Estructura de programa en Rust

[lib]
crate-type = ["cdylib", "lib"]

use borsh::{BorshDeserialize, BorshSerialize};
use solana_program::{
    account_info::{next_account_info, AccountInfo},
    entrypoint,
    entrypoint::ProgramResult,
    msg,
    program::invoke,
    program_error::ProgramError,
    pubkey::Pubkey,
    system_instruction,
    sysvar::{rent::Rent, Sysvar},
};

entrypoint!(process_instruction);

pub fn process_instruction(
    program_id: &Pubkey,
    accounts: &[AccountInfo],
    instruction_data: &[u8],
) -> ProgramResult {
    Ok(())
}

#[no_mangle]
pub unsafe extern "C" fn entrypoint(input: *mut u8) -> u64;

#[derive(BorshSerialize, BorshDeserialize, Debug)]
pub struct CounterAccount {
    pub count: u64,
}

#[derive(BorshSerialize, BorshDeserialize, Debug)]
pub enum CounterInstruction {
    InitializeCounter { initial_value: u64 },
    IncrementCounter,
}

pub fn process_instruction(
    program_id: &Pubkey,
    accounts: &[AccountInfo],
    instruction_data: &[u8],
) -> ProgramResult {
    let instruction = CounterInstruction::try_from_slice(instruction_data)
        .map_err(|_| ProgramError::InvalidInstructionData)?;

    Ok(())
}

pub fn process_instruction(
    program_id: &Pubkey,
    accounts: &[AccountInfo],
    instruction_data: &[u8],
) -> ProgramResult {
    let instruction = CounterInstruction::try_from_slice(instruction_data)
        .map_err(|_| ProgramError::InvalidInstructionData)?;

    match instruction {
        CounterInstruction::InitializeCounter { initial_value } => {
            process_initialize_counter(program_id, accounts, initial_value)?
        }
        CounterInstruction::IncrementCounter => {
            process_increment_counter(program_id, accounts)?
        }
    };
    Ok(())
}

fn process_initialize_counter(
    program_id: &Pubkey,
    accounts: &[AccountInfo],
    initial_value: u64,
) -> ProgramResult {
    Ok(())
}

fn process_increment_counter(
    program_id: &Pubkey,
    accounts: &[AccountInfo],
) -> ProgramResult {
    Ok(())
}

fn process_initialize_counter(
    program_id: &Pubkey,
    accounts: &[AccountInfo],
    initial_value: u64,
) -> ProgramResult {
    let accounts_iter = &mut accounts.iter();

    let counter_account = next_account_info(accounts_iter)?;
    let payer_account = next_account_info(accounts_iter)?;
    let system_program = next_account_info(accounts_iter)?;

    let account_space = 8;

    let rent = Rent::get()?;
    let required_lamports = rent.minimum_balance(account_space);

    invoke(
        &system_instruction::create_account(
            payer_account.key,
            counter_account.key,
            required_lamports,
            account_space as u64,
            program_id,
        ),
        &[
            payer_account.clone(),
            counter_account.clone(),
            system_program.clone(),
        ],
    )?;

    let counter_data = CounterAccount {
        count: initial_value,
    };

    let mut account_data = &mut counter_account.data.borrow_mut()[..];
    counter_data.serialize(&mut account_data)?;

    msg!("Counter initialized with value: {}", initial_value);

    Ok(())
}

fn process_increment_counter(
    program_id: &Pubkey,
    accounts: &[AccountInfo],
) -> ProgramResult {
    let accounts_iter = &mut accounts.iter();

    let counter_account = next_account_info(accounts_iter)?;

    if counter_account.owner != program_id {
        return Err(ProgramError::IncorrectProgramId);
    }

    let mut data = counter_account.data.borrow_mut();

    let mut counter_data: CounterAccount = CounterAccount::try_from_slice(&data)?;

    counter_data.count = counter_data
        .count
        .checked_add(1)
        .ok_or(ProgramError::InvalidAccountData)?;

    counter_data.serialize(&mut &mut data[..])?;

    msg!("Counter incremented to: {}", counter_data.count);

