ocpi_tariffs/

lib.rs

//! # OCPI Tariffs library
//!
//! Calculate the (sub)totals of a [charge session](https://github.com/ocpi/ocpi/blob/release-2.2.1-bugfixes/mod_cdrs.asciidoc)
//! using the [`cdr::price`] function and use the generated [`price::Report`] to review and compare the calculated
//! totals versus the sources from the `CDR`.
//!
//! See the [`price::Report`] for a detailed list of all the fields that help analyze and valitate the pricing of a `CDR`.
//!
//! - Use the [`cdr::parse`] and [`tariff::parse`] function to parse and guess which OCPI version of a CDR or tariff you have.
//! - Use the [`cdr::parse_with_version`] and [`tariff::parse_with_version`] functions to parse a CDR of tariff as the given version.
//! - Use the [`tariff::lint`] to lint a tariff: flag common errors, bugs, dangerous constructs and stylistic flaws in the tariff.

/// Module containing the functionality to price charge sessions with provided tariffs.
pub mod cdr;
pub mod country;
pub mod currency;
mod datetime;
mod de;
mod duration;
mod energy;
pub mod guess;
pub mod json;
pub mod lint;
mod money;
mod number;
pub mod price;
pub mod tariff;
pub mod timezone;
mod types;
mod v211;
mod v221;
pub mod warning;

use std::{collections::BTreeSet, fmt};

use serde::{Deserialize, Deserializer};

use datetime::{Date, DateTime, Time};
use duration::{HoursDecimal, SecondsRound};
use energy::{Ampere, Kw, Kwh};
use number::Number;
use types::DayOfWeek;
use warning::{IntoCaveat, IntoWarning};

pub use money::{Money, Price, Vat};
#[doc(inline)]
pub use warning::{Caveat, Verdict, VerdictExt, Warning};

/// Set of unexpected fields encountered while parsing a CDR or tariff.
pub type UnexpectedFields = BTreeSet<String>;

/// The Id for a tariff used in the pricing of a CDR.
pub type TariffId = String;

/// The OCPI versions supported by this crate
#[derive(Clone, Copy, Debug, PartialEq)]
pub enum Version {
    V221,
    V211,
}

impl Versioned for Version {
    fn version(&self) -> Version {
        *self
    }
}

impl fmt::Display for Version {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            Version::V221 => f.write_str("v221"),
            Version::V211 => f.write_str("v211"),
        }
    }
}

/// An object for a specific OCPI [`Version`].
pub trait Versioned: fmt::Debug {
    /// Return the `Version` this object is for.
    fn version(&self) -> Version;
}

/// An object with an uncertain [`Version`].
pub trait Unversioned: fmt::Debug {
    /// The concrete [`Versioned`] type.
    type Versioned: Versioned;

    /// Forced an [`Unversioned`] object to be the given [`Version`].
    fn force_into_versioned(self, version: Version) -> Self::Versioned;
}

#[derive(Debug)]
pub struct DeserializeError {
    /// The type of object we were trying to deserialize.
    object: ObjectType,

    /// The error that occurred while deserializing.
    err: Box<dyn std::error::Error + 'static>,
}

impl std::error::Error for DeserializeError {
    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
        Some(&*self.err)
    }
}

impl fmt::Display for DeserializeError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "{}", self.err)
    }
}

impl DeserializeError {
    /// Create a [`DeserializeError`] from a generic std Error for the given object.
    fn from_err<E>(object: ObjectType, err: E) -> Self
    where
        E: std::error::Error + 'static,
    {
        Self {
            object,
            err: err.into(),
        }
    }

    /// Create a [`DeserializeError`] from a generic std Error for a CDR object.
    fn from_cdr_err<E>(err: E) -> Self
    where
        E: std::error::Error + 'static,
    {
        Self::from_err(ObjectType::Cdr, err)
    }

    /// Create a [`DeserializeError`] from a generic std Error for a tariff object.
    fn from_tariff_err<E>(err: E) -> Self
    where
        E: std::error::Error + 'static,
    {
        Self::from_err(ObjectType::Tariff, err)
    }

    /// Return a deconstucted [`DeserializeError`].
    pub fn into_parts(self) -> (ObjectType, Box<dyn std::error::Error + 'static>) {
        (self.object, self.err)
    }
}

/// The type of OCPI objects that can be parsed.
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub enum ObjectType {
    /// An OCPI Charge Detail Record.
    ///
    /// * See: [OCPI spec 2.2.1: CDR](<https://github.com/ocpi/ocpi/blob/release-2.2.1-bugfixes/mod_cdrs.asciidoc>)
    Cdr,

