polynode 0.12.3

//! Trading module — place orders on Polymarket with local credential custody
//! and builder attribution via the polynode co-signer.
//!
//! # Quick Start
//!
//! ```rust,no_run
//! use polynode::trading::{PolyNodeTrader, TraderConfig, PrivateKeySigner, OrderParams, OrderSide};
//!
//! #[tokio::main]
//! async fn main() -> polynode::Result<()> {
//!     let mut trader = PolyNodeTrader::new(TraderConfig {
//!         polynode_key: "pn_live_...".into(),
//!         ..Default::default()
//!     })?;
//!
//!     let signer = PrivateKeySigner::from_hex("0xdeadbeef...")?;
//!     let status = trader.ensure_ready(Box::new(signer), None).await?;
//!     println!("Ready: {:?}", status.funder_address);
//!
//!     let result = trader.order(OrderParams {
//!         token_id: "123...".into(),
//!         side: OrderSide::Buy,
//!         price: 0.55,
//!         size: 100.0,
//!         ..Default::default()
//!     }).await?;
//!
//!     println!("Order: {:?}", result);
//!     trader.close();
//!     Ok(())
//! }
//! ```

pub mod constants;
pub mod constants_v2;
pub mod types;
pub mod signer;
pub mod onboarding;
pub mod cosigner;
pub mod sqlite_backend;
pub mod position_management;
pub mod escrow;
pub mod relayer;

#[cfg(feature = "privy")]
pub mod privy;

use crate::error::{Error, Result};
use self::constants::{CLOB_HOST, CHAIN_ID, CTF_EXCHANGE, NEG_RISK_CTF_EXCHANGE};
use self::constants_v2::{V2_CLOB_HOST, V2_CTF_EXCHANGE, V2_NEG_RISK_EXCHANGE_A, V2_DOMAIN_VERSION, V2_DOMAIN_NAME};
use self::cosigner::{send_via_cosigner, CosignerConfig};
use self::onboarding::create_clob_credentials;
use self::sqlite_backend::OrderHistoryInsert;

// Re-exports for public API
pub use self::types::*;
pub use self::signer::{TradingSigner, PrivateKeySigner};
pub use self::onboarding::{
    derive_safe_address, derive_proxy_address, derive_funder_address,
    detect_wallet_type, is_safe_deployed,
};
pub use self::cosigner::build_l2_headers;
pub use self::sqlite_backend::TradingSqliteBackend;

/// Re-export `Address` so custom signer implementors don't need `alloy-primitives` as a direct dep.
pub use alloy_primitives::Address;

/// Re-export `async_trait` so custom signer implementors don't need it as a direct dep.
pub use async_trait::async_trait;

#[cfg(feature = "privy")]
pub use self::privy::{PrivyConfig, PrivySigner};

/// Main trading client with local credential custody.
pub struct PolyNodeTrader {
    config: TraderConfig,
    db: Option<TradingSqliteBackend>,
    active_signer: Option<Box<dyn TradingSigner>>,
    active_wallet: Option<String>,
    http: reqwest::Client,
}

impl PolyNodeTrader {
    /// Create a new trader instance.
    pub fn new(config: TraderConfig) -> Result<Self> {
        Ok(Self {
            config,
            db: None,
            active_signer: None,
            active_wallet: None,
            http: reqwest::Client::new(),
        })
    }

    /// Generate a fresh EOA wallet. Returns (private_key_hex, address_hex).
    pub fn generate_wallet() -> (String, String) {
        let (signer, key) = PrivateKeySigner::generate();
        let addr = format!("{}", signer.inner().address());
        (key, addr)
    }

    fn get_db_mut(&mut self) -> Result<&TradingSqliteBackend> {
        if self.db.is_none() {
            self.db = Some(TradingSqliteBackend::open(&self.config.db_path)?);
        }
        Ok(self.db.as_ref().unwrap())
    }

    fn cosigner_config(&self) -> CosignerConfig {
        CosignerConfig {
            cosigner_url: self.config.cosigner_url.clone(),
            polynode_key: self.config.polynode_key.clone(),
            fallback_direct: self.config.fallback_direct,
            builder_credentials: self.config.builder_credentials.clone(),
        }
    }

    // ── Onboarding ──

    /// One-call onboarding: derive addresses, deploy Safe if needed,
    /// set approvals if needed, create/derive CLOB credentials.
    pub async fn ensure_ready(
        &mut self,
        signer: Box<dyn TradingSigner>,
        opts: Option<EnsureReadyOpts>,
    ) -> Result<ReadyStatus> {
        let eoa = signer.address();
        let mut actions = Vec::new();

        // Detect or use explicit signature type
        let (sig_type, funder_address) = if let Some(ref o) = opts {
            if let Some(t) = o.signature_type {
                (t, derive_funder_address(eoa, t))
            } else {
                let (t, f) = detect_wallet_type(eoa).await?;
                actions.push(format!("auto_detected_type_{}", t.as_u8()));
                (t, f)
            }
        } else {
            let (t, f) = detect_wallet_type(eoa).await?;
            actions.push(format!("auto_detected_type_{}", t.as_u8()));
            (t, f)
        };

        // Check existing credentials
        let db = self.get_db_mut()?;
        let existing = db.get_credentials(&format!("{}", eoa))?;
        let mut safe_deployed = existing.as_ref().map(|c| c.safe_deployed).unwrap_or(false);
        let mut approvals_set = existing.as_ref().map(|c| c.approvals_set).unwrap_or(false);

        // For Safe wallets: check deployment
        if sig_type == SignatureType::PolyGnosisSafe && !safe_deployed {
            let deployed = is_safe_deployed(funder_address).await.unwrap_or(false);
            if deployed {
                safe_deployed = true;
                actions.push("safe_already_deployed".into());
            } else {
                actions.push("safe_needs_deployment".into());
                // Note: Safe deployment requires the cosigner/relayer integration.
                // For now, mark as needing deployment — users can deploy via the TS SDK
                // or a separate deployment step.
            }
        }

        // Check approvals
        if !approvals_set {
            match onboarding::check_approvals(funder_address, &self.config.rpc_url, self.config.exchange_version).await {
                Ok(status) => {
                    if status.all_approved {
                        approvals_set = true;
                        actions.push("approvals_already_set".into());
                    } else {
                        actions.push("approvals_missing".into());
                    }
                }
                Err(_) => {
                    actions.push("approval_check_failed".into());
                }
            }
        }

        // Create/derive CLOB credentials
        let creds = if let Some(ref existing) = existing {
            actions.push("credentials_loaded".into());
            ClobCredentials {
                api_key: existing.api_key.clone(),
                api_secret: existing.api_secret.clone(),
                api_passphrase: existing.api_passphrase.clone(),
            }
        } else {
            let creds = create_clob_credentials(&*signer, funder_address, sig_type).await?;
            actions.push("credentials_created".into());
            creds
        };

