automapper_validation/eval/
evaluator.rs

1//! Core condition evaluation traits.
2
3use super::context::EvaluationContext;
4
5/// Three-valued result of evaluating a single condition.
6///
7/// Unlike the C# implementation which uses `bool`, we use three-valued logic
8/// to support partial evaluation when external conditions are unavailable.
9#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
10pub enum ConditionResult {
11    /// The condition is satisfied.
12    True,
13    /// The condition is not satisfied.
14    False,
15    /// The condition cannot be determined (e.g., external condition without a provider).
16    Unknown,
17}
18
19impl ConditionResult {
20    /// Returns `true` if this is `ConditionResult::True`.
21    pub fn is_true(self) -> bool {
22        matches!(self, ConditionResult::True)
23    }
24
25    /// Returns `true` if this is `ConditionResult::False`.
26    pub fn is_false(self) -> bool {
27        matches!(self, ConditionResult::False)
28    }
29
30    /// Returns `true` if this is `ConditionResult::Unknown`.
31    pub fn is_unknown(self) -> bool {
32        matches!(self, ConditionResult::Unknown)
33    }
34
35    /// Three-valued AND: `False` if either is, `True` if both are, else `Unknown`.
36    pub fn and(self, other: ConditionResult) -> ConditionResult {
37        match (self, other) {
38            (ConditionResult::False, _) | (_, ConditionResult::False) => ConditionResult::False,
39            (ConditionResult::True, ConditionResult::True) => ConditionResult::True,
40            _ => ConditionResult::Unknown,
41        }
42    }
43
44    /// Three-valued OR: `True` if either is, `False` if both are, else `Unknown`.
45    pub fn or(self, other: ConditionResult) -> ConditionResult {
46        match (self, other) {
47            (ConditionResult::True, _) | (_, ConditionResult::True) => ConditionResult::True,
48            (ConditionResult::False, ConditionResult::False) => ConditionResult::False,
49            _ => ConditionResult::Unknown,
50        }
51    }
52
53    /// Three-valued NOT.
54    pub fn negate(self) -> ConditionResult {
55        match self {
56            ConditionResult::True => ConditionResult::False,
57            ConditionResult::False => ConditionResult::True,
58            ConditionResult::Unknown => ConditionResult::Unknown,
59        }
60    }
61
62    /// Converts to `Option<bool>`: True -> Some(true), False -> Some(false), Unknown -> None.
63    pub fn to_option(self) -> Option<bool> {
64        match self {
65            ConditionResult::True => Some(true),
66            ConditionResult::False => Some(false),
67            ConditionResult::Unknown => None,
68        }
69    }
70}
71
72impl From<bool> for ConditionResult {
73    fn from(value: bool) -> Self {
74        if value {
75            ConditionResult::True
76        } else {
77            ConditionResult::False
78        }
79    }
80}
81
82impl std::fmt::Display for ConditionResult {
83    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
84        match self {
85            ConditionResult::True => write!(f, "True"),
86            ConditionResult::False => write!(f, "False"),
87            ConditionResult::Unknown => write!(f, "Unknown"),
88        }
89    }
90}
91
92/// Evaluates individual AHB conditions by number.
93///
94/// Implementations are typically generated from AHB XML schemas (one per
95/// message type and format version). Each condition number maps to a
96/// specific business rule check.
97pub trait ConditionEvaluator: Send + Sync {
98    /// Evaluate a single condition by number.
99    ///
100    /// Returns `ConditionResult::Unknown` for unrecognized condition numbers
101    /// or conditions that require unavailable external context.
102    fn evaluate(&self, condition: u32, ctx: &EvaluationContext) -> ConditionResult;
103
104    /// Returns `true` if the given condition requires external context
105    /// (i.e., cannot be determined from the EDIFACT message alone).
106    fn is_external(&self, condition: u32) -> bool;
107
108    /// Returns `true` if this evaluator has an implementation for the given
109    /// condition number (whether internal or external). Conditions that fall
110    /// through to the `_ => Unknown` wildcard return `false`.
111    ///
112    /// This allows distinguishing "implemented but returned Unknown because
113    /// the relevant data isn't present in the message" from "not implemented
114    /// at all".
115    fn is_known(&self, _condition: u32) -> bool {
116        false
117    }
118
119    /// Returns the message type this evaluator handles (e.g., "UTILMD").
120    fn message_type(&self) -> &str;
121
122    /// Returns the format version this evaluator handles (e.g., "FV2510").
