use crate::{
    decode_error::DecodeError,
    instruction::{AccountMeta, Instruction},
    nonce,
    pubkey::Pubkey,
    system_program,
    sysvar::{recent_blockhashes, rent},
};
use num_derive::{FromPrimitive, ToPrimitive};
use thiserror::Error;

#[derive(Error, Debug, Serialize, Clone, PartialEq, FromPrimitive, ToPrimitive)]
pub enum SystemError {
    #[error("an account with the same address already exists")]
    AccountAlreadyInUse,
    #[error("account does not have enough SOL to perform the operation")]
    ResultWithNegativeLamports,
    #[error("cannot assign account to this program id")]
    InvalidProgramId,
    #[error("cannot allocate account data of this length")]
    InvalidAccountDataLength,
    #[error("length of requested seed is too long")]
    MaxSeedLengthExceeded,
    #[error("provided address does not match addressed derived from seed")]
    AddressWithSeedMismatch,
}

impl<T> DecodeError<T> for SystemError {
    fn type_of() -> &'static str {
        "SystemError"
    }
}

#[derive(Error, Debug, Clone, PartialEq, FromPrimitive, ToPrimitive)]
pub enum NonceError {
    #[error("recent blockhash list is empty")]
    NoRecentBlockhashes,
    #[error("stored nonce is still in recent_blockhashes")]
    NotExpired,
    #[error("specified nonce does not match stored nonce")]
    UnexpectedValue,
    #[error("cannot handle request in current account state")]
    BadAccountState,
}

impl<E> DecodeError<E> for NonceError {
    fn type_of() -> &'static str {
        "NonceError"
    }
}

/// maximum permitted size of data: 10 MB
pub const MAX_PERMITTED_DATA_LENGTH: u64 = 10 * 1024 * 1024;

#[derive(Serialize, Deserialize, Debug, Clone, PartialEq)]
pub enum SystemInstruction {
    /// Create a new account
    ///
    /// # Account references
    ///   0. [WRITE, SIGNER] Funding account
    ///   1. [WRITE, SIGNER] New account
    CreateAccount {
        /// Number of lamports to transfer to the new account
        lamports: u64,

        /// Number of bytes of memory to allocate
        space: u64,

        /// Address of program that will own the new account
        owner: Pubkey,
    },

    /// Assign account to a program
    ///
    /// # Account references
    ///   0. [WRITE, SIGNER] Assigned account public key
    Assign {
        /// Owner program account
        owner: Pubkey,
    },

    /// Transfer lamports
    ///
    /// # Account references
    ///   0. [WRITE, SIGNER] Funding account
    ///   1. [WRITE] Recipient account
    Transfer { lamports: u64 },

    /// Create a new account at an address derived from a base pubkey and a seed
    ///
    /// # Account references
    ///   0. [WRITE, SIGNER] Funding account
    ///   1. [WRITE] Created account
    ///   2. [SIGNER] Base account
    CreateAccountWithSeed {
        /// Base public key
        base: Pubkey,

        /// String of ASCII chars, no longer than `Pubkey::MAX_SEED_LEN`
        seed: String,

        /// Number of lamports to transfer to the new account
        lamports: u64,

        /// Number of bytes of memory to allocate
        space: u64,

        /// Owner program account address
        owner: Pubkey,
    },

    /// Consumes a stored nonce, replacing it with a successor
    ///
    /// # Account references
    ///   0. [WRITE, SIGNER] Nonce account
    ///   1. [] RecentBlockhashes sysvar
    ///   2. [SIGNER] Nonce authority
    AdvanceNonceAccount,

    /// Withdraw funds from a nonce account
    ///
    /// # Account references
    ///   0. [WRITE] Nonce account
    ///   1. [WRITE] Recipient account
    ///   2. [] RecentBlockhashes sysvar
    ///   3. [] Rent sysvar
    ///   4. [SIGNER] Nonce authority
    ///
    /// The `u64` parameter is the lamports to withdraw, which must leave the
    /// account balance above the rent exempt reserve or at zero.
    WithdrawNonceAccount(u64),

