import { DatabaseSync } from 'node:sqlite';
import { randomUUID } from 'node:crypto';
import { mkdir, chmod } from 'node:fs/promises';
import { join } from 'node:path';
import { NETWORK, CONSENSUS, nftTransferMessage, testnetOwnerOf, transactionCardIds,
  type TestnetSnapshot, type NftTransfer } from '../../shared/testnet.ts';
import { ADDITIONAL_MARKET_FEE, marketCommandSchema, marketMessage, type MarketCommand, type MarketListing,
  type MarketOrder, type MarketInfo } from '../../shared/market.ts';
import { isXmrListing, isXmrOrder, marketCommandV3Schema, marketMessageV3,
  type MarketActivityV3, type MarketCommandV3, type MarketListingRecord, type MarketListingV3,
  type MarketOrderRecord, type MarketOrderV3 } from '../../shared/market-v3.ts';
import { CHAIN_ID, transactionId, transferSchema, verifySignature } from '../testnet/consensus.ts';
import { mockQuote, mockXmrQuote, paymentMode } from './payments.ts';
import { RpcError } from '../resources.ts';
import type { CanonicalEvents, IndexedNft } from '../testnet/canonical-index.ts';
import { z } from 'zod';

type Chain = { snapshot(): TestnetSnapshot; summary?(): { tip: string; revision: number; height?: number };
  submitTransfer(raw: unknown): Promise<string>; nft?(token: string): IndexedNft | undefined;
  canonicalTransaction?(id: string): { height: number; blockHash: string } | undefined;
  canonicalHead?(): number; canonicalEvents?(after: number, limit?: number): CanonicalEvents;
  pendingTransactions?(): TestnetSnapshot['pendingTransfers'] };
type ChainView = { height: number; pendingTransfers: TestnetSnapshot['pendingTransfers'];
  nft(token: string): IndexedNft | undefined; transaction(id: string): { height: number; blockHash: string } | undefined };
type Config = { feeBps: number; confirmations: number };
export function marketConfig(env: NodeJS.ProcessEnv = process.env): Config {
  paymentMode(env);
  const integer = (name: string, fallback: number, min: number, max: number) => {
    const text = env[name] ?? String(fallback);
    if (!/^\d+$/.test(text)) throw new Error(`Invalid ${name}`);
    const n = Number(text);
    if (!Number.isSafeInteger(n) || n < min || n > max) throw new Error(`Invalid ${name}`);
    return n;
  };
  return { feeBps: integer('WIKIDECK_MARKET_FEE_BPS', 250, 0, 5000),
    confirmations: integer('WIKIDECK_MARKET_CONFIRMATIONS', 10, 2, 1000) };
}
const PAYMENT_WINDOW = 30 * 60_000;
const DELIVERY_WINDOW = 48 * 60 * 60_000;
const cursorSchema = z.object({ version: z.literal(1), streamId: z.string().uuid(),
  cursor: z.number().int().nonnegative().safe(), anchor: z.string().regex(/^[a-f0-9]{64}$/) }).strict();

/** Node-local marketplace, NOT consensus escrow. Its SQLite journal is backed up with the ledger. */
export class Market {
  private queue: Promise<unknown> = Promise.resolve();
  private queued = 0;
  private reconciled: { tip: string; revision: number; at: number } | undefined;
  private eventCursor = 0;
  private eventCheckpoint: z.infer<typeof cursorSchema> | undefined;
  private eventBacklog = false;
  private readonly db: DatabaseSync;
  private readonly chain: Chain;
  readonly config: Config;
  readonly id: string;
  private readonly now: () => number;
  private constructor(db: DatabaseSync, chain: Chain, config: Config, id: string, now: () => number) {
    this.db = db; this.chain = chain; this.config = config; this.id = id; this.now = now;
    const cursor = db.prepare("SELECT value FROM market_meta WHERE key='canonical_event_cursor'").get() as { value: string } | undefined;
    if (cursor) {
      this.eventCheckpoint = cursorSchema.parse(JSON.parse(cursor.value));
      this.eventCursor = this.eventCheckpoint.cursor;
    }
  }

  static async open(directory: string, chain: Chain, config = marketConfig(), now = Date.now): Promise<Market> {
    const folder = join(directory, NETWORK.includes('mainnet') ? 'mainnet' : 'testnet');
    await mkdir(folder, { recursive: true, mode: 0o700 });
    const file = join(folder, 'market.sqlite');
    const db = new DatabaseSync(file);
    try {
      db.exec(`PRAGMA journal_mode=WAL; PRAGMA synchronous=FULL; PRAGMA busy_timeout=5000;
        CREATE TABLE IF NOT EXISTS market_meta(key TEXT PRIMARY KEY, value TEXT NOT NULL);
        CREATE TABLE IF NOT EXISTS listings(id TEXT PRIMARY KEY, card TEXT NOT NULL, status TEXT NOT NULL, data TEXT NOT NULL);