123    fn format_version(&self) -> &str;
124}
125
126impl<T: ConditionEvaluator + ?Sized> ConditionEvaluator for std::sync::Arc<T> {
127    fn evaluate(&self, condition: u32, ctx: &EvaluationContext) -> ConditionResult {
128        (**self).evaluate(condition, ctx)
129    }
130
131    fn is_external(&self, condition: u32) -> bool {
132        (**self).is_external(condition)
133    }
134
135    fn is_known(&self, condition: u32) -> bool {
136        (**self).is_known(condition)
137    }
138
139    fn message_type(&self) -> &str {
140        (**self).message_type()
141    }
142
143    fn format_version(&self) -> &str {
144        (**self).format_version()
145    }
146}
147
148/// Provider for external conditions that depend on context outside the EDIFACT message.
149///
150/// External conditions are things like:
151/// - [1] "Wenn Aufteilung vorhanden" (message splitting status)
152/// - [14] "Wenn Datum bekannt" (whether a date is known)
153/// - [30] "Wenn Antwort auf Aktivierung" (response to activation)
154///
155/// These cannot be determined from the EDIFACT content alone and require
156/// business context from the calling system.
157pub trait ExternalConditionProvider: Send + Sync {
158    /// Evaluate an external condition by name.
159    ///
160    /// The `condition_name` corresponds to the speaking name from the
161    /// generated external conditions constants (e.g., "MessageSplitting",
162    /// "DateKnown").
163    fn evaluate(&self, condition_name: &str) -> ConditionResult;
164}
165
166/// A no-op external condition provider that returns `Unknown` for everything.
167///
168/// Useful when no external context is available — conditions will propagate
169/// as `Unknown` through the expression evaluator.
170pub struct NoOpExternalProvider;
171
172impl ExternalConditionProvider for NoOpExternalProvider {
173    fn evaluate(&self, _condition_name: &str) -> ConditionResult {
174        ConditionResult::Unknown
175    }
176}
177
178/// The number of a message type's bare "Wenn vorhanden" condition, if it has one.
179///
180/// The condition is self-referential: its value is whether the element or
181/// group it annotates is present. `Soll [166]` on a group means "send it if
182/// you have it", which only the sender knows, so an absent group annotated
183/// with it is never missing. The generated evaluators answer it with `True`
184/// ("the rule applies wherever it is evaluated"), which is right for a present
185/// element and wrong for an absent one — see [`AbsentTarget`].
186///
187/// The numbers are stable across every format version in
188/// `xml-migs-and-ahbs/` (FV2410–FV2610); keyed by [`ConditionEvaluator::message_type`]
189/// rather than by evaluator so aliased and regenerated evaluators need no edit.
190pub fn presence_condition(message_type: &str) -> Option<u32> {
191    match message_type {
192        "UTILMD_Strom" | "UTILMD_Gas" => Some(166),
193        "INVOIC" => Some(22),
194        "ORDERS" => Some(12),
195        _ => None,
196    }
197}
198
199/// Every condition of a message type that answers "does the annotated thing
200/// exist?", which an absent element or group answers with no.
201///
202/// The [`presence_condition`], plus conditions that ask for one repetition per
203/// real-world object the message cannot see. UTILMD_Strom [2003] ("Einmal für
204/// jede ruhende Marktlokation, die der Marktlokation »Kundenanlage« …
205/// untergeordnet ist", FV2504–FV2610, absent in Gas) is `Soll` on the ruhende
206/// Marktlokation: zero ruhende MaLos means zero groups, and only the sender
207/// knows how many exist. The generated evaluators cannot decide it and answer
208/// `Unknown`, which reported every message without a ruhende MaLo.
209pub fn presence_conditions(message_type: &str) -> &'static [u32] {
210    match message_type {
211        "UTILMD_Strom" => &[166, 2003],
212        "UTILMD_Gas" => &[166],
213        "INVOIC" => &[22],
214        "ORDERS" => &[12],
215        _ => &[],
216    }
217}
218
219/// The condition of a message type that allows a group or segment once per
220/// transaction, and the transaction group: UTILMD's `[2061]` "Segment bzw.
221/// Segmentgruppe ist genau einmal je SG4 IDE (Vorgang) anzugeben" (Strom and
222/// Gas, FV2504–FV2610). The conditions evaluate it as `True` wherever there is
223/// a transaction, so what it limits — the count — is checked on its own; see
224/// [`binds_once`].
225pub fn once_per_transaction(message_type: &str) -> Option<(u32, &'static str)> {
226    match message_type {
227        "UTILMD_Strom" | "UTILMD_Gas" => Some((2061, "SG4")),
228        _ => None,
229    }
230}
231
232/// Whether `status` limits what it annotates to once per transaction: the
233/// condition `once` is a conjunct of every line (`Muss [483] ∧ [2061]`). Where
234/// it sits in one branch only (`Soll [165] ∧ (([2061] ∧ [583]) ∨ [584])`), the
235/// other branch allows more.
