURS = Number(process.env.LIVE_RETAIN_HOURS || 24);
const STATE_EVERY_MS = 2000;
const FLUSH_EVERY_MS = 500;
const PRUNE_EVERY_MS = 60_000;
const QUIET_AFTER_MS = 5 * 60_000;
const DIFFICULTY_STEP = 0.05;
const STARTED_AT = new Date();

// ---------- Neon ----------
function databaseUrl() {
  if (process.env.DATABASE_URL) return process.env.DATABASE_URL;
  let env = '';
  try { env = readFileSync(`${homedir()}/.config/igneum/env`, 'utf8'); } catch { }
  const m = /^DATABASE_URL=(.*)$/m.exec(env);
  if (!m) { console.error('DATABASE_URL is not set and ~/.config/igneum/env has none'); process.exit(1); }
  return m[1].trim().replace(/^['"]|['"]$/g, '');
}
const DB_URL = databaseUrl();
const DB_HOST = new URL(DB_URL).hostname.replace('-pooler', '');

async function sql(query, params = []) {
  const r = await fetch(`https://${DB_HOST}/sql`, {
    method: 'POST',
    headers: { 'Neon-Connection-String': DB_URL, 'Content-Type': 'application/json' },
    body: JSON.stringify({ query, params }),
  });
  const j = await r.json();
  if (!r.ok) throw new Error(j.message || JSON.stringify(j));
  return j.rows || [];
}

async function setupSchema() {
  const stmts = [
    `CREATE TABLE IF NOT EXISTS live_blocks (
       hash text PRIMARY KEY,
       blue_score bigint NOT NULL,
       daa_score bigint NOT NULL,
       timestamp_ms bigint NOT NULL,
       parents int NOT NULL,
       parent_hashes text[] NOT NULL DEFAULT '{}',
       is_chain_block boolean NOT NULL DEFAULT false,
       vote_key_hash text,
       miner_address text,
       engine text,
       received_at timestamptz NOT NULL DEFAULT now())`,
    `CREATE INDEX IF NOT EXISTS live_blocks_received_at ON live_blocks (received_at)`,
    `CREATE INDEX IF NOT EXISTS live_blocks_timestamp_ms ON live_blocks (timestamp_ms)`,
    `CREATE INDEX IF NOT EXISTS live_blocks_vote_key_received ON live_blocks (vote_key_hash, received_at)`,
    `CREATE TABLE IF NOT EXISTS live_state (
       id int PRIMARY KEY DEFAULT 1 CHECK (id = 1),
       block_count bigint, header_count bigint, blue_score bigint, difficulty double precision,
       hashes_per_second_estimate bigint, peers int, mempool int,
       node_version text, network text,
       blocks_60s int, blocks_per_minute jsonb,
       observer_started_at timestamptz, updated_at timestamptz)`,
    `CREATE TABLE IF NOT EXISTS live_events (
       id bigserial PRIMARY KEY,
       ts timestamptz NOT NULL DEFAULT now(),
       kind text NOT NULL,
       text text NOT NULL)`,
    `CREATE INDEX IF NOT EXISTS live_events_ts ON live_events (ts)`,
  ];
  for (const s of stmts) await sql(s);
}

