episteme 0.3.6

Knowledge graph for software engineering — design patterns, refactorings, and laws for AI agents
Documentation
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
use std::collections::HashSet;

use crate::domain::graph::KnowledgeGraph;
use crate::domain::inference::{EffortLevel, RefactoringSuggestion, SuggestionMetadata};
use crate::domain::metrics::SmellDetection;
use crate::domain::types::Entity;

// ---------------------------------------------------------------------------
// RefactoringRanker — merged from episteme-infer/src/ranker.rs
// ---------------------------------------------------------------------------

/// Ranks refactoring suggestions based on multiple criteria.
///
/// Ported from `episteme.cli.infer.RefactoringRanker` (Python).
///
/// Composite scoring formula:
/// - Severity weight: 40% (smell confidence)
/// - Effort inverse: 30% (prefer smaller effort)
/// - Principle alignment: 20% (how many violated principles it fixes)
/// - Usage frequency: 10% (popularity heuristic)
pub struct RefactoringRanker {
    graph: KnowledgeGraph,
}

// Effort weights (inverse -- smaller effort = higher score).
const EFFORT_WEIGHT_SMALL: f64 = 1.0;
const EFFORT_WEIGHT_MEDIUM: f64 = 0.6;
const EFFORT_WEIGHT_LARGE: f64 = 0.3;

impl RefactoringRanker {
    pub fn new(graph: KnowledgeGraph) -> Self {
        Self { graph }
    }

    /// Rank refactorings based on multiple criteria.
    ///
    /// Returns suggestions sorted by priority score descending.
    pub fn rank_refactorings(
        &self,
        detection: &SmellDetection,
        refactoring_ids: &[String],
    ) -> Vec<RefactoringSuggestion> {
        let mut suggestions = Vec::new();

        for rf_id in refactoring_ids {
            let Some(rf_entity) = self.graph.get_entity(rf_id) else {
                continue;
            };

            // Calculate composite score
            let severity_score = detection.confidence; // 0.0 - 1.0
            let effort_score = self.calculate_effort_score(rf_entity);
            let principle_score = self.calculate_principle_alignment(detection, rf_entity);
            let usage_score = self.calculate_usage_frequency(rf_id);

            let priority_score = 0.4 * severity_score
                + 0.3 * effort_score
                + 0.2 * principle_score
                + 0.1 * usage_score;

            // Get effort level
            let effort = Self::extract_effort(rf_entity);

            // Get enforced principles
            let enforced = rf_entity
                .relations
                .get("enforces")
                .cloned()
                .unwrap_or_default();

            // Generate description
            let description = self.generate_description(detection, rf_entity, &enforced);

            suggestions.push(RefactoringSuggestion {
                refactoring_id: rf_id.clone(),
                title: if rf_entity.title.is_empty() {
                    "Unknown".to_owned()
                } else {
                    rf_entity.title.clone()
                },
                priority_score,
                effort,
                principles_enforced: enforced,
                description,
                metadata: SuggestionMetadata {
                    severity_score,
                    effort_score,
                    principle_score,
                    usage_score,
                },
            });
        }

        // Sort by priority descending
        suggestions.sort_by(|a, b| {
            b.priority_score
                .partial_cmp(&a.priority_score)
                .unwrap_or(std::cmp::Ordering::Equal)
        });

        suggestions
    }

    /// Estimate effort score (inverse of effort).
    fn calculate_effort_score(&self, rf_entity: &Entity) -> f64 {
        match Self::extract_effort(rf_entity) {
            EffortLevel::Small => EFFORT_WEIGHT_SMALL,
            EffortLevel::Medium => EFFORT_WEIGHT_MEDIUM,
            EffortLevel::Large => EFFORT_WEIGHT_LARGE,
        }
    }

    /// Extract effort estimate from entity metadata using context heuristics.
    fn extract_effort(rf_entity: &Entity) -> EffortLevel {
        let context = &rf_entity.context;

        let when_to_use = context
            .get("when_to_use")
            .map(|v| v.join(" "))
            .unwrap_or_default()
            .to_lowercase();

        let benefits = context
            .get("benefits")
            .map(|v| v.join(" "))
            .unwrap_or_default()
            .to_lowercase();

        if when_to_use.contains("simple") || benefits.contains("quick") {
            EffortLevel::Small
        } else if when_to_use.contains("complex") || benefits.contains("significant") {
            EffortLevel::Large
        } else {
            EffortLevel::Medium
        }
    }