236pub fn binds_once(status: &str, once: u32) -> bool {
237    fn conjunct(expr: &crate::expr::ConditionExpr, once: u32) -> bool {
238        match expr {
239            crate::expr::ConditionExpr::Ref(id) => *id == once,
240            crate::expr::ConditionExpr::And(exprs) => exprs.iter().any(|e| conjunct(e, once)),
241            _ => false,
242        }
243    }
244    let lines: Vec<&str> = status
245        .lines()
246        .map(str::trim)
247        .filter(|l| !l.is_empty())
248        .collect();
249    !lines.is_empty()
250        && lines.iter().all(|line| {
251            matches!(
252                crate::expr::ConditionParser::parse(line),
253                Ok(Some(expr)) if conjunct(&expr, once)
254            )
255        })
256}
257
258/// Evaluates conditions for an element or group that is known to be absent.
259///
260/// Identical to the wrapped evaluator except that the message type's
261/// [`presence_conditions`] are `False`: whatever the condition annotates is not
262/// there. Use it wherever a status is evaluated to decide whether something
263/// missing is required.
264pub struct AbsentTarget<'a, E: ConditionEvaluator + ?Sized>(pub &'a E);
265
266impl<E: ConditionEvaluator + ?Sized> ConditionEvaluator for AbsentTarget<'_, E> {
267    fn evaluate(&self, condition: u32, ctx: &EvaluationContext) -> ConditionResult {
268        if presence_conditions(self.0.message_type()).contains(&condition) {
269            return ConditionResult::False;
270        }
271        self.0.evaluate(condition, ctx)
272    }
273
274    fn is_external(&self, condition: u32) -> bool {
275        self.0.is_external(condition)
276    }
277
278    fn is_known(&self, condition: u32) -> bool {
279        self.0.is_known(condition)
280    }
281
282    fn message_type(&self) -> &str {
283        self.0.message_type()
284    }
285
286    fn format_version(&self) -> &str {
287        self.0.format_version()
288    }
289}
290
291/// Evaluates conditions for an element or group that is known to be present,
292/// to decide whether it is allowed there.
293///
294/// The message type's [`presence_conditions`] are `True`: whatever the
295/// condition annotates is there. Only the AHB's conditions proper (`[1]` to
296/// `[499]`) decide; notes (`[500]`–`[899]`), formats (`[900]`–`[999]`) and
297/// repetition rules (`[2000]` and up: "genau einmal je SG8 …") say nothing about
298/// whether something may be sent, and are `Unknown` — so `[197] ∧ [2308]` is
299/// false when `[197]` is, and `[2317] ⊻ [2318]` is never.
300pub struct PresentTarget<'a, E: ConditionEvaluator + ?Sized>(pub &'a E);
301
302impl<E: ConditionEvaluator + ?Sized> ConditionEvaluator for PresentTarget<'_, E> {
303    fn evaluate(&self, condition: u32, ctx: &EvaluationContext) -> ConditionResult {
304        if presence_conditions(self.0.message_type()).contains(&condition) {
305            return ConditionResult::True;
306        }
307        if !(1..500).contains(&condition) {
308            return ConditionResult::Unknown;
309        }
310        self.0.evaluate(condition, ctx)
311    }
312
313    fn is_external(&self, condition: u32) -> bool {
314        self.0.is_external(condition)
315    }
316
317    fn is_known(&self, condition: u32) -> bool {
318        self.0.is_known(condition)
319    }
320
321    fn message_type(&self) -> &str {
322        self.0.message_type()
323    }
324
325    fn format_version(&self) -> &str {
326        self.0.format_version()
327    }
328}
329
330/// Whether something present under `status` is not allowed where `ctx` is: a
331/// `Muss`/`X` status with a condition that evaluates to false through
332/// [`PresentTarget`]. `Soll`/`Kann`, an unconditional status, an undecidable
333/// condition, a package (`[19P1..1]`, judged by its own check) and a status of
334/// several lines refuse nothing.