        CREATE UNIQUE INDEX IF NOT EXISTS one_active_listing ON listings(card) WHERE status IN ('open','reserved');
        CREATE TABLE IF NOT EXISTS orders(id TEXT PRIMARY KEY, data TEXT NOT NULL);
        CREATE TABLE IF NOT EXISTS receipts(id TEXT PRIMARY KEY, digest TEXT NOT NULL, expires INTEGER NOT NULL, data TEXT NOT NULL);`);
      db.exec(`CREATE INDEX IF NOT EXISTS listings_by_status ON listings(status);
        CREATE INDEX IF NOT EXISTS listings_by_seller ON listings(json_extract(data,'$.seller'));
        CREATE INDEX IF NOT EXISTS orders_by_seller ON orders(json_extract(data,'$.seller'));
        CREATE INDEX IF NOT EXISTS orders_by_buyer ON orders(json_extract(data,'$.buyer'));`);
      const meta = db.prepare('SELECT value FROM market_meta WHERE key=?').get('identity') as { value: string } | undefined;
      let id: string;
      if (meta) {
        const identity = JSON.parse(meta.value);
        if (identity.network !== NETWORK || identity.chainId !== CHAIN_ID || identity.version !== 1 ||
            typeof identity.id !== 'string') throw new Error('Marketplace network/schema mismatch');
        id = identity.id;
      } else {
        id = randomUUID();
        db.prepare('INSERT INTO market_meta VALUES(?,?)').run('identity', JSON.stringify({ version: 1, network: NETWORK, chainId: CHAIN_ID, id }));
      }
      if (process.platform !== 'win32') await chmod(file, 0o600);
      return new Market(db, chain, config, id, now);
    } catch (error) { db.close(); throw error; }
  }
  close() { this.db.close(); }
  diagnostics() {
    const states=this.db.prepare("SELECT json_extract(data,'$.status') AS status,COUNT(*) AS count FROM orders GROUP BY json_extract(data,'$.status')").all();
    return { queued:this.queued,lastReconciledAt:this.reconciled?.at??null,orderStates:states,
      canonicalEventCursor:this.eventCursor,canonicalEventHead:this.chain.canonicalHead?.()??null,eventBacklog:this.eventBacklog };
  }
  info(): MarketInfo {
    return { network: NETWORK, chainId: CHAIN_ID, marketId: this.id, paymentMode: 'mock', marketVersion: 3, feeBps: this.config.feeBps,
      additionalFee: { ...ADDITIONAL_MARKET_FEE },
      deliveryConfirmations: this.config.confirmations, serverTime: this.now() };
  }
  private rows<T>(table: 'listings' | 'orders'): T[] {
    return (this.db.prepare(`SELECT data FROM ${table} ORDER BY rowid DESC LIMIT 10000`).all() as { data: string }[])
      .map(row => JSON.parse(row.data) as T);
  }
  private listing(id: string): MarketListingRecord {
    const row = this.db.prepare('SELECT data FROM listings WHERE id=?').get(id) as { data: string } | undefined;
    if (!row) throw new Error('Listing not found');
    return JSON.parse(row.data) as MarketListingRecord;
  }
  private order(id: string): MarketOrderRecord {
    const row = this.db.prepare('SELECT data FROM orders WHERE id=?').get(id) as { data: string } | undefined;
    if (!row) throw new Error('Order not found');
    return JSON.parse(row.data) as MarketOrderRecord;
  }
  private saveListing(l: MarketListingRecord) {
    this.db.prepare('INSERT INTO listings VALUES(?,?,?,?) ON CONFLICT(id) DO UPDATE SET status=excluded.status,data=excluded.data WHERE listings.data<>excluded.data')
      .run(l.id, l.cardHash, l.status, JSON.stringify(l));
  }
  private saveOrder(o: MarketOrderRecord) {
    this.db.prepare('INSERT INTO orders VALUES(?,?) ON CONFLICT(id) DO UPDATE SET data=excluded.data WHERE orders.data<>excluded.data').run(o.id, JSON.stringify(o));
  }
  private atomic<T>(fn: () => T): T {
    this.db.exec('BEGIN IMMEDIATE');
    try { const result = fn(); this.db.exec('COMMIT'); return result; }
    catch (error) { this.db.exec('ROLLBACK'); throw error; }
  }
  private view(): ChainView {
    if (this.chain.nft && this.chain.canonicalTransaction && this.chain.pendingTransactions && this.chain.summary) {
      const height = this.chain.summary().height;
      if (height === undefined) throw new Error('Indexed chain height missing');
      return { height, pendingTransfers: this.chain.pendingTransactions(), nft: token => this.chain.nft!(token),
        transaction: id => this.chain.canonicalTransaction!(id) };
    }
    // Compatibility boundary for unit-test/legacy adapters only. The actual node always supplies indexed queries.
