NFT Collection Smart Contract

## ROLE
You are an NFT smart contract developer who has launched 50+ collections across Ethereum and L2s. You understand the evolution from basic ERC-721 to ERC-721A and the tradeoffs of different minting architectures.

## OBJECTIVE
Create a production-ready NFT collection contract for [COLLECTION NAME] with [MAX SUPPLY] NFTs on [CHAIN] featuring allowlist minting, public minting, and delayed reveal.

## TASK

### Contract Foundation
- Base contract: ERC721A for gas-efficient batch minting vs standard ERC721 with justification
- Metadata: on-chain vs off-chain (IPFS/Arweave) with URI management
- Royalty standard: ERC-2981 royalty info with operator filter registry for marketplace enforcement
- Ownership: Ownable2Step for secure ownership transfer
- Supply management: maximum supply, reserved tokens for team/airdrops

### Minting Phases
- Phase 1 — Allowlist mint: Merkle tree verification, per-wallet limits, reduced price
- Phase 2 — Public mint: open minting with per-transaction and per-wallet limits
- Phase 3 — Dutch auction (optional): price decreasing over time blocks
- Free claim: separate merkle root for free mint allocations
- Phase transitions: owner-controlled with automatic time-based fallback

### Reveal Mechanism
- Pre-reveal: all tokens point to a single placeholder metadata URI
- Reveal trigger: owner function that sets base URI and randomization seed
- Randomization: Chainlink VRF for provably fair token-to-art mapping
- Provenance hash: pre-commitment hash of final metadata ordering
- Batch reveal: optional partial reveals for collections with staggered drops

### Gas Optimization
- ERC721A batch minting: mint 5+ tokens for nearly the cost of minting 1
- Merkle proof verification: O(log n) verification vs O(n) array checking
- Bitmap for claimed status: pack 256 claim flags into a single storage slot
- Lazy minting: defer token data writes until first transfer
- Minimized storage: avoid storing redundant data derivable from token ID

### Security Considerations
- Bot prevention: max per-transaction limits, max per-wallet limits, no contract minting
- Signature-based minting: EIP-712 signed messages as alternative to merkle trees
- Withdrawal pattern: pull-based ETH withdrawal to avoid reentrancy
- Fund splitting: automated royalty splits to multiple recipients
- Emergency controls: pause minting, update merkle root, adjust pricing

### Marketplace Integration
- Operator filter: DefaultOperatorFilterer for royalty-enforcing marketplaces
- Metadata standards: OpenSea, LooksRare, Blur metadata compatibility
- Collection-level metadata: contractURI() for collection name, description, image
- Token-level metadata: proper JSON schema with attributes, image, animation_url

## OUTPUT FORMAT
Complete Solidity contract with minting logic, reveal system, deployment checklist, and Hardhat/Foundry test outline.

## CONSTRAINTS
- Must work with both EOA and smart contract wallets (EIP-4337)
- Gas cost for single mint must be under 100K gas
- Contract must be verified on block explorer immediately after deployment
- Include fallback for Chainlink VRF failure (owner backup reveal)
- Metadata must conform to OpenSea metadata standards