use crate::config::StoreConfigError;
use crate::hot_cold_store::{HotColdDBError, StateSummaryIteratorError};
use crate::{DBColumn, hdiff};
#[cfg(feature = "leveldb")]
use leveldb::error::Error as LevelDBError;
use ssz::DecodeError;
use state_processing::BlockReplayError;
use types::{BeaconStateError, EpochCacheError, Hash256, InconsistentFork, Slot};

pub type Result<T> = std::result::Result<T, Error>;

#[derive(Debug)]
pub enum Error {
    SszDecodeError(DecodeError),
    BeaconStateError(BeaconStateError),
    HotColdDBError(HotColdDBError),
    DBError {
        message: String,
    },
    RlpError(String),
    BlockNotFound(Hash256),
    NoContinuationData,
    SplitPointModified(Slot, Slot),
    ConfigError(StoreConfigError),
    MigrationError(String),
    /// The store's `anchor_info` is still the default uninitialized value when attempting a state
    /// write
    AnchorUninitialized,
    /// The store's `anchor_info` was mutated concurrently, the latest modification wasn't applied.
    AnchorInfoConcurrentMutation,
    /// The store's `blob_info` was mutated concurrently, the latest modification wasn't applied.
    BlobInfoConcurrentMutation,
    /// The store's `data_column_info` was mutated concurrently, the latest modification wasn't applied.
    DataColumnInfoConcurrentMutation,
    /// The block or state is unavailable due to weak subjectivity sync.
    HistoryUnavailable,
    /// State reconstruction cannot commence because not all historic blocks are known.
    MissingHistoricBlocks {
        oldest_block_slot: Slot,
    },
    /// State reconstruction failed because it didn't reach the upper limit slot.
    ///
    /// This should never happen (it's a logic error).
    StateReconstructionLogicError,
    StateReconstructionRootMismatch {
        slot: Slot,
        expected: Hash256,
        computed: Hash256,
    },
    MissingState(Hash256),
    MissingHotStateSummary(Hash256),
    MissingHotStateSnapshot(Hash256, Slot),
    MissingGenesisState,
    MissingSnapshot(Slot),
    LoadingHotHdiffBufferError(String, Hash256, Box<Error>),
    LoadingHotStateError(String, Hash256, Box<Error>),
    BlockReplayError(BlockReplayError),
    AddPayloadLogicError,
    InvalidKey(String),
    InvalidBytes,
    InconsistentFork(InconsistentFork),
    #[cfg(feature = "leveldb")]
    LevelDbError(LevelDBError),
    #[cfg(feature = "redb")]
    RedbError(Box<redb::Error>),
    CacheBuildError(EpochCacheError),
    RandaoMixOutOfBounds,
    MilhouseError(milhouse::Error),
    SszTypesError(ssz_types::Error),
    Compression(std::io::Error),
    FinalizedStateDecreasingSlot,
    FinalizedStateUnaligned,
    StateForCacheHasPendingUpdates {
        state_root: Hash256,
        slot: Slot,
    },
    Hdiff(hdiff::Error),
    ForwardsIterInvalidColumn(DBColumn),
    ForwardsIterGap(DBColumn, Slot, Slot),
    StateShouldNotBeRequired(Slot),
    MissingBlock(Hash256),
    GenesisStateUnknown,
    ArithError(safe_arith::ArithError),
    MismatchedDiffBaseState {
        expected_slot: Slot,
        stored_slot: Slot,
    },
    SnapshotDiffBaseState {
        slot: Slot,
    },
    LoadAnchorInfo(Box<Error>),
    LoadSplit(Box<Error>),
    LoadBlobInfo(Box<Error>),
    LoadDataColumnInfo(Box<Error>),
    LoadConfig(Box<Error>),
    LoadHotStateSummary(Hash256, Box<Error>),
    LoadHotStateSummaryForSplit(Box<Error>),
    StateSummaryIteratorError {
        error: StateSummaryIteratorError,
        from_state_root: Hash256,
        from_state_slot: Slot,
        target_slot: Slot,
    },
}