    /// An OCPI tariff.
    ///
    /// * See: [OCPI spec 2.2.1: Tariff](<https://github.com/ocpi/ocpi/blob/release-2.2.1-bugfixes/mod_tariffs.asciidoc>)
    Tariff,
}

fn null_default<'de, D, T>(deserializer: D) -> Result<T, D::Error>
where
    T: Default + Deserialize<'de>,
    D: Deserializer<'de>,
{
    let opt = Option::deserialize(deserializer)?;
    Ok(opt.unwrap_or_default())
}

#[cfg(test)]
mod test {
    use std::{env, fmt, io::IsTerminal as _, path::Path, sync::Once};

    use serde::{
        de::{value::StrDeserializer, IntoDeserializer as _},
        Deserialize,
    };
    use tracing::debug;
    use tracing_subscriber::util::SubscriberInitExt as _;

    use crate::{json, DateTime};

    /// Creates and sets the default tracing subscriber if not already done.
    #[track_caller]
    pub fn setup() {
        static INITIALIZED: Once = Once::new();

        INITIALIZED.call_once_force(|state| {
            if state.is_poisoned() {
                return;
            }

            let is_tty = std::io::stderr().is_terminal();

            let level = match env::var("RUST_LOG") {
                Ok(s) => s.parse().unwrap_or(tracing::Level::INFO),
                Err(err) => match err {
                    env::VarError::NotPresent => tracing::Level::INFO,
                    env::VarError::NotUnicode(_) => {
                        panic!("`RUST_LOG` is not unicode");
                    }
                },
            };

            let subscriber = tracing_subscriber::fmt()
                .with_ansi(is_tty)
                .with_file(true)
                .with_level(false)
                .with_line_number(true)
                .with_max_level(level)
                .with_target(false)
                .with_test_writer()
                .without_time()
                .finish();

            subscriber
                .try_init()
                .expect("Init tracing_subscriber::Subscriber");
        });
    }

    #[track_caller]
    pub fn assert_no_unexpected_fields(unexpected_fields: &json::UnexpectedFields<'_>) {
        if !unexpected_fields.is_empty() {
            const MAX_FIELD_DISPLAY: usize = 20;

            if unexpected_fields.len() > MAX_FIELD_DISPLAY {
                let truncated_fields = unexpected_fields
                    .iter()
                    .take(MAX_FIELD_DISPLAY)
                    .map(|path| path.to_string())
                    .collect::<Vec<_>>();

                panic!(
                    "Unexpected fields found({}); displaying the first ({}): \n{}\n... and {} more",
                    unexpected_fields.len(),
                    truncated_fields.len(),
                    truncated_fields.join(",\n"),
                    unexpected_fields.len() - truncated_fields.len(),
                )
            } else {
                panic!(
                    "Unexpected fields found({}):\n{}",
                    unexpected_fields.len(),
                    unexpected_fields.to_strings().join(",\n")
                )
            };
        }
    }

    #[track_caller]
    pub fn assert_unexpected_fields(
        unexpected_fields: &json::UnexpectedFields<'_>,
        expected: &[&'static str],
    ) {
        if unexpected_fields.len() != expected.len() {
            let unexpected_fields = unexpected_fields
                .into_iter()
                .map(|path| path.to_string())
                .collect::<Vec<_>>();

            panic!(
                "The unexpected fields and expected fields lists have different lengths.\n\nUnexpected fields found:\n{}",
                unexpected_fields.join(",\n")
            );
        }

        let unmatched_paths = unexpected_fields
            .into_iter()
            .zip(expected.iter())
            .filter(|(a, b)| a != *b)
            .collect::<Vec<_>>();

        if !unmatched_paths.is_empty() {
            let unmatched_paths = unmatched_paths
                .into_iter()
                .map(|(a, b)| format!("{a} != {b}"))
                .collect::<Vec<_>>();

            panic!(
                "The unexpected fields don't match the expected fields.\n\nUnexpected fields found:\n{}",
                unmatched_paths.join(",\n")
            );
        }
    }

    /// A Field in the expect JSON.
    ///
    /// We need to distinguish between a field that's present and null and absent.
    #[derive(Debug, Default)]
    pub enum Expectation<T> {
        /// The field is present.
        Present(ExpectValue<T>),

        /// The field is not preent.
        #[default]
        Absent,
    }

    /// The value of an expectation field.
    #[derive(Debug)]
    pub enum ExpectValue<T> {
        /// The field has a value.
        Some(T),