    /// Calculate principle alignment score.
    ///
    /// How many principles violated by the smell are enforced by the refactoring?
    fn calculate_principle_alignment(&self, detection: &SmellDetection, rf_entity: &Entity) -> f64 {
        let Some(smell_entity) = self.graph.get_entity(&detection.smell_id) else {
            return 0.5;
        };

        let violated_laws: HashSet<&str> = smell_entity
            .relations
            .get("violates")
            .map(|v| v.iter().map(|s| s.as_str()).collect())
            .unwrap_or_default();

        let enforced_laws: HashSet<&str> = rf_entity
            .relations
            .get("enforces")
            .map(|v| v.iter().map(|s| s.as_str()).collect())
            .unwrap_or_default();

        if violated_laws.is_empty() {
            return 0.5; // No violation info, neutral score
        }

        let overlap = violated_laws.intersection(&enforced_laws).count();
        let max_possible = violated_laws.len();

        if max_possible > 0 {
            overlap as f64 / max_possible as f64
        } else {
            0.0
        }
    }

    /// Estimate usage frequency (popularity heuristic).
    ///
    /// More related entities = more popular. Normalized to 0.0-1.0 (max 20 relations).
    fn calculate_usage_frequency(&self, rf_id: &str) -> f64 {
        let Some(rf_entity) = self.graph.get_entity(rf_id) else {
            return 0.0;
        };

        let total_relations: usize = rf_entity.relations.values().map(|v| v.len()).sum();

        (total_relations as f64 / 20.0).min(1.0)
    }

    /// Generate human-readable description.
    fn generate_description(
        &self,
        detection: &SmellDetection,
        rf_entity: &Entity,
        enforced_laws: &[String],
    ) -> String {
        let rf_title = if rf_entity.title.is_empty() {
            "Unknown"
        } else {
            &rf_entity.title
        };

        // Get principle names (limit to 3)
        let mut law_names = Vec::new();
        for law_id in enforced_laws.iter().take(3) {
            if let Some(law_entity) = self.graph.get_entity(law_id) {
                let name = if law_entity.title.is_empty() {
                    law_id.clone()
                } else {
                    law_entity.title.clone()
                };
                law_names.push(name);
            }
        }

        let principles_text = if law_names.is_empty() {
            "code quality".to_owned()
        } else {
            law_names.join(", ")
        };

        // Extract context benefits
        let benefit_text = rf_entity
            .context
            .get("benefits")
            .and_then(|v| v.first())
            .map(|s| s.as_str())
            .unwrap_or("improve code structure");

        format!(
            "Apply {} to {}. This addresses {} and improves {}.",
            rf_title, benefit_text, detection.smell_name, principles_text
        )
    }

    /// Provide access to the underlying graph (for engine composition).
    pub fn graph(&self) -> &KnowledgeGraph {
        &self.graph
    }
}

// ---------------------------------------------------------------------------
// RefactoringInferenceEngine — merged from episteme-infer/src/engine.rs
// ---------------------------------------------------------------------------

/// Main engine for code smell to refactoring inference.
///
/// Ported from `episteme.cli.infer.RefactoringInferenceEngine` (Python).
///
/// For each detected smell, the engine:
/// 1. Looks up `solved_by` refactoring IDs from the knowledge graph
/// 2. Ranks them using composite scoring
/// 3. Returns the top-k suggestions
pub struct RefactoringInferenceEngine {
    ranker: RefactoringRanker,
}

impl RefactoringInferenceEngine {
    /// Create a new engine from a loaded knowledge graph.
    pub fn new(graph: KnowledgeGraph) -> Self {
        let ranker = RefactoringRanker::new(graph);
        Self { ranker }
    }

