Marketplace & Club Ops

This page goes deep on how managers mint, list, buy, train, loan, and graduate talent on Gaff and how the economy stays fair, liquid, and fun.

5.1 NFT Marketplace

What lives on-chain

• Player NFTs (ERC-721): unique ID, immutable genesis (academy cohort, origin scout), dynamic attributes (form, stamina, total goals/assists, appearances).
• Club Badge NFTs (ERC-721, optional): club identity & cosmetics.
• Receipts (ERC-1155 or event logs): tournament entries, prize receipts for verifiable history.

Player metadata (example)

{
  "name": "Cristiano Messi (ST, Left)",
  "description": "Academy Class S4 · Brazil · Pressing forward.",
  "image": "ipfs://Qm.../render.png",
  "attributes": [
    { "trait_type": "Position", "value": "ST" },
    { "trait_type": "Foot", "value": "Left" },
    { "trait_type": "Strength", "value": 72 },
    { "trait_type": "Stamina", "value": 83 },
    { "trait_type": "Injury Proneness", "value": 0.18 },
    { "trait_type": "Form (roll-5)", "value": [7, 6, 8, 7, 6] },
    { "trait_type": "Nationality", "value": "BRA" },
    { "trait_type": "Cohort", "value": "ACA-S4" },
    { "trait_type": "Age", "value": 19 }
  ],
  "external_url": "https://gaff.coach/player/12345"
}

Minting paths

• New Gen (Primary):
  • Source: academy graduation, special drops, partner leagues.
  • Supply policy: season-based caps per position & cohort to avoid meta inflation.
  • Randomness: VRF-backed seeding for base profile, club training develops it.
• Convert Prospects → NFTs (Academy grads):
  • Triggered when graduation threshold is met (see §6.4).
  • Mint fee covers storage + fraud proofs, discounted via referral.

Listing: gasless → on-chain settlement

• Gasless listing uses EIP-712 signatures:
  • Seller signs {tokenId, collection, minPrice, expiry, nonce}.
  • Order is stored off-chain (indexer), no gas.
  • On purchase: buyer calls fulfill(order, sig), contract verifies signer, price, expiry, ownership & nonce, then transfers NFT and splits funds.
• Cancel listing: seller signs a cancel, indexer prunes, or seller revokes nonce on-chain (optional advanced flow).

EIP-712 typed data (example)

struct Ask {
  address seller;
  address collection;
  uint256 tokenId;
  uint256 minPrice;
  uint256 expiry;  // unix
  uint256 nonce;
  address payoutCurrency; // native or ERC20
}

Offers & bids

• Maker bids (gasless): bidder signs a bid with price floors/expiry.
• Taker fills: seller fills best bid on-chain, contract handles escrow & splits.
• Collection bids (optional roadmap): “any ST ≥ strength 70”.

Fees & royalties

Component	Default	Notes
Protocol fee	1.5%	Goes to Gaff treasury for tournaments & grants.
Creator royalty	2.0%	On primary & secondary (respect creator setting, capped at 4%).
Referral kickback	0.5%	To referrer on first marketplace transaction by referee.
L1/L2 gas	chain	Settlement gas at buyer’s cost, listings remain gasless.

Anti-wash: same-wallet or tightly-linked wallets don’t earn referral kickbacks, on-chain heuristics + risk thresholds throttle abuse.

Fraud & abuse controls

• Blacklist stolen tokens (integrations), freeze payouts to suspicious sellers until dispute cleared.
• Nonces and per-seller daily cap on order spam to protect indexers.
• Banned price bands for newly minted academy grads (e.g., no <$0.1 for 24h) to reduce bot sniping.

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5.2 Scouting & Signing

What matters when scouting

• Ratings: strength (overall), position weights, footedness, height archetype.
• Form: last 5 match ratings (1–10) rolling.
• Stamina & Fatigue: current stamina (0–100) impacts match sim and injury risk.
• Injury risk: risk = proneness × (100 - stamina)/100 (bounded).
• Discipline: yellow/red history (affects fair-play tie-breakers in some events).
• Chemistry hooks: position fit vs current formation.

