Starknet Substreams Type Glossary

pub struct Block {
    pub block_hash: Vec<u8>,
    pub parent_hash: Vec<u8>,
    pub block_number: u64,
    pub new_root: Vec<u8>,
    pub timestamp: u64,
    pub sequencer_address: Vec<u8>,
    pub l1_gas_price: Option<ResourcePrice>,
    pub l1_data_gas_price: Option<ResourcePrice>,
    pub l1_da_mode: i32,
    pub starknet_version: String,
    pub transactions: Vec<TransactionWithReceipt>,
    pub state_update: Option<StateUpdate>,
}

pub enum L1DaMode {
    Unspecified = 0,    // Default mode when not specified
    Calldata = 1,       // Data posted as calldata on L1 (traditional method)
    Blob = 2,           // Data posted as blob on L1 (EIP-4844)
}

fn analyze_block(block: &Block) -> BlockAnalysis {
    BlockAnalysis {
        timestamp: block.timestamp,
        transaction_count: block.transactions.len(),
        version: block.starknet_version.clone(),
        da_mode: match block.l1_da_mode {
            1 => "Calldata",
            2 => "Blob",
            _ => "Unknown"
        }.to_string(),
        has_state_update: block.state_update.is_some()
    }
}

pub struct ResourcePrice {
    pub price_in_fri: Vec<u8>,
    pub price_in_wei: Vec<u8>,
}

fn calculate_transaction_costs(
    resource_price: &ResourcePrice,
    gas_used: u64
) -> TransactionCosts {
    // Convert bytes to numeric values
    let fri_price = BigInt::from_bytes_be(Sign::Plus, &resource_price.price_in_fri);
    let wei_price = BigInt::from_bytes_be(Sign::Plus, &resource_price.price_in_wei);
    
    TransactionCosts {
        cost_in_fri: fri_price * gas_used,
        cost_in_wei: wei_price * gas_used,
    }
}
 
// Example of price comparison
fn is_price_favorable(
    current: &ResourcePrice,
    threshold: &ResourcePrice
) -> bool {
    let current_wei = BigInt::from_bytes_be(Sign::Plus, &current.price_in_wei);
    let threshold_wei = BigInt::from_bytes_be(Sign::Plus, &threshold.price_in_wei);
    
    current_wei <= threshold_wei
}

// Example of typical resource price structure
let typical_price = ResourcePrice {
    price_in_fri: vec![0, 0, 0, 0, 0, 0, 0, 100],  // 100 FRI
    price_in_wei: vec![0, 0, 0, 0, 0, 0, 1, 0],    // 256 Wei
};
 
// Example of high gas price scenario
let high_price = ResourcePrice {
    price_in_fri: vec![0, 0, 0, 0, 0, 1, 0, 0],    // Higher FRI amount
    price_in_wei: vec![0, 0, 0, 0, 1, 0, 0, 0],    // Higher Wei amount
};

pub struct TransactionWithReceipt {
    pub receipt: Option<TransactionReceipt>,
    pub transaction: Option<transaction_with_receipt::Transaction>,
}
 
pub enum Transaction {
    InvokeTransactionV0(InvokeTransactionV0),
    InvokeTransactionV1(InvokeTransactionV1),
    InvokeTransactionV3(InvokeTransactionV3),
    L1HandlerTransaction(L1HandlerTransaction),
    DeclareTransactionV0(DeclareTransactionV0),
    DeclareTransactionV1(DeclareTransactionV1),
    DeclareTransactionV2(DeclareTransactionV2),
    DeclareTransactionV3(DeclareTransactionV3),
    DeployTransactionV0(DeployTransactionV0),
    DeployAccountTransactionV1(DeployAccountTransactionV1),
    DeployAccountTransactionV3(DeployAccountTransactionV3),
}

fn process_transaction(tx_with_receipt: &TransactionWithReceipt) -> TransactionAnalysis {
    let tx_type = match &tx_with_receipt.transaction {
        Some(tx) => match tx {
            Transaction::InvokeTransactionV0(_) => "Invoke V0",
            Transaction::InvokeTransactionV1(_) => "Invoke V1",
            Transaction::InvokeTransactionV3(_) => "Invoke V3",
            Transaction::L1HandlerTransaction(_) => "L1 Handler",
            Transaction::DeclareTransactionV0(_) => "Declare V0",
            Transaction::DeclareTransactionV1(_) => "Declare V1",
            Transaction::DeclareTransactionV2(_) => "Declare V2",
            Transaction::DeclareTransactionV3(_) => "Declare V3",
            Transaction::DeployTransactionV0(_) => "Deploy V0",
            Transaction::DeployAccountTransactionV1(_) => "Deploy Account V1",
            Transaction::DeployAccountTransactionV3(_) => "Deploy Account V3",
        },
        None => "Unknown",
    };
 
    let status = tx_with_receipt.receipt.as_ref().map(|r| r.execution_status);
    