    /// Analyze a batch of smell detections and return ranked suggestions.
    ///
    /// For each detection:
    /// - Finds refactorings that solve the smell via graph traversal
    /// - Ranks them by composite score
    /// - Truncates to `top_k`
    pub fn analyze_detections(
        &self,
        detections: &[SmellDetection],
        top_k: usize,
    ) -> Vec<crate::domain::inference::SmellAnalysis> {
        let mut results = Vec::new();

        for detection in detections {
            // Step 1: Find refactorings via graph traversal
            let refactoring_ids = self.find_refactorings_for_smell(&detection.smell_id);

            // Step 2: Rank refactorings
            let suggestions = self.ranker.rank_refactorings(detection, &refactoring_ids);

            // Step 3: Truncate to top_k
            let suggestions = suggestions.into_iter().take(top_k).collect();

            // Serialize the detection as JSON value (mirrors Python's `asdict(detection)`)
            let smell_value = serde_json::to_value(detection).unwrap_or(serde_json::Value::Null);

            results.push(crate::domain::inference::SmellAnalysis {
                smell: smell_value,
                suggestions,
            });
        }

        results
    }

    /// Find refactoring IDs that solve a code smell.
    ///
    /// Looks up the smell entity's `solved_by` relations in the knowledge graph.
    fn find_refactorings_for_smell(&self, smell_id: &str) -> Vec<String> {
        self.ranker
            .graph()
            .get_neighbors(smell_id, Some("solved_by"))
    }
}

// ---------------------------------------------------------------------------
// Tests (from both engine.rs and ranker.rs)
// ---------------------------------------------------------------------------

#[cfg(test)]
mod tests {
    use super::*;
    use crate::domain::inference::EffortLevel;
    use crate::domain::metrics::CodeMetrics;
    use crate::domain::types::Entity;
    use std::collections::HashMap;

    fn blank_entity(id: &str) -> Entity {
        Entity {
            id: id.to_owned(),
            r#type: String::new(),
            title: String::new(),
            description: String::new(),
            name: String::new(),
            category: String::new(),
            tags: vec![],
            relations: HashMap::new(),
            context: HashMap::new(),
            file_path: String::new(),
            source: serde_json::Value::Null,
        }
    }

    fn build_graph(entities: Vec<Entity>) -> KnowledgeGraph {
        let map: HashMap<String, Entity> =
            entities.into_iter().map(|e| (e.id.clone(), e)).collect();
        KnowledgeGraph::from_entities(map)
    }

    fn make_detection(smell_id: &str, smell_name: &str, confidence: f64) -> SmellDetection {
        SmellDetection {
            smell_id: smell_id.to_owned(),
            smell_name: smell_name.to_owned(),
            confidence,
            location: "test.py:10".to_owned(),
            function_name: "test_fn".to_owned(),
            metrics: CodeMetrics::default(),
            reasons: vec!["test reason".to_owned()],
        }
    }

    // -- Ranker tests -------------------------------------------------------

    #[test]
    fn test_extract_effort_small() {
        let mut entity = blank_entity("RF-001");
        entity.title = "Extract Method".to_owned();
        entity
            .context
            .insert("when_to_use".to_owned(), vec!["simple refactor".to_owned()]);
        assert_eq!(
            RefactoringRanker::extract_effort(&entity),
            EffortLevel::Small
        );
    }

    #[test]
    fn test_extract_effort_large() {
        let mut entity = blank_entity("RF-002");
        entity.title = "Decompose Conditional".to_owned();
        entity.context.insert(
            "benefits".to_owned(),
            vec!["significant improvement".to_owned()],
        );
        assert_eq!(
            RefactoringRanker::extract_effort(&entity),
            EffortLevel::Large
        );
    }

    #[test]
    fn test_extract_effort_medium_default() {
        let entity = blank_entity("RF-003");
        assert_eq!(
            RefactoringRanker::extract_effort(&entity),
            EffortLevel::Medium
        );
    }