pub trait HandleUnavailable<T> {
    fn handle_unavailable(self) -> std::result::Result<Option<T>, Error>;
}

impl<T> HandleUnavailable<T> for Result<T> {
    fn handle_unavailable(self) -> std::result::Result<Option<T>, Error> {
        match self {
            Ok(x) => Ok(Some(x)),
            Err(Error::HistoryUnavailable) => Ok(None),
            Err(e) => Err(e),
        }
    }
}

impl From<DecodeError> for Error {
    fn from(e: DecodeError) -> Error {
        Error::SszDecodeError(e)
    }
}

impl From<HotColdDBError> for Error {
    fn from(e: HotColdDBError) -> Error {
        Error::HotColdDBError(e)
    }
}

impl From<BeaconStateError> for Error {
    fn from(e: BeaconStateError) -> Error {
        Error::BeaconStateError(e)
    }
}

impl From<DBError> for Error {
    fn from(e: DBError) -> Error {
        Error::DBError { message: e.message }
    }
}

impl From<StoreConfigError> for Error {
    fn from(e: StoreConfigError) -> Error {
        Error::ConfigError(e)
    }
}

impl From<milhouse::Error> for Error {
    fn from(e: milhouse::Error) -> Self {
        Self::MilhouseError(e)
    }
}

impl From<ssz_types::Error> for Error {
    fn from(e: ssz_types::Error) -> Self {
        Self::SszTypesError(e)
    }
}

impl From<hdiff::Error> for Error {
    fn from(e: hdiff::Error) -> Self {
        Self::Hdiff(e)
    }
}

impl From<BlockReplayError> for Error {
    fn from(e: BlockReplayError) -> Error {
        Error::BlockReplayError(e)
    }
}

impl From<InconsistentFork> for Error {
    fn from(e: InconsistentFork) -> Error {
        Error::InconsistentFork(e)
    }
}

#[cfg(feature = "leveldb")]
impl From<LevelDBError> for Error {
    fn from(e: LevelDBError) -> Error {
        Error::LevelDbError(e)
    }
}

#[cfg(feature = "redb")]
impl From<redb::Error> for Error {
    fn from(e: redb::Error) -> Self {
        Error::RedbError(Box::new(e))
    }
}

#[cfg(feature = "redb")]
impl From<redb::TableError> for Error {
    fn from(e: redb::TableError) -> Self {
        Error::RedbError(Box::new(e.into()))
    }
}

#[cfg(feature = "redb")]
impl From<redb::TransactionError> for Error {
    fn from(e: redb::TransactionError) -> Self {
        Error::RedbError(Box::new(e.into()))
    }
}

#[cfg(feature = "redb")]
impl From<redb::DatabaseError> for Error {
    fn from(e: redb::DatabaseError) -> Self {
        Error::RedbError(Box::new(e.into()))
    }
}

#[cfg(feature = "redb")]
impl From<redb::StorageError> for Error {
    fn from(e: redb::StorageError) -> Self {
        Error::RedbError(Box::new(e.into()))
    }
}

#[cfg(feature = "redb")]
impl From<redb::CommitError> for Error {
    fn from(e: redb::CommitError) -> Self {
        Error::RedbError(Box::new(e.into()))
    }
}

#[cfg(feature = "redb")]
impl From<redb::CompactionError> for Error {
    fn from(e: redb::CompactionError) -> Self {
        Error::RedbError(Box::new(e.into()))
    }
}

impl From<EpochCacheError> for Error {
    fn from(e: EpochCacheError) -> Error {
        Error::CacheBuildError(e)
    }
}

impl From<safe_arith::ArithError> for Error {
    fn from(e: safe_arith::ArithError) -> Error {
        Error::ArithError(e)
    }
}

#[derive(Debug)]
pub struct DBError {
    pub message: String,
}

impl DBError {
    pub fn new(message: String) -> Self {
        Self { message }
    }
}