    TransactionAnalysis {
        transaction_type: tx_type.to_string(),
        success: matches!(status, Some(1)), // ExecutionStatus::Success
        has_events: tx_with_receipt.receipt
            .as_ref()
            .map(|r| !r.events.is_empty())
            .unwrap_or(false)
    }
}

// Example of an invoke transaction with receipt
let invoke_tx = TransactionWithReceipt {
    transaction: Some(Transaction::InvokeTransactionV3(InvokeTransactionV3 {
        // Invoke transaction details
    })),
    receipt: Some(TransactionReceipt {
        execution_status: 1, // Success
        events: vec![/* ... */],
        // Other receipt fields
    })
};
 
// Example of a declare transaction with receipt
let declare_tx = TransactionWithReceipt {
    transaction: Some(Transaction::DeclareTransactionV2(DeclareTransactionV2 {
        // Contract declaration details
    })),
    receipt: Some(TransactionReceipt {
        execution_status: 1, // Success
        // Other receipt fields
    })
};

pub struct TransactionReceipt {
    pub transaction_hash: Vec<u8>,
    pub actual_fee: Option<ActualFee>,
    pub execution_status: i32,
    pub revert_reason: String,
    pub r#type: i32,
    pub message_hash: String,
    pub messages_sent: Vec<MessagesSent>,
    pub events: Vec<Event>,
    pub execution_resources: Option<ExecutionResources>,
    pub contract_address: Vec<u8>,
}

pub enum ExecutionStatus {
    Unspecified = 0,    // Default/unknown execution status
    Succeeded = 1,      // Transaction executed successfully
    Reverted = 2,       // Transaction execution was reverted
}

pub enum TransactionType {
    Unspecified = 0,            // Default/unknown transaction type
    Declare = 1,                // Contract class declaration
    Deploy = 2,                 // Contract deployment
    DeployAccount = 3,          // Account contract deployment
    Invoke = 4,                 // Contract function invocation
    L1Handler = 5,              // L1 to L2 message handler
    Initialize = 6,             // Contract initialization
}

fn analyze_receipt(receipt: &TransactionReceipt) -> ReceiptAnalysis {
    ReceiptAnalysis {
        success: receipt.execution_status == 1,
        has_messages: !receipt.messages_sent.is_empty(),
        event_count: receipt.events.len(),
        fee_info: receipt.actual_fee.as_ref().map(|fee| {
            format!("{} {}", fee.amount, fee.unit)
        }),
        error: if receipt.execution_status == 2 {
            Some(receipt.revert_reason.clone())
        } else {
            None
        }
    }
}
 
// Example of processing L2->L1 messages
fn process_l1_messages(receipt: &TransactionReceipt) -> Vec<L1Message> {
    receipt.messages_sent.iter().map(|msg| {
        L1Message {
            from: msg.from_address.clone(),
            to: msg.to_address.clone(),
            payload: msg.payload.clone()
        }
    }).collect()
}

// Successful transaction receipt
let success_receipt = TransactionReceipt {
    transaction_hash: vec![/* hash */],
    execution_status: 1, // Success
    actual_fee: Some(ActualFee {
        amount: vec![/* amount */],
        unit: "WEI".to_string()
    }),
    events: vec![/* events */],
    messages_sent: vec![],
    revert_reason: "".to_string(),
    // ... other fields
};
 
// Failed transaction receipt
let failed_receipt = TransactionReceipt {
    transaction_hash: vec![/* hash */],
    execution_status: 2, // Reverted
    revert_reason: "Insufficient funds".to_string(),
    actual_fee: Some(ActualFee {
        amount: vec![/* amount */],
        unit: "WEI".to_string()
    }),
    // ... other fields
};

pub struct MessagesSent {
    pub from_address: Vec<u8>,
    pub to_address: Vec<u8>,
    pub payload: Vec<Vec<u8>>,
}

fn process_l2_to_l1_message(message: &MessagesSent) -> MessageAnalysis {
    // Convert addresses to hex strings
    let from_hex = format!("0x{}", hex::encode(&message.from_address));
    let to_hex = format!("0x{}", hex::encode(&message.to_address));
    
    // Analyze payload
    let payload_analysis = if !message.payload.is_empty() {
        analyze_message_payload(&message.payload)
    } else {
        PayloadType::Empty
    };
    