    #[test]
    fn test_rank_refactorings_sorts_by_priority() {
        let mut smell_entity = blank_entity("SMELL-01");
        smell_entity.title = "Long Method".to_owned();
        smell_entity.r#type = "smell".to_owned();
        smell_entity
            .relations
            .insert("violates".to_owned(), vec!["LAW-001".to_owned()]);
        smell_entity.relations.insert(
            "solved_by".to_owned(),
            vec!["RF-001".to_owned(), "RF-002".to_owned()],
        );

        // RF-001 has more relations -> higher usage score
        let mut rf1 = blank_entity("RF-001");
        rf1.title = "Extract Method".to_owned();
        rf1.r#type = "refactoring".to_owned();
        rf1.relations
            .insert("enforces".to_owned(), vec!["LAW-001".to_owned()]);
        rf1.relations
            .insert("solves".to_owned(), vec!["SMELL-01".to_owned()]);
        rf1.relations.insert(
            "related_to".to_owned(),
            (0..12).map(|i| format!("DP-{i}")).collect(),
        );
        rf1.context
            .insert("when_to_use".to_owned(), vec!["simple".to_owned()]);
        rf1.context
            .insert("benefits".to_owned(), vec!["quick win".to_owned()]);

        // RF-002 has fewer relations -> lower usage score
        let mut rf2 = blank_entity("RF-002");
        rf2.title = "Replace Method with Method Object".to_owned();
        rf2.r#type = "refactoring".to_owned();
        rf2.relations
            .insert("enforces".to_owned(), vec!["LAW-001".to_owned()]);
        rf2.relations
            .insert("solves".to_owned(), vec!["SMELL-01".to_owned()]);
        rf2.context.insert(
            "benefits".to_owned(),
            vec!["complex restructuring".to_owned()],
        );

        let graph = build_graph(vec![smell_entity, rf1, rf2]);
        let ranker = RefactoringRanker::new(graph);

        let detection = make_detection("SMELL-01", "Long Method", 0.8);
        let rf_ids = vec!["RF-001".to_owned(), "RF-002".to_owned()];

        let suggestions = ranker.rank_refactorings(&detection, &rf_ids);
        assert_eq!(suggestions.len(), 2);

        // RF-001 should be ranked first (small effort + higher usage)
        assert_eq!(suggestions[0].refactoring_id, "RF-001");
        assert!(suggestions[0].priority_score > suggestions[1].priority_score);
    }

    #[test]
    fn test_calculate_principle_alignment_overlap() {
        let mut smell_entity = blank_entity("SMELL-01");
        smell_entity.title = "Long Method".to_owned();
        smell_entity.r#type = "smell".to_owned();
        smell_entity.relations.insert(
            "violates".to_owned(),
            vec!["LAW-001".to_owned(), "LAW-002".to_owned()],
        );

        let mut rf_entity = blank_entity("RF-001");
        rf_entity.title = "Extract Method".to_owned();
        rf_entity.r#type = "refactoring".to_owned();
        // Enforces one of the two violated laws
        rf_entity
            .relations
            .insert("enforces".to_owned(), vec!["LAW-001".to_owned()]);

        let graph = build_graph(vec![smell_entity, rf_entity]);
        let ranker = RefactoringRanker::new(graph);

        let detection = make_detection("SMELL-01", "Long Method", 0.8);
        let score = ranker.calculate_principle_alignment(
            &detection,
            ranker.graph().get_entity("RF-001").unwrap(),
        );

        // 1 overlap out of 2 violated = 0.5
        assert!((score - 0.5).abs() < f64::EPSILON);
    }

    #[test]
    fn test_calculate_principle_alignment_no_violated_laws() {
        let smell_entity = blank_entity("SMELL-01");
        let rf_entity = blank_entity("RF-001");

        let graph = build_graph(vec![smell_entity, rf_entity]);
        let ranker = RefactoringRanker::new(graph);

        let detection = make_detection("SMELL-01", "Long Method", 0.8);
        let score = ranker.calculate_principle_alignment(
            &detection,
            ranker.graph().get_entity("RF-001").unwrap(),
        );

        // No violated laws -> neutral 0.5
        assert!((score - 0.5).abs() < f64::EPSILON);
    }