        // Store credentials
        let now = std::time::SystemTime::now()
            .duration_since(std::time::UNIX_EPOCH)
            .unwrap()
            .as_secs_f64();

        let db = self.get_db_mut()?;
        db.upsert_credentials(&StoredCredentials {
            wallet_address: format!("{}", eoa),
            funder_address: Some(format!("{}", funder_address)),
            api_key: creds.api_key.clone(),
            api_secret: creds.api_secret.clone(),
            api_passphrase: creds.api_passphrase.clone(),
            signature_type: sig_type,
            safe_deployed,
            approvals_set,
            created_at: existing.as_ref().map(|c| c.created_at).unwrap_or(now),
            updated_at: now,
        })?;

        self.active_wallet = Some(format!("{}", eoa));
        self.active_signer = Some(signer);

        Ok(ReadyStatus {
            wallet: format!("{}", eoa),
            funder_address: format!("{}", funder_address),
            signature_type: sig_type,
            safe_deployed,
            approvals_set,
            credentials_stored: true,
            credentials: creds,
            actions,
        })
    }

    /// Link a wallet manually (derive credentials, store locally).
    pub async fn link_wallet(
        &mut self,
        signer: Box<dyn TradingSigner>,
        opts: Option<LinkOpts>,
    ) -> Result<LinkResult> {
        let eoa = signer.address();
        let sig_type = opts
            .as_ref()
            .and_then(|o| o.signature_type)
            .unwrap_or(self.config.default_signature_type);
        let funder_address = derive_funder_address(eoa, sig_type);

        let db = self.get_db_mut()?;
        let existing = db.get_credentials(&format!("{}", eoa))?;

        let creds = if let Some(ref ex) = existing {
            ClobCredentials {
                api_key: ex.api_key.clone(),
                api_secret: ex.api_secret.clone(),
                api_passphrase: ex.api_passphrase.clone(),
            }
        } else {
            create_clob_credentials(&*signer, funder_address, sig_type).await?
        };

        let now = std::time::SystemTime::now()
            .duration_since(std::time::UNIX_EPOCH)
            .unwrap()
            .as_secs_f64();

        let db = self.get_db_mut()?;
        db.upsert_credentials(&StoredCredentials {
            wallet_address: format!("{}", eoa),
            funder_address: Some(format!("{}", funder_address)),
            api_key: creds.api_key.clone(),
            api_secret: creds.api_secret.clone(),
            api_passphrase: creds.api_passphrase.clone(),
            signature_type: sig_type,
            safe_deployed: existing.as_ref().map(|c| c.safe_deployed).unwrap_or(false),
            approvals_set: existing.as_ref().map(|c| c.approvals_set).unwrap_or(false),
            created_at: existing.as_ref().map(|c| c.created_at).unwrap_or(now),
            updated_at: now,
        })?;

        self.active_wallet = Some(format!("{}", eoa));
        self.active_signer = Some(signer);

        Ok(LinkResult {
            wallet: format!("{}", eoa),
            funder_address: format!("{}", funder_address),
            signature_type: sig_type,
            credentials: creds,
        })
    }

    /// Import existing CLOB credentials directly (no signing needed).
    pub fn link_credentials(&mut self, opts: LinkCredentialsOpts) -> Result<()> {
        let now = std::time::SystemTime::now()
            .duration_since(std::time::UNIX_EPOCH)
            .unwrap()
            .as_secs_f64();

        let db = self.get_db_mut()?;
        db.upsert_credentials(&StoredCredentials {
            wallet_address: opts.wallet.clone(),
            funder_address: opts.funder_address,
            api_key: opts.api_key,
            api_secret: opts.api_secret,
            api_passphrase: opts.api_passphrase,
            signature_type: opts.signature_type.unwrap_or(SignatureType::Eoa),
            safe_deployed: true,
            approvals_set: true,
            created_at: now,
            updated_at: now,
        })?;
        self.active_wallet = Some(opts.wallet);
        Ok(())
    }

    /// Get all linked wallets.
    pub fn get_linked_wallets(&mut self) -> Result<Vec<WalletInfo>> {
        let db = self.get_db_mut()?;
        let creds = db.get_all_credentials()?;
        Ok(creds
            .into_iter()
            .map(|c| WalletInfo {
                wallet: c.wallet_address.clone(),
                funder_address: c.funder_address.unwrap_or(c.wallet_address),
                signature_type: c.signature_type,
                credentials: ClobCredentials {
                    api_key: c.api_key,
                    api_secret: c.api_secret,
                    api_passphrase: c.api_passphrase,
                },
                created_at: c.created_at,
            })
            .collect())
    }

    // ── Export / Backup ──

    /// Export a wallet's full state for backup.
    pub fn export_wallet(&mut self, wallet: Option<&str>) -> Result<Option<WalletExport>> {
        let addr = wallet
            .map(String::from)
            .or_else(|| self.active_wallet.clone())
            .ok_or_else(|| Error::Trading("No wallet specified".into()))?;
        let db = self.get_db_mut()?;
        let creds = db.get_credentials(&addr)?;
        Ok(creds.map(|c| WalletExport {
            wallet: c.wallet_address.clone(),
            funder_address: c.funder_address.unwrap_or(c.wallet_address),
            signature_type: c.signature_type,
            credentials: ClobCredentials {
                api_key: c.api_key,
                api_secret: c.api_secret,
                api_passphrase: c.api_passphrase,
            },
            safe_deployed: c.safe_deployed,
            approvals_set: c.approvals_set,
            created_at: c.created_at,
        }))
    }

    /// Import a previously exported wallet.
    pub fn import_wallet(&mut self, exported: WalletExport) -> Result<()> {
        let now = std::time::SystemTime::now()
            .duration_since(std::time::UNIX_EPOCH)
            .unwrap()
            .as_secs_f64();
        let db = self.get_db_mut()?;
        db.upsert_credentials(&StoredCredentials {
            wallet_address: exported.wallet,
            funder_address: Some(exported.funder_address),
            api_key: exported.credentials.api_key,
            api_secret: exported.credentials.api_secret,
            api_passphrase: exported.credentials.api_passphrase,
            signature_type: exported.signature_type,
            safe_deployed: exported.safe_deployed,
            approvals_set: exported.approvals_set,
            created_at: exported.created_at,
            updated_at: now,
        })?;
        Ok(())
    }

    // ── Pre-Trade Checks ──

    /// Check on-chain token approvals.
    pub async fn check_approvals(&mut self, wallet: Option<&str>) -> Result<ApprovalStatus> {
        let creds = self.get_stored_creds(wallet)?;
        let funder = creds.funder_address.as_deref().unwrap_or(&creds.wallet_address);
        let addr: Address = funder
            .parse()
            .map_err(|_| Error::Trading(format!("Invalid address: {}", funder)))?;
        onboarding::check_approvals(addr, &self.config.rpc_url, self.config.exchange_version).await
    }

    /// Check collateral (USDC.e for V1, pUSD for V2) and MATIC balances.
    pub async fn check_balance(&mut self, wallet: Option<&str>) -> Result<BalanceInfo> {
        let creds = self.get_stored_creds(wallet)?;
        let funder = creds.funder_address.as_deref().unwrap_or(&creds.wallet_address);
        let addr: Address = funder
            .parse()
            .map_err(|_| Error::Trading(format!("Invalid address: {}", funder)))?;
        onboarding::check_balance(addr, &self.config.rpc_url, self.config.exchange_version).await
    }