    MessageAnalysis {
        l2_sender: from_hex,
        l1_recipient: to_hex,
        payload_type: payload_analysis,
        payload_size: message.payload.len()
    }
}
 
// Example of common message patterns
fn analyze_message_payload(payload: &[Vec<u8>]) -> PayloadType {
    if let Some(first_word) = payload.first() {
        match first_word.as_slice() {
            // Common function selectors
            [0x12, 0x34, 0x56, 0x78, ..] => PayloadType::TokenTransfer,
            [0xa9, 0x05, 0x9c, 0xbb, ..] => PayloadType::TokenApproval,
            _ => PayloadType::Unknown
        }
    } else {
        PayloadType::Empty
    }
}

// Token bridge message example
let token_bridge_message = MessagesSent {
    from_address: vec![/* L2 bridge contract address */],
    to_address: vec![/* L1 bridge contract address */],
    payload: vec![
        vec![0x12, 0x34, 0x56, 0x78],  // transfer function selector
        vec![/* token amount */],
        vec![/* recipient address */]
    ]
};
 
// State verification message
let verification_message = MessagesSent {
    from_address: vec![/* L2 verifier contract */],
    to_address: vec![/* L1 verifier contract */],
    payload: vec![
        vec![/* state root */],
        vec![/* block number */],
        vec![/* timestamp */]
    ]
};

pub struct Event {
    pub from_address: Vec<u8>,
    pub keys: Vec<Vec<u8>>,
    pub data: Vec<Vec<u8>>,
}

fn process_event(event: &Event) -> EventAnalysis {
    // Convert event selector (first key) to identify event type
    let event_type = if let Some(selector) = event.keys.first() {
        match selector.as_slice() {
            // Common event selectors
            [0x12, 0x34, 0x56, 0x78, ..] => "Transfer",
            [0xa9, 0x05, 0x9c, 0xbb, ..] => "Approval",
            [0xdc, 0x13, 0x45, 0x67, ..] => "Swap",
            _ => "Unknown"
        }
    } else {
        "Unknown"
    };
 
    EventAnalysis {
        emitter: format!("0x{}", hex::encode(&event.from_address)),
        event_type: event_type.to_string(),
        indexed_params: event.keys.len() - 1, // Subtract selector
        data_params: event.data.len()
    }
}
 
// Example of processing transfer events
fn process_transfer_event(event: &Event) -> Option<TransferDetails> {
    if event.keys.len() < 3 || event.data.is_empty() {
        return None;
    }
 
    Some(TransferDetails {
        from: event.keys[1].clone(),  // First indexed param
        to: event.keys[2].clone(),    // Second indexed param
        amount: event.data[0].clone() // First data param
    })
}

// Transfer event example
let transfer_event = Event {
    from_address: vec![/* token contract address */],
    keys: vec![
        vec![0x12, 0x34, 0x56, 0x78],  // Transfer event selector
        vec![/* from address */],       // Indexed
        vec![/* to address */]          // Indexed
    ],
    data: vec![
        vec![/* amount */]              // Non-indexed
    ]
};
 
// Swap event example
let swap_event = Event {
    from_address: vec![/* DEX contract address */],
    keys: vec![
        vec![0xdc, 0x13, 0x45, 0x67],  // Swap event selector
        vec![/* token_in */],           // Indexed
        vec![/* token_out */]           // Indexed
    ],
    data: vec![
        vec![/* amount_in */],          // Non-indexed
        vec![/* amount_out */],         // Non-indexed
        vec![/* recipient */]           // Non-indexed
    ]
};

pub struct ExecutionResources {
    pub steps: u64,
    pub memory_holes: u64,
    pub range_check_builtin_applications: u64,
    pub pedersen_builtin_applications: u64,
    pub poseidon_builtin_applications: u64,
    pub ec_op_builtin_applications: u64,
    pub ecdsa_builtin_applications: u64,
    pub bitwise_builtin_applications: u64,
    pub keccak_builtin_applications: u64,
    pub segment_arena_builtin: u64,
}

fn analyze_execution_cost(resources: &ExecutionResources) -> ResourceAnalysis {
    ResourceAnalysis {
        total_steps: resources.steps,
        crypto_operations: resources.pedersen_builtin_applications 
            + resources.poseidon_builtin_applications 
            + resources.ec_op_builtin_applications 
            + resources.ecdsa_builtin_applications,
        hash_operations: resources.pedersen_builtin_applications 
            + resources.poseidon_builtin_applications 
            + resources.keccak_builtin_applications,
        memory_efficiency: calculate_memory_efficiency(
            resources.steps,
            resources.memory_holes
        )
    }
}
 