    const s = this.chain.snapshot();
    const txs = new Map(s.blocks.flatMap(b => b.transactions.map(tx => [transactionId(tx), { height: b.height, blockHash: b.hash }] as const)));
    return { height: s.blocks.length, pendingTransfers: s.pendingTransfers, transaction: id => txs.get(id), nft: token => {
      const block = s.blocks.find(b => b.tokenId === token);
      return block ? { block, owner: testnetOwnerOf(s, token)!, sequence: s.transfers.filter(tx => transactionCardIds(tx).includes(token)).length,
        confirmations: s.blocks.length + 1 - block.height } : undefined;
    } };
  }
  private card(view: ChainView, hash: string, owner: string, sequence: number): boolean {
    const nft = view.nft(hash);
    return !!nft && nft.owner === owner && nft.sequence === sequence && nft.confirmations >= CONSENSUS.coinbaseMaturity;
  }
  private deliveryId(order: MarketOrderRecord): string {
    // Identity excludes signature bytes. Recognize exact sale delivery through ANY submission route,
    // including peer gossip or a direct /api/transfer, even before the market records delivery intent.
    return transactionId({ network: NETWORK, chainId: CHAIN_ID, cardHash: order.cardHash,
      from: order.seller, to: order.buyer, sequence: order.sequence, publicKey: '', signature: '' });
  }
  /** Reconcile from canonical transaction identity, never from a mempool acknowledgement. */
  private reconcile() {
    const events = this.chain.canonicalEvents?.(this.eventCursor, 64);
    if (events && this.eventCheckpoint && (events.streamId !== this.eventCheckpoint.streamId ||
      events.previousAnchor !== this.eventCheckpoint.anchor)) throw new RpcError(409, 'Canonical event history changed; restore matching ledger and market backups.');
    const s = this.view(), now = this.now();
    const pendingIds = new Set(s.pendingTransfers.map(transactionId));
    this.atomic(() => {
      // Process every disconnect, even if the same delivery reappeared before this consumer caught up.
      // Never infer that a current tip erases an intermediate loss of previously settled evidence.
      const disconnected = new Set(events?.events.filter(e => e.type === 'disconnect').flatMap(e => e.transactionIds) ?? []);
      if (events) {
        for (const o of this.rows<MarketOrderRecord>('orders')) {
          if (o.status === 'complete' && disconnected.has(this.deliveryId(o))) {
            o.status = 'review'; o.payout = 'review';
            if (o.additionalFee) o.additionalFee.payout = 'review';
            this.saveOrder(o);
          }
        }
        this.db.prepare('INSERT INTO market_meta VALUES(?,?) ON CONFLICT(key) DO UPDATE SET value=excluded.value')
          .run('canonical_event_cursor', JSON.stringify({ version: 1, streamId: events.streamId, cursor: events.cursor, anchor: events.anchor }));
        // Catch-up is bounded per pass. No new payout, timeout/refund decision or mutation while events remain.
        if (!events.caughtUp) return;
      }
      for (const o of this.rows<MarketOrderRecord>('orders')) {
        const l = this.listing(o.listingId);
        if (o.status === 'refunded' || o.status === 'expired') continue;
        const deliveryId = this.deliveryId(o);
        const delivery = s.transaction(deliveryId);
        const confirmations = delivery ? s.height - delivery.height + 1 : 0;
        o.deliveryConfirmations = confirmations;
        if (o.status === 'complete' || o.status === 'review') {
          if (!delivery || confirmations < o.requiredConfirmations) {
            o.status = 'review'; o.payout = 'review';
            if (o.additionalFee) o.additionalFee.payout = 'review';
          }
          this.saveOrder(o); continue; // Never automatically pay a second time after a reorganization.
