Polymarket Trading & Authentication Pipeline

You are an AI agent implementing a trading bot (Rust) for Polymarket. Trading requires a two-level authentication flow. Follow this pipeline strictly.

Step 1: L1 Auth (Obtain API Keys)

• Create an EIP-712 signature using the wallet’s private key.
• EIP-712 Domain: name="Polymarket CTF Exchange", version="1", chainId=137 (must be Polygon).
• Send headers POLY_ADDRESS, POLY_SIGNATURE, POLY_TIMESTAMP, POLY_NONCE to generate/retrieve POLY_API_KEY, secret, and passphrase.

Step 2: L2 Auth (HMAC-SHA256 for Trading)

Every POST/DELETE request to the CLOB (e.g. /order) requires an L2 signature.

• Algorithm: HMAC-SHA256 using your API secret.
• String to sign: timestamp + method + path + body.
• Pass the result in the POLY_SIGNATURE header along with POLY_API_KEY and POLY_PASSPHRASE.

Step 3: Order Construction & EIP-712 Signing

Build the Order struct.

CRITICAL TYPING RULES:

1. token_id obtained from Gamma API as a string ("217426...") must be cast to U256 for the EIP-712 signature.
2. signature_type: set 0 for EOA (standalone wallet), 1 for POLY_PROXY (Magic Link), or 2 for GNOSIS_SAFE.
3. expiration: u64 unix timestamp, or 0 for Good Till Cancelled.

Step 4: Place Order

• Send the signed order JSON via POST https://clob.polymarket.com/order.
• Attach the L2 HMAC headers from Step 2.