    /// Ask the V2 CLOB to refresh its cached balance/allowance view.
    /// Call this after setting/changing on-chain approvals — the V2 CLOB
    /// rejects orders with "not enough balance / allowance" until it has
    /// seen the new state. No-op for V1.
    ///
    /// `asset_type` is "COLLATERAL" (pUSD) or "CONDITIONAL" (CTF tokens).
    pub async fn refresh_balance_allowance(
        &mut self,
        asset_type: &str,
        wallet: Option<&str>,
    ) -> Result<(bool, u16)> {
        if self.config.exchange_version != ExchangeVersion::V2 {
            return Ok((true, 0));
        }
        let creds = self.get_stored_creds(wallet)?;
        let sig_type = creds.signature_type.as_u8();
        let path = "/balance-allowance/update";
        let headers = build_l2_headers(
            &creds.api_key,
            &creds.api_secret,
            &creds.api_passphrase,
            &creds.wallet_address,
            "GET",
            path,          // HMAC over base path only (NO query string)
            None,
        );
        let url = format!(
            "{}{}?asset_type={}&signature_type={}",
            V2_CLOB_HOST, path, asset_type, sig_type
        );
        let mut req = self.http.get(&url);
        for (k, v) in &headers {
            req = req.header(k, v);
        }
        let resp = req.send().await
            .map_err(|e| Error::Trading(format!("refresh_balance_allowance failed: {}", e)))?;
        Ok((resp.status().is_success(), resp.status().as_u16()))
    }

    /// Read the V2 CLOB's current cached view of balance + allowance.
    /// Returns (balance_raw_string, allowances_by_spender) or None for V1.
    pub async fn get_balance_allowance(
        &mut self,
        asset_type: &str,
        wallet: Option<&str>,
    ) -> Result<Option<serde_json::Value>> {
        if self.config.exchange_version != ExchangeVersion::V2 {
            return Ok(None);
        }
        let creds = self.get_stored_creds(wallet)?;
        let sig_type = creds.signature_type.as_u8();
        let path = "/balance-allowance";
        let headers = build_l2_headers(
            &creds.api_key,
            &creds.api_secret,
            &creds.api_passphrase,
            &creds.wallet_address,
            "GET",
            path,
            None,
        );
        let url = format!(
            "{}{}?asset_type={}&signature_type={}",
            V2_CLOB_HOST, path, asset_type, sig_type
        );
        let mut req = self.http.get(&url);
        for (k, v) in &headers {
            req = req.header(k, v);
        }
        let resp = req.send().await
            .map_err(|e| Error::Trading(format!("get_balance_allowance failed: {}", e)))?;
        if !resp.status().is_success() {
            return Ok(None);
        }
        let json: serde_json::Value = resp.json().await
            .map_err(|e| Error::Trading(format!("get_balance_allowance parse: {}", e)))?;
        Ok(Some(json))
    }

    // ── V2 Collateral (wrap/unwrap/balance) ──

    /// Wrap USDC.e into PolyUSD via the Collateral Onramp.
    /// Routes through the Polymarket relayer (gasless) for Safe/Proxy wallets,
    /// and sends directly for EOA wallets.
    /// Amount is in raw units (6 decimals, e.g. 1_000_000 = 1 USDC).
    pub async fn wrap_to_polyusd(&mut self, amount: u64) -> Result<String> {
        let creds = self.get_stored_creds(None)?;
        let signer = self.active_signer.as_ref()
            .ok_or_else(|| Error::Trading("No active signer. Call ensure_ready() first.".into()))?;
        let _eoa = signer.address();
        let funder: Address = creds.funder_address.as_deref().unwrap_or(&creds.wallet_address).parse()
            .map_err(|_| Error::Trading("bad funder address".into()))?;

        let usdc_addr: Address = constants::USDC.parse().unwrap();
        let onramp_addr: Address = constants_v2::COLLATERAL_ONRAMP.parse().unwrap();
        let amount_u256 = alloy_primitives::U256::from(amount);
        let max_u256 = alloy_primitives::U256::MAX;

        let approve_data = onboarding::encode_approve(onramp_addr, max_u256);
        let wrap_data = onboarding::encode_wrap(usdc_addr, funder, amount_u256);

        // Safe / Proxy wallets → relayer path
        if matches!(creds.signature_type, SignatureType::PolyGnosisSafe | SignatureType::PolyProxy) {
            let bc = self.config.builder_credentials.clone().ok_or_else(|| {
                Error::Trading(
                    "wrap_to_polyusd on a Safe/Proxy wallet requires builder_credentials in \
                     TraderConfig. Pass your Polymarket builder key/secret/passphrase.".into()
                )
            })?;
            let rc = relayer::RelayClient::new(bc);
            let txns = vec![
                relayer::SafeSubTx { to: usdc_addr, value: alloy_primitives::U256::ZERO, data: approve_data, operation: 0 },
                relayer::SafeSubTx { to: onramp_addr, value: alloy_primitives::U256::ZERO, data: wrap_data, operation: 0 },
            ];
            return rc.execute_safe(signer.as_ref(), txns).await;
        }

        // EOA path: direct send
        let rpc_url = &self.config.rpc_url;
        let client = &self.http;
        let tx1 = self.send_raw_tx(signer.as_ref(), client, rpc_url, usdc_addr, alloy_primitives::U256::ZERO, &approve_data).await?;
        tracing::info!("USDC.e approve tx: {}", tx1);
        self.send_raw_tx(signer.as_ref(), client, rpc_url, onramp_addr, alloy_primitives::U256::ZERO, &wrap_data).await
    }

    /// Unwrap PolyUSD back to USDC.e via the Collateral Offramp.
    /// Routes through the Polymarket relayer (gasless) for Safe/Proxy wallets,
    /// and sends directly for EOA wallets.
    /// Amount is in raw units (6 decimals, e.g. 1_000_000 = 1 USDC).
    pub async fn unwrap_from_polyusd(&mut self, amount: u64) -> Result<String> {
        let creds = self.get_stored_creds(None)?;
        let signer = self.active_signer.as_ref()
            .ok_or_else(|| Error::Trading("No active signer. Call ensure_ready() first.".into()))?;
        let _eoa = signer.address();
        let funder: Address = creds.funder_address.as_deref().unwrap_or(&creds.wallet_address).parse()
            .map_err(|_| Error::Trading("bad funder address".into()))?;

        let usdc_addr: Address = constants::USDC.parse().unwrap();
        let polyusd_addr: Address = constants_v2::POLY_USD.parse().unwrap();
        let offramp_addr: Address = constants_v2::COLLATERAL_OFFRAMP.parse().unwrap();
        let amount_u256 = alloy_primitives::U256::from(amount);
        let max_u256 = alloy_primitives::U256::MAX;

        let approve_data = onboarding::encode_approve(offramp_addr, max_u256);
        let unwrap_data = onboarding::encode_unwrap(usdc_addr, funder, amount_u256);