    #[test]
    fn test_calculate_usage_frequency() {
        let mut rf_entity = blank_entity("RF-001");
        rf_entity.title = "Extract Method".to_owned();
        rf_entity.r#type = "refactoring".to_owned();
        rf_entity
            .relations
            .insert("enforces".to_owned(), vec!["LAW-001".to_owned()]);
        rf_entity.relations.insert(
            "solves".to_owned(),
            vec!["SMELL-01".to_owned(), "SMELL-02".to_owned()],
        );
        // total = 3 relations

        let graph = build_graph(vec![rf_entity]);
        let ranker = RefactoringRanker::new(graph);

        let score = ranker.calculate_usage_frequency("RF-001");
        // 3 / 20.0 = 0.15
        assert!((score - 0.15).abs() < f64::EPSILON);
    }

    #[test]
    fn test_calculate_usage_frequency_capped_at_one() {
        let mut rf_entity = blank_entity("RF-001");
        rf_entity.title = "Popular Refactoring".to_owned();
        rf_entity.r#type = "refactoring".to_owned();
        // 25 relations -> should cap at 1.0
        rf_entity.relations.insert(
            "enforces".to_owned(),
            (0..25).map(|i| format!("LAW-{i}")).collect(),
        );

        let graph = build_graph(vec![rf_entity]);
        let ranker = RefactoringRanker::new(graph);

        let score = ranker.calculate_usage_frequency("RF-001");
        assert!((score - 1.0).abs() < f64::EPSILON);
    }

    #[test]
    fn test_generate_description_with_laws() {
        let mut law_entity = blank_entity("LAW-001");
        law_entity.title = "Single Responsibility Principle".to_owned();
        law_entity.r#type = "law".to_owned();

        let mut rf_entity = blank_entity("RF-001");
        rf_entity.title = "Extract Method".to_owned();
        rf_entity.r#type = "refactoring".to_owned();
        rf_entity
            .relations
            .insert("enforces".to_owned(), vec!["LAW-001".to_owned()]);
        rf_entity
            .context
            .insert("benefits".to_owned(), vec!["reduce complexity".to_owned()]);

        let graph = build_graph(vec![law_entity, rf_entity]);
        let ranker = RefactoringRanker::new(graph);

        let detection = make_detection("SMELL-01", "Long Method", 0.8);
        let desc = ranker.generate_description(
            &detection,
            ranker.graph().get_entity("RF-001").unwrap(),
            &["LAW-001".to_owned()],
        );

        assert!(desc.contains("Extract Method"));
        assert!(desc.contains("reduce complexity"));
        assert!(desc.contains("Long Method"));
        assert!(desc.contains("Single Responsibility Principle"));
    }

    #[test]
    fn test_generate_description_no_laws() {
        let rf_entity = blank_entity("RF-001");

        let graph = build_graph(vec![rf_entity]);
        let ranker = RefactoringRanker::new(graph);

        let detection = make_detection("SMELL-01", "Long Method", 0.8);
        let desc = ranker.generate_description(
            &detection,
            ranker.graph().get_entity("RF-001").unwrap(),
            &[],
        );

        assert!(desc.contains("code quality"));
    }

    #[test]
    fn test_unknown_refactoring_id_skipped() {
        let graph = build_graph(vec![]);
        let ranker = RefactoringRanker::new(graph);

        let detection = make_detection("SMELL-01", "Long Method", 0.8);
        let suggestions = ranker.rank_refactorings(&detection, &["RF-NONEXISTENT".to_owned()]);

        assert!(suggestions.is_empty());
    }

    #[test]
    fn test_composite_score_formula() {
        // Verify exact formula: 0.4 * severity + 0.3 * effort + 0.2 * principle + 0.1 * usage
        let mut smell_entity = blank_entity("SMELL-01");
        smell_entity
            .relations
            .insert("violates".to_owned(), vec!["LAW-001".to_owned()]);

        let mut rf_entity = blank_entity("RF-001");
        rf_entity.title = "Test Refactoring".to_owned();
        rf_entity.r#type = "refactoring".to_owned();
        rf_entity
            .relations
            .insert("enforces".to_owned(), vec!["LAW-001".to_owned()]);
        // 2 relations total -> usage = 2/20 = 0.1
        rf_entity
            .relations
            .insert("solves".to_owned(), vec!["SMELL-01".to_owned()]);
        // no context -> medium effort -> 0.6

        let graph = build_graph(vec![smell_entity, rf_entity]);
        let ranker = RefactoringRanker::new(graph);

        let detection = make_detection("SMELL-01", "Long Method", 0.9);
        let suggestions = ranker.rank_refactorings(&detection, &["RF-001".to_owned()]);

        assert_eq!(suggestions.len(), 1);
        let s = &suggestions[0];