        }
        if (delivery && o.status === 'awaiting-payment') {
          // A gift/direct delivery is not evidence that payment was received. Never pay an unpaid order.
          o.status = 'review'; o.payout = 'review';
          if (o.additionalFee) o.additionalFee.payout = 'review';
        } else if (delivery) {
          o.transferId = deliveryId;
          o.status = 'delivery-pending';
          if (confirmations >= o.requiredConfirmations) {
            o.status = 'complete'; o.payout = 'mock-paid'; l.status = 'sold';
            if (o.additionalFee) o.additionalFee.payout = 'mock-paid';
          }
        } else if (o.status === 'awaiting-payment' && now >= o.payBy) {
          o.status = 'expired'; l.status = l.kind === 'fixed' ? 'open' : 'expired';
        } else if (o.status !== 'awaiting-payment') {
          const pending = pendingIds.has(deliveryId);
          const conflict = s.pendingTransfers.some(tx => transactionCardIds(tx).includes(o.cardHash) && transactionId(tx) !== deliveryId);
          if (!this.card(s, o.cardHash, o.seller, o.sequence) || conflict || (now >= o.deliverBy && !pending)) o.status = 'refund-required';
          else if (o.status === 'delivery-pending' && !pending) o.status = 'paid';
        }
        this.saveOrder(o); this.saveListing(l);
      }
      for (const l of this.rows<MarketListingRecord>('listings')) {
        if (l.status !== 'open') continue;
        if (l.additionalFee?.bps !== ADDITIONAL_MARKET_FEE.bps || l.additionalFee?.address !== ADDITIONAL_MARKET_FEE.address ||
          !this.card(s, l.cardHash, l.seller, l.sequence) || s.pendingTransfers.some(tx => transactionCardIds(tx).includes(l.cardHash))) l.status = 'invalid';
        else if (l.kind === 'auction' && now >= l.endsAt! + PAYMENT_WINDOW) l.status = 'expired';
        else if (l.kind === 'auction' && now >= l.endsAt! && !l.highestBid) l.status = 'expired';
        this.saveListing(l);
      }
      this.db.prepare('DELETE FROM receipts WHERE expires < ?').run(now - 86400_000);
    });
    if (events) {
      this.eventCursor = events.cursor; this.eventBacklog = !events.caughtUp;
      this.eventCheckpoint = { version: 1, streamId: events.streamId, cursor: events.cursor, anchor: events.anchor };
    }
    const summary = this.chain.summary?.();
    if (summary && !this.eventBacklog) this.reconciled = { ...summary, at: now };
  }
  browse(offset = 0): { listings: MarketListingRecord[]; next: number | null; info: MarketInfo } {
    if (!Number.isSafeInteger(offset) || offset < 0 || offset > 10000) throw new Error('Invalid marketplace page');
    // Reconciliation must not interleave with delivery submission while its chain await is outstanding.
    const summary = this.chain.summary?.();
    const last = this.reconciled;
    if (!this.queued && (!summary || !last || summary.tip !== last.tip || summary.revision !== last.revision || this.now() - last.at >= 1000)) this.reconcile();
    const rows = this.db.prepare("SELECT data FROM listings WHERE status IN ('open','reserved') ORDER BY rowid DESC LIMIT 25 OFFSET ?")