        // Safe / Proxy wallets → relayer path
        if matches!(creds.signature_type, SignatureType::PolyGnosisSafe | SignatureType::PolyProxy) {
            let bc = self.config.builder_credentials.clone().ok_or_else(|| {
                Error::Trading(
                    "unwrap_from_polyusd on a Safe/Proxy wallet requires builder_credentials in \
                     TraderConfig. Pass your Polymarket builder key/secret/passphrase.".into()
                )
            })?;
            // Check allowance first — skip redundant approve
            let client = reqwest::Client::new();
            let allowance = onboarding::eth_call_u256(
                &client, &self.config.rpc_url, polyusd_addr,
                onboarding::encode_allowance(funder, offramp_addr),
            ).await.unwrap_or(alloy_primitives::U256::ZERO);
            let rc = relayer::RelayClient::new(bc);
            let mut txns = Vec::new();
            if allowance < amount_u256 {
                txns.push(relayer::SafeSubTx { to: polyusd_addr, value: alloy_primitives::U256::ZERO, data: approve_data, operation: 0 });
            }
            txns.push(relayer::SafeSubTx { to: offramp_addr, value: alloy_primitives::U256::ZERO, data: unwrap_data, operation: 0 });
            return rc.execute_safe(signer.as_ref(), txns).await;
        }

        // EOA path: direct send
        let rpc_url = &self.config.rpc_url;
        let client = &self.http;
        let tx1 = self.send_raw_tx(signer.as_ref(), client, rpc_url, polyusd_addr, alloy_primitives::U256::ZERO, &approve_data).await?;
        tracing::info!("PolyUSD approve tx: {}", tx1);
        self.send_raw_tx(signer.as_ref(), client, rpc_url, offramp_addr, alloy_primitives::U256::ZERO, &unwrap_data).await
    }

    /// Get PolyUSD balance for the funder address (Safe/Proxy/EOA as configured).
    /// Returns raw units (6 decimals).
    pub async fn get_polyusd_balance(&mut self) -> Result<u64> {
        let creds = self.get_stored_creds(None)?;
        let funder: Address = creds.funder_address.as_deref().unwrap_or(&creds.wallet_address).parse()
            .map_err(|_| Error::Trading("bad funder address".into()))?;
        let polyusd_addr: Address = constants_v2::POLY_USD.parse().unwrap();
        let data = onboarding::encode_balance_of(funder);
        let val = onboarding::eth_call_u256(&self.http, &self.config.rpc_url, polyusd_addr, data).await?;
        Ok(u64::try_from(val).unwrap_or(u64::MAX))
    }

    /// Get USDC.e balance for the funder address (Safe/Proxy/EOA as configured).
    /// Returns raw units (6 decimals).
    pub async fn get_usdce_balance(&mut self) -> Result<u64> {
        let creds = self.get_stored_creds(None)?;
        let funder: Address = creds.funder_address.as_deref().unwrap_or(&creds.wallet_address).parse()
            .map_err(|_| Error::Trading("bad funder address".into()))?;
        let usdc_addr: Address = constants::USDC.parse().unwrap();
        let data = onboarding::encode_balance_of(funder);
        let val = onboarding::eth_call_u256(&self.http, &self.config.rpc_url, usdc_addr, data).await?;
        Ok(u64::try_from(val).unwrap_or(u64::MAX))
    }

    /// Build, sign, and send a legacy transaction on-chain.
    async fn send_raw_tx(
        &self,
        signer: &dyn TradingSigner,
        client: &reqwest::Client,
        rpc_url: &str,
        to: Address,
        value: alloy_primitives::U256,
        data: &[u8],
    ) -> Result<String> {
        let from = signer.address();

        // Fetch nonce and gas price
        let nonce = onboarding::eth_get_transaction_count(client, rpc_url, from).await?;
        let gas_price = onboarding::eth_gas_price(client, rpc_url).await?;
        // Add 20% to gas price for faster inclusion
        let gas_price = gas_price + gas_price / 5;

        // Use a generous gas limit for approve/wrap/unwrap calls
        let gas_limit: u64 = 150_000;

        // Build the unsigned transaction hash (EIP-155)
        let tx_hash = onboarding::build_legacy_tx_hash(nonce, gas_price, gas_limit, to, value, data);

        // Sign the hash
        let signature = signer.sign_hash(&tx_hash).await?;

        // Build the signed raw transaction
        let raw_tx = onboarding::build_legacy_tx_raw(nonce, gas_price, gas_limit, to, value, data, &signature);

        // Send it
        onboarding::eth_send_raw_transaction(client, rpc_url, &raw_tx).await
    }

    // ── Trading ──

    /// Get the CLOB host URL based on the configured exchange version.
    fn get_clob_host(&self) -> &str {
        match self.config.exchange_version {
            ExchangeVersion::V1 => CLOB_HOST,
            ExchangeVersion::V2 => V2_CLOB_HOST,
        }
    }

    /// Place an order on Polymarket.
    pub async fn order(&mut self, params: OrderParams) -> Result<OrderResult> {
        let creds = self.get_stored_creds(None)?;

        // Get signer address before mutable borrow
        let signer_addr = self.active_signer.as_ref()
            .ok_or_else(|| Error::Trading("No active signer. Call ensure_ready() first.".into()))?
            .address();

        // Fetch market metadata
        let meta = self.fetch_meta(&params.token_id).await?;

        // Build the order EIP-712 payload — dispatch by exchange version
        let exchange_version = self.config.exchange_version;
        let order_payload = match exchange_version {
            ExchangeVersion::V1 => build_order_payload(signer_addr, &creds, &params, &meta)?,
            ExchangeVersion::V2 => build_v2_order_payload(signer_addr, &creds, &params, &meta)?,
        };

        let signer = self.active_signer.as_ref()
            .ok_or_else(|| Error::Trading("No active signer".into()))?;
        let signature = signer.sign_typed_data(&order_payload).await?;
        let sig_hex = format!("0x{}", hex::encode(&signature));

        // Build the order JSON body — dispatch by exchange version
        let body = match exchange_version {
            ExchangeVersion::V1 => build_order_body(&params, &order_payload, &sig_hex, &creds.api_key, &creds, &meta)?,
            ExchangeVersion::V2 => build_v2_order_body(&params, &order_payload, &sig_hex, &creds.api_key, &creds)?,
        };
        let body_str = serde_json::to_string(&body)
            .map_err(|e| Error::Trading(format!("Failed to serialize order: {}", e)))?;

        // Build L2 headers
        let headers = build_l2_headers(
            &creds.api_key,
            &creds.api_secret,
            &creds.api_passphrase,
            &creds.wallet_address,
            "POST",
            "/order",
            Some(&body_str),
        );

        // Log locally
        let now = std::time::SystemTime::now()
            .duration_since(std::time::UNIX_EPOCH)
            .unwrap()
            .as_secs_f64();

        let db = self.get_db_mut()?;
        let local_id = db.insert_order(&creds.wallet_address, &OrderHistoryInsert {
            order_id: None,
            token_id: params.token_id.clone(),
            side: params.side.to_string(),
            price: params.price,
            size: params.size,
            order_type: params.order_type.to_string(),
            status: "submitting".into(),
            error_msg: None,
            response_json: None,
            created_at: now,
            fee_amount_raw: None,
            escrow_order_id: None,
            fee_escrow_tx_hash: None,
        })?;