        // severity = 0.9, effort = 0.6, principle = 1.0 (1/1 overlap), usage = 0.1
        let expected = 0.4 * 0.9 + 0.3 * 0.6 + 0.2 * 1.0 + 0.1 * 0.1;
        assert!(
            (s.priority_score - expected).abs() < 1e-10,
            "expected {}, got {}",
            expected,
            s.priority_score
        );

        assert!((s.metadata.severity_score - 0.9).abs() < f64::EPSILON);
        assert!((s.metadata.effort_score - 0.6).abs() < f64::EPSILON);
        assert!((s.metadata.principle_score - 1.0).abs() < f64::EPSILON);
        assert!((s.metadata.usage_score - 0.1).abs() < f64::EPSILON);
    }

    // -- Engine tests -------------------------------------------------------

    #[test]
    fn test_analyze_detections_basic() {
        let mut law = blank_entity("LAW-001");
        law.title = "Single Responsibility Principle".to_owned();
        law.r#type = "law".to_owned();

        let mut smell = blank_entity("SMELL-01");
        smell.title = "Long Method".to_owned();
        smell.r#type = "smell".to_owned();
        smell
            .relations
            .insert("violates".to_owned(), vec!["LAW-001".to_owned()]);
        smell.relations.insert(
            "solved_by".to_owned(),
            vec!["RF-001".to_owned(), "RF-002".to_owned()],
        );

        let mut rf1 = blank_entity("RF-001");
        rf1.title = "Extract Method".to_owned();
        rf1.r#type = "refactoring".to_owned();
        rf1.relations
            .insert("enforces".to_owned(), vec!["LAW-001".to_owned()]);
        rf1.relations
            .insert("solves".to_owned(), vec!["SMELL-01".to_owned()]);
        rf1.context
            .insert("when_to_use".to_owned(), vec!["simple refactor".to_owned()]);
        rf1.context
            .insert("benefits".to_owned(), vec!["quick win".to_owned()]);

        let mut rf2 = blank_entity("RF-002");
        rf2.title = "Replace Temp with Query".to_owned();
        rf2.r#type = "refactoring".to_owned();
        rf2.relations
            .insert("enforces".to_owned(), vec!["LAW-001".to_owned()]);
        rf2.relations
            .insert("solves".to_owned(), vec!["SMELL-01".to_owned()]);

        let graph = build_graph(vec![law, smell, rf1, rf2]);
        let engine = RefactoringInferenceEngine::new(graph);

        let detection = make_detection("SMELL-01", "Long Method", 0.8);
        let results = engine.analyze_detections(&[detection], 3);

        assert_eq!(results.len(), 1);
        let analysis = &results[0];

        // Smell should be serialized as JSON object
        assert!(analysis.smell.is_object());
        assert_eq!(analysis.smell["smell_id"], "SMELL-01");

        // Should have 2 suggestions (both refactorings are in the graph)
        assert_eq!(analysis.suggestions.len(), 2);

        // First should be Extract Method (small effort -> higher score)
        assert_eq!(analysis.suggestions[0].refactoring_id, "RF-001");
        assert_eq!(analysis.suggestions[0].title, "Extract Method");
    }