      .all(offset) as { data: string }[];
    return { listings: rows.slice(0,24).map(r=>JSON.parse(r.data)), next: rows.length>24?offset+24:null, info: this.info() };
  }
  execute(raw: unknown): Promise<MarketActivityV3 | MarketListingRecord | MarketOrderRecord> {
    const current = marketCommandV3Schema.safeParse(raw);
    const cmd = current.success ? current.data : marketCommandSchema.parse(raw);
    if (this.queued >= 64) return Promise.reject(new Error('Marketplace busy; retry shortly'));
    this.queued++;
    const result = this.queue.then(async () => {
      try { return await this.run(cmd); }
      finally { this.queued--; }
    });
    this.queue = result.catch(() => undefined);
    return result;
  }
  private async run(c: MarketCommand | MarketCommandV3): Promise<MarketActivityV3 | MarketListingRecord | MarketOrderRecord> {
    const now = this.now();
    const isV3 = 'version' in c;
    const message = isV3 ? marketMessageV3(c) : marketMessage(c);
    if (c.chainId !== CHAIN_ID || c.marketId !== this.id || c.expiresAt < now || c.expiresAt > now + 5 * 60_000 ||
      !verifySignature(c.publicKey, c.actor, message, c.signature)) throw new Error('Invalid or expired marketplace signature');
    const key = `${c.actor}:${c.nonce}`, digest = message;
    const old = this.db.prepare('SELECT digest,data FROM receipts WHERE id=?').get(key) as { digest: string; data: string } | undefined;
    if (old) {
      if (old.digest !== digest) throw new Error('Nonce already used for different terms');
      return JSON.parse(old.data);
    }
    const a = c.action;
    const summary = this.chain.summary?.(), last = this.reconciled;
    if (a.type !== 'activity' || !summary || !last || summary.tip !== last.tip || summary.revision !== last.revision ||
      this.now() - last.at >= 1000) this.reconcile();
    if (this.eventBacklog && a.type !== 'activity') throw new RpcError(503, 'Market canonical reconciliation is catching up; retry shortly.');
    if (a.type === 'activity') return {
      orders: (this.db.prepare("SELECT data FROM orders WHERE json_extract(data,'$.seller')=? OR json_extract(data,'$.buyer')=? ORDER BY rowid DESC")
        .all(c.actor,c.actor) as { data: string }[]).map(r=>JSON.parse(r.data) as MarketOrderRecord),
      listings: (this.db.prepare("SELECT data FROM listings WHERE json_extract(data,'$.seller')=? ORDER BY rowid DESC")
        .all(c.actor) as { data: string }[]).map(r=>JSON.parse(r.data) as MarketListingRecord) };
    if (a.type === 'deliver') {
      const o = this.order(a.orderId), tx = transferSchema.parse(a.transfer);
      if (isV3 && !isXmrOrder(o) || !isV3 && isXmrOrder(o) || o.seller !== c.actor || !['paid', 'delivery-pending'].includes(o.status)) throw new Error('Only the paid order seller can deliver under the order terms');
      if (tx.cardHash !== o.cardHash || tx.sequence !== o.sequence || tx.from !== o.seller || tx.to !== o.buyer ||
          !verifySignature(tx.publicKey, tx.from, nftTransferMessage(tx), tx.signature)) throw new Error('Delivery does not match this sale');
      // Persist intent before the ledger await. A crash/restart reconciles by deterministic tx ID.
      o.transfer = tx; o.transferId = transactionId(tx); o.status = 'delivery-pending'; this.saveOrder(o);
      await this.chain.submitTransfer(tx);
      return this.receipt(key, digest, c.expiresAt, o);
    }
    return this.atomic(() => {
      const result = isV3 ? this.mutateV3(c) : this.mutateV2(c);
      return this.receipt(key, digest, c.expiresAt, result);
    });
  }
  private receipt<T>(key: string, digest: string, expires: number, value: T): T {
    this.db.prepare('INSERT INTO receipts VALUES(?,?,?,?)').run(key, digest, expires, JSON.stringify(value));
    return value;
  }
  private mutateV2(c: MarketCommand): MarketActivityV3 | MarketListingRecord | MarketOrderRecord {
    const a = c.action, now = this.now(), s = this.view();
    if (a.type === 'list') {
      throw new Error('USD listing terms are retired; create a new native-XMR listing');
    }
    if (a.type === 'cancel') {
      const l = this.listing(a.listingId);
      if (isXmrListing(l) || l.status !== 'open') throw new Error('USD legacy listing cannot be changed under this command');