// Example of resource usage estimation
fn estimate_gas_cost(resources: &ExecutionResources) -> u64 {
    let base_cost = resources.steps * STEP_COST;
    let builtin_cost = 
        resources.pedersen_builtin_applications * PEDERSEN_COST +
        resources.ecdsa_builtin_applications * ECDSA_COST +
        resources.bitwise_builtin_applications * BITWISE_COST;
    
    base_cost + builtin_cost
}

// Simple transfer transaction resources
let transfer_resources = ExecutionResources {
    steps: 1000,
    memory_holes: 10,
    range_check_builtin_applications: 20,
    pedersen_builtin_applications: 2,
    poseidon_builtin_applications: 0,
    ec_op_builtin_applications: 0,
    ecdsa_builtin_applications: 1,
    bitwise_builtin_applications: 0,
    keccak_builtin_applications: 0,
    segment_arena_builtin: 5,
};
 
// Complex DeFi transaction resources
let defi_resources = ExecutionResources {
    steps: 5000,
    memory_holes: 50,
    range_check_builtin_applications: 100,
    pedersen_builtin_applications: 10,
    poseidon_builtin_applications: 5,
    ec_op_builtin_applications: 2,
    ecdsa_builtin_applications: 1,
    bitwise_builtin_applications: 30,
    keccak_builtin_applications: 3,
    segment_arena_builtin: 25,
};

pub struct InvokeTransactionV0 {
    pub max_fee: Vec<u8>,
    pub signature: Vec<Vec<u8>>,
    pub contract_address: Vec<u8>,
    pub entry_point_selector: Vec<u8>,
    pub calldata: Vec<Vec<u8>>,
}

fn process_invoke_v0(tx: &InvokeTransactionV0) -> InvokeAnalysis {
    // Convert function selector to identify the function
    let function_name = match tx.entry_point_selector.as_slice() {
        [0x12, 0x34, 0x56, 0x78, ..] => "transfer",
        [0xa9, 0x05, 0x9c, 0xbb, ..] => "approve",
        _ => "unknown"
    };
 
    InvokeAnalysis {
        contract: format!("0x{}", hex::encode(&tx.contract_address)),
        function: function_name.to_string(),
        argument_count: tx.calldata.len(),
        max_fee: format!("0x{}", hex::encode(&tx.max_fee)),
        signed: !tx.signature.is_empty()
    }
}

// ERC20 transfer transaction
let transfer_tx = InvokeTransactionV0 {
    max_fee: vec![0, 0, 0, 0, 0, 1, 0, 0],  // 256 wei
    signature: vec![
        vec![/* r signature component */],
        vec![/* s signature component */]
    ],
    contract_address: vec![/* ERC20 contract address */],
    entry_point_selector: vec![0x12, 0x34, 0x56, 0x78],  // transfer
    calldata: vec![
        vec![/* recipient address */],
        vec![/* amount */]
    ]
};
 
// Contract interaction transaction
let interaction_tx = InvokeTransactionV0 {
    max_fee: vec![0, 0, 0, 0, 0, 2, 0, 0],  // 512 wei
    signature: vec![
        vec![/* r signature component */],
        vec![/* s signature component */]
    ],
    contract_address: vec![/* contract address */],
    entry_point_selector: vec![/* custom function selector */],
    calldata: vec![
        vec![/* parameter 1 */],
        vec![/* parameter 2 */],
        vec![/* parameter 3 */]
    ]
};

pub struct InvokeTransactionV1 {
    pub max_fee: Vec<u8>,
    pub signature: Vec<Vec<u8>>,
    pub nonce: Vec<u8>,
    pub sender_address: Vec<u8>,
    pub calldata: Vec<Vec<u8>>,
}

fn process_invoke_v1(tx: &InvokeTransactionV1) -> InvokeV1Analysis {
    // Parse calldata to extract calls
    let calls = parse_calldata(&tx.calldata);
    
    InvokeV1Analysis {
        sender: format!("0x{}", hex::encode(&tx.sender_address)),
        nonce: u64::from_be_bytes(tx.nonce.try_into().unwrap_or([0; 8])),
        call_count: calls.len(),
        max_fee: format!("0x{}", hex::encode(&tx.max_fee)),
        signed: !tx.signature.is_empty()
    }
}
 
fn parse_calldata(calldata: &[Vec<u8>]) -> Vec<Call> {
    let mut calls = Vec::new();
    let mut i = 0;
    while i < calldata.len() {
        if i + 2 < calldata.len() {
            calls.push(Call {
                contract: calldata[i].clone(),
                selector: calldata[i + 1].clone(),
                params: if i + 2 < calldata.len() {
                    calldata[i + 2].clone()
                } else {
                    vec![]
                }
            });
        }
        i += 3;
    }
    calls
}