// ---------- Address decoding (crypto/addresses/src/bech32.rs, ported) ----------
const CHARSET = 'qpzry9x8gf2tvdw0s3jn54khce6mua7l';
function polymod(values) {
  let c = 1n;
  for (const d of values) {
    const c0 = c >> 35n;
    c = ((c & 0x07ffffffffn) << 5n) ^ BigInt(d);
    if (c0 & 0x01n) c ^= 0x98f2bc8e61n;
    if (c0 & 0x02n) c ^= 0x79b76d99e2n;
    if (c0 & 0x04n) c ^= 0xf33e5fb3c4n;
    if (c0 & 0x08n) c ^= 0xae2eabe2a8n;
    if (c0 & 0x10n) c ^= 0x1e4f43e470n;
  }
  return c ^ 1n;
}
function conv8to5(bytes) {
  const out = []; let buff = 0, bits = 0;
  for (const b of bytes) {
    buff = ((buff << 8) | b) & 0xffff; bits += 8;
    while (bits >= 5) { bits -= 5; out.push((buff >> bits) & 31); buff &= (1 << bits) - 1; }
  }
  if (bits > 0) out.push((buff << (5 - bits)) & 31);
  return out;
}
export function encodeAddress(prefix, version, payload) {
  const five = conv8to5([version, ...payload]);
  const pre = [...prefix].map(ch => ch.charCodeAt(0) & 0x1f);
  const sum = polymod([...pre, 0, ...five, 0, 0, 0, 0, 0, 0, 0, 0]);
  const sumBytes = []; for (let i = 4; i >= 0; i--) sumBytes.push(Number((sum >> BigInt(i * 8)) & 0xffn));
  return `${prefix}:${[...five, ...conv8to5(sumBytes)].map(v => CHARSET[v]).join('')}`;
}
function scriptToAddress(prefix, script) {
  if (script.length === 34 && script[0] === 0x20 && script[33] === 0xac) return encodeAddress(prefix, 0, script.slice(1, 33));
  if (script.length === 35 && script[0] === 0x21 && script[34] === 0xab) return encodeAddress(prefix, 1, script.slice(1, 34));
  if (script.length === 35 && script[0] === 0xaa && script[1] === 0x20 && script[34] === 0x87) return encodeAddress(prefix, 8, script.slice(2, 34));
  return null;
}
function payloadBytes(p) {
  if (Array.isArray(p)) return Uint8Array.from(p);
  if (typeof p === 'string') return Uint8Array.from(Buffer.from(p, 'hex'));
  return new Uint8Array();
}
// Coinbase payload: blue score u64 LE, subsidy u64 LE, script version u16 LE, script length u8, script, extra data.
function minerFromCoinbase(block, prefix) {
  const tx = block.transactions && block.transactions[0];
  if (!tx) return { address: null, extra: null };
  const b = payloadBytes(tx.payload);
  if (b.length < 19) return { address: null, extra: null };
  const len = b[18];
  const script = b.slice(19, 19 + len);
  const extra = b.slice(19 + len);
  // The node prefixes the extra data with its own version tag ("2.1.0/"). Anything after that is the
  // miner's tag (engine or label). The node exposes no engine name over RPC, so this is null on devnet v0.
  const text = Buffer.from(extra).toString('utf8').replace(/[^\x20-\x7e]/g, '').replace(/^\d+\.\d+\.\d+(-[\w.]+)?\//, '').trim();
  return { address: scriptToAddress(prefix, script), extra: text ? text.slice(0, 64) : null };
}

// ---------- RPC client ----------
class Rpc {
  constructor(url) { this.url = url; this.id = 0; this.pending = new Map(); this.onNotification = () => { }; this.ws = null; this.open = false; }
  connect() {
    return new Promise((resolve) => {
      const ws = new WebSocket(this.url); this.ws = ws;
      ws.onopen = () => { this.open = true; log('rpc connected', this.url); resolve(true); };
      ws.onmessage = (e) => {
        let m; try { m = JSON.parse(e.data); } catch { return; }
        if (m.id !== undefined && m.id !== null && this.pending.has(m.id)) {
          const p = this.pending.get(m.id); this.pending.delete(m.id);
          m.error ? p.reject(new Error(m.error.message || JSON.stringify(m.error))) : p.resolve(m.params);
        } else if (m.method) this.onNotification(m.method, m.params);
      };
      ws.onerror = () => { };
      ws.onclose = () => {
        const wasOpen = this.open; this.open = false;
        for (const p of this.pending.values()) p.reject(new Error('rpc closed'));
        this.pending.clear();
        if (wasOpen) log('rpc closed'); else resolve(false);
        this.onClose && this.onClose();
      };
    });
  }
  call(method, params = {}) {
    return new Promise((resolve, reject) => {
      if (!this.open) return reject(new Error('rpc not connected'));
      const id = ++this.id; this.pending.set(id, { resolve, reject });
      this.ws.send(JSON.stringify({ id, method, params }));
      setTimeout(() => { if (this.pending.has(id)) { this.pending.delete(id); reject(new Error(`${method} timed out`)); } }, 10_000);
    });
  }
}