      if (l.seller !== c.actor || l.highestBid) throw new Error('Only the seller can cancel, and auctions with bids cannot be cancelled');
      l.status = 'cancelled'; this.saveListing(l); return l;
    }
    if (a.type === 'mock-pay' || a.type === 'refund') {
      const o = this.order(a.orderId);
      if (isXmrOrder(o)) throw new Error('Use native-XMR signed terms for this order');
      if (o.buyer !== c.actor) throw new Error('Only the order buyer can perform this action');
      if (a.type === 'mock-pay') {
        if (o.status !== 'awaiting-payment' || now >= o.payBy) throw new Error('Invoice is not payable');
        if (!this.card(s, o.cardHash, o.seller, o.sequence) || s.pendingTransfers.some(tx => transactionCardIds(tx).includes(o.cardHash))) throw new Error('Seller card changed; do not pay');
        o.status = 'paid'; o.deliverBy = now + DELIVERY_WINDOW;
      } else {
        if (o.status !== 'refund-required' || s.pendingTransfers.some(tx => transactionCardIds(tx).includes(o.cardHash)) ||
          s.transaction(this.deliveryId(o))) throw new Error('Refund requires failed delivery and no pending/canonical sale transfer');
        o.status = 'refunded'; const l = this.listing(o.listingId); l.status = 'cancelled'; this.saveListing(l);
      }
      this.saveOrder(o); return o;
    }
    if (a.type === 'activity') return {
      orders: (this.db.prepare("SELECT data FROM orders WHERE json_extract(data,'$.seller')=? OR json_extract(data,'$.buyer')=? ORDER BY rowid DESC")
        .all(c.actor,c.actor) as { data: string }[]).map(r=>JSON.parse(r.data) as MarketOrderRecord),
      listings: (this.db.prepare("SELECT data FROM listings WHERE json_extract(data,'$.seller')=? ORDER BY rowid DESC")
        .all(c.actor) as { data: string }[]).map(r=>JSON.parse(r.data) as MarketListingRecord) };
    if (a.type === 'deliver') throw new Error('Legacy delivery is handled by the common signed-order delivery path');
    throw new Error('Legacy USD bids and checkout are retired; only already-created orders may proceed');
  }

  private mutateV3(c: MarketCommandV3): MarketActivityV3 | MarketListingRecord | MarketOrderRecord {
    const a = c.action, now = this.now(), s = this.view();
    if (a.type === 'list') {
      if (a.feeBps !== this.config.feeBps) throw new Error('Market fee changed; review and sign again');
      if (!this.card(s, a.cardHash, c.actor, a.sequence) || s.pendingTransfers.some(tx => transactionCardIds(tx).includes(a.cardHash))) throw new Error('Card is missing, stale, immature, or already pending');
      if (a.kind === 'fixed' ? a.endsAt !== null : a.endsAt === null || a.endsAt < now + 60_000 || a.endsAt > now + 30 * 86400_000) throw new Error('Auction duration must be 1 minute to 30 days; fixed listings have no end');
      if (this.rows<MarketListingRecord>('listings').filter(l => l.seller === c.actor && ['open','reserved'].includes(l.status)).length >= 100) throw new Error('Limit: 100 active listings per seller');
      if ((this.db.prepare('SELECT COUNT(*) AS n FROM listings').get() as { n: number }).n >= 10000) throw new Error('Marketplace journal limit reached; operator archival required');
      if (this.db.prepare("SELECT 1 FROM listings WHERE card=? AND status IN ('open','reserved')").get(a.cardHash)) throw new Error('Card already listed');
      const mint = s.nft(a.cardHash)!.block;
      const l: MarketListingV3 = { id: randomUUID(), termsVersion: 3, cardHash: a.cardHash, sequence: a.sequence,
        seller: c.actor, title: mint.article.title, image: mint.article.image!, kind: a.kind,
        priceAtomicXmr: a.priceAtomicXmr, feeBps: a.feeBps, additionalFee: { ...ADDITIONAL_MARKET_FEE },
        createdAt: now, endsAt: a.endsAt, status: 'open', highestBid: null };
      this.saveListing(l); return l;
    }
    if (a.type === 'retire-legacy-listing') {
      const listing = this.listing(a.listingId);
      if (isXmrListing(listing)) throw new Error('Native-XMR listings use the signed cancel action');
      if (listing.seller !== c.actor || !['open','invalid'].includes(listing.status)) throw new Error('Only the seller can retire an unreserved legacy listing');
      if (listing.highestBid) throw new Error('Legacy auction has bids; resolve or wait for its original terms before retirement');
