okane_core/report/eval/
single_amount.rs

1use std::{
2    fmt::Display,
3    ops::{Mul, Neg},
4};
5
6use rust_decimal::Decimal;
7
8use crate::report::{commodity::CommodityTag, ReportContext};
9
10use super::error::EvalError;
11
12/// Amount with only one commodity.
13#[derive(Debug, PartialEq, Eq, Clone, Copy)]
14pub struct SingleAmount<'ctx> {
15    pub(crate) value: Decimal,
16    pub(crate) commodity: CommodityTag<'ctx>,
17}
18
19impl Neg for SingleAmount<'_> {
20    type Output = Self;
21
22    fn neg(self) -> Self::Output {
23        SingleAmount {
24            value: -self.value,
25            commodity: self.commodity,
26        }
27    }
28}
29
30impl Mul<Decimal> for SingleAmount<'_> {
31    type Output = Self;
32
33    fn mul(self, rhs: Decimal) -> Self::Output {
34        Self {
35            value: self.value * rhs,
36            commodity: self.commodity,
37        }
38    }
39}
40
41impl<'ctx> SingleAmount<'ctx> {
42    /// Constructs an instance with single commodity.
43    #[inline]
44    pub fn from_value(value: Decimal, commodity: CommodityTag<'ctx>) -> Self {
45        Self { value, commodity }
46    }
47
48    /// Adds the amount with keeping commodity single.
49    pub fn check_add(self, rhs: Self) -> Result<Self, EvalError<'ctx>> {
50        if self.commodity != rhs.commodity {
51            Err(EvalError::UnmatchingCommodities(
52                self.commodity,
53                rhs.commodity,
54            ))
55        } else {
56            Ok(Self {
57                value: self
58                    .value
59                    .checked_add(rhs.value)
60                    .ok_or(EvalError::NumberOverflow)?,
61                commodity: self.commodity,
62            })
63        }
64    }
65
66    /// Subtracts the amount with keeping the commodity single.
67    pub fn check_sub(self, rhs: Self) -> Result<Self, EvalError<'ctx>> {
68        self.check_add(-rhs)
69    }
70
71    /// Divides by given Decimal.
72    pub fn check_div(self, rhs: Decimal) -> Result<Self, EvalError<'ctx>> {
73        if rhs.is_zero() {
74            return Err(EvalError::DivideByZero);
75        }
76        Ok(Self {
77            value: self
78                .value
79                .checked_div(rhs)
80                .ok_or(EvalError::NumberOverflow)?,
81            commodity: self.commodity,
82        })
83    }
84
85    /// Returns an absolute value of the current value.
86    pub fn abs(self) -> Self {
87        Self {
88            value: self.value.abs(),
89            commodity: self.commodity,
90        }
91    }
92
93    /// Rounds the Amount with the given context provided precision.
94    pub fn round(self, ctx: &ReportContext) -> Self {
95        match ctx.commodities.get_decimal_point(self.commodity) {
96            None => self,
97            Some(dp) => Self {
98                value: self.value.round_dp_with_strategy(
99                    dp,
100                    rust_decimal::RoundingStrategy::MidpointNearestEven,
101                ),
102                commodity: self.commodity,
103            },
104        }
105    }
106
107    /// Returns a new instance with having the same sign with given SingleAmount.
108    pub(crate) fn with_sign_of(mut self, sign: Self) -> Self {
109        self.value.set_sign_positive(sign.value.is_sign_positive());
110        self
111    }
112
113    /// Returns an instance which can be displayed.
114    pub fn as_display<'a>(&'a self, ctx: &'a ReportContext<'ctx>) -> impl Display + 'a
115    where
116        'a: 'ctx,
117    {
118        SingleAmountDisplay(self, ctx)
119    }
120}
121
122struct SingleAmountDisplay<'a, 'ctx>(&'a SingleAmount<'ctx>, &'a ReportContext<'ctx>);
123
124impl Display for SingleAmountDisplay<'_, '_> {
125    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
126        write!(
127            f,
128            "{} {}",
129            self.0.value,
130            self.0.commodity.to_str_lossy(&self.1.commodities)
131        )
132    }
133}
134
135#[cfg(test)]
136mod tests {
137    use super::*;
138
139    use bumpalo::Bump;
140    use pretty_assertions::assert_eq;
141    use pretty_decimal::PrettyDecimal;
142    use rust_decimal_macros::dec;
143
144    use crate::report::ReportContext;
145
146    #[test]
147    fn neg_returns_negative_value() {
148        let arena = Bump::new();
149        let mut ctx = ReportContext::new(&arena);
150
151        let jpy = ctx.commodities.insert("JPY").unwrap();
152
153        assert_eq!(
154            SingleAmount::from_value(dec!(-5), jpy),
155            -SingleAmount::from_value(dec!(5), jpy)
156        );
157    }
158
159    #[test]
160    fn check_add_fails_different_commodity() {
161        let arena = Bump::new();
162        let mut ctx = ReportContext::new(&arena);
163
164        let jpy = ctx.commodities.insert("JPY").unwrap();
165        let chf = ctx.commodities.insert("CHF").unwrap();
166
167        assert_eq!(
168            Err(EvalError::UnmatchingCommodities(jpy.into(), chf.into())),
169            SingleAmount::from_value(dec!(10), jpy)
170                .check_add(SingleAmount::from_value(dec!(20), chf))