// Single contract call
let single_call_tx = InvokeTransactionV1 {
    max_fee: vec![0, 0, 0, 0, 0, 1, 0, 0],
    signature: vec![
        vec![/* r signature component */],
        vec![/* s signature component */]
    ],
    nonce: vec![0, 0, 0, 1],
    sender_address: vec![/* account address */],
    calldata: vec![
        vec![/* contract address */],
        vec![/* function selector */],
        vec![/* parameters */]
    ]
};
 
// Multi-call transaction
let multi_call_tx = InvokeTransactionV1 {
    max_fee: vec![0, 0, 0, 0, 0, 2, 0, 0],
    signature: vec![
        vec![/* r signature component */],
        vec![/* s signature component */]
    ],
    nonce: vec![0, 0, 0, 2],
    sender_address: vec![/* account address */],
    calldata: vec![
        // First call
        vec![/* contract address 1 */],
        vec![/* function selector 1 */],
        vec![/* parameters 1 */],
        // Second call
        vec![/* contract address 2 */],
        vec![/* function selector 2 */],
        vec![/* parameters 2 */]
    ]
};

pub struct InvokeTransactionV3 {
    pub sender_address: Vec<u8>,
    pub calldata: Vec<Vec<u8>>,
    pub signature: Vec<Vec<u8>>,
    pub nonce: Vec<u8>,
    pub resource_bounds: Option<ResourceBounds>,
    pub tip: Vec<u8>,
    pub paymaster_data: Vec<Vec<u8>>,
    pub account_deployment_data: Vec<Vec<u8>>,
    pub nonce_data_availability_mode: i32,
    pub fee_data_availability_mode: i32,
}

pub enum FeeDataAvailabilityMode {
    Unspecified = 0,    // Default mode when not specified
    L1 = 1,             // Fee data stored on L1
    L2 = 2,             // Fee data stored on L2
}

fn process_invoke_v3(tx: &InvokeTransactionV3) -> InvokeV3Analysis {
    InvokeV3Analysis {
        sender: format!("0x{}", hex::encode(&tx.sender_address)),
        is_account_deployment: !tx.account_deployment_data.is_empty(),
        has_paymaster: !tx.paymaster_data.is_empty(),
        resource_bounds: tx.resource_bounds.as_ref().map(analyze_bounds),
        da_mode: analyze_da_modes(
            tx.nonce_data_availability_mode,
            tx.fee_data_availability_mode
        ),
        tip_amount: u64::from_be_bytes(tx.tip.try_into().unwrap_or([0; 8]))
    }
}
 
// Example of paymaster integration
fn create_paymaster_tx(
    base_tx: InvokeTransactionV3,
    paymaster: &PaymasterInfo
) -> InvokeTransactionV3 {
    InvokeTransactionV3 {
        paymaster_data: vec![
            paymaster.address.clone(),
            paymaster.signature.clone(),
            paymaster.extra_data.clone()
        ],
        ..base_tx
    }
}

// Account deployment with transaction
let deployment_tx = InvokeTransactionV3 {
    sender_address: vec![/* new account address */],
    calldata: vec![/* initial transaction calldata */],
    signature: vec![/* signature components */],
    nonce: vec![0, 0, 0, 0],  // Initial nonce
    resource_bounds: Some(ResourceBounds {
        max_amount: vec![/* resource limits */],
        max_price_per_unit: vec![/* price limits */]
    }),
    account_deployment_data: vec![
        vec![/* account class hash */],
        vec![/* constructor params */]
    ],
    ..Default::default()
};
 
// Paymaster-sponsored transaction
let sponsored_tx = InvokeTransactionV3 {
    sender_address: vec![/* user account */],
    calldata: vec![/* transaction calldata */],
    signature: vec![/* user signature */],
    nonce: vec![0, 0, 0, 1],
    resource_bounds: Some(ResourceBounds { /* ... */ }),
    paymaster_data: vec![
        vec![/* paymaster contract */],
        vec![/* paymaster signature */]
    ],
    fee_data_availability_mode: 1,  // L1
    ..Default::default()
};

pub struct L1HandlerTransaction {
    pub contract_address: Vec<u8>,
    pub entry_point_selector: Vec<u8>,
    pub calldata: Vec<Vec<u8>>,
    pub nonce: Vec<u8>,
    pub version: i32,
}

fn process_l1_handler(tx: &L1HandlerTransaction) -> L1HandlerAnalysis {
    // Identify common L1 handler types
    let handler_type = match tx.entry_point_selector.as_slice() {
        [0x12, 0x34, 0x56, 0x78, ..] => "TokenBridge",
        [0xa9, 0x05, 0x9c, 0xbb, ..] => "StateUpdate",
        [0xdc, 0x13, 0x45, 0x67, ..] => "MessageHandler",
        _ => "Unknown"
    };
 