        // Build fee auth if escrow is enabled
        let fee_config = params.fee_config.as_ref().or(self.config.fee_config.as_ref());
        let mut fee_auth_req: Option<FeeAuthRequest> = None;
        let mut fee_amount_raw: u64 = 0;

        if let Some(fc) = fee_config {
            if fc.fee_bps > 0 {
                let aff = fc.affiliate.as_deref().unwrap_or("");
                if aff.is_empty() || aff == "0x0000000000000000000000000000000000000000" {
                    return Err(Error::Trading("fee_config.affiliate is required when fee_bps > 0 — set it to the wallet address where you want fees sent".into()));
                }
                fee_amount_raw = escrow::calculate_fee(params.price, params.size, fc.fee_bps);
                if fee_amount_raw > 0 {
                    let funder = creds.funder_address.as_deref().unwrap_or(&creds.wallet_address);
                    let escrow_addr = escrow::fee_escrow_address_for(self.config.exchange_version);
                    let nonce = escrow::fetch_escrow_nonce(
                        &self.config.rpc_url,
                        &format!("{}", signer_addr),
                        escrow_addr,
                    ).await?;
                    let deadline = std::time::SystemTime::now()
                        .duration_since(std::time::UNIX_EPOCH)
                        .unwrap()
                        .as_secs() + 300;
                    let escrow_oid = escrow::generate_escrow_order_id();

                    let signer_ref = self.active_signer.as_ref()
                        .ok_or_else(|| Error::Trading("No active signer".into()))?;

                    fee_auth_req = Some(escrow::sign_fee_auth(
                        signer_ref.as_ref(),
                        &escrow_oid,
                        funder,
                        fee_amount_raw,
                        deadline,
                        nonce,
                        fc.affiliate.as_deref(),
                        fc.affiliate_share_bps,
                        self.config.exchange_version,
                    ).await?);
                }
            }
        }

        // Submit via co-signer
        let result = send_via_cosigner(
            &self.cosigner_config(),
            &CosignerRequest {
                method: "POST".into(),
                path: "/order".into(),
                body: Some(body_str),
                headers,
                builder_credentials: self.config.builder_credentials.clone(),
                fee_auth: fee_auth_req.clone(),
                clob_host: Some(self.get_clob_host().to_string()),
            },
        ).await?;

        // Update local record
        let order_id = result.get("orderID")
            .or_else(|| result.get("orderId"))
            .and_then(|v| v.as_str())
            .map(String::from);
        let success = order_id.is_some() || result.get("success").and_then(|v| v.as_bool()).unwrap_or(false);
        let error = result.get("error")
            .or_else(|| result.get("errorMsg"))
            .and_then(|v| v.as_str())
            .map(String::from);

        let db = self.get_db_mut()?;
        let fee_tx = result.get("feeEscrowTxHash").and_then(|v| v.as_str());
        db.update_order_status(
            local_id,
            if success { "submitted" } else { "failed" },
            order_id.as_deref(),
            error.as_deref(),
            Some(&result.to_string()),
            fee_auth_req.as_ref().map(|fa| fa.fee_amount.as_str()),
            fee_auth_req.as_ref().map(|fa| fa.escrow_order_id.as_str()),
            fee_tx,
        )?;

        Ok(OrderResult {
            success,
            order_id,
            status: result.get("status").and_then(|v| v.as_str()).map(String::from),
            error,
            making_amount: result.get("makingAmount").and_then(|v| v.as_str()).map(String::from),
            taking_amount: result.get("takingAmount").and_then(|v| v.as_str()).map(String::from),
            fee_escrow_tx_hash: result.get("feeEscrowTxHash").and_then(|v| v.as_str()).map(String::from),
            fee_amount: if fee_amount_raw > 0 { Some(format!("{:.6}", fee_amount_raw as f64 / 1e6)) } else { None },
        })
    }

    /// Cancel an order.
    pub async fn cancel_order(&mut self, order_id: &str) -> Result<CancelResult> {
        let creds = self.get_stored_creds(None)?;
        let body_str = serde_json::to_string(&serde_json::json!({ "orderID": order_id }))
            .map_err(|e| Error::Trading(format!("serialize failed: {}", e)))?;
        let headers = build_l2_headers(
            &creds.api_key, &creds.api_secret, &creds.api_passphrase,
            &creds.wallet_address, "DELETE", "/order", Some(&body_str),
        );

        let result = send_via_cosigner(&self.cosigner_config(), &CosignerRequest {
            method: "DELETE".into(),
            path: "/order".into(),
            body: Some(body_str),
            headers,
            builder_credentials: self.config.builder_credentials.clone(),
            fee_auth: None,
            clob_host: Some(self.get_clob_host().to_string()),
        }).await?;

        Ok(CancelResult {
            canceled: result.get("canceled")
                .and_then(|v| v.as_array())
                .map(|a| a.iter().filter_map(|v| v.as_str().map(String::from)).collect())
                .unwrap_or_default(),
            not_canceled: result.get("not_canceled")
                .and_then(|v| serde_json::from_value(v.clone()).ok())
                .unwrap_or_default(),
        })
    }

    /// Cancel all orders, optionally for a specific market.
    pub async fn cancel_all(&mut self, market: Option<&str>) -> Result<CancelResult> {
        let creds = self.get_stored_creds(None)?;
        let path = if market.is_some() { "/cancel-market-orders" } else { "/cancel-all" };
        let body = market.map(|m| serde_json::json!({ "market": m }).to_string());
        let headers = build_l2_headers(
            &creds.api_key, &creds.api_secret, &creds.api_passphrase,
            &creds.wallet_address, "DELETE", path, body.as_deref(),
        );

        let result = send_via_cosigner(&self.cosigner_config(), &CosignerRequest {
            method: "DELETE".into(),
            path: path.into(),
            body,
            headers,
            builder_credentials: self.config.builder_credentials.clone(),
            fee_auth: None,
            clob_host: Some(self.get_clob_host().to_string()),
        }).await?;

        Ok(CancelResult {
            canceled: result.get("canceled")
                .and_then(|v| v.as_array())
                .map(|a| a.iter().filter_map(|v| v.as_str().map(String::from)).collect())
                .unwrap_or_default(),
            not_canceled: result.get("not_canceled")
                .and_then(|v| serde_json::from_value(v.clone()).ok())
                .unwrap_or_default(),
        })
    }