Scouting UI signals (examples)

• Reliability index (0–100): model of availability: low proneness, high stamina habits.
• Trajectory: 4-week trend of ratings & stamina management.
• Role fit: “Ideal as pressing forward in 4-3-3”, “sub-optimal in 5-3-2”.

Contracts & wages (optional, toggle per league)

Term	Range	Effect
Wage/week	% of treasury	Impacts club upkeep, non-payment flags player unhappy modifier.
Duration	2–16 weeks	Early break penalties (clause) or transfer windows.
Bonuses	Goals/Assists/Win	Small token payouts, caps to avoid farm.

Loan market

• Parameters: duration (weeks), recall window (yes/no, week n), wage split (%), optional buy option (price/expiry).
• Recall rules:
  • If recallable, lender can recall after recall window, must honor scheduled matches already locked this round.
  • If non-recallable, only club mutual termination with penalty.
• Collateral (optional): borrower posts a bond, forfeited on default/abuse.

Loan Record (on-chain storage)

struct Loan {
  address originalOwner;
  address borrowerClub;
  address collection;
  uint256 tokenId;
  uint64  startWeek;
  uint64  endWeek;
  bool    recallable;
  uint64  recallWeek;  // if recallable
  uint16  wageSplitBps;  // lender share
  uint256 buyOptionPrice; // 0 if none
  uint64  buyOptionExpiry;
}

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Diagrams

Marketplace Flow (gasless listing → on-chain fill)

sequenceDiagram
  participant Seller
  participant Frontend
  participant Indexer
  participant Buyer
  participant MarketplaceSC

  Seller->>Frontend: Create Ask (price, expiry)
  Frontend->>Seller: EIP-712 message
  Seller->>Frontend: Signature
  Frontend->>Indexer: Store order off-chain
  Buyer->>Frontend: Click "Buy"
  Frontend->>MarketplaceSC: fulfill(order, sig, value)
  MarketplaceSC->>MarketplaceSC: verify sig, nonce, expiry, ownership
  MarketplaceSC->>Seller: payout - fees - royalties
  MarketplaceSC->>Buyer: transfer NFT
  MarketplaceSC->>Indexer: emit Filled(orderId)

Club Ops Flywheel

flowchart LR
  A[Academy] --> B[Mint Graduate]
  B --> C[Train & Play]
  C --> D[Performance Data]
  D --> E[Scouting Signal ↑]
  E --> F[Marketplace Liquidity]
  F --> G[Reinvest in Academy & Shop]
  G --> C

Loan Lifecycle

stateDiagram-v2
  [*] --> Proposed
  Proposed --> Active: Borrower accepts
  Active --> Recalled: Lender recall (if allowed)
  Active --> EarlyBuy: Borrower exercises buy option
  Recalled --> Settled
  EarlyBuy --> Settled
  Active --> Expired: End week reached
  Expired --> Settled

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Dev Notes (implementation hints)

• Separation of concerns: marketplace contracts do not mutate player attributes, they only transfer and settle. Training & matches are separate systems writing to on-chain stats or off-chain proofs that are pulled into metadata refresh.
• Indexing: use order books keyed by (collection, tokenId) and (seller, nonce), prune on fills/cancels.
• Oracles: no price oracles required, settlement uses buyer’s currency (native or whitelisted ERC-20).
• Events: emit granular events (AskCreated, AskCancelled, AskFilled, BidCreated, BidFilled, LoanCreated, LoanRecalled, LoanSettled) for analytics.

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FAQ

Q: Can I list gasless and cancel on-chain later?
Yes. Gasless list, if you want an irrevocable cancel, call invalidate(nonce) on-chain. Otherwise, UI removal + indexer pruning hides it.

Q: Do boosts make pay-to-win?
No, boosts are capped per account/player, come with cooldowns, and cannot override core attributes. They help availability and consistency, not raw strength spikes.

Q: Can I loan with buy option?
Yes, price and expiry are part of the loan struct, exercising transfers immediately and settles royalties/fees.