    Ok(())
}

#[cfg(test)]
mod test {
    use super::*;
    use litesvm::LiteSVM;
    use solana_sdk::{
        account::ReadableAccount,
        instruction::{AccountMeta, Instruction},
        message::Message,
        signature::{Keypair, Signer},
        system_program,
        transaction::Transaction,
    };

    #[test]
    fn test_counter_program() {
        // Test implementation will go here
    }
}

let mut svm = LiteSVM::new();

let payer = Keypair::new();

svm.airdrop(&payer.pubkey(), 1_000_000_000)
    .expect("Failed to airdrop");

let program_keypair = Keypair::new();
let program_id = program_keypair.pubkey();

svm.add_program_from_file(
    program_id,
    "target/deploy/counter_program.so"
).expect("Failed to load program");

let counter_keypair = Keypair::new();
let initial_value: u64 = 42;

println!("Testing counter initialization...");

let init_instruction_data =
    borsh::to_vec(&CounterInstruction::InitializeCounter { initial_value })
        .expect("Failed to serialize instruction");

let initialize_instruction = Instruction::new_with_bytes(
    program_id,
    &init_instruction_data,
    vec![
        AccountMeta::new(counter_keypair.pubkey(), true),
        AccountMeta::new(payer.pubkey(), true),
        AccountMeta::new_readonly(system_program::id(), false),
    ],
);

let message = Message::new(&[initialize_instruction], Some(&payer.pubkey()));
let transaction = Transaction::new(
    &[&payer, &counter_keypair],
    message,
    svm.latest_blockhash()
);

let result = svm.send_transaction(transaction);
assert!(result.is_ok(), "Initialize transaction should succeed");

let logs = result.unwrap().logs;
println!("Transaction logs:\n{:#?}", logs);

let account = svm
    .get_account(&counter_keypair.pubkey())
    .expect("Failed to get counter account");

let counter: CounterAccount = CounterAccount::try_from_slice(account.data())
    .expect("Failed to deserialize counter data");

assert_eq!(counter.count, 42);
println!("Counter initialized successfully with value: {}", counter.count);

println!("Testing counter increment...");

let increment_instruction_data =
    borsh::to_vec(&CounterInstruction::IncrementCounter)
        .expect("Failed to serialize instruction");

let increment_instruction = Instruction::new_with_bytes(
    program_id,
    &increment_instruction_data,
    vec![AccountMeta::new(counter_keypair.pubkey(), true)],
);

let message = Message::new(&[increment_instruction], Some(&payer.pubkey()));
let transaction = Transaction::new(
    &[&payer, &counter_keypair],
    message,
    svm.latest_blockhash()
);

let result = svm.send_transaction(transaction);
assert!(result.is_ok(), "Increment transaction should succeed");

let logs = result.unwrap().logs;
println!("Transaction logs:\n{:#?}", logs);

let account = svm
    .get_account(&counter_keypair.pubkey())
    .expect("Failed to get counter account");

let counter: CounterAccount = CounterAccount::try_from_slice(account.data())
    .expect("Failed to deserialize counter data");
assert_eq!(counter.count, 43);
println!("Counter incremented successfully to: {}", counter.count);

Testing counter initialization...
Transaction logs:
[
    "Program 3QpyHXhFtYY32iY7foF3EjkVdCDrUppADk9aDwSWn6Sq invoke [1]",
    "Program 11111111111111111111111111111111 invoke [2]",
    "Program 11111111111111111111111111111111 success",
    "Program log: Counter initialized with value: 42",
    "Program 3QpyHXhFtYY32iY7foF3EjkVdCDrUppADk9aDwSWn6Sq consumed 3803 of 200000 compute units",
    "Program 3QpyHXhFtYY32iY7foF3EjkVdCDrUppADk9aDwSWn6Sq success",
]
Counter initialized successfully with value: 42
Testing counter increment...
Transaction logs:
[
    "Program 3QpyHXhFtYY32iY7foF3EjkVdCDrUppADk9aDwSWn6Sq invoke [1]",
    "Program log: Counter incremented to: 43",
    "Program 3QpyHXhFtYY32iY7foF3EjkVdCDrUppADk9aDwSWn6Sq consumed 762 of 200000 compute units",
    "Program 3QpyHXhFtYY32iY7foF3EjkVdCDrUppADk9aDwSWn6Sq success",
]
Counter incremented successfully to: 43