    #[test]
    fn test_analyze_detections_top_k() {
        let mut smell = blank_entity("SMELL-01");
        smell.title = "Long Method".to_owned();
        smell.r#type = "smell".to_owned();
        smell.relations.insert(
            "solved_by".to_owned(),
            vec![
                "RF-001".to_owned(),
                "RF-002".to_owned(),
                "RF-003".to_owned(),
            ],
        );

        let mut rf1 = blank_entity("RF-001");
        rf1.title = "Extract Method".to_owned();
        rf1.r#type = "refactoring".to_owned();

        let mut rf2 = blank_entity("RF-002");
        rf2.title = "Replace Method".to_owned();
        rf2.r#type = "refactoring".to_owned();

        let mut rf3 = blank_entity("RF-003");
        rf3.title = "Decompose Conditional".to_owned();
        rf3.r#type = "refactoring".to_owned();

        let graph = build_graph(vec![smell, rf1, rf2, rf3]);
        let engine = RefactoringInferenceEngine::new(graph);

        let detection = make_detection("SMELL-01", "Long Method", 0.8);
        let results = engine.analyze_detections(&[detection], 2);

        assert_eq!(results.len(), 1);
        assert_eq!(results[0].suggestions.len(), 2);
    }

    #[test]
    fn test_analyze_detections_no_refactorings() {
        let mut smell = blank_entity("SMELL-99");
        smell.title = "Unknown Smell".to_owned();
        smell.r#type = "smell".to_owned();

        let graph = build_graph(vec![smell]);
        let engine = RefactoringInferenceEngine::new(graph);

        let detection = make_detection("SMELL-99", "Unknown Smell", 0.5);
        let results = engine.analyze_detections(&[detection], 3);

        assert_eq!(results.len(), 1);
        assert!(results[0].suggestions.is_empty());
    }

    #[test]
    fn test_analyze_multiple_detections() {
        let mut smell1 = blank_entity("SMELL-01");
        smell1.title = "Long Method".to_owned();
        smell1.r#type = "smell".to_owned();
        smell1
            .relations
            .insert("solved_by".to_owned(), vec!["RF-001".to_owned()]);

        let mut smell2 = blank_entity("SMELL-02");
        smell2.title = "Long Parameter List".to_owned();
        smell2.r#type = "smell".to_owned();
        smell2
            .relations
            .insert("solved_by".to_owned(), vec!["RF-002".to_owned()]);

        let mut rf1 = blank_entity("RF-001");
        rf1.title = "Extract Method".to_owned();
        rf1.r#type = "refactoring".to_owned();

        let mut rf2 = blank_entity("RF-002");
        rf2.title = "Introduce Parameter Object".to_owned();
        rf2.r#type = "refactoring".to_owned();

        let graph = build_graph(vec![smell1, smell2, rf1, rf2]);
        let engine = RefactoringInferenceEngine::new(graph);

        let det1 = make_detection("SMELL-01", "Long Method", 0.8);
        let det2 = make_detection("SMELL-02", "Long Parameter List", 0.7);

        let results = engine.analyze_detections(&[det1, det2], 3);

        assert_eq!(results.len(), 2);
        assert_eq!(results[0].suggestions.len(), 1);
        assert_eq!(results[0].suggestions[0].refactoring_id, "RF-001");
        assert_eq!(results[1].suggestions[0].refactoring_id, "RF-002");
    }

    #[test]
    fn test_find_refactorings_for_smell() {
        let mut smell = blank_entity("SMELL-01");
        smell.title = "Long Method".to_owned();
        smell.r#type = "smell".to_owned();
        smell.relations.insert(
            "solved_by".to_owned(),
            vec!["RF-001".to_owned(), "RF-002".to_owned()],
        );
        smell
            .relations
            .insert("violates".to_owned(), vec!["LAW-001".to_owned()]);

        let graph = build_graph(vec![smell]);
        let engine = RefactoringInferenceEngine::new(graph);

        let ids = engine.find_refactorings_for_smell("SMELL-01");
        assert_eq!(ids.len(), 2);
        assert!(ids.contains(&"RF-001".to_owned()));
        assert!(ids.contains(&"RF-002".to_owned()));
    }

    #[test]
    fn test_find_refactorings_unknown_smell() {
        let graph = build_graph(vec![]);
        let engine = RefactoringInferenceEngine::new(graph);

        let ids = engine.find_refactorings_for_smell("SMELL-NONEXISTENT");
        assert!(ids.is_empty());
    }
}