    L1HandlerAnalysis {
        contract: format!("0x{}", hex::encode(&tx.contract_address)),
        handler_type: handler_type.to_string(),
        nonce: u64::from_be_bytes(tx.nonce.try_into().unwrap_or([0; 8])),
        version: tx.version,
        param_count: tx.calldata.len()
    }
}
 
// Example of parsing L1 message data
fn parse_l1_message(tx: &L1HandlerTransaction) -> Option<L1Message> {
    if tx.calldata.len() < 2 {
        return None;
    }
 
    Some(L1Message {
        from_address: tx.calldata[0].clone(),
        payload: tx.calldata[1..].to_vec()
    })
}

// Token bridge message handler
let bridge_handler = L1HandlerTransaction {
    contract_address: vec![/* bridge contract address */],
    entry_point_selector: vec![0x12, 0x34, 0x56, 0x78], // handle_bridge
    calldata: vec![
        vec![/* L1 bridge address */],
        vec![/* token address */],
        vec![/* recipient */],
        vec![/* amount */]
    ],
    nonce: vec![0, 0, 0, 1],
    version: 1
};
 
// State update handler
let state_handler = L1HandlerTransaction {
    contract_address: vec![/* state contract address */],
    entry_point_selector: vec![0xa9, 0x05, 0x9c, 0xbb], // handle_state
    calldata: vec![
        vec![/* L1 contract */],
        vec![/* state root */],
        vec![/* block number */]
    ],
    nonce: vec![0, 0, 0, 2],
    version: 1
};

pub struct DeclareTransactionV0 {
    pub max_fee: Vec<u8>,
    pub signature: Vec<Vec<u8>>,
    pub class_hash: Vec<u8>,
    pub sender_address: Vec<u8>,
}

fn process_declare_v0(tx: &DeclareTransactionV0) -> DeclareAnalysis {
    DeclareAnalysis {
        declarer: format!("0x{}", hex::encode(&tx.sender_address)),
        class: format!("0x{}", hex::encode(&tx.class_hash)),
        max_fee: u64::from_be_bytes(tx.max_fee.try_into().unwrap_or([0; 8])),
        signed: !tx.signature.is_empty()
    }
}
 
// Example of validating a declare transaction
fn validate_declare_v0(tx: &DeclareTransactionV0) -> Result<(), String> {
    // Check signature presence
    if tx.signature.is_empty() {
        return Err("Missing signature".to_string());
    }
 
    // Validate class hash length
    if tx.class_hash.len() != 32 {
        return Err("Invalid class hash length".to_string());
    }
 
    // Validate sender address
    if tx.sender_address.len() != 32 {
        return Err("Invalid sender address length".to_string());
    }
 
    Ok(())
}

// Basic contract declaration
let basic_declare = DeclareTransactionV0 {
    max_fee: vec![0, 0, 0, 0, 0, 1, 0, 0],  // 256 wei
    signature: vec![
        vec![/* r signature component */],
        vec![/* s signature component */]
    ],
    class_hash: vec![/* contract class hash */],
    sender_address: vec![/* account address */]
};
 
// System contract declaration
let system_declare = DeclareTransactionV0 {
    max_fee: vec![0, 0, 0, 0, 0, 2, 0, 0],  // 512 wei
    signature: vec![
        vec![/* r signature component */],
        vec![/* s signature component */]
    ],
    class_hash: vec![/* system contract class hash */],
    sender_address: vec![/* privileged account address */]
};

pub struct DeclareTransactionV1 {
    pub max_fee: Vec<u8>,
    pub signature: Vec<Vec<u8>>,
    pub nonce: Vec<u8>,
    pub class_hash: Vec<u8>,
    pub sender_address: Vec<u8>,
}

fn process_declare_v1(tx: &DeclareTransactionV1) -> DeclareV1Analysis {
    DeclareV1Analysis {
        declarer: format!("0x{}", hex::encode(&tx.sender_address)),
        class: format!("0x{}", hex::encode(&tx.class_hash)),
        nonce: u64::from_be_bytes(tx.nonce.try_into().unwrap_or([0; 8])),
        max_fee: u64::from_be_bytes(tx.max_fee.try_into().unwrap_or([0; 8])),
        signed: !tx.signature.is_empty()
    }
}
 