    /// Get open orders from Polymarket CLOB.
    pub async fn get_open_orders(&mut self, market: Option<&str>) -> Result<Vec<OpenOrder>> {
        let creds = self.get_stored_creds(None)?;
        let mut path = "/data/orders".to_string();
        if let Some(m) = market {
            path = format!("{}?market={}", path, m);
        }
        let headers = build_l2_headers(
            &creds.api_key, &creds.api_secret, &creds.api_passphrase,
            &creds.wallet_address, "GET", &path, None,
        );

        let result = send_via_cosigner(&self.cosigner_config(), &CosignerRequest {
            method: "GET".into(),
            path,
            body: None,
            headers,
            builder_credentials: self.config.builder_credentials.clone(),
            fee_auth: None,
            clob_host: Some(self.get_clob_host().to_string()),
        }).await?;

        let orders: Vec<OpenOrder> = if result.is_array() {
            serde_json::from_value(result).unwrap_or_default()
        } else {
            result.get("data")
                .or_else(|| result.get("orders"))
                .and_then(|v| serde_json::from_value(v.clone()).ok())
                .unwrap_or_default()
        };
        Ok(orders)
    }

    // ── History ──

    /// Get local order history.
    pub fn get_order_history(&mut self, params: Option<HistoryParams>) -> Result<Vec<OrderHistoryRow>> {
        let wallet = self.active_wallet.as_ref()
            .ok_or_else(|| Error::Trading("No active wallet".into()))?
            .clone();
        let db = self.get_db_mut()?;
        db.get_order_history(&wallet, &params.unwrap_or_default())
    }

    // ── Position Management (split/merge/convert) ──

    /// Build a split transaction: USDC → YES + NO outcome tokens.
    /// Returns a [`TransactionRequest`] to submit via the Polymarket relayer or on-chain.
    ///
    /// For gasless execution via the relayer, use the TypeScript SDK's `trader.split()`.
    pub fn split(&self, params: types::SplitParams) -> Result<types::TransactionRequest> {
        // TODO: auto-detect neg_risk from metadata lookup
        // For now, default to neg-risk (most multi-outcome markets)
        Ok(position_management::build_split_txn(&params.condition_id, params.amount, true))
    }

    /// Build a merge transaction: YES + NO outcome tokens → USDC.
    /// Returns a [`TransactionRequest`] to submit via the Polymarket relayer or on-chain.
    pub fn merge(&self, params: types::MergeParams) -> Result<types::TransactionRequest> {
        Ok(position_management::build_merge_txn(&params.condition_id, params.amount, true))
    }

    /// Build a convert transaction: NO positions → USDC + YES on complementary outcomes.
    /// Only works on neg-risk multi-outcome markets.
    /// Returns a [`TransactionRequest`] to submit via the Polymarket relayer or on-chain.
    pub fn convert(&self, params: types::ConvertParams) -> Result<types::TransactionRequest> {
        Ok(position_management::build_convert_txn(
            &params.market_id,
            &params.outcome_indices,
            params.amount,
        ))
    }

    // ── Lifecycle ──

    /// Close the trader and release resources.
    pub fn close(&mut self) {
        if let Some(db) = self.db.take() {
            db.close();
        }
        self.active_signer = None;
        self.active_wallet = None;
    }

    // ── Internal ──

    fn get_stored_creds(&mut self, wallet: Option<&str>) -> Result<StoredCredentials> {
        let addr = wallet
            .map(String::from)
            .or_else(|| self.active_wallet.clone())
            .ok_or_else(|| Error::Trading("No active wallet. Call ensure_ready() first.".into()))?;
        let db = self.get_db_mut()?;
        db.get_credentials(&addr)?
            .ok_or_else(|| Error::Trading(format!("No credentials for {}. Call ensure_ready() first.", addr)))
    }

    async fn fetch_meta(&mut self, token_id: &str) -> Result<MarketMeta> {
        let db = self.get_db_mut()?;
        if let Some(cached) = db.get_market_meta(token_id)? {
            // Check TTL
            let now = std::time::SystemTime::now()
                .duration_since(std::time::UNIX_EPOCH)
                .unwrap()
                .as_secs_f64();
            if now - cached.fetched_at < constants::META_TTL_SECONDS {
                return Ok(cached);
            }
        }

        // Fetch tick size and neg_risk from CLOB (use version-appropriate host)
        let clob_host = self.get_clob_host();
        let tick_resp: serde_json::Value = self.http
            .get(format!("{}/tick-size?token_id={}", clob_host, token_id))
            .send().await?
            .json().await?;
        let neg_resp: serde_json::Value = self.http
            .get(format!("{}/neg-risk?token_id={}", clob_host, token_id))
            .send().await?
            .json().await?;

        // Fetch fee rate: get condition_id from book, then market details
        let mut fee_rate_bps: i32 = 0;
        let book_resp: serde_json::Value = self.http
            .get(format!("{}/book?token_id={}", clob_host, token_id))
            .send().await?
            .json().await?;
        if let Some(condition_id) = book_resp.get("market").and_then(|v| v.as_str()) {
            if let Ok(market_resp) = self.http
                .get(format!("{}/markets/{}", clob_host, condition_id))
                .send().await
            {
                if let Ok(market_data) = market_resp.json::<serde_json::Value>().await {
                    fee_rate_bps = market_data
                        .get("maker_base_fee")
                        .and_then(|v| v.as_i64())
                        .unwrap_or(0) as i32;
                }
            }
        }

        let now = std::time::SystemTime::now()
            .duration_since(std::time::UNIX_EPOCH)
            .unwrap()
            .as_secs_f64();

        let meta = MarketMeta {
            token_id: token_id.into(),
            tick_size: tick_resp.get("minimum_tick_size")
                .and_then(|v| v.as_f64())
                .map(|v| v.to_string())
                .or_else(|| tick_resp.as_str().map(|s| s.to_string()))
                .unwrap_or_else(|| "0.01".to_string()),
            fee_rate_bps,
            neg_risk: neg_resp.get("neg_risk")
                .and_then(|v| v.as_bool())
                .unwrap_or(false),
            fetched_at: now,
        };

        let db = self.get_db_mut()?;
        db.upsert_market_meta(&meta)?;
        Ok(meta)
    }
}

// ── Options structs ──

#[derive(Debug, Clone, Default)]
pub struct EnsureReadyOpts {
    pub signature_type: Option<SignatureType>,
}

#[derive(Debug, Clone, Default)]
pub struct LinkOpts {
    pub signature_type: Option<SignatureType>,
}

#[derive(Debug, Clone)]
pub struct LinkCredentialsOpts {
    pub wallet: String,
    pub api_key: String,
    pub api_secret: String,
    pub api_passphrase: String,
    pub signature_type: Option<SignatureType>,
    pub funder_address: Option<String>,
}

// ── Order Building ──

fn build_order_payload(
    signer_address: Address,
    creds: &StoredCredentials,
    params: &OrderParams,
    meta: &MarketMeta,
) -> Result<Eip712Payload> {
    // Determine which exchange to use based on neg_risk
    let exchange = if meta.neg_risk { NEG_RISK_CTF_EXCHANGE } else { CTF_EXCHANGE };

