use crate::{
    assets::AssetVault,
    utils::serde::{ByteReader, ByteWriter, Deserializable, DeserializationError, Serializable},
    AccountError, Digest, Felt, Hasher, Word, ZERO,
};

pub mod account_id;
pub use account_id::{
    AccountId, AccountStorageType, AccountType, ACCOUNT_ISFAUCET_MASK, ACCOUNT_STORAGE_MASK_SHIFT,
    ACCOUNT_TYPE_MASK_SHIFT,
};

pub mod auth;
pub use auth::AuthSecretKey;

pub mod code;
pub use code::{procedure::AccountProcedureInfo, AccountCode};

pub mod delta;
pub use delta::{
    AccountDelta, AccountStorageDelta, AccountVaultDelta, FungibleAssetDelta,
    NonFungibleAssetDelta, NonFungibleDeltaAction, StorageMapDelta,
};

mod seed;
pub use seed::{get_account_seed, get_account_seed_single};

mod storage;
pub use storage::{AccountStorage, SlotItem, StorageMap, StorageSlot, StorageSlotType};

mod stub;
pub use stub::AccountStub;

mod data;
pub use data::AccountData;

// ACCOUNT
// ================================================================================================

/// An account which can store assets and define rules for manipulating them.
///
/// An account consists of the following components:
/// - Account ID, which uniquely identifies the account and also defines basic properties of the
///   account.
/// - Account vault, which stores assets owned by the account.
/// - Account storage, which is a key-value map (both keys and values are words) used to store
///   arbitrary user-defined data.
/// - Account code, which is a set of Miden VM programs defining the public interface of the
///   account.
/// - Account nonce, a value which is incremented whenever account state is updated.
///
/// Out of the above components account ID is always immutable (once defined it can never be
/// changed). Other components may be mutated throughout the lifetime of the account. However,
/// account state can be changed only by invoking one of account interface methods.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Account {
    id: AccountId,
    vault: AssetVault,
    storage: AccountStorage,
    code: AccountCode,
    nonce: Felt,
}

impl Account {
    // CONSTRUCTORS
    // --------------------------------------------------------------------------------------------

    /// Creates and returns a new [Account] instantiated with the specified code, storage, and
    /// account seed.
    ///
    /// The returned account has an empty asset vault and the nonce which is initialized to ZERO.
    ///
    /// # Errors
    /// Returns an error if deriving account ID from the specified seed fails.
    pub fn new(
        seed: Word,
        code: AccountCode,
        storage: AccountStorage,
    ) -> Result<Self, AccountError> {
        let id = AccountId::new(seed, code.commitment(), storage.root())?;
        let vault = AssetVault::default();
        let nonce = ZERO;
        Ok(Self { id, vault, storage, code, nonce })
    }

    /// Returns an [Account] instantiated with the provided components.
    pub fn from_parts(
        id: AccountId,
        vault: AssetVault,
        storage: AccountStorage,
        code: AccountCode,
        nonce: Felt,
    ) -> Self {
        Self { id, vault, storage, code, nonce }
    }

    // PUBLIC ACCESSORS
    // --------------------------------------------------------------------------------------------

    /// Returns hash of this account.
    ///
    /// Hash of an account is computed as hash(id, nonce, vault_root, storage_root,
    /// code_commitment). Computing the account hash requires 2 permutations of the hash
    /// function.
    pub fn hash(&self) -> Digest {
        hash_account(
            self.id,
            self.nonce,
            self.vault.commitment(),
            self.storage.root(),
            self.code.commitment(),
        )
    }

    /// Returns hash of this account as used for the initial account state hash in transaction
    /// proofs.
    ///
    /// For existing accounts, this is exactly the same as [Account::hash()], however, for new
    /// accounts this value is set to [crate::EMPTY_WORD]. This is because when a transaction is
    /// executed against a new account, public input for the initial account state is set to
    /// [crate::EMPTY_WORD] to distinguish new accounts from existing accounts. The actual hash of
    /// the initial account state (and the initial state itself), are provided to the VM via the
    /// advice provider.
    pub fn init_hash(&self) -> Digest {
        if self.is_new() {
            Digest::default()
        } else {
            self.hash()
        }
    }