        /// The field is set to `null`.
        Null,
    }

    impl<T> ExpectValue<T>
    where
        T: fmt::Debug,
    {
        /// Convert the expectation into an `Option`.
        pub fn into_option(self) -> Option<T> {
            match self {
                Self::Some(v) => Some(v),
                Self::Null => None,
            }
        }

        /// Consume the expectation and return the inner value of type `T`.
        ///
        /// # Panics
        ///
        /// Parnics if the `FieldValue` is `Null`.
        #[track_caller]
        pub fn expect_value(self) -> T {
            match self {
                ExpectValue::Some(v) => v,
                ExpectValue::Null => panic!("the field expects a value"),
            }
        }
    }

    impl<'de, T> Deserialize<'de> for Expectation<T>
    where
        T: Deserialize<'de>,
    {
        #[expect(clippy::unwrap_in_result, reason = "This is test util code")]
        #[track_caller]
        fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
        where
            D: serde::Deserializer<'de>,
        {
            let value = serde_json::Value::deserialize(deserializer)?;

            if value.is_null() {
                return Ok(Expectation::Present(ExpectValue::Null));
            }

            let v = T::deserialize(value).unwrap();
            Ok(Expectation::Present(ExpectValue::Some(v)))
        }
    }

    /// Create a `DateTime` from a RFC 3339 formatted string.
    #[track_caller]
    pub fn datetime_from_str(s: &str) -> DateTime {
        let de: StrDeserializer<'_, serde::de::value::Error> = s.into_deserializer();
        DateTime::deserialize(de).unwrap()
    }

    /// Try read an expectation JSON file based on the name of the given object JSON file.
    ///
    /// If the JSON object file is called `cdr.json` with a feature of `price` an expectation file
    /// called `expect_cdr_price.json` is searched for.
    #[track_caller]
    pub fn read_expect_json(json_file_path: &Path, feature: &str) -> Option<String> {
        let json_dir = json_file_path
            .parent()
            .expect("The given file should live in a dir");

        let json_file_name = json_file_path
            .file_stem()
            .expect("The `json_file_path` should be a file")
            .to_str()
            .expect("The `json_file_path` should have a valid name");

        // An underscore is prefixed to the filename to exclude the file from being included
        // as input for a `test_each` glob driven test.
        let expect_file_name = format!("output_{feature}__{json_file_name}.json");

        debug!("Try to read expectation file: `{expect_file_name}`");

        let s = std::fs::read_to_string(json_dir.join(&expect_file_name))
            .ok()
            .map(|mut s| {
                json_strip_comments::strip(&mut s).ok();
                s
            });

        debug!("Successfully Read expectation file: `{expect_file_name}`");
        s
    }
}

#[cfg(test)]
mod test_rust_decimal_arbitrary_precision {
    use rust_decimal_macros::dec;

    use crate::Number;

    #[test]
    fn should_serialize_decimal_with_12_fraction_digits() {
        let dec = dec!(0.123456789012);
        let actual = serde_json::to_string(&dec).unwrap();
        assert_eq!(actual, r#""0.123456789012""#.to_owned());
    }

    #[test]
    fn should_serialize_decimal_with_8_fraction_digits() {
        let dec = dec!(37.12345678);
        let actual = serde_json::to_string(&dec).unwrap();
        assert_eq!(actual, r#""37.12345678""#.to_owned());
    }

    #[test]
    fn should_serialize_0_decimal_without_fraction_digits() {
        let dec = dec!(0);
        let actual = serde_json::to_string(&dec).unwrap();
        assert_eq!(actual, r#""0""#.to_owned());
    }

    #[test]
    fn should_serialize_12_num_with_4_fraction_digits() {
        let num: Number = dec!(0.1234).try_into().unwrap();
        let actual = serde_json::to_string(&num).unwrap();
        assert_eq!(actual, r#""0.1234""#.to_owned());
    }

    #[test]
    fn should_serialize_8_num_with_4_fraction_digits() {
        let num: Number = dec!(37.1234).try_into().unwrap();
        let actual = serde_json::to_string(&num).unwrap();
        assert_eq!(actual, r#""37.1234""#.to_owned());
    }

    #[test]
    fn should_serialize_0_num_without_fraction_digits() {
        let num: Number = dec!(0).try_into().unwrap();
        let actual = serde_json::to_string(&num).unwrap();
        assert_eq!(actual, r#""0""#.to_owned());
    }
}