// ---------- Observer ----------
const log = (...a) => console.log(new Date().toISOString(), ...a);
const short = h => (h || '').slice(0, 8);

const pendingBlocks = [];          // rows waiting for the next flush
const pendingChain = { add: new Set(), remove: new Set() };
const miners = new Map();          // vote_key_hash -> { lastSeen ms, quiet bool }
const minuteCounts = new Map();    // minute epoch -> count (last 60 minutes)
const recentArrivals = [];         // ms timestamps of arrivals in the last 60 s
const workSamples = [];            // { t: ms, w: BigInt blue work } of the heaviest header seen, last 10 min
let lastDifficultyEvent = null;

// Fallback hash-rate estimate when the node refuses estimateNetworkHashesPerSecond (it needs a 1,000-block
// window): blue work added per second over the last 10 minutes, the same quantity the node measures.
function noteWork(now, blueWorkHex) {
  if (!blueWorkHex) return;
  let w; try { w = BigInt('0x' + blueWorkHex); } catch { return; }
  const last = workSamples[workSamples.length - 1];
  if (last && w <= last.w) return;
  workSamples.push({ t: now, w });
  while (workSamples.length && workSamples[0].t < now - 10 * 60_000) workSamples.shift();
}
function localHashesPerSecond() {
  if (workSamples.length < 2) return null;
  const a = workSamples[0], b = workSamples[workSamples.length - 1];
  const secs = (b.t - a.t) / 1000;
  if (secs < 20) return null;
  return Number((b.w - a.w) / BigInt(Math.round(secs)));
}
let knownPeers = null;             // Set of peer ids from the previous tick
let network = 'igneum-devnet';
let addressPrefix = 'igneumdev';
let nodeVersion = null;
let sinkHash = null;

async function recordEvent(kind, text) {
  log('event', kind, text);
  try { await sql('INSERT INTO live_events (kind, text) VALUES ($1, $2)', [kind, text]); } catch (e) { log('event write failed', e.message); }
}

function noteArrival(now) {
  recentArrivals.push(now);
  const minute = Math.floor(now / 60_000) * 60_000;
  minuteCounts.set(minute, (minuteCounts.get(minute) || 0) + 1);
  for (const k of minuteCounts.keys()) if (k < now - 61 * 60_000) minuteCounts.delete(k);
}
function blocks60s(now) {
  while (recentArrivals.length && recentArrivals[0] < now - 60_000) recentArrivals.shift();
  return recentArrivals.length;
}
function blocksPerMinute(now) {
  const out = []; const start = Math.floor(now / 60_000) * 60_000 - 59 * 60_000;
  for (let m = start; m <= now; m += 60_000) out.push([m, minuteCounts.get(m) || 0]);
  return out;
}

function onBlock(block) {
  const h = block.header; if (!h || !h.hash) return;
  const now = Date.now();
  const parents = (h.parentsByLevel && h.parentsByLevel[0]) || [];
  const miner = minerFromCoinbase(block, addressPrefix);
  const vk = h.voteKeyHash || null;
  pendingBlocks.push({
    hash: h.hash, blue_score: h.blueScore, daa_score: h.daaScore, timestamp_ms: h.timestamp,
    parents: parents.length, parent_hashes: parents,
    is_chain_block: !!(block.verboseData && block.verboseData.isChainBlock),
    vote_key_hash: vk, miner_address: miner.address, engine: miner.extra,
  });
  noteArrival(now);
  noteWork(now, h.blueWork);
  if (vk) {
    const m = miners.get(vk);
    if (!m) { miners.set(vk, { lastSeen: now, quiet: false }); recordEvent('miner_seen', `New miner ${short(vk)} seen${miner.address ? ` (${miner.address.slice(0, 24)}...)` : ''}`); }
    else { if (m.quiet) { m.quiet = false; recordEvent('miner_back', `Miner ${short(vk)} is back after a quiet spell`); } m.lastSeen = now; }
  }
}

function pgArray(list) { return `{${list.map(s => `"${String(s).replace(/["\\]/g, '')}"`).join(',')}}`; }

async function flushBlocks() {
  if (!pendingBlocks.length) return;
  const rows = pendingBlocks.splice(0, 200);
  const cols = ['hash', 'blue_score', 'daa_score', 'timestamp_ms', 'parents', 'parent_hashes', 'is_chain_block', 'vote_key_hash', 'miner_address', 'engine'];
  const params = []; const values = [];
  for (const r of rows) {
    const ph = [];
    for (const c of cols) { params.push(c === 'parent_hashes' ? pgArray(r[c]) : r[c]); ph.push(`$${params.length}${c === 'parent_hashes' ? '::text[]' : ''}`); }
    values.push(`(${ph.join(',')})`);
  }
  try {
    await sql(`INSERT INTO live_blocks (${cols.join(',')}) VALUES ${values.join(',')} ON CONFLICT (hash) DO NOTHING`, params);
  } catch (e) { log('block insert failed', e.message); pendingBlocks.unshift(...rows.slice(0, 50)); }
  if (pendingBlocks.length) await flushBlocks();
}

