import { spawn, spawnSync, type ChildProcess } from 'node:child_process';
import fs from 'node:fs';
import { getDb } from '../db/index.js';
import { PhotonPacketParser } from 'photon-packet-parser';

/**
 * Passive sniffer for the user's OWN Albion client traffic (UDP 5056).
 * Capture is done by spawning tshark (Wireshark CLI, which bundles Npcap on
 * Windows) so no native Node modules are needed; payloads are decoded with the
 * pure-JS Photon protocol parser. Read-only observation — the SBI-tolerated
 * category (same technique as the Albion Data Project client). No memory
 * reading, no injection, no automation.
 *
 * Consumers:
 *  1. Market orders: whenever the player opens a marketplace in game, the
 *     auction responses contain order JSON — we detect them by shape (any
 *     string parameter parsing as JSON with UnitPriceSilver), which survives
 *     patches, and feed fresh firsthand prices into market_prices.
 *  2. Event-code debug log: counts photon event codes seen, so destiny-board
 *     related codes can be identified in a live session and added later.
 */

const TSHARK_CANDIDATES = [
  'C:\\Program Files\\Wireshark\\tshark.exe',
  'C:\\Program Files (x86)\\Wireshark\\tshark.exe',
];

/** Market LocationId -> city (protocol ids, not cluster ids). Editable if a patch changes them. */
const MARKET_LOCATIONS: Record<string, string> = {
  '0007': 'Thetford',
  '7': 'Thetford',
  '1002': 'Lymhurst',
  '2004': 'Bridgewatch',
  '3005': 'Caerleon',
  '3008': 'Martlock',
  '4002': 'Fort Sterling',
  '5003': 'Brecilien',
  '3003': 'Black Market',
};

export function findTshark(): string | null {
  for (const p of TSHARK_CANDIDATES) if (fs.existsSync(p)) return p;
  const which = spawnSync('where', ['tshark'], { encoding: 'utf8' });
  const found = which.stdout?.split(/\r?\n/).find((l) => l.trim().endsWith('tshark.exe'));
  return found?.trim() ?? null;
}

export interface SnifferStatus {
  tsharkPath: string | null;
  running: boolean;
  packets: number;
  photonEvents: number;
  marketOrdersSeen: number;
  pricesStored: number;
  startedAt: string | null;
  lastError: string | null;
  eventCodeCounts: Record<string, number>;
  recentOrders: CapturedOrder[];
}

export interface CapturedOrder {
  item: string;
  city: string;
  quality: number;
  auctionType: string;
  unitPriceSilver: number;
  amount: number;
  seenAt: string;
}

interface AlbionOrder {
  UnitPriceSilver: number;
  Amount: number;
  AuctionType: string;
  ItemTypeId: string;
  EnchantmentLevel: number;
  QualityLevel: number;
  LocationId: string | number;
}

let proc: ChildProcess | null = null;
const state = {
  packets: 0,
  photonEvents: 0,
  marketOrdersSeen: 0,
  pricesStored: 0,
  startedAt: null as string | null,
  lastError: null as string | null,
  eventCodeCounts: new Map<number, number>(),
  recentOrders: [] as CapturedOrder[],
};

export function listInterfaces(): { id: string; name: string }[] {
  const tshark = findTshark();
  if (!tshark) return [];
  const res = spawnSync(tshark, ['-D'], { encoding: 'utf8', timeout: 15000 });
  return (res.stdout ?? '')
    .split(/\r?\n/)
    .filter(Boolean)
    .map((line) => {
      const m = line.match(/^(\d+)\.\s+(.*)$/);
      return m ? { id: m[1], name: m[2] } : null;
    })
    .filter((x): x is { id: string; name: string } => x != null);
}

function toItemId(o: AlbionOrder): string {
  if (o.ItemTypeId.includes('@')) return o.ItemTypeId;
  return o.EnchantmentLevel > 0 ? `${o.ItemTypeId}@${o.EnchantmentLevel}` : o.ItemTypeId;
}

/** Group captured orders into best sell (min) / best buy (max) and store them as fresh prices. */
function storeOrders(orders: AlbionOrder[]): void {
  const best = new Map<string, { sell: number | null; buy: number | null; item: string; city: string; quality: number }>();
  for (const o of orders) {
    const city = MARKET_LOCATIONS[String(o.LocationId)];
    if (!city) continue;
    const item = toItemId(o);
    const quality = Math.max(1, o.QualityLevel || 1);
    const price = o.UnitPriceSilver / 10000; // protocol prices are silver * 10000
    const key = `${item}|${city}|${quality}`;
    const cur = best.get(key) ?? { sell: null, buy: null, item, city, quality };
    if (o.AuctionType === 'offer') cur.sell = cur.sell == null ? price : Math.min(cur.sell, price);
    else if (o.AuctionType === 'request') cur.buy = cur.buy == null ? price : Math.max(cur.buy, price);
    best.set(key, cur);

    state.recentOrders.unshift({
      item,
      city,
      quality,
      auctionType: o.AuctionType,
      unitPriceSilver: price,
      amount: o.Amount,
      seenAt: new Date().toISOString(),
    });
  }
  state.recentOrders = state.recentOrders.slice(0, 50);