335pub fn refuses_presence<E: ConditionEvaluator + ?Sized>(
336    status: &str,
337    evaluator: &E,
338    ctx: &EvaluationContext,
339    ub_definitions: &std::collections::BTreeMap<String, crate::expr::ConditionExpr>,
340) -> bool {
341    let status = status.trim();
342    let package = status.split('[').skip(1).any(|term| {
343        term.trim_start_matches(|c: char| c.is_ascii_digit())
344            .starts_with('P')
345    });
346    if status.contains('\n') || !status.contains('[') || package {
347        return false;
348    }
349    let keyword = &status[..status
350        .find(|c: char| !c.is_alphabetic())
351        .unwrap_or(status.len())];
352    if !matches!(keyword, "Muss" | "X") {
353        return false;
354    }
355    let present = PresentTarget(evaluator);
356    super::ConditionExprEvaluator::new(&present).evaluate_status_with_ub(
357        status,
358        ctx,
359        ub_definitions,
360    ) == ConditionResult::False
361}
362
363#[cfg(test)]
364mod tests {
365    use super::*;
366
367    struct AlwaysTrue(&'static str);
368
369    impl ConditionEvaluator for AlwaysTrue {
370        fn evaluate(&self, _: u32, _: &EvaluationContext) -> ConditionResult {
371            ConditionResult::True
372        }
373        fn is_external(&self, _: u32) -> bool {
374            false
375        }
376        fn message_type(&self) -> &str {
377            self.0
378        }
379        fn format_version(&self) -> &str {
380            "FV2604"
381        }
382    }
383
384    #[test]
385    fn once_per_transaction_binds_where_every_line_has_it() {
386        assert!(binds_once("Muss [483] ∧ [2061]", 2061));
387        assert!(binds_once("Muss [2061]", 2061));
388        assert!(binds_once(
389            "Muss ([77] ∧ [78]) ∧ [347] ∧ [2061]\r\nKann [2061]",
390            2061
391        ));
392        assert!(!binds_once("Soll [165] ∧ (([2061] ∧ [583]) ∨ [584])", 2061));
393        assert!(!binds_once(
394            "Muss ([32] ∧ [2061] ∧ [651]) ⊻ ([200] ∧ [601])",
395            2061
396        ));
397        assert!(!binds_once("Muss [483]", 2061));
398        assert!(!binds_once("", 2061));
399    }
400
401    #[test]
402    fn absent_target_answers_only_the_presence_condition_with_false() {
403        let external = NoOpExternalProvider;
404        let ctx = EvaluationContext::new("55043", &external, &[]);
405        let inner = AlwaysTrue("UTILMD_Strom");
406        let absent = AbsentTarget(&inner);
407        assert_eq!(absent.evaluate(166, &ctx), ConditionResult::False);
408        assert_eq!(absent.evaluate(674, &ctx), ConditionResult::True);
409        // [2003]: one group per ruhende Marktlokation the sender knows of.
410        assert_eq!(absent.evaluate(2003, &ctx), ConditionResult::False);
411
412        // [166] of another message type is an unrelated condition.
413        let invoic = AlwaysTrue("INVOIC");
414        assert_eq!(
415            AbsentTarget(&invoic).evaluate(166, &ctx),
416            ConditionResult::True
417        );
418        assert_eq!(
419            AbsentTarget(&invoic).evaluate(22, &ctx),
420            ConditionResult::False
421        );
422    }
423
424    #[test]
425    fn test_condition_result_is_methods() {
426        assert!(ConditionResult::True.is_true());
427        assert!(!ConditionResult::True.is_false());
428        assert!(!ConditionResult::True.is_unknown());
429
430        assert!(!ConditionResult::False.is_true());
431        assert!(ConditionResult::False.is_false());
432
433        assert!(ConditionResult::Unknown.is_unknown());
434    }
435
436    #[test]
437    fn three_valued_and_or_not() {
438        use ConditionResult::{False as F, True as T, Unknown as U};
439        assert_eq!(T.and(T), T);
440        assert_eq!(T.and(U), U);
441        assert_eq!(U.and(F), F);
442        assert_eq!(F.or(F), F);
443        assert_eq!(F.or(U), U);
444        assert_eq!(U.or(T), T);
445        assert_eq!(U.negate(), U);
446        assert_eq!(T.negate(), F);
447    }
448
449    #[test]
450    fn test_condition_result_to_option() {
451        assert_eq!(ConditionResult::True.to_option(), Some(true));
452        assert_eq!(ConditionResult::False.to_option(), Some(false));
453        assert_eq!(ConditionResult::Unknown.to_option(), None);
454    }
455
456    #[test]
457    fn test_condition_result_from_bool() {
458        assert_eq!(ConditionResult::from(true), ConditionResult::True);
459        assert_eq!(ConditionResult::from(false), ConditionResult::False);
460    }
461
462    #[test]
463    fn test_condition_result_display() {
464        assert_eq!(format!("{}", ConditionResult::True), "True");
465        assert_eq!(format!("{}", ConditionResult::False), "False");
466        assert_eq!(format!("{}", ConditionResult::Unknown), "Unknown");
467    }
468
469    #[test]
470    fn test_noop_external_provider() {
471        let provider = NoOpExternalProvider;
472        assert_eq!(
473            provider.evaluate("MessageSplitting"),
474            ConditionResult::Unknown
475        );
476        assert_eq!(provider.evaluate("anything"), ConditionResult::Unknown);
477    }
478}
automapper_validation/eval/evaluator.rs

automapper_validation/eval/
evaluator.rs