async function flushChain() {
  if (pendingChain.add.size) { const a = [...pendingChain.add]; pendingChain.add.clear(); try { await sql('UPDATE live_blocks SET is_chain_block = true WHERE hash = ANY($1::text[]) AND NOT is_chain_block', [pgArray(a)]); } catch (e) { log('chain update failed', e.message); } }
  if (pendingChain.remove.size) { const r = [...pendingChain.remove]; pendingChain.remove.clear(); try { await sql('UPDATE live_blocks SET is_chain_block = false WHERE hash = ANY($1::text[]) AND is_chain_block', [pgArray(r)]); } catch (e) { log('chain update failed', e.message); } }
}

async function tick(rpc) {
  const now = Date.now();
  let dag, info, peersRes, hps;
  try {
    [dag, info, peersRes, hps] = await Promise.all([
      rpc.call('getBlockDagInfo', {}),
      rpc.call('getInfo', {}),
      rpc.call('getConnectedPeerInfo', {}),
      rpc.call('estimateNetworkHashesPerSecond', { windowSize: 1000, startHash: null }).catch(() => null),
    ]);
  } catch (e) { log('tick failed', e.message); return; }
  if (dag.network) network = String(dag.network).startsWith('igneum') ? dag.network : `igneum-${dag.network}`;
  nodeVersion = info.serverVersion || nodeVersion;
  if (dag.sink && dag.sink !== sinkHash) { sinkHash = dag.sink; pendingChain.add.add(dag.sink); }

  // peers joined or left
  const peers = peersRes.peerInfo || [];
  const ids = new Map(peers.map(p => [p.id, `${p.address && p.address.ip}:${p.address && p.address.port}`]));
  if (knownPeers) {
    for (const [id, addr] of ids) if (!knownPeers.has(id)) recordEvent('peer_joined', `Peer joined: ${addr}`);
    for (const [id, addr] of knownPeers) if (!ids.has(id)) recordEvent('peer_left', `Peer left: ${addr}`);
  }
  knownPeers = ids;

  // difficulty step over 5%
  const diff = Number(dag.difficulty) || 0;
  if (lastDifficultyEvent === null) lastDifficultyEvent = diff;
  else if (lastDifficultyEvent > 0 && Math.abs(diff - lastDifficultyEvent) / lastDifficultyEvent > DIFFICULTY_STEP) {
    const pct = ((diff - lastDifficultyEvent) / lastDifficultyEvent * 100).toFixed(1);
    recordEvent('difficulty', `Difficulty ${diff > lastDifficultyEvent ? 'up' : 'down'} ${Math.abs(pct)}% to ${diff.toLocaleString('en-GB', { maximumFractionDigits: 0 })}`);
    lastDifficultyEvent = diff;
  }

  // miners gone quiet
  for (const [vk, m] of miners) if (!m.quiet && now - m.lastSeen > QUIET_AFTER_MS) { m.quiet = true; recordEvent('miner_quiet', `Miner ${short(vk)} has gone quiet (no block for 5 min)`); }

  try {
    await sql(`INSERT INTO live_state (id, block_count, header_count, blue_score, difficulty, hashes_per_second_estimate, peers, mempool,
                 node_version, network, blocks_60s, blocks_per_minute, observer_started_at, updated_at)
               VALUES (1, $1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11::jsonb, $12, now())
               ON CONFLICT (id) DO UPDATE SET block_count = EXCLUDED.block_count, header_count = EXCLUDED.header_count, blue_score = EXCLUDED.blue_score,
                 difficulty = EXCLUDED.difficulty, hashes_per_second_estimate = EXCLUDED.hashes_per_second_estimate, peers = EXCLUDED.peers,
                 mempool = EXCLUDED.mempool, node_version = EXCLUDED.node_version, network = EXCLUDED.network, blocks_60s = EXCLUDED.blocks_60s,
                 blocks_per_minute = EXCLUDED.blocks_per_minute, observer_started_at = EXCLUDED.observer_started_at, updated_at = now()`,
      [dag.blockCount, dag.headerCount, (await rpc.call('getSinkBlueScore', {}).catch(() => ({}))).blueScore ?? null, diff,
        hps ? hps.networkHashesPerSecond : localHashesPerSecond(), peers.length, info.mempoolSize ?? 0,
        nodeVersion, network, blocks60s(now), JSON.stringify(blocksPerMinute(now)), STARTED_AT.toISOString()]);
  } catch (e) { log('state write failed', e.message); }
}