171        );
172    }
173
174    #[test]
175    fn check_add_succeeds() {
176        let arena = Bump::new();
177        let mut ctx = ReportContext::new(&arena);
178
179        let jpy = ctx.commodities.insert("JPY").unwrap();
180
181        assert_eq!(
182            SingleAmount::from_value(dec!(-10), jpy),
183            SingleAmount::from_value(dec!(10), jpy)
184                .check_add(SingleAmount::from_value(dec!(-20), jpy))
185                .unwrap()
186        );
187    }
188
189    #[test]
190    fn check_sub_fails_different_commodity() {
191        let arena = Bump::new();
192        let mut ctx = ReportContext::new(&arena);
193
194        let jpy = ctx.commodities.insert("JPY").unwrap();
195        let chf = ctx.commodities.insert("CHF").unwrap();
196
197        assert_eq!(
198            Err(EvalError::UnmatchingCommodities(jpy.into(), chf.into())),
199            SingleAmount::from_value(dec!(10), jpy)
200                .check_sub(SingleAmount::from_value(dec!(0), chf))
201        );
202    }
203
204    #[test]
205    fn check_sub_succeeds() {
206        let arena = Bump::new();
207        let mut ctx = ReportContext::new(&arena);
208
209        let jpy = ctx.commodities.insert("JPY").unwrap();
210
211        assert_eq!(
212            SingleAmount::from_value(dec!(5), jpy),
213            SingleAmount::from_value(dec!(10), jpy)
214                .check_sub(SingleAmount::from_value(dec!(5), jpy))
215                .unwrap()
216        );
217    }
218
219    #[test]
220    fn single_amount_to_string() {
221        let arena = Bump::new();
222        let mut ctx = ReportContext::new(&arena);
223
224        let usd = ctx.commodities.insert("USD").unwrap();
225
226        assert_eq!(
227            "1.20 USD".to_string(),
228            SingleAmount::from_value(dec!(1.20), usd)
229                .as_display(&ctx)
230                .to_string()
231        );
232    }
233
234    #[test]
235    fn single_amount_round() {
236        let arena = Bump::new();
237        let mut ctx = ReportContext::new(&arena);
238        let jpy = ctx.commodities.ensure("JPY");
239        let eur = ctx.commodities.ensure("EUR");
240        let chf = ctx.commodities.ensure("CHF");
241
242        ctx.commodities
243            .set_format(jpy, PrettyDecimal::comma3dot(dec!(12345)));
244        ctx.commodities
245            .set_format(eur, PrettyDecimal::plain(dec!(123.45)));
246        ctx.commodities
247            .set_format(chf, PrettyDecimal::comma3dot(dec!(123.450)));
248
249        // as-is
250        assert_eq!(
251            SingleAmount::from_value(dec!(812), jpy),
252            SingleAmount::from_value(dec!(812), jpy).round(&ctx),
253        );
254        assert_eq!(
255            SingleAmount::from_value(dec!(-100.00), eur),
256            SingleAmount::from_value(dec!(-100.0), eur).round(&ctx),
257        );
258        assert_eq!(
259            SingleAmount::from_value(dec!(6.660), chf),
260            SingleAmount::from_value(dec!(6.66), chf).round(&ctx),
261        );
262
263        assert_eq!(
264            SingleAmount::from_value(dec!(812), jpy),
265            SingleAmount::from_value(dec!(812.5), jpy).round(&ctx),
266        );
267        assert_eq!(
268            SingleAmount::from_value(dec!(-100.02), eur),
269            SingleAmount::from_value(dec!(-100.015), eur).round(&ctx),
270        );
271        assert_eq!(
272            SingleAmount::from_value(dec!(6.666), chf),
273            SingleAmount::from_value(dec!(6.6665), chf).round(&ctx),
274        );
275    }
276
277    #[test]
278    fn with_sign_negative() {
279        let arena = Bump::new();
280        let mut ctx = ReportContext::new(&arena);
281
282        let jpy = ctx.commodities.insert("JPY").unwrap();
283        let eur = ctx.commodities.insert("EUR").unwrap();
284
285        let positive = SingleAmount::from_value(dec!(1000), jpy);
286        assert_eq!(
287            SingleAmount::from_value(dec!(15), eur),
288            SingleAmount::from_value(dec!(15), eur).with_sign_of(positive)
289        );
290        assert_eq!(
291            SingleAmount::from_value(dec!(0), eur),
292            SingleAmount::from_value(dec!(0), eur).with_sign_of(positive)
293        );
294        assert_eq!(
295            SingleAmount::from_value(dec!(15), eur),
296            SingleAmount::from_value(dec!(-15), eur).with_sign_of(positive)
297        );
298
299        let negative = SingleAmount::from_value(dec!(-1000), jpy);
300        assert_eq!(
301            SingleAmount::from_value(dec!(-15), eur),
302            SingleAmount::from_value(dec!(15), eur).with_sign_of(negative)
303        );
304        assert_eq!(
305            SingleAmount::from_value(dec!(0), eur),
306            SingleAmount::from_value(dec!(0), eur).with_sign_of(negative)
307        );
308        assert_eq!(
309            SingleAmount::from_value(dec!(-15), eur),
310            SingleAmount::from_value(dec!(-15), eur).with_sign_of(negative)
311        );
312    }
313}
okane_core/report/eval/single_amount.rs

okane_core/report/eval/
single_amount.rs