    // Convert price and size to raw amounts using tick-size-based rounding
    // (matches TS SDK's ROUNDING_CONFIG + getOrderRawAmounts)
    let tick_size_str = meta.tick_size.as_str();
    let rc = match tick_size_str {
        "0.1"    => RoundingConfig { price: 1, size: 2, amount: 3 },
        "0.001"  => RoundingConfig { price: 3, size: 2, amount: 5 },
        "0.0001" => RoundingConfig { price: 4, size: 2, amount: 6 },
        _        => RoundingConfig { price: 2, size: 2, amount: 4 }, // "0.01" default
    };

    let raw_price = round_normal(params.price, rc.price);
    let side_num: u8;
    let making_amount: u64;
    let taking_amount: u64;

    match params.side {
        OrderSide::Buy => {
            side_num = 0;
            let raw_taker = round_down(params.size, rc.size);
            let mut raw_maker = raw_taker * raw_price;
            if decimal_places(raw_maker) > rc.amount {
                raw_maker = round_up(raw_maker, rc.amount + 4);
                if decimal_places(raw_maker) > rc.amount {
                    raw_maker = round_down(raw_maker, rc.amount);
                }
            }
            // parseUnits(x, 6) — `.round() as u64` avoids the float-truncation bug
            // where e.g. 0.43 * 4 = 1.7199999... cast to u64 yields 1719999, not 1720000.
            making_amount = (raw_maker * 1_000_000.0).round() as u64;
            taking_amount = (raw_taker * 1_000_000.0).round() as u64;
        }
        OrderSide::Sell => {
            side_num = 1;
            let raw_maker = round_down(params.size, rc.size);
            let mut raw_taker = raw_maker * raw_price;
            if decimal_places(raw_taker) > rc.amount {
                raw_taker = round_up(raw_taker, rc.amount + 4);
                if decimal_places(raw_taker) > rc.amount {
                    raw_taker = round_down(raw_taker, rc.amount);
                }
            }
            making_amount = (raw_maker * 1_000_000.0).round() as u64;
            taking_amount = (raw_taker * 1_000_000.0).round() as u64;
        }
    }

    let funder = creds.funder_address.as_deref().unwrap_or(&creds.wallet_address);
    // Polymarket CLOB requires GTD expiration >= now + 1 minute (security threshold).
    // Automatically add the 60-second buffer if the user's expiration is too close.
    let expiration = match params.expiration {
        Some(exp) => {
            let now = std::time::SystemTime::now()
                .duration_since(std::time::UNIX_EPOCH)
                .unwrap()
                .as_secs();
            if exp > 0 && exp < now + 90 {
                // Too close to now — add the 60-second security threshold
                exp + 60
            } else {
                exp
            }
        }
        None => 0,
    };
    // Salt must fit in u32 range (Python SDK uses randbelow(2**32), TS uses random u32)
    let nonce: u64 = (rand::random::<u32>()) as u64;

    let domain = serde_json::json!({
        "name": "Polymarket CTF Exchange",
        "version": "1",
        "chainId": CHAIN_ID,
        "verifyingContract": exchange,
    });

    let types = serde_json::json!({
        "EIP712Domain": [
            {"name": "name", "type": "string"},
            {"name": "version", "type": "string"},
            {"name": "chainId", "type": "uint256"},
            {"name": "verifyingContract", "type": "address"}
        ],
        "Order": [
            {"name": "salt", "type": "uint256"},
            {"name": "maker", "type": "address"},
            {"name": "signer", "type": "address"},
            {"name": "taker", "type": "address"},
            {"name": "tokenId", "type": "uint256"},
            {"name": "makerAmount", "type": "uint256"},
            {"name": "takerAmount", "type": "uint256"},
            {"name": "expiration", "type": "uint256"},
            {"name": "nonce", "type": "uint256"},
            {"name": "feeRateBps", "type": "uint256"},
            {"name": "side", "type": "uint8"},
            {"name": "signatureType", "type": "uint8"}
        ]
    });

    let message = serde_json::json!({
        "salt": nonce.to_string(),
        "maker": funder,
        "signer": format!("{}", signer_address),
        "taker": "0x0000000000000000000000000000000000000000",
        "tokenId": params.token_id,
        "makerAmount": making_amount.to_string(),
        "takerAmount": taking_amount.to_string(),
        "expiration": expiration.to_string(),
        "nonce": "0",
        "feeRateBps": meta.fee_rate_bps.to_string(),
        "side": side_num.to_string(),
        "signatureType": creds.signature_type.as_u8().to_string(),
    });

    Ok(Eip712Payload {
        domain,
        types,
        primary_type: "Order".into(),
        message,
    })
}

fn build_order_body(
    params: &OrderParams,
    payload: &Eip712Payload,
    signature: &str,
    funder: &str,
    creds: &StoredCredentials,
    _meta: &MarketMeta,
) -> Result<serde_json::Value> {
    let order_type = params.order_type.to_string();

    // The CLOB expects specific types in the order JSON body:
    // - salt: number (parsed from string)
    // - side: "BUY" or "SELL" (not numeric)
    // - signatureType: number (not string)
    // The EIP-712 message uses string representations, but the body format differs.
    let salt: u64 = payload.message["salt"].as_str()
        .and_then(|s| s.parse().ok())
        .unwrap_or(0);

    let side_str = match params.side {
        OrderSide::Buy => "BUY",
        OrderSide::Sell => "SELL",
    };

    let sig_type = creds.signature_type.as_u8();

    let mut body = serde_json::json!({
        "order": {
            "salt": salt,
            "maker": payload.message["maker"],
            "signer": payload.message["signer"],
            "taker": payload.message["taker"],
            "tokenId": payload.message["tokenId"],
            "makerAmount": payload.message["makerAmount"],
            "takerAmount": payload.message["takerAmount"],
            "expiration": payload.message["expiration"],
            "nonce": payload.message["nonce"],
            "feeRateBps": payload.message["feeRateBps"],
            "side": side_str,
            "signatureType": sig_type,
            "signature": signature,
        },
        "owner": funder,
        "orderType": order_type,
        "deferExec": false,
    });

    if params.post_only {
        body["postOnly"] = serde_json::Value::Bool(true);
    }

    Ok(body)
}

// ── V2 Order Building ──

fn build_v2_order_payload(
    signer_address: Address,
    creds: &StoredCredentials,
    params: &OrderParams,
    meta: &MarketMeta,
) -> Result<Eip712Payload> {
    // V2 exchange selection: CTF_EXCHANGE for normal, NEG_RISK_EXCHANGE_A for neg_risk
    let exchange = if meta.neg_risk { V2_NEG_RISK_EXCHANGE_A } else { V2_CTF_EXCHANGE };