async function prune() {
  try {
    await sql(`DELETE FROM live_blocks WHERE received_at < now() - ($1 || ' hours')::interval`, [String(RETAIN_HOURS)]);
    await sql(`DELETE FROM live_events WHERE ts < now() - interval '7 days'`);
  } catch (e) { log('prune failed', e.message); }
}

async function seedFromDb() {
  try {
    const rows = await sql(`SELECT vote_key_hash, max(received_at) AS last FROM live_blocks WHERE vote_key_hash IS NOT NULL AND received_at > now() - interval '1 day' GROUP BY 1`);
    for (const r of rows) miners.set(r.vote_key_hash, { lastSeen: new Date(r.last).getTime(), quiet: Date.now() - new Date(r.last).getTime() > QUIET_AFTER_MS });
    const mins = await sql(`SELECT (floor(extract(epoch from received_at) / 60) * 60000)::bigint AS m, count(*)::int AS n FROM live_blocks WHERE received_at > now() - interval '61 minutes' GROUP BY 1`);
    for (const r of mins) minuteCounts.set(Number(r.m), r.n);
    const st = await sql(`SELECT difficulty FROM live_state WHERE id = 1`);
    if (st.length && st[0].difficulty) lastDifficultyEvent = Number(st[0].difficulty);
  } catch (e) { log('seed failed', e.message); }
}

async function main() {
  await setupSchema();
  await seedFromDb();
  log(`observer started, rpc ${RPC}, keeping ${RETAIN_HOURS} h of blocks, ${miners.size} miners known`);
  const rpc = new Rpc(RPC);
  rpc.onNotification = (method, params) => {
    const inner = params && (params.BlockAdded || params.VirtualChainChanged || params);
    if (method === 'blockAddedNotification' && inner && inner.block) onBlock(inner.block);
    else if (method === 'virtualChainChangedNotification' && inner) {
      for (const h of inner.addedChainBlockHashes || []) { pendingChain.remove.delete(h); pendingChain.add.add(h); }
      for (const h of inner.removedChainBlockHashes || []) { pendingChain.add.delete(h); pendingChain.remove.add(h); }
    }
  };
  let connected = false;
  const connect = async () => {
    while (!(await rpc.connect())) { log('rpc connect failed, retrying in 3 s'); await new Promise(r => setTimeout(r, 3000)); }
    try {
      const srv = await rpc.call('getServerInfo', {});
      nodeVersion = srv.serverVersion || null;
      const net = String(srv.networkId || 'devnet');
      network = net.startsWith('igneum') ? net : `igneum-${net}`;
      addressPrefix = network.includes('devnet') ? 'igneumdev' : network.includes('testnet') ? 'igneumtest' : network.includes('simnet') ? 'igneumsim' : 'igneum';
      await rpc.call('subscribe', { BlockAdded: {} });
      await rpc.call('subscribe', { VirtualChainChanged: { include_accepted_transaction_ids: false } });
      log(`subscribed on ${network}, node ${nodeVersion}`);
      if (connected) recordEvent('observer', 'Observer reconnected to the node'); else recordEvent('observer', `Observer started against ${network}`);
      connected = true;
    } catch (e) { log('subscribe failed', e.message); }
  };
  rpc.onClose = () => { setTimeout(connect, 2000); };
  await connect();

  setInterval(async () => { await flushBlocks(); await flushChain(); }, FLUSH_EVERY_MS);
  setInterval(() => tick(rpc), STATE_EVERY_MS);
  setInterval(prune, PRUNE_EVERY_MS);
  tick(rpc); prune();
}

process.on('unhandledRejection', e => log('unhandled', e && e.message));
main().catch(e => { console.error(e); process.exit(1); });