// Example of transaction sequencing validation
fn validate_declare_sequence(
    tx: &DeclareTransactionV1,
    current_nonce: &[u8]
) -> Result<(), String> {
    if tx.nonce <= current_nonce {
        return Err("Invalid nonce sequence".to_string());
    }
    
    // Additional validation logic
    Ok(())
}

// Standard contract declaration
let standard_declare = DeclareTransactionV1 {
    max_fee: vec![0, 0, 0, 0, 0, 1, 0, 0],  // 256 wei
    signature: vec![
        vec![/* r signature component */],
        vec![/* s signature component */]
    ],
    nonce: vec![0, 0, 0, 1],
    class_hash: vec![/* contract class hash */],
    sender_address: vec![/* account address */]
};
 
// Upgraded contract version declaration
let upgrade_declare = DeclareTransactionV1 {
    max_fee: vec![0, 0, 0, 0, 0, 2, 0, 0],  // 512 wei
    signature: vec![
        vec![/* r signature component */],
        vec![/* s signature component */]
    ],
    nonce: vec![0, 0, 0, 2],
    class_hash: vec![/* upgraded class hash */],
    sender_address: vec![/* account address */]
};

pub struct DeclareTransactionV2 {
    pub max_fee: Vec<u8>,
    pub signature: Vec<Vec<u8>>,
    pub nonce: Vec<u8>,
    pub class_hash: Vec<u8>,
    pub sender_address: Vec<u8>,
    pub compiled_class_hash: Vec<u8>,
}

fn process_declare_v2(tx: &DeclareTransactionV2) -> DeclareV2Analysis {
    DeclareV2Analysis {
        declarer: format!("0x{}", hex::encode(&tx.sender_address)),
        sierra_class: format!("0x{}", hex::encode(&tx.class_hash)),
        casm_class: format!("0x{}", hex::encode(&tx.compiled_class_hash)),
        nonce: u64::from_be_bytes(tx.nonce.try_into().unwrap_or([0; 8])),
        max_fee: u64::from_be_bytes(tx.max_fee.try_into().unwrap_or([0; 8])),
        signed: !tx.signature.is_empty()
    }
}
 
// Example of class hash validation
fn validate_class_hashes(tx: &DeclareTransactionV2) -> Result<(), String> {
    // Validate Sierra class hash
    if tx.class_hash.len() != 32 {
        return Err("Invalid Sierra class hash length".to_string());
    }
 
    // Validate CASM class hash
    if tx.compiled_class_hash.len() != 32 {
        return Err("Invalid CASM class hash length".to_string());
    }
 
    // Additional validation logic
    Ok(())
}

// Sierra contract declaration
let sierra_declare = DeclareTransactionV2 {
    max_fee: vec![0, 0, 0, 0, 0, 1, 0, 0],
    signature: vec![
        vec![/* r signature component */],
        vec![/* s signature component */]
    ],
    nonce: vec![0, 0, 0, 1],
    class_hash: vec![/* Sierra class hash */],
    compiled_class_hash: vec![/* CASM class hash */],
    sender_address: vec![/* account address */]
};
 
// Upgraded Sierra contract declaration
let upgrade_declare = DeclareTransactionV2 {
    max_fee: vec![0, 0, 0, 0, 0, 2, 0, 0],
    signature: vec![
        vec![/* r signature component */],
        vec![/* s signature component */]
    ],
    nonce: vec![0, 0, 0, 2],
    class_hash: vec![/* new Sierra class hash */],
    compiled_class_hash: vec![/* new CASM class hash */],
    sender_address: vec![/* account address */]
};

pub struct DeclareTransactionV3 {
    pub sender_address: Vec<u8>,
    pub signature: Vec<Vec<u8>>,
    pub nonce: Vec<u8>,
    pub class_hash: Vec<u8>,
    pub compiled_class_hash: Vec<u8>,
    pub resource_bounds: Option<ResourceBounds>,
    pub tip: Vec<u8>,
    pub paymaster_data: Vec<Vec<u8>>,
    pub account_deployment_data: Vec<Vec<u8>>,
    pub nonce_data_availability_mode: i32,
    pub fee_data_availability_mode: i32,
}

pub enum FeeDataAvailabilityMode {
    Unspecified = 0,    // Default mode when not specified
    L1 = 1,             // Fee data stored on L1
    L2 = 2,             // Fee data stored on L2
}