    /// Drive state of Uninitalized nonce account to Initialized, setting the nonce value
    ///
    /// # Account references
    ///   0. [WRITE] Nonce account
    ///   1. [] RecentBlockhashes sysvar
    ///   2. [] Rent sysvar
    ///
    /// The `Pubkey` parameter specifies the entity authorized to execute nonce
    /// instruction on the account
    ///
    /// No signatures are required to execute this instruction, enabling derived
    /// nonce account addresses
    InitializeNonceAccount(Pubkey),

    /// Change the entity authorized to execute nonce instructions on the account
    ///
    /// # Account references
    ///   0. [WRITE, SIGNER] Nonce account
    ///
    /// The `Pubkey` parameter identifies the entity to authorize
    AuthorizeNonceAccount(Pubkey),

    /// Allocate space in a (possibly new) account without funding
    ///
    /// # Account references
    ///   0. [WRITE, SIGNER] New account
    Allocate {
        /// Number of bytes of memory to allocate
        space: u64,
    },

    /// Allocate space for and assign an account at an address
    ///    derived from a base public key and a seed
    ///
    /// # Account references
    ///   0. [WRITE] Allocated account
    ///   1. [SIGNER] Base account
    AllocateWithSeed {
        /// Base public key
        base: Pubkey,

        /// String of ASCII chars, no longer than `pubkey::MAX_SEED_LEN`
        seed: String,

        /// Number of bytes of memory to allocate
        space: u64,

        /// Owner program account
        owner: Pubkey,
    },

    /// Assign account to a program based on a seed
    ///
    /// # Account references
    ///   0. [WRITE] Assigned account
    ///   1. [SIGNER] Base account
    AssignWithSeed {
        /// Base public key
        base: Pubkey,

        /// String of ASCII chars, no longer than `pubkey::MAX_SEED_LEN`
        seed: String,

        /// Owner program account
        owner: Pubkey,
    },
}

pub fn create_account(
    from_pubkey: &Pubkey,
    to_pubkey: &Pubkey,
    lamports: u64,
    space: u64,
    owner: &Pubkey,
) -> Instruction {
    let account_metas = vec![
        AccountMeta::new(*from_pubkey, true),
        AccountMeta::new(*to_pubkey, true),
    ];
    Instruction::new(
        system_program::id(),
        &SystemInstruction::CreateAccount {
            lamports,
            space,
            owner: *owner,
        },
        account_metas,
    )
}

// we accept `to` as a parameter so that callers do their own error handling when
//   calling create_address_with_seed()
pub fn create_account_with_seed(
    from_pubkey: &Pubkey,
    to_pubkey: &Pubkey, // must match create_address_with_seed(base, seed, owner)
    base: &Pubkey,
    seed: &str,
    lamports: u64,
    space: u64,
    owner: &Pubkey,
) -> Instruction {
    let account_metas = vec![
        AccountMeta::new(*from_pubkey, true),
        AccountMeta::new(*to_pubkey, false),
        AccountMeta::new_readonly(*base, true),
    ];

    Instruction::new(
        system_program::id(),
        &SystemInstruction::CreateAccountWithSeed {
            base: *base,
            seed: seed.to_string(),
            lamports,
            space,
            owner: *owner,
        },
        account_metas,
    )
}

pub fn assign(pubkey: &Pubkey, owner: &Pubkey) -> Instruction {
    let account_metas = vec![AccountMeta::new(*pubkey, true)];
    Instruction::new(
        system_program::id(),
        &SystemInstruction::Assign { owner: *owner },
        account_metas,
    )
}

pub fn assign_with_seed(
    address: &Pubkey, // must match create_address_with_seed(base, seed, owner)
    base: &Pubkey,
    seed: &str,
    owner: &Pubkey,
) -> Instruction {
    let account_metas = vec![
        AccountMeta::new(*address, false),
        AccountMeta::new_readonly(*base, true),
    ];
    Instruction::new(
        system_program::id(),
        &SystemInstruction::AssignWithSeed {
            base: *base,
            seed: seed.to_string(),
            owner: *owner,
        },
        account_metas,
    )
}