    /// Returns unique identifier of this account.
    pub fn id(&self) -> AccountId {
        self.id
    }

    /// Returns the account type
    pub fn account_type(&self) -> AccountType {
        self.id.account_type()
    }

    /// Returns a reference to the vault of this account.
    pub fn vault(&self) -> &AssetVault {
        &self.vault
    }

    /// Returns a reference to the storage of this account.
    pub fn storage(&self) -> &AccountStorage {
        &self.storage
    }

    /// Returns a reference to the code of this account.
    pub fn code(&self) -> &AccountCode {
        &self.code
    }

    /// Returns nonce for this account.
    pub fn nonce(&self) -> Felt {
        self.nonce
    }

    /// Returns true if this account can issue assets.
    pub fn is_faucet(&self) -> bool {
        self.id.is_faucet()
    }

    /// Returns true if this is a regular account.
    pub fn is_regular_account(&self) -> bool {
        self.id.is_regular_account()
    }

    /// Returns true if this account is on-chain.
    pub fn is_on_chain(&self) -> bool {
        self.id.is_on_chain()
    }

    /// Returns true if the account is new (i.e. it has not been initialized yet).
    pub fn is_new(&self) -> bool {
        self.nonce == ZERO
    }

    // DATA MUTATORS
    // --------------------------------------------------------------------------------------------

    /// Applies the provided delta to this account. This updates account vault, storage, and nonce
    /// to the values specified by the delta.
    ///
    /// # Errors
    /// Returns an error if:
    /// - Applying vault sub-delta to the vault of this account fails.
    /// - Applying storage sub-delta to the storage of this account fails.
    /// - The nonce specified in the provided delta smaller than or equal to the current account
    ///   nonce.
    pub fn apply_delta(&mut self, delta: &AccountDelta) -> Result<(), AccountError> {
        // update vault; we don't check vault delta validity here because `AccountDelta` can contain
        // only valid vault deltas
        self.vault
            .apply_delta(delta.vault())
            .map_err(AccountError::AssetVaultUpdateError)?;

        // update storage
        self.storage.apply_delta(delta.storage())?;

        // update nonce
        if let Some(nonce) = delta.nonce() {
            self.set_nonce(nonce)?;
        }

        Ok(())
    }

    /// Sets the nonce of this account to the specified nonce value.
    ///
    /// # Errors
    /// Returns an error if:
    /// - The new nonce is smaller than the actual account nonce
    /// - The new nonce is equal to the actual account nonce
    pub fn set_nonce(&mut self, nonce: Felt) -> Result<(), AccountError> {
        if self.nonce.as_int() >= nonce.as_int() {
            return Err(AccountError::NonceNotMonotonicallyIncreasing {
                current: self.nonce.as_int(),
                new: nonce.as_int(),
            });
        }

        self.nonce = nonce;

        Ok(())
    }

    // TEST HELPERS
    // --------------------------------------------------------------------------------------------

    #[cfg(feature = "testing")]
    /// Returns a mutable reference to the vault of this account.
    pub fn vault_mut(&mut self) -> &mut AssetVault {
        &mut self.vault
    }
}

// SERIALIZATION
// ================================================================================================

impl Serializable for Account {
    fn write_into<W: ByteWriter>(&self, target: &mut W) {
        let Account { id, vault, storage, code, nonce } = self;

        id.write_into(target);
        vault.write_into(target);
        storage.write_into(target);
        code.write_into(target);
        nonce.write_into(target);
    }
}

impl Deserializable for Account {
    fn read_from<R: ByteReader>(source: &mut R) -> Result<Self, DeserializationError> {
        let id = AccountId::read_from(source)?;
        let vault = AssetVault::read_from(source)?;
        let storage = AccountStorage::read_from(source)?;
        let code = AccountCode::read_from(source)?;
        let nonce = Felt::read_from(source)?;

        Ok(Self::from_parts(id, vault, storage, code, nonce))
    }
}

#[cfg(feature = "serde")]
impl serde::Serialize for Account {
    fn serialize<S: serde::Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
        let bytes = self.to_bytes();
        serializer.serialize_bytes(&bytes)
    }
}