  const db = getDb();
  const now = new Date().toISOString();
  const upsert = db.prepare(`
    INSERT INTO market_prices (item, city, quality, sell_price_min, sell_min_date, buy_price_max, buy_max_date, fetched_at)
    VALUES (@item, @city, @quality, @sell, @sellDate, @buy, @buyDate, @now)
    ON CONFLICT(item, city, quality) DO UPDATE SET
      sell_price_min = COALESCE(excluded.sell_price_min, market_prices.sell_price_min),
      sell_min_date  = CASE WHEN excluded.sell_price_min IS NOT NULL THEN excluded.sell_min_date ELSE market_prices.sell_min_date END,
      buy_price_max  = COALESCE(excluded.buy_price_max, market_prices.buy_price_max),
      buy_max_date   = CASE WHEN excluded.buy_price_max IS NOT NULL THEN excluded.buy_max_date ELSE market_prices.buy_max_date END,
      fetched_at     = excluded.fetched_at
  `);
  db.transaction(() => {
    for (const b of best.values()) {
      upsert.run({
        item: b.item,
        city: b.city,
        quality: b.quality,
        sell: b.sell,
        sellDate: b.sell != null ? now : null,
        buy: b.buy,
        buyDate: b.buy != null ? now : null,
        now,
      });
      state.pricesStored++;
    }
  })();
}

/** Recursively hunt for market-order JSON strings in photon parameters. */
function extractOrders(value: unknown, out: AlbionOrder[], depth = 0): void {
  if (depth > 4 || value == null) return;
  if (typeof value === 'string') {
    if (value.length > 20 && value.includes('UnitPriceSilver')) {
      try {
        const parsed = JSON.parse(value);
        if (parsed && typeof parsed === 'object' && 'UnitPriceSilver' in parsed) out.push(parsed as AlbionOrder);
      } catch {
        /* not JSON */
      }
    }
    return;
  }
  if (Array.isArray(value)) {
    for (const v of value) extractOrders(v, out, depth + 1);
    return;
  }
  if (typeof value === 'object') {
    for (const v of Object.values(value)) extractOrders(v, out, depth + 1);
  }
}

function handlePhotonMessage(data: any, isEvent: boolean): void {
  if (isEvent) {
    state.photonEvents++;
    const code = data?.code ?? data?.Code;
    if (typeof code === 'number') {
      state.eventCodeCounts.set(code, (state.eventCodeCounts.get(code) ?? 0) + 1);
    }
  }
  const orders: AlbionOrder[] = [];
  extractOrders(data?.parameters ?? data?.Parameters ?? data, orders);
  if (orders.length > 0) {
    state.marketOrdersSeen += orders.length;
    try {
      storeOrders(orders);
    } catch (e) {
      state.lastError = `storing sniffed orders failed: ${e instanceof Error ? e.message : e}`;
    }
  }
}

export function startSniffer(interfaceIds?: string[]): { started: boolean; error?: string } {
  if (proc) return { started: false, error: 'sniffer already running' };
  const tshark = findTshark();
  if (!tshark) {
    return {
      started: false,
      error:
        'tshark.exe not found. Install Wireshark (https://www.wireshark.org) with the bundled Npcap driver — the sniffer uses it to read your own game traffic passively.',
    };
  }

  const parser = new PhotonPacketParser();
  parser.on('event', (d: any) => handlePhotonMessage(d, true));
  parser.on('response', (d: any) => handlePhotonMessage(d, false));
  parser.on('request', () => undefined);
  parser.on('error', () => undefined);

  const ifaces = interfaceIds && interfaceIds.length > 0 ? interfaceIds : listInterfaces().map((i) => i.id);
  const ifaceArgs = ifaces.flatMap((i) => ['-i', i]);
  const args = [...ifaceArgs, '-l', '-n', '-q', '-f', 'udp port 5056', '-T', 'fields', '-e', 'data'];

  proc = spawn(tshark, args, { windowsHide: true });
  state.packets = 0;
  state.photonEvents = 0;
  state.marketOrdersSeen = 0;
  state.pricesStored = 0;
  state.startedAt = new Date().toISOString();
  state.lastError = null;
  state.eventCodeCounts.clear();
  state.recentOrders = [];

  let pending = '';
  proc.stdout!.on('data', (chunk: Buffer) => {
    pending += chunk.toString('ascii');
    const lines = pending.split('\n');
    pending = lines.pop() ?? '';
    for (const line of lines) {
      const hex = line.trim().replace(/:/g, '');
      if (!hex || hex.length < 24) continue;
      state.packets++;
      try {
        parser.handle(Buffer.from(hex, 'hex'));
      } catch {
        /* malformed packet — ignore */
      }
    }
  });
  proc.stderr!.on('data', (chunk: Buffer) => {
    const msg = chunk.toString('utf8').trim();
    // tshark prints capture stats to stderr; only keep real errors
    if (msg && !/^Capturing on/i.test(msg) && !/^\d+ packets?/i.test(msg)) state.lastError = msg.slice(0, 400);
  });
  proc.on('exit', (code) => {
    if (code !== 0 && code != null) state.lastError = state.lastError ?? `tshark exited with code ${code}`;
    proc = null;
  });

  return { started: true };
}

export function stopSniffer(): void {
  if (proc) {
    proc.kill();
    proc = null;
  }
}

export function snifferStatus(): SnifferStatus {
  return {
    tsharkPath: findTshark(),
    running: proc != null,
    packets: state.packets,
    photonEvents: state.photonEvents,
    marketOrdersSeen: state.marketOrdersSeen,
    pricesStored: state.pricesStored,
    startedAt: state.startedAt,
    lastError: state.lastError,
    eventCodeCounts: Object.fromEntries([...state.eventCodeCounts.entries()].sort((a, b) => b[1] - a[1]).slice(0, 40)),
    recentOrders: state.recentOrders,
  };
}