pub fn transfer(from_pubkey: &Pubkey, to_pubkey: &Pubkey, lamports: u64) -> Instruction {
    let account_metas = vec![
        AccountMeta::new(*from_pubkey, true),
        AccountMeta::new(*to_pubkey, false),
    ];
    Instruction::new(
        system_program::id(),
        &SystemInstruction::Transfer { lamports },
        account_metas,
    )
}

pub fn allocate(pubkey: &Pubkey, space: u64) -> Instruction {
    let account_metas = vec![AccountMeta::new(*pubkey, true)];
    Instruction::new(
        system_program::id(),
        &SystemInstruction::Allocate { space },
        account_metas,
    )
}

pub fn allocate_with_seed(
    address: &Pubkey, // must match create_address_with_seed(base, seed, owner)
    base: &Pubkey,
    seed: &str,
    space: u64,
    owner: &Pubkey,
) -> Instruction {
    let account_metas = vec![
        AccountMeta::new(*address, false),
        AccountMeta::new_readonly(*base, true),
    ];
    Instruction::new(
        system_program::id(),
        &SystemInstruction::AllocateWithSeed {
            base: *base,
            seed: seed.to_string(),
            space,
            owner: *owner,
        },
        account_metas,
    )
}

/// Create and sign new SystemInstruction::Transfer transaction to many destinations
pub fn transfer_many(from_pubkey: &Pubkey, to_lamports: &[(Pubkey, u64)]) -> Vec<Instruction> {
    to_lamports
        .iter()
        .map(|(to_pubkey, lamports)| transfer(from_pubkey, to_pubkey, *lamports))
        .collect()
}

pub fn create_nonce_account_with_seed(
    from_pubkey: &Pubkey,
    nonce_pubkey: &Pubkey,
    base: &Pubkey,
    seed: &str,
    authority: &Pubkey,
    lamports: u64,
) -> Vec<Instruction> {
    vec![
        create_account_with_seed(
            from_pubkey,
            nonce_pubkey,
            base,
            seed,
            lamports,
            nonce::State::size() as u64,
            &system_program::id(),
        ),
        Instruction::new(
            system_program::id(),
            &SystemInstruction::InitializeNonceAccount(*authority),
            vec![
                AccountMeta::new(*nonce_pubkey, false),
                AccountMeta::new_readonly(recent_blockhashes::id(), false),
                AccountMeta::new_readonly(rent::id(), false),
            ],
        ),
    ]
}

pub fn create_nonce_account(
    from_pubkey: &Pubkey,
    nonce_pubkey: &Pubkey,
    authority: &Pubkey,
    lamports: u64,
) -> Vec<Instruction> {
    vec![
        create_account(
            from_pubkey,
            nonce_pubkey,
            lamports,
            nonce::State::size() as u64,
            &system_program::id(),
        ),
        Instruction::new(
            system_program::id(),
            &SystemInstruction::InitializeNonceAccount(*authority),
            vec![
                AccountMeta::new(*nonce_pubkey, false),
                AccountMeta::new_readonly(recent_blockhashes::id(), false),
                AccountMeta::new_readonly(rent::id(), false),
            ],
        ),
    ]
}

pub fn advance_nonce_account(nonce_pubkey: &Pubkey, authorized_pubkey: &Pubkey) -> Instruction {
    let account_metas = vec![
        AccountMeta::new(*nonce_pubkey, false),
        AccountMeta::new_readonly(recent_blockhashes::id(), false),
        AccountMeta::new_readonly(*authorized_pubkey, true),
    ];
    Instruction::new(
        system_program::id(),
        &SystemInstruction::AdvanceNonceAccount,
        account_metas,
    )
}