#[cfg(feature = "serde")]
impl<'de> serde::Deserialize<'de> for Account {
    fn deserialize<D: serde::Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
        use alloc::vec::Vec;

        let bytes: Vec<u8> = <Vec<u8> as serde::Deserialize>::deserialize(deserializer)?;
        Self::read_from_bytes(&bytes).map_err(serde::de::Error::custom)
    }
}

// HELPERS
// ================================================================================================

/// Returns hash of an account with the specified ID, nonce, vault root, storage root, and code
/// commitment.
///
/// Hash of an account is computed as hash(id, nonce, vault_root, storage_root, code_commitment).
/// Computing the account hash requires 2 permutations of the hash function.
pub fn hash_account(
    id: AccountId,
    nonce: Felt,
    vault_root: Digest,
    storage_root: Digest,
    code_commitment: Digest,
) -> Digest {
    let mut elements = [ZERO; 16];
    elements[0] = id.into();
    elements[3] = nonce;
    elements[4..8].copy_from_slice(&*vault_root);
    elements[8..12].copy_from_slice(&*storage_root);
    elements[12..].copy_from_slice(&*code_commitment);
    Hasher::hash_elements(&elements)
}

// TESTS
// ================================================================================================

#[cfg(test)]
mod tests {
    use alloc::collections::BTreeMap;

    use miden_crypto::{
        utils::{Deserializable, Serializable},
        Felt, Word,
    };
    use vm_processor::Digest;

    use super::{AccountDelta, AccountStorageDelta, AccountVaultDelta};
    use crate::{
        accounts::{Account, SlotItem, StorageMap, StorageMapDelta},
        testing::storage::{
            build_account, build_account_delta, build_assets, AccountStorageDeltaBuilder,
        },
    };

    #[test]
    fn test_serde_account() {
        let init_nonce = Felt::new(1);
        let (asset_0, _) = build_assets();
        let word = [Felt::new(1), Felt::new(2), Felt::new(3), Felt::new(4)];
        let slot_item = SlotItem::new_value(0, 0, word);
        let account = build_account(vec![asset_0], init_nonce, vec![slot_item], None);

        let serialized = account.to_bytes();
        let deserialized = Account::read_from_bytes(&serialized).unwrap();
        assert_eq!(deserialized, account);
    }

    #[test]
    fn test_serde_account_delta() {
        let final_nonce = Felt::new(2);
        let (asset_0, asset_1) = build_assets();
        let storage_delta = AccountStorageDeltaBuilder::default()
            .add_cleared_items([0])
            .add_updated_items([(1_u8, [Felt::new(1), Felt::new(2), Felt::new(3), Felt::new(4)])])
            .build()
            .unwrap();
        let account_delta =
            build_account_delta(vec![asset_1], vec![asset_0], final_nonce, storage_delta);

        let serialized = account_delta.to_bytes();
        let deserialized = AccountDelta::read_from_bytes(&serialized).unwrap();
        assert_eq!(deserialized, account_delta);
    }

    #[test]
    fn valid_account_delta_is_correctly_applied() {
        // build account
        let init_nonce = Felt::new(1);
        let (asset_0, asset_1) = build_assets();

        // Simple SlotItem
        let word = [Felt::new(1), Felt::new(2), Felt::new(3), Felt::new(4)];
        let slot_item = SlotItem::new_value(0, 0, word);

        // StorageMap with values
        let storage_map_leaves_2: [(Digest, Word); 2] = [
            (
                Digest::new([Felt::new(101), Felt::new(102), Felt::new(103), Felt::new(104)]),
                [Felt::new(1_u64), Felt::new(2_u64), Felt::new(3_u64), Felt::new(4_u64)],
            ),
            (
                Digest::new([Felt::new(105), Felt::new(106), Felt::new(107), Felt::new(108)]),
                [Felt::new(5_u64), Felt::new(6_u64), Felt::new(7_u64), Felt::new(8_u64)],
            ),
        ];
        let mut storage_map = StorageMap::with_entries(storage_map_leaves_2).unwrap();
        let mut maps = BTreeMap::new();
        maps.insert(2u8, storage_map.clone());
        let storage_map_root_as_slot_item = SlotItem::new_map(2u8, 0, storage_map.root().into());

