midnight-proofs 0.7.1

use std::{error, fmt, io};

use super::{Any, Column, TableColumn};

/// This is an error that could occur during proving or circuit synthesis.
// TODO: these errors need to be cleaned up
#[derive(Debug)]
pub enum Error {
    /// This is an error that can occur during synthesis of the circuit, for
    /// example, when the witness is not present.
    Synthesis(String),
    /// The provided instances do not match the circuit parameters.
    InvalidInstances,
    /// The constraint system is not satisfied.
    ConstraintSystemFailure,
    /// Out of bounds index passed to a backend
    BoundsFailure,
    /// Opening error
    Opening,
    /// Transcript error
    Transcript(io::Error),
    /// `k` is too small for the given circuit.
    NotEnoughRowsAvailable {
        /// The current value of `k` being used.
        current_k: u32,
    },
    /// Instance provided exceeds number of available rows
    InstanceTooLarge,
    /// Circuit synthesis requires global constants, but circuit configuration
    /// did not call [`ConstraintSystem::enable_constant`] on fixed columns
    /// with sufficient space.
    ///
    /// [`ConstraintSystem::enable_constant`]: crate::plonk::ConstraintSystem::enable_constant
    NotEnoughColumnsForConstants,
    /// The instance sets up a copy constraint involving a column that has not
    /// been included in the permutation.
    ColumnNotInPermutation(Column<Any>),
    /// An error relating to a lookup table.
    TableError(TableError),
    /// The SRS provided does not have the correct size for the Circuit
    SrsError(usize, usize),
}

impl From<io::Error> for Error {
    fn from(error: io::Error) -> Self {
        // The only place we can get io::Error from is the transcript.
        Error::Transcript(error)
    }
}

impl Error {
    /// Constructs an `Error::NotEnoughRowsAvailable`.
    pub(crate) fn not_enough_rows_available(current_k: u32) -> Self {
        Error::NotEnoughRowsAvailable { current_k }
    }
}

impl fmt::Display for Error {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            Error::Synthesis(msg) => write!(f, "Synthesis error: {msg}"),
            Error::InvalidInstances => write!(f, "Provided instances do not match the circuit"),
            Error::ConstraintSystemFailure => write!(f, "The constraint system is not satisfied"),
            Error::BoundsFailure => write!(f, "An out-of-bounds index was passed to the backend"),
            Error::Opening => write!(f, "Multi-opening proof was invalid"),
            Error::Transcript(e) => write!(f, "Transcript error: {e}"),
            Error::NotEnoughRowsAvailable { current_k } => write!(
                f,
                "k = {current_k} is too small for the given circuit. Try using a larger value of k",
            ),
            Error::InstanceTooLarge => write!(f, "Instance vectors are larger than the circuit"),
            Error::NotEnoughColumnsForConstants => {
                write!(
                    f,
                    "Too few fixed columns are enabled for global constants usage"
                )
            }
            Error::ColumnNotInPermutation(column) => write!(
                f,
                "Column {column:?} must be included in the permutation. Help: try applying `meta.enable_equalty` on the column",
            ),
            Error::TableError(error) => write!(f, "{error}"),
            Error::SrsError(srs_k, circuit_k) => write!(f, "The SRS (with size {srs_k}) does not match for the given circuit (of size {circuit_k})")
        }
    }
}

impl error::Error for Error {
    fn source(&self) -> Option<&(dyn error::Error + 'static)> {
        match self {
            Error::Transcript(e) => Some(e),
            _ => None,
        }
    }
}

/// This is an error that could occur during table synthesis.
#[derive(Debug)]
pub enum TableError {
    /// A `TableColumn` has not been assigned.
    ColumnNotAssigned(TableColumn),
    /// A Table has columns of uneven lengths.
    UnevenColumnLengths((TableColumn, usize), (TableColumn, usize)),
    /// Attempt to assign a used `TableColumn`
    UsedColumn(TableColumn),
    /// Attempt to overwrite a default value
    OverwriteDefault(TableColumn, String, String),
}

impl fmt::Display for TableError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            TableError::ColumnNotAssigned(col) => {
                write!(
                    f,
                    "{col:?} not fully assigned. Help: assign a value at offset 0.",
                )
            }
            TableError::UnevenColumnLengths((col, col_len), (table, table_len)) => write!(
                f,
                "{col:?} has length {col_len} while {table:?} has length {table_len}",
            ),
            TableError::UsedColumn(col) => {
                write!(f, "{col:?} has already been used")
            }
            TableError::OverwriteDefault(col, default, val) => {
                write!(
                    f,
                    "Attempted to overwrite default value {default} with {val} in {col:?}",
                )
            }
        }
    }
}