      if (this.db.prepare("SELECT 1 FROM orders WHERE json_extract(data,'$.listingId')=? AND json_extract(data,'$.status') IN ('awaiting-payment','paid','delivery-pending','refund-required','review') LIMIT 1").get(listing.id)) {
        throw new Error('Legacy listing has an in-flight order; preserve that order under its original terms');
      }
      listing.status = 'cancelled'; this.saveListing(listing); return listing;
    }
    if (a.type === 'bid' || a.type === 'buy' || a.type === 'cancel') {
      const l = this.listing(a.listingId);
      if (!isXmrListing(l)) throw new Error('Legacy USD listings are read-only; seller must retire and relist with fresh XMR authorization');
      if (l.status !== 'open') throw new Error('Listing is no longer available');
      if (a.type === 'cancel') {
        if (l.seller !== c.actor || l.highestBid) throw new Error('Only the seller can cancel, and auctions with bids cannot be cancelled');
        l.status = 'cancelled'; this.saveListing(l); return l;
      }
      if (l.seller === c.actor) throw new Error('Cannot buy or bid on your own card');
      if (a.type === 'bid') {
        if (l.kind !== 'auction' || now >= l.endsAt!) throw new Error('Auction is not accepting bids');
        const minimum = l.highestBid ? BigInt(l.highestBid.priceAtomicXmr) + 1n : BigInt(l.priceAtomicXmr);
        if (BigInt(a.priceAtomicXmr) < minimum) throw new Error('Bid must meet the start price and exceed the current bid by one atomic unit');
        l.highestBid = { bidder: c.actor, priceAtomicXmr: a.priceAtomicXmr }; this.saveListing(l); return l;
      }
      const price = l.kind === 'fixed' ? l.priceAtomicXmr : l.highestBid?.priceAtomicXmr;
      if (l.kind === 'auction' && (now < l.endsAt! || now >= l.endsAt! + PAYMENT_WINDOW || l.highestBid?.bidder !== c.actor)) throw new Error('Only the auction winner can check out within 30 minutes of closing');
      if (price !== a.priceAtomicXmr || l.feeBps !== a.feeBps) throw new Error('Sale terms changed; review and sign again');
      if (!this.card(s, l.cardHash, l.seller, l.sequence) || s.pendingTransfers.some(tx => transactionCardIds(tx).includes(l.cardHash))) throw new Error('Card is no longer available');
      if ((this.db.prepare('SELECT COUNT(*) AS n FROM orders').get() as { n: number }).n >= 10000) throw new Error('Marketplace order limit reached; operator archival required');
      const payBy = l.kind === 'auction' ? l.endsAt! + PAYMENT_WINDOW : now + PAYMENT_WINDOW;
      const order: MarketOrderV3 = { id: randomUUID(), termsVersion: 3, listingId: l.id, seller: l.seller, buyer: c.actor,
        cardHash: l.cardHash, sequence: l.sequence, priceAtomicXmr: price!, feeBps: l.feeBps, createdAt: now, payBy,
        deliverBy: payBy + DELIVERY_WINDOW, status: 'awaiting-payment', ...mockXmrQuote(price!, l.feeBps),
        payout: 'not-started', deliveryConfirmations: 0, requiredConfirmations: this.config.confirmations };
      l.status = 'reserved'; this.saveListing(l); this.saveOrder(order); return order;
    }
    if (a.type === 'mock-pay' || a.type === 'refund') {
      const order = this.order(a.orderId);
      if (!isXmrOrder(order)) throw new Error('Legacy USD orders keep their original terms and cannot be changed through native-XMR actions');
      if (order.buyer !== c.actor) throw new Error('Only the order buyer can perform this action');
      if (a.type === 'mock-pay') {
        if (order.status !== 'awaiting-payment' || now >= order.payBy) throw new Error('Invoice is not payable');
        if (!this.card(s, order.cardHash, order.seller, order.sequence) || s.pendingTransfers.some(tx => transactionCardIds(tx).includes(order.cardHash))) throw new Error('Seller card changed; do not pay');
        order.status = 'paid'; order.deliverBy = now + DELIVERY_WINDOW;
      } else {
        if (order.status !== 'refund-required' || s.pendingTransfers.some(tx => transactionCardIds(tx).includes(order.cardHash)) ||
          s.transaction(this.deliveryId(order))) throw new Error('Refund requires failed delivery and no pending/canonical sale transfer');
        order.status = 'refunded'; const listing = this.listing(order.listingId); listing.status = 'cancelled'; this.saveListing(listing);
      }
      this.saveOrder(order); return order;
    }
    throw new Error('Unsupported native-XMR market action');
  }
}