pactole-core 0.2.0

use crate::models::{AccountName, CommodityName};
use chrono::NaiveDate;
use rust_decimal::Decimal;
use thiserror::Error;

/// Errors raised when building core model values: purely grammatical /
/// structural checks (e.g. the shape of a name), with no knowledge of the
/// rest of the journal.
#[derive(Error, Debug, Clone, PartialEq, Eq)]
pub enum ModelError {
    /// An account name does not satisfy the Pactole account grammar.
    #[error(
        "invalid account name `{0}`: expected colon-separated segments, the first one starting \
         with an uppercase letter, each made of letters, digits, `_` or `-`"
    )]
    InvalidAccountName(String),
    /// A commodity name does not satisfy the Pactole commodity grammar.
    #[error(
        "invalid commodity name `{0}`: expected 2 to 24 characters, starting with an uppercase \
         letter, ending with an uppercase letter or digit, made of uppercase letters, digits, \
         `'`, `.`, `_` or `-` in between"
    )]
    InvalidCommodityName(String),
    /// A metadata key does not satisfy the lowercase-key grammar.
    #[error("invalid metadata key `{0}`: expected only lowercase letters, `_` or `-`")]
    InvalidMetadataKey(String),
}

/// Errors raised when validating a [`crate::Journal`] as a whole: checks
/// that require knowing about other entries of the journal, as opposed to
/// the purely grammatical checks reported as [`ModelError`].
#[derive(Error, Debug, Clone, PartialEq, Eq)]
pub enum ValidationError {
    /// An account is opened while it is already open.
    #[error("account `{account}` is already open on {date}")]
    AccountAlreadyOpen {
        /// Account name involved in the duplicate opening.
        account: AccountName,
        /// Date of the duplicate opening.
        date: NaiveDate,
    },
    /// An account is used or closed while it is not open.
    #[error("account `{account}` is not open on {date}")]
    AccountNotOpen {
        /// Account name that was used while closed or unopened.
        account: AccountName,
        /// Date of the invalid use.
        date: NaiveDate,
    },
    /// A commodity is declared more than once.
    #[error("commodity `{commodity}` is already declared on {date}")]
    CommodityAlreadyDeclared {
        /// Commodity declared more than once.
        commodity: CommodityName,
        /// Date of the duplicate declaration.
        date: NaiveDate,
    },
    /// A commodity is used before being declared.
    #[error("commodity `{commodity}` is not declared on {date}")]
    CommodityNotDeclared {
        /// Commodity used before its declaration.
        commodity: CommodityName,
        /// Date of the invalid use.
        date: NaiveDate,
    },
    /// A payee is declared more than once.
    #[error("payee `{payee}` is already declared")]
    PayeeAlreadyDeclared {
        /// Payee declared more than once.
        payee: String,
    },
    /// A transaction uses a payee that has not been declared.
    #[error("payee `{payee}` is not declared (transaction on {date})")]
    PayeeNotDeclared {
        /// Payee used by the transaction.
        payee: String,
        /// Date of the transaction.
        date: NaiveDate,
    },
    /// More than one transaction posting has no amount.
    #[error(
        "transaction on {date} has {count} postings without an amount, but at most one posting \
         can be left without an amount for auto-balancing"
    )]
    TooManyPostingsWithoutAmount {
        /// Number of postings without an amount.
        count: usize,
        /// Date of the transaction.
        date: NaiveDate,
    },
    /// The commodity of an inferred amount cannot be determined uniquely.
    #[error(
        "cannot auto-balance transaction: unable to determine a single commodity for the \
         missing amount from the other postings on {date} (commodities found: {commodities:?})"
    )]
    AmbiguousAutoBalanceCommodity {
        /// Commodities found among the explicitly valued postings.
        commodities: Vec<String>,
        /// Date of the transaction.
        date: NaiveDate,
    },
    /// Explicit transaction postings do not balance.
    #[error(
        "transaction on {date} is not balanced: postings for commodity `{commodity}` sum to \
         `{sum}` instead of zero"
    )]
    TransactionNotBalanced {
        /// Commodity whose postings do not sum to zero.
        commodity: String,
        /// Non-zero sum of the postings.
        sum: Decimal,
        /// Date of the transaction.
        date: NaiveDate,
    },
    /// A posting uses a commodity excluded by the account's opening.
    #[error(
        "commodity `{commodity}` is not allowed on account `{account}` (posting on {date}): the \
         account was opened with a restricted list of commodities that does not include it"
    )]
    CommodityNotAllowed {
        /// Account carrying the restricted commodity.
        account: AccountName,
        /// Commodity excluded by the account opening.
        commodity: CommodityName,
        /// Date of the posting.
        date: NaiveDate,
    },
    /// A balance assertion differs from the calculated balance beyond tolerance.
    #[error(
        "balance assertion failed on {date}: account `{account}` has a balance of `{actual}` \
         {commodity}, expected `{expected}` {commodity} (tolerance ~ {tolerance})"
    )]
    BalanceAssertionFailed {
        /// Account whose balance was asserted.
        account: AccountName,
        /// Commodity of the assertion.
        commodity: CommodityName,
        /// Date of the assertion.
        date: NaiveDate,
        /// Expected balance.
        expected: Decimal,
        /// Calculated balance.
        actual: Decimal,
        /// Allowed difference.
        tolerance: Decimal,
    },
}