//! @brief Example Rust-based BPF program that issues a cross-program-invocation

#![allow(unreachable_code)]

extern crate solana_sdk;

use solana_bpf_rust_invoked::instruction::*;
use solana_sdk::{
    account_info::AccountInfo,
    entrypoint,
    entrypoint::{ProgramResult, MAX_PERMITTED_DATA_INCREASE},
    info,
    program::{invoke, invoke_signed},
    program_error::ProgramError,
    pubkey::{Pubkey, PubkeyError},
    system_instruction,
};

const TEST_SUCCESS: u8 = 1;
const TEST_PRIVILEGE_ESCALATION_SIGNER: u8 = 2;
const TEST_PRIVILEGE_ESCALATION_WRITABLE: u8 = 3;

// const MINT_INDEX: usize = 0;
const ARGUMENT_INDEX: usize = 1;
const INVOKED_PROGRAM_INDEX: usize = 2;
const INVOKED_ARGUMENT_INDEX: usize = 3;
const INVOKED_PROGRAM_DUP_INDEX: usize = 4;
// const ARGUMENT_DUP_INDEX: usize = 5;
const DERIVED_KEY1_INDEX: usize = 6;
const DERIVED_KEY2_INDEX: usize = 7;
const DERIVED_KEY3_INDEX: usize = 8;
// const SYSTEM_PROGRAM_INDEX: usize = 9;
const FROM_INDEX: usize = 10;

entrypoint!(process_instruction);
fn process_instruction(
    program_id: &Pubkey,
    accounts: &[AccountInfo],
    instruction_data: &[u8],
) -> ProgramResult {
    info!("invoke Rust program");

    let nonce1 = instruction_data[1];
    let nonce2 = instruction_data[2];
    let nonce3 = instruction_data[3];

    match instruction_data[0] {
        TEST_SUCCESS => {
            info!("Call system program create account");
            {
                let from_lamports = accounts[FROM_INDEX].lamports();
                let to_lamports = accounts[DERIVED_KEY1_INDEX].lamports();
                assert_eq!(accounts[DERIVED_KEY1_INDEX].data_len(), 0);
                assert!(solana_sdk::system_program::check_id(
                    accounts[DERIVED_KEY1_INDEX].owner
                ));

                let instruction = system_instruction::create_account(
                    accounts[FROM_INDEX].key,
                    accounts[DERIVED_KEY1_INDEX].key,
                    42,
                    MAX_PERMITTED_DATA_INCREASE as u64,
                    program_id,
                );
                invoke_signed(&instruction, accounts, &[&[b"You pass butter", &[nonce1]]])?;

                assert_eq!(accounts[FROM_INDEX].lamports(), from_lamports - 42);
                assert_eq!(accounts[DERIVED_KEY1_INDEX].lamports(), to_lamports + 42);
                assert_eq!(program_id, accounts[DERIVED_KEY1_INDEX].owner);
                assert_eq!(
                    accounts[DERIVED_KEY1_INDEX].data_len(),
                    MAX_PERMITTED_DATA_INCREASE
                );
                let mut data = accounts[DERIVED_KEY1_INDEX].try_borrow_mut_data()?;
                assert_eq!(data[MAX_PERMITTED_DATA_INCREASE - 1], 0);
                data[MAX_PERMITTED_DATA_INCREASE - 1] = 0x0f;
                assert_eq!(data[MAX_PERMITTED_DATA_INCREASE - 1], 0x0f);
                for i in 0..20 {
                    data[i] = i as u8;
                }
            }

            info!("Call system program transfer");
            {
                let from_lamports = accounts[FROM_INDEX].lamports();
                let to_lamports = accounts[DERIVED_KEY1_INDEX].lamports();
                let instruction = system_instruction::transfer(
                    accounts[FROM_INDEX].key,
                    accounts[DERIVED_KEY1_INDEX].key,
                    1,
                );
                invoke(&instruction, accounts)?;
                assert_eq!(accounts[FROM_INDEX].lamports(), from_lamports - 1);
                assert_eq!(accounts[DERIVED_KEY1_INDEX].lamports(), to_lamports + 1);
            }

            info!("Test data translation");
            {
                {
                    let mut data = accounts[ARGUMENT_INDEX].try_borrow_mut_data()?;
                    for i in 0..100 {
                        data[i as usize] = i;
                    }
                }

                let instruction = create_instruction(
                    *accounts[INVOKED_PROGRAM_INDEX].key,
                    &[
                        (accounts[ARGUMENT_INDEX].key, true, true),
                        (accounts[INVOKED_ARGUMENT_INDEX].key, true, true),
                        (accounts[INVOKED_PROGRAM_INDEX].key, false, false),
                        (accounts[INVOKED_PROGRAM_DUP_INDEX].key, false, false),
                    ],
                    vec![TEST_VERIFY_TRANSLATIONS, 1, 2, 3, 4, 5],
                );
                invoke(&instruction, accounts)?;
            }

            info!("Test return error");
            {
                let instruction = create_instruction(
                    *accounts[INVOKED_PROGRAM_INDEX].key,
                    &[(accounts[ARGUMENT_INDEX].key, true, true)],
                    vec![TEST_RETURN_ERROR],
                );
                assert_eq!(
                    invoke(&instruction, accounts),
                    Err(ProgramError::Custom(42))
                );
            }

            info!("Test create_program_address");
            {
                assert_eq!(
                    &Pubkey::create_program_address(&[b"You pass butter", &[nonce1]], program_id)?,
                    accounts[DERIVED_KEY1_INDEX].key
                );
                assert_eq!(
                    Pubkey::create_program_address(&[b"You pass butter"], &Pubkey::default())
                        .unwrap_err(),
                    PubkeyError::InvalidSeeds
                );
            }