    // Same rounding logic as V1
    let tick_size_str = meta.tick_size.as_str();
    let rc = match tick_size_str {
        "0.1"    => RoundingConfig { price: 1, size: 2, amount: 3 },
        "0.001"  => RoundingConfig { price: 3, size: 2, amount: 5 },
        "0.0001" => RoundingConfig { price: 4, size: 2, amount: 6 },
        _        => RoundingConfig { price: 2, size: 2, amount: 4 }, // "0.01" default
    };

    let raw_price = round_normal(params.price, rc.price);
    let side_num: u8;
    let making_amount: u64;
    let taking_amount: u64;

    match params.side {
        OrderSide::Buy => {
            side_num = 0;
            let raw_taker = round_down(params.size, rc.size);
            let mut raw_maker = raw_taker * raw_price;
            if decimal_places(raw_maker) > rc.amount {
                raw_maker = round_up(raw_maker, rc.amount + 4);
                if decimal_places(raw_maker) > rc.amount {
                    raw_maker = round_down(raw_maker, rc.amount);
                }
            }
            // `.round() as u64` — float->int cast truncates toward zero; `.round()` avoids the
            // 0.43 * 4 = 1.7199999...  →  1719999 bug that breaks V2 CLOB amount validation.
            making_amount = (raw_maker * 1_000_000.0).round() as u64;
            taking_amount = (raw_taker * 1_000_000.0).round() as u64;
        }
        OrderSide::Sell => {
            side_num = 1;
            let raw_maker = round_down(params.size, rc.size);
            let mut raw_taker = raw_maker * raw_price;
            if decimal_places(raw_taker) > rc.amount {
                raw_taker = round_up(raw_taker, rc.amount + 4);
                if decimal_places(raw_taker) > rc.amount {
                    raw_taker = round_down(raw_taker, rc.amount);
                }
            }
            making_amount = (raw_maker * 1_000_000.0).round() as u64;
            taking_amount = (raw_taker * 1_000_000.0).round() as u64;
        }
    }

    let funder = creds.funder_address.as_deref().unwrap_or(&creds.wallet_address);

    // V2 uses timestamp in milliseconds (not salt from random u32)
    let timestamp_ms = std::time::SystemTime::now()
        .duration_since(std::time::UNIX_EPOCH)
        .unwrap()
        .as_millis() as u64;

    // V2 salt = timestamp in ms (matching verified working order format)
    let salt = timestamp_ms;

    // V2 metadata defaults to zero bytes32; builder optionally supplied by caller.
    let zero_bytes32 = "0x0000000000000000000000000000000000000000000000000000000000000000";
    let builder_hex = params.builder.as_deref().unwrap_or(zero_bytes32);

    let domain = serde_json::json!({
        "name": V2_DOMAIN_NAME,
        "version": V2_DOMAIN_VERSION,
        "chainId": CHAIN_ID,
        "verifyingContract": exchange,
    });

    let types = serde_json::json!({
        "EIP712Domain": [
            {"name": "name", "type": "string"},
            {"name": "version", "type": "string"},
            {"name": "chainId", "type": "uint256"},
            {"name": "verifyingContract", "type": "address"}
        ],
        "Order": [
            {"name": "salt", "type": "uint256"},
            {"name": "maker", "type": "address"},
            {"name": "signer", "type": "address"},
            {"name": "tokenId", "type": "uint256"},
            {"name": "makerAmount", "type": "uint256"},
            {"name": "takerAmount", "type": "uint256"},
            {"name": "side", "type": "uint8"},
            {"name": "signatureType", "type": "uint8"},
            {"name": "timestamp", "type": "uint256"},
            {"name": "metadata", "type": "bytes32"},
            {"name": "builder", "type": "bytes32"}
        ]
    });

    let message = serde_json::json!({
        "salt": salt.to_string(),
        "maker": funder,
        "signer": format!("{}", signer_address),
        "tokenId": params.token_id,
        "makerAmount": making_amount.to_string(),
        "takerAmount": taking_amount.to_string(),
        "side": side_num.to_string(),
        "signatureType": creds.signature_type.as_u8().to_string(),
        "timestamp": timestamp_ms.to_string(),
        "metadata": zero_bytes32,
        "builder": builder_hex,
    });

    Ok(Eip712Payload {
        domain,
        types,
        primary_type: "Order".into(),
        message,
    })
}

fn build_v2_order_body(
    params: &OrderParams,
    payload: &Eip712Payload,
    signature: &str,
    owner: &str,
    creds: &StoredCredentials,
) -> Result<serde_json::Value> {
    let order_type = params.order_type.to_string();

    // V2 CLOB body format (matches @polymarket/clob-client-v2):
    // - salt: NUMBER (not string)
    // - side: "BUY"/"SELL" string
    // - signatureType: NUMBER
    // - tokenId: string
    // - makerAmount/takerAmount: string
    // - timestamp: string (ms since epoch)
    // - expiration: string ("0" = no expiration)
    // - metadata/builder: bytes32 hex string
    // - NO taker, nonce, feeRateBps fields (OrderV2 type drops them)

    let salt: u64 = payload.message["salt"].as_str()
        .and_then(|s| s.parse().ok())
        .unwrap_or(0);

    let side_str = match params.side {
        OrderSide::Buy => "BUY",
        OrderSide::Sell => "SELL",
    };

    let sig_type = creds.signature_type.as_u8();

    // V2 CLOB wire format (matches @polymarket/clob-client-v2):
    //   top-level: { order, owner, orderType, postOnly, deferExec }
    //   order:     includes taker = zero address, expiration = "0" (post-sign fields)
    let body = serde_json::json!({
        "order": {
            "salt": salt,
            "maker": payload.message["maker"],
            "signer": payload.message["signer"],
            "taker": "0x0000000000000000000000000000000000000000",
            "tokenId": payload.message["tokenId"],
            "makerAmount": payload.message["makerAmount"],
            "takerAmount": payload.message["takerAmount"],
            "side": side_str,
            "signatureType": sig_type,
            "timestamp": payload.message["timestamp"],
            "expiration": "0",
            "metadata": payload.message["metadata"],
            "builder": payload.message["builder"],
            "signature": signature,
        },
        "owner": owner,
        "orderType": order_type,
        "postOnly": params.post_only,
        "deferExec": false,
    });

    Ok(body)
}

impl Default for OrderParams {
    fn default() -> Self {
        Self {
            token_id: String::new(),
            side: OrderSide::Buy,
            price: 0.0,
            size: 0.0,
            order_type: OrderType::GTC,
            expiration: None,
            post_only: false,
            fee_config: None,
            builder: None,
        }
    }
}

// ── Rounding helpers (ported from TS SDK's ROUNDING_CONFIG + utilities) ──

struct RoundingConfig {
    price: u32,
    size: u32,
    amount: u32,
}

fn decimal_places(num: f64) -> u32 {
    if num.fract() == 0.0 {
        return 0;
    }
    let s = format!("{}", num);
    match s.split_once('.') {
        Some((_, frac)) => frac.len() as u32,
        None => 0,
    }
}

fn round_normal(num: f64, decimals: u32) -> f64 {
    if decimal_places(num) <= decimals {
        return num;
    }
    let factor = 10f64.powi(decimals as i32);
    ((num + f64::EPSILON) * factor).round() / factor
}

fn round_down(num: f64, decimals: u32) -> f64 {
    if decimal_places(num) <= decimals {
        return num;
    }
    let factor = 10f64.powi(decimals as i32);
    (num * factor).floor() / factor
}

fn round_up(num: f64, decimals: u32) -> f64 {
    if decimal_places(num) <= decimals {
        return num;
    }
    let factor = 10f64.powi(decimals as i32);
    (num * factor).ceil() / factor
}