[[example]]
name = "client"
path = "examples/client.rs"

let program_id = Pubkey::from_str("BDLLezrtFEXVGYqG3aS7eAC7GVeojJ4JHhKJM6pAFCDH")
    .expect("Invalid program ID");

use solana_client::rpc_client::RpcClient;
use solana_sdk::{
    commitment_config::CommitmentConfig,
    instruction::{AccountMeta, Instruction},
    pubkey::Pubkey,
    signature::{Keypair, Signer},
    system_program,
    transaction::Transaction,
};
use std::str::FromStr;
use counter_program::CounterInstruction;

#[tokio::main]
async fn main() {
    // Replace with your actual program ID from deployment
    let program_id = Pubkey::from_str("BDLLezrtFEXVGYqG3aS7eAC7GVeojJ4JHhKJM6pAFCDH")
        .expect("Invalid program ID");

    // Connect to local cluster
    let rpc_url = String::from("http://localhost:8899");
    let client = RpcClient::new_with_commitment(rpc_url, CommitmentConfig::confirmed());

    // Generate a new keypair for paying fees
    let payer = Keypair::new();

    // Request airdrop of 1 SOL for transaction fees
    println!("Requesting airdrop...");
    let airdrop_signature = client
        .request_airdrop(&payer.pubkey(), 1_000_000_000)
        .expect("Failed to request airdrop");

    // Wait for airdrop confirmation
    loop {
        if client
            .confirm_transaction(&airdrop_signature)
            .unwrap_or(false)
        {
            break;
        }
        std::thread::sleep(std::time::Duration::from_millis(500));
    }
    println!("Airdrop confirmed");

    println!("\nInitializing counter...");
    let counter_keypair = Keypair::new();
    let initial_value = 100u64;

    // Serialize the initialize instruction data
    let instruction_data = borsh::to_vec(&CounterInstruction::InitializeCounter { initial_value })
        .expect("Failed to serialize instruction");

    let initialize_instruction = Instruction::new_with_bytes(
        program_id,
        &instruction_data,
        vec![
            AccountMeta::new(counter_keypair.pubkey(), true),
            AccountMeta::new(payer.pubkey(), true),
            AccountMeta::new_readonly(system_program::id(), false),
        ],
    );

    let mut transaction =
        Transaction::new_with_payer(&[initialize_instruction], Some(&payer.pubkey()));

    let blockhash = client
        .get_latest_blockhash()
        .expect("Failed to get blockhash");
    transaction.sign(&[&payer, &counter_keypair], blockhash);

    match client.send_and_confirm_transaction(&transaction) {
        Ok(signature) => {
            println!("Counter initialized!");
            println!("Transaction: {}", signature);
            println!("Counter address: {}", counter_keypair.pubkey());
        }
        Err(err) => {
            eprintln!("Failed to initialize counter: {}", err);
            return;
        }
    }

    println!("\nIncrementing counter...");
    // Serialize the increment instruction data
    let increment_data = borsh::to_vec(&CounterInstruction::IncrementCounter)
        .expect("Failed to serialize instruction");

    let increment_instruction = Instruction::new_with_bytes(
        program_id,
        &increment_data,
        vec![AccountMeta::new(counter_keypair.pubkey(), true)],
    );

    let mut transaction =
        Transaction::new_with_payer(&[increment_instruction], Some(&payer.pubkey()));

    transaction.sign(&[&payer, &counter_keypair], blockhash);

    match client.send_and_confirm_transaction(&transaction) {
        Ok(signature) => {
            println!("Counter incremented!");
            println!("Transaction: {}", signature);
        }
        Err(err) => {
            eprintln!("Failed to increment counter: {}", err);
        }
    }
}