pub fn withdraw_nonce_account(
    nonce_pubkey: &Pubkey,
    authorized_pubkey: &Pubkey,
    to_pubkey: &Pubkey,
    lamports: u64,
) -> Instruction {
    let account_metas = vec![
        AccountMeta::new(*nonce_pubkey, false),
        AccountMeta::new(*to_pubkey, false),
        AccountMeta::new_readonly(recent_blockhashes::id(), false),
        AccountMeta::new_readonly(rent::id(), false),
        AccountMeta::new_readonly(*authorized_pubkey, true),
    ];
    Instruction::new(
        system_program::id(),
        &SystemInstruction::WithdrawNonceAccount(lamports),
        account_metas,
    )
}

pub fn authorize_nonce_account(
    nonce_pubkey: &Pubkey,
    authorized_pubkey: &Pubkey,
    new_authority: &Pubkey,
) -> Instruction {
    let account_metas = vec![
        AccountMeta::new(*nonce_pubkey, false),
        AccountMeta::new_readonly(*authorized_pubkey, true),
    ];
    Instruction::new(
        system_program::id(),
        &SystemInstruction::AuthorizeNonceAccount(*new_authority),
        account_metas,
    )
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::instruction::{Instruction, InstructionError};

    fn get_keys(instruction: &Instruction) -> Vec<Pubkey> {
        instruction.accounts.iter().map(|x| x.pubkey).collect()
    }

    #[test]
    fn test_move_many() {
        let alice_pubkey = Pubkey::new_rand();
        let bob_pubkey = Pubkey::new_rand();
        let carol_pubkey = Pubkey::new_rand();
        let to_lamports = vec![(bob_pubkey, 1), (carol_pubkey, 2)];

        let instructions = transfer_many(&alice_pubkey, &to_lamports);
        assert_eq!(instructions.len(), 2);
        assert_eq!(get_keys(&instructions[0]), vec![alice_pubkey, bob_pubkey]);
        assert_eq!(get_keys(&instructions[1]), vec![alice_pubkey, carol_pubkey]);
    }

    #[test]
    fn test_create_nonce_account() {
        let from_pubkey = Pubkey::new_rand();
        let nonce_pubkey = Pubkey::new_rand();
        let authorized = nonce_pubkey;
        let ixs = create_nonce_account(&from_pubkey, &nonce_pubkey, &authorized, 42);
        assert_eq!(ixs.len(), 2);
        let ix = &ixs[0];
        assert_eq!(ix.program_id, system_program::id());
        let pubkeys: Vec<_> = ix.accounts.iter().map(|am| am.pubkey).collect();
        assert!(pubkeys.contains(&from_pubkey));
        assert!(pubkeys.contains(&nonce_pubkey));
    }

    #[test]
    fn test_nonce_error_decode() {
        use num_traits::FromPrimitive;
        fn pretty_err<T>(err: InstructionError) -> String
        where
            T: 'static + std::error::Error + DecodeError<T> + FromPrimitive,
        {
            if let InstructionError::Custom(code) = err {
                let specific_error: T = T::decode_custom_error_to_enum(code).unwrap();
                format!(
                    "{:?}: {}::{:?} - {}",
                    err,
                    T::type_of(),
                    specific_error,
                    specific_error,
                )
            } else {
                "".to_string()
            }
        }
        assert_eq!(
            "Custom(0): NonceError::NoRecentBlockhashes - recent blockhash list is empty",
            pretty_err::<NonceError>(NonceError::NoRecentBlockhashes.into())
        );
        assert_eq!(
            "Custom(1): NonceError::NotExpired - stored nonce is still in recent_blockhashes",
            pretty_err::<NonceError>(NonceError::NotExpired.into())
        );
        assert_eq!(
            "Custom(2): NonceError::UnexpectedValue - specified nonce does not match stored nonce",
            pretty_err::<NonceError>(NonceError::UnexpectedValue.into())
        );
        assert_eq!(
            "Custom(3): NonceError::BadAccountState - cannot handle request in current account state",
            pretty_err::<NonceError>(NonceError::BadAccountState.into())
        );
    }
}