            info!("Test derived signers");
            {
                assert!(!accounts[DERIVED_KEY1_INDEX].is_signer);
                assert!(!accounts[DERIVED_KEY2_INDEX].is_signer);
                assert!(!accounts[DERIVED_KEY3_INDEX].is_signer);

                let invoked_instruction = create_instruction(
                    *accounts[INVOKED_PROGRAM_INDEX].key,
                    &[
                        (accounts[INVOKED_PROGRAM_INDEX].key, false, false),
                        (accounts[DERIVED_KEY1_INDEX].key, true, true),
                        (accounts[DERIVED_KEY2_INDEX].key, true, false),
                        (accounts[DERIVED_KEY3_INDEX].key, false, false),
                    ],
                    vec![TEST_DERIVED_SIGNERS, nonce2, nonce3],
                );
                invoke_signed(
                    &invoked_instruction,
                    accounts,
                    &[&[b"You pass butter", &[nonce1]]],
                )?;

                let invoked_instruction = create_instruction(
                    *accounts[INVOKED_PROGRAM_INDEX].key,
                    &[
                        (accounts[DERIVED_KEY1_INDEX].key, true, false),
                        (accounts[DERIVED_KEY2_INDEX].key, true, true),
                        (accounts[DERIVED_KEY3_INDEX].key, false, true),
                    ],
                    vec![TEST_VERIFY_NESTED_SIGNERS],
                );
                invoke_signed(
                    &invoked_instruction,
                    accounts,
                    &[
                        &[b"Lil'", b"Bits", &[nonce2]],
                        &[accounts[DERIVED_KEY2_INDEX].key.as_ref(), &[nonce3]],
                    ],
                )?;
            }

            info!("Test readonly with writable account");
            {
                let invoked_instruction = create_instruction(
                    *accounts[INVOKED_PROGRAM_INDEX].key,
                    &[(accounts[ARGUMENT_INDEX].key, false, true)],
                    vec![TEST_VERIFY_WRITER],
                );
                invoke(&invoked_instruction, accounts)?;
            }

            info!("Test nested invoke");
            {
                assert!(accounts[ARGUMENT_INDEX].is_signer);

                **accounts[ARGUMENT_INDEX].lamports.borrow_mut() -= 5;
                **accounts[INVOKED_ARGUMENT_INDEX].lamports.borrow_mut() += 5;

                info!("First invoke");
                let instruction = create_instruction(
                    *accounts[INVOKED_PROGRAM_INDEX].key,
                    &[
                        (accounts[ARGUMENT_INDEX].key, true, true),
                        (accounts[INVOKED_ARGUMENT_INDEX].key, true, true),
                    ],
                    vec![TEST_NESTED_INVOKE],
                );
                invoke(&instruction, accounts)?;
                info!("2nd invoke from first program");
                invoke(&instruction, accounts)?;

                info!(line!(), 0, 0, 0, accounts[ARGUMENT_INDEX].lamports());
                assert_eq!(accounts[ARGUMENT_INDEX].lamports(), 42 - 5 + 1 + 1);
                assert_eq!(accounts[INVOKED_ARGUMENT_INDEX].lamports(), 10 + 5 - 1 - 1);
            }

            info!("Verify data values are retained and updated");
            {
                let data = accounts[ARGUMENT_INDEX].try_borrow_data()?;
                for i in 0..100 {
                    assert_eq!(data[i as usize], i);
                }
                let data = accounts[INVOKED_ARGUMENT_INDEX].try_borrow_data()?;
                for i in 0..10 {
                    assert_eq!(data[i as usize], i);
                }
            }
        }
        TEST_PRIVILEGE_ESCALATION_SIGNER => {
            info!("Test privilege escalation signer");
            let mut invoked_instruction = create_instruction(
                *accounts[INVOKED_PROGRAM_INDEX].key,
                &[(accounts[DERIVED_KEY3_INDEX].key, false, false)],
                vec![TEST_VERIFY_PRIVILEGE_ESCALATION],
            );
            invoke(&invoked_instruction, accounts)?;

            // Signer privilege escalation will always fail the whole transaction
            invoked_instruction.accounts[0].is_signer = true;
            assert_eq!(
                invoke(&invoked_instruction, accounts),
                Err(ProgramError::Custom(0x0b9f_0002))
            );
        }
        TEST_PRIVILEGE_ESCALATION_WRITABLE => {
            info!("Test privilege escalation writable");
            let mut invoked_instruction = create_instruction(
                *accounts[INVOKED_PROGRAM_INDEX].key,
                &[(accounts[DERIVED_KEY3_INDEX].key, false, false)],
                vec![TEST_VERIFY_PRIVILEGE_ESCALATION],
            );
            invoke(&invoked_instruction, accounts)?;

            // Writable privilege escalation will always fail the whole transaction
            invoked_instruction.accounts[0].is_writable = true;
            assert_eq!(
                invoke(&invoked_instruction, accounts),
                Err(ProgramError::Custom(0x0b9f_0002))
            );
        }
        _ => panic!(),
    }

    Ok(())
}

#[cfg(test)]
mod test {
    use super::*;
    // Pull in syscall stubs when building for non-BPF targets
    solana_sdk::program_stubs!();

    #[test]
    fn create_program_address_is_defined() {
        assert_eq!(
            Pubkey::create_program_address(&[b"You pass butter"], &Pubkey::default()).unwrap_err(),
            PubkeyError::InvalidSeeds
        );
    }
}