// Virtual miner against one igneumd over wRPC JSON. The test network runs with skip_proof_of_work, so a block is
// "found" by a Poisson clock whose rate follows the hash share and the current difficulty:
//   rate = bps x share x target(template bits) / target(genesis bits)
// Found blocks are submitted through getBlockTemplate + submitBlock, the path a real miner uses. Timestamp and
// vote_key_hash are set by the policy; the nonce carries the miner id (the node ignores it under skip PoW).

import { createHash } from 'node:crypto';
import { submitReport, Rpc } from './rpc.mjs';
import { log, sleep } from './net.mjs';
import { devAddress } from './address.mjs';

export const GENESIS_BITS = 0x1d100000; // devnet genesis (consensus/core/src/config/genesis.rs)
export function targetOfBits(bits) {
  const exp = bits >>> 24; const mant = bits & 0xffffff;
  return exp <= 3 ? mant / Math.pow(256, 3 - exp) : mant * Math.pow(256, exp - 3);
}
export const GENESIS_TARGET = targetOfBits(GENESIS_BITS);
export function difficultyRatio(bits) { return GENESIS_TARGET / targetOfBits(bits); }

export function voteKeyHashFor(label) {
  // Any nonzero 32 bytes satisfy the devnet v0 presence rule; a label-derived value keeps miners distinct.
  return createHash('sha256').update('igneum-harness-vote-key/' + label).digest('hex');
}

export function expSample(rate) { return -Math.log(1 - Math.random()) / rate; }

export class Miner {
  /**
   * @param {object} o  { node, share, label, bps=1, timestamp: (tmpl, now) => ms, hold: n (withhold n then release), onBlock }
   */
  constructor(o) {
    this.node = o.node; this.share = o.share; this.label = o.label || 'miner'; this.bps = o.bps || 1;
    this.timestampPolicy = o.timestamp || null; this.hold = o.hold || 1; this.onBlock = o.onBlock || (() => { });
    this.address = o.address || devAddress(this.label);
    this.found = 0; this.accepted = 0; this.rejected = 0; this.errors = 0; this.running = false; this.rpc = null;
    this.private = []; this.lastBits = GENESIS_BITS; this.rateMult = o.rateMult || 1; this.history = [];
  }
  async start() {
    this.rpc = new Rpc(this.node.json, { timeoutMs: 15_000 });
    if (!await this.rpc.connect()) throw new Error('miner rpc');
    this.running = true;
    this.loop();
    return this;
  }
  stop() { this.running = false; if (this.rpc) this.rpc.close(); }
  rate() { return this.bps * this.share * this.rateMult * targetOfBits(this.lastBits) / GENESIS_TARGET; }
  async loop() {
    while (this.running) {
      const waitS = expSample(Math.max(this.rate(), 1e-9));
      await sleep(Math.max(1, waitS * 1000));
      if (!this.running) break;
      try { await this.mineOne(); } catch (e) { this.errors++; if (this.errors < 5) log(`${this.label} error ${e.message}`); }
    }
  }
  async template() {
    const t = await this.rpc.call('getBlockTemplate', { payAddress: this.address, extraData: [] });
    this.lastBits = t.block.header.bits;
    return t;
  }
  async mineOne() {
    const t = await this.template();
    const block = t.block;
    block.header.voteKeyHash = voteKeyHashFor(this.label);
    block.header.nonce = this.nonce || 1;
    if (this.timestampPolicy) block.header.timestamp = this.timestampPolicy(block.header, Date.now(), t);
    this.found++;
    if (this.hold > 1) {
      this.private.push(block);
      if (this.private.length >= this.hold) {
        const batch = this.private.splice(0);
        for (const b of batch) await this.submit(b);
      }
      return;
    }
    await this.submit(block);
  }
  async submit(block) {
    const t0 = Date.now();
    const res = await this.rpc.call('submitBlock', { block, allowNonDaaBlocks: false });
    const r = submitReport(res);
    if (r === 'accepted') this.accepted++; else this.rejected++;
    this.history.push({ t: t0, bits: block.header.bits, ts: block.header.timestamp, result: r });
    this.onBlock(block, r, Date.now() - t0);
    return r;
  }
}

/// Measures getBlockTemplate latency on a node at a fixed cadence; returns a stats summary on stop().
export class LatencyProbe {
  constructor(node, { periodMs = 100, label = 'honest' } = {}) { this.node = node; this.periodMs = periodMs; this.label = label; this.samples = []; this.running = false; this.rpc = null; this.failures = 0; }
  async start() {
    this.rpc = new Rpc(this.node.json, { timeoutMs: 5000 });
    if (!await this.rpc.connect()) throw new Error('probe rpc');
    this.running = true;
    (async () => {
      while (this.running) {
        const t0 = performance.now();
        try { await this.rpc.call('getBlockTemplate', { payAddress: devAddress('probe'), extraData: [] }); this.samples.push(performance.now() - t0); }
        catch { this.failures++; this.samples.push(5000); }
        await sleep(this.periodMs);
      }
    })();
    return this;
  }
  stop() { this.running = false; if (this.rpc) this.rpc.close(); return this.stats(); }
  stats() { return summarize(this.samples); }
}

export function summarize(xs) {
  if (!xs.length) return { n: 0 };
  const s = [...xs].sort((a, b) => a - b);
  const q = (p) => s[Math.min(s.length - 1, Math.floor(p * s.length))];
  return { n: s.length, p50: +q(0.5).toFixed(1), p95: +q(0.95).toFixed(1), p99: +q(0.99).toFixed(1), max: +s[s.length - 1].toFixed(1), mean: +(s.reduce((a, b) => a + b, 0) / s.length).toFixed(1) };
}