fn process_declare_v3(tx: &DeclareTransactionV3) -> DeclareV3Analysis {
    DeclareV3Analysis {
        declarer: format!("0x{}", hex::encode(&tx.sender_address)),
        sierra_class: format!("0x{}", hex::encode(&tx.class_hash)),
        casm_class: format!("0x{}", hex::encode(&tx.compiled_class_hash)),
        has_paymaster: !tx.paymaster_data.is_empty(),
        is_account_deployment: !tx.account_deployment_data.is_empty(),
        resource_bounds: tx.resource_bounds.as_ref().map(analyze_bounds),
        tip_amount: u64::from_be_bytes(tx.tip.try_into().unwrap_or([0; 8]))
    }
}
 
// Example of paymaster-sponsored declaration
fn create_sponsored_declare(
    base_tx: DeclareTransactionV3,
    paymaster: &PaymasterInfo
) -> DeclareTransactionV3 {
    DeclareTransactionV3 {
        paymaster_data: vec![
            paymaster.address.clone(),
            paymaster.signature.clone()
        ],
        fee_data_availability_mode: 1, // L1
        ..base_tx
    }
}

// Standard Sierra declaration
let standard_declare = DeclareTransactionV3 {
    sender_address: vec![/* account address */],
    signature: vec![/* signature components */],
    nonce: vec![0, 0, 0, 1],
    class_hash: vec![/* Sierra class hash */],
    compiled_class_hash: vec![/* CASM class hash */],
    resource_bounds: Some(ResourceBounds {
        max_amount: vec![/* resource limits */],
        max_price_per_unit: vec![/* price limits */]
    }),
    tip: vec![0, 0, 0, 0],
    paymaster_data: vec![],
    account_deployment_data: vec![],
    nonce_data_availability_mode: 1,
    fee_data_availability_mode: 1,
};
 
// Sponsored declaration with account deployment
let sponsored_declare = DeclareTransactionV3 {
    sender_address: vec![/* new account address */],
    signature: vec![/* signature components */],
    nonce: vec![0, 0, 0, 0],
    class_hash: vec![/* Sierra class hash */],
    compiled_class_hash: vec![/* CASM class hash */],
    resource_bounds: Some(ResourceBounds { /* ... */ }),
    paymaster_data: vec![/* paymaster info */],
    account_deployment_data: vec![
        vec![/* account class hash */],
        vec![/* constructor params */]
    ],
    ..Default::default()
};

pub struct DeployTransactionV0 {
    pub version: i32,
    pub contract_address: Vec<u8>,
    pub contract_address_salt: Vec<u8>,
    pub class_hash: Vec<u8>,
    pub constructor_calldata: Vec<Vec<u8>>,
}

fn process_deploy_v0(tx: &DeployTransactionV0) -> DeployAnalysis {
    DeployAnalysis {
        address: format!("0x{}", hex::encode(&tx.contract_address)),
        class: format!("0x{}", hex::encode(&tx.class_hash)),
        salt: format!("0x{}", hex::encode(&tx.contract_address_salt)),
        constructor_args: tx.constructor_calldata.len(),
        version: tx.version
    }
}
 
// Example of address computation validation
fn validate_contract_address(
    tx: &DeployTransactionV0,
    computed_address: &[u8]
) -> Result<(), String> {
    if tx.contract_address != computed_address {
        return Err("Invalid contract address computation".to_string());
    }
    
    // Additional validation logic
    Ok(())
}

// Basic contract deployment
let basic_deploy = DeployTransactionV0 {
    version: 0,
    contract_address: vec![/* computed contract address */],
    contract_address_salt: vec![/* random salt */],
    class_hash: vec![/* contract class hash */],
    constructor_calldata: vec![
        vec![/* initial parameter */]
    ]
};
 
// Token contract deployment
let token_deploy = DeployTransactionV0 {
    version: 0,
    contract_address: vec![/* computed address */],
    contract_address_salt: vec![/* unique salt */],
    class_hash: vec![/* ERC20 class hash */],
    constructor_calldata: vec![
        vec![/* name */],
        vec![/* symbol */],
        vec![/* decimals */],
        vec![/* initial_supply */],
        vec![/* owner */]
    ]
};

pub struct DeployAccountTransactionV1 {
    pub max_fee: Vec<u8>,
    pub signature: Vec<Vec<u8>>,
    pub nonce: Vec<u8>,
    pub contract_address_salt: Vec<u8>,
    pub constructor_calldata: Vec<Vec<u8>>,
    pub class_hash: Vec<u8>,
}