        let mut account = build_account(
            vec![asset_0],
            init_nonce,
            vec![slot_item, storage_map_root_as_slot_item],
            Some(maps.clone()),
        );

        let new_map_entry = (
            Digest::new([Felt::new(101), Felt::new(102), Felt::new(103), Felt::new(104)]),
            [Felt::new(9_u64), Felt::new(10_u64), Felt::new(11_u64), Felt::new(12_u64)],
        );
        let updated_map =
            StorageMapDelta::from_iters([], [(new_map_entry.0.into(), new_map_entry.1)]);
        storage_map.insert(new_map_entry.0, new_map_entry.1);
        maps.insert(2u8, storage_map.clone());

        // build account delta
        let final_nonce = Felt::new(2);
        let storage_delta = AccountStorageDeltaBuilder::default()
            .add_cleared_items([0])
            .add_updated_items([(1_u8, [Felt::new(1), Felt::new(2), Felt::new(3), Felt::new(4)])])
            .add_updated_maps([(2_u8, updated_map)])
            .build()
            .unwrap();
        let account_delta =
            build_account_delta(vec![asset_1], vec![asset_0], final_nonce, storage_delta);

        // apply delta and create final_account
        account.apply_delta(&account_delta).unwrap();

        let final_account = build_account(
            vec![asset_1],
            final_nonce,
            vec![
                SlotItem::new_value(0, 0, Word::default()),
                SlotItem::new_value(1, 0, word),
                SlotItem::new_map(2, 0, storage_map.root().into()),
            ],
            Some(maps),
        );

        // assert account is what it should be
        assert_eq!(account, final_account);
    }

    #[test]
    #[should_panic]
    fn valid_account_delta_with_unchanged_nonce() {
        // build account
        let init_nonce = Felt::new(1);
        let (asset, _) = build_assets();
        let mut account = build_account(
            vec![asset],
            init_nonce,
            vec![SlotItem::new_value(0, 0, Word::default())],
            None,
        );

        // build account delta
        let storage_delta = AccountStorageDeltaBuilder::default()
            .add_cleared_items([0])
            .add_updated_items([(1_u8, [Felt::new(1), Felt::new(2), Felt::new(3), Felt::new(4)])])
            .build()
            .unwrap();
        let account_delta = build_account_delta(vec![], vec![asset], init_nonce, storage_delta);

        // apply delta
        account.apply_delta(&account_delta).unwrap()
    }

    #[test]
    #[should_panic]
    fn valid_account_delta_with_decremented_nonce() {
        // build account
        let init_nonce = Felt::new(2);
        let (asset, _) = build_assets();
        let mut account = build_account(
            vec![asset],
            init_nonce,
            vec![SlotItem::new_value(0, 0, Word::default())],
            None,
        );

        // build account delta
        let final_nonce = Felt::new(1);
        let storage_delta = AccountStorageDeltaBuilder::default()
            .add_cleared_items([0])
            .add_updated_items([(1_u8, [Felt::new(1), Felt::new(2), Felt::new(3), Felt::new(4)])])
            .build()
            .unwrap();
        let account_delta = build_account_delta(vec![], vec![asset], final_nonce, storage_delta);

        // apply delta
        account.apply_delta(&account_delta).unwrap()
    }

    #[test]
    fn empty_account_delta_with_incremented_nonce() {
        // build account
        let init_nonce = Felt::new(1);
        let word = [Felt::new(1), Felt::new(2), Felt::new(3), Felt::new(4)];
        let slot_item = SlotItem::new_value(0, 0, word);
        let mut account = build_account(vec![], init_nonce, vec![slot_item], None);

        // build account delta
        let final_nonce = Felt::new(2);
        let account_delta = AccountDelta::new(
            AccountStorageDelta::default(),
            AccountVaultDelta::default(),
            Some(final_nonce),
        )
        .unwrap();

        // apply delta
        account.apply_delta(&account_delta).unwrap()
    }
}