neptune-consensus 0.14.0

use neptune_mutator_set::removal_record::removal_record_list::RemovalRecordListUnpackError;

use crate::type_scripts::native_currency_amount::NativeCurrencyAmount;

/// The reasons why a [`Block`](crate::block::Block) can be
/// invalid.
///
/// Conversely, defines what it means for a block to be "valid".
#[derive(Debug, Clone, Copy, thiserror::Error, PartialEq, Eq)]
pub enum BlockValidationError {
    // 0. `previous_block` is consistent with current block
    ///   0.a) Block height is previous plus one
    #[error("block height must equal that of predecessor plus one")]
    BlockHeight,
    ///   0.b) Block header points to previous block
    #[error("block header must point to predecessor block")]
    PrevBlockDigest,
    ///   0.c) Block mmr updated correctly
    #[error("block mmr must contain predecessor digest")]
    BlockMmrUpdate,
    ///   0.d) Block timestamp is greater than (or equal to) timestamp of
    ///      previous block plus minimum block time
    #[error("block timestamp must be later than predecessor in excess of minimum block time")]
    MinimumBlockTime,
    ///   0.e) Target difficulty was updated correctly
    #[error("target difficulty must be updated correctly")]
    Difficulty,
    /// 0.f) Cumulative PoW was updated correctly
    #[error("block cumulative proof-of-work must be updated correctly")]
    CumulativeProofOfWork,
    ///   0.g) Block timestamp is less than host-time (utc) + 1 minute + 1ms
    #[error("block must not be from the future")]
    FutureDating,

    // 1. Block proof is valid
    ///   1.a) Verify appendix contains required claims
    #[error("block appendix must contain expected claims")]
    AppendixMissingClaim,
    ///   1.b) Disallow appendices with too many claims
    #[error("block appendix cannot contain too many claims")]
    AppendixTooLarge,
    ///   1.c) Block proof must be SingleProof
    #[error("block proof must be SingleProof")]
    ProofQuality,
    ///   1.d) Block proof is valid
    #[error("block proof must be valid")]
    ProofValidity,
    ///   1.e) Max block size is not exceeded
    #[error("block must not exceed max size")]
    MaxSize,
    ///   1.f) Version field consistent
    #[error("Version in pow field and in header must match")]
    VersionMismatch,

    // 2. The transaction is valid.
    ///   2.a) Unpack the transaction's inputs (removal records). This operation
    ///        is fallible but must succeed.
    #[error("cannot unpack removal records")]
    RemovalRecordsUnpackFailure,
    ///   2.b) Verify that MS removal records are valid, done against previous
    ///      `mutator_set_accumulator`,
    #[error("all removal records must be valid relative to predecessor block's mutator set")]
    RemovalRecordsValidity,
    ///   2.c) Verify that all removal records have unique index sets
    #[error("all removal records must be unique")]
    RemovalRecordsUniqueness,
    ///   2.d) Verify that the mutator set update induced by the block
    ///        is possible
    #[error("mutator set update must be possible")]
    MutatorSetUpdateImpossible,
    ///   2.e) Verify that the mutator set update induced by the block sends
    ///      the old mutator set accumulator to the new one.
    #[error("mutator set must evolve in accordance with transaction")]
    MutatorSetUpdateIntegrity,
    ///   2.f) transaction timestamp <= block timestamp, and not more than 3
    ///        days in the past
    #[error("transaction timestamp must not exceed block timestamp, nor be too old")]
    TransactionTimestamp,
    ///   2.g) transaction coinbase <= block subsidy, and not negative.
    #[error("coinbase cannot exceed block subsidy")]
    CoinbaseTooBig,
    ///   2.h) transaction coinbase <= block subsidy, and not negative.
    #[error("coinbase cannot be negative")]
    NegativeCoinbase,
    ///   2.i) 0 <= transaction fee (also checked in block program).
    #[error("fee must be non-negative")]
    NegativeFee,
    ///   2.j) restrict number of inputs.
    #[error("number of inputs may not be too large")]
    TooManyInputs,
    ///   2.k) restrict number of outputs.
    #[error("number of outputs may not be too large")]
    TooManyOutputs,
    ///   2.l) restrict number of announcements.
    #[error("number of announcements may not be too large")]
    TooManyAnnouncements,

    ///   2.m) Lustration status can be parsed
    #[error("Could not parse lustration counter")]
    BadLustrationCounterEncoding,
    ///   2.n) Lustration status of parent can be parsed
    #[error("Could not parse lustration counter of parent")]
    BadLustrationCounterEncodingOfParent,
    ///   2.o) Missing lustration announcement
    #[error("Missing lustration announcement in transaction kernel")]
    MissingLustrationAnnouncement,
    ///   2.p) Lustration counter is updated correctly
    #[error("Lustration barrier must be correctly updated. Got {got}, expected: {expected}")]
    BadLustrationCounter {
        got: NativeCurrencyAmount,
        expected: NativeCurrencyAmount,
    },
    ///   2.q Value for which AOCL leaf indices must lustrate is correct. Once
    ///       set, all descendents of that block must have the same value.
    #[error(
        "Lustration AOCL leaf index threshold must set correctly. Got {got}, expected: {expected}."
    )]
    BadLustrationAoclThreshold { got: u64, expected: u64 },
    ///  2.r
    #[error("Negative lustration counter: {got}")]
    NegativeLustrationCounter { got: NativeCurrencyAmount },
    /// 2.s
    #[error("Lustration counter exceeds initial value. Got: {got}, initial: {initial}")]
    LustrationCounterExceedsInitialValue {
        got: NativeCurrencyAmount,
        initial: NativeCurrencyAmount,
    },

    /// xxx -- unknown lustration error -- hopefully dead code
    #[error("Unknown lustration problem. This should not happen.")]
    UnknownLustrationProblem,

    /// 2.t
    #[error("Transaction mutator set must match parent block")]
    TransactionMutatorSetMismatch,
}

impl From<RemovalRecordListUnpackError> for BlockValidationError {
    fn from(_: RemovalRecordListUnpackError) -> Self {
        Self::RemovalRecordsUnpackFailure
    }
}