feat: add BuildCodeGraph use case, sink orchestration out of presentation

crates/application/src/use_cases/build_code_graph.rs

@@ -0,0 +1,67 @@
+use std::path::Path;
+
+use archlens_domain::{
+    AnalysisConfig, AnalysisWarning, DiagramLevel, DomainError, NormalizedGraph,
+    ports::{FileDiscovery, ProjectAnalyzer, SourceAnalyzer},
+};
+
+use crate::queries::AnalyzeCodebase;
+
+#[derive(Debug)]
+pub struct BuildCodeGraphResult {
+    pub graph: NormalizedGraph,
+    pub warnings: Vec<AnalysisWarning>,
+}
+
+pub struct BuildCodeGraph<F, S>
+where
+    F: FileDiscovery + Send + Sync,
+    S: SourceAnalyzer,
+{
+    pub discovery: F,
+    pub source_analyzer: S,
+    pub project_analyzer: Option<Box<dyn ProjectAnalyzer>>,
+}
+
+impl<F, S> BuildCodeGraph<F, S>
+where
+    F: FileDiscovery + Send + Sync,
+    S: SourceAnalyzer,
+{
+    pub fn execute(
+        self,
+        root: &Path,
+        config: &AnalysisConfig,
+        level: DiagramLevel,
+    ) -> Result<BuildCodeGraphResult, DomainError> {
+        match level {
+            DiagramLevel::Project => {
+                let pa = self.project_analyzer.ok_or_else(|| {
+                    DomainError::AnalysisError(
+                        "no project analyzer available for Project level".into(),
+                    )
+                })?;
+                let cg = pa.analyze(root)?;
+                Ok(BuildCodeGraphResult {
+                    graph: NormalizedGraph::from_project(cg),
+                    warnings: Vec::new(),
+                })
+            }
+            DiagramLevel::Module | DiagramLevel::Type => {
+                let analyze = AnalyzeCodebase::new(self.discovery, self.source_analyzer);
+                let result = analyze.execute(root, config)?;
+                let mut graph = result.graph().clone();
+                if level == DiagramLevel::Module {
+                    if let Some(pa) = self.project_analyzer {
+                        let project_cg = pa.analyze(root)?;
+                        graph.merge_project_edges(&project_cg);
+                    }
+                }
+                Ok(BuildCodeGraphResult {
+                    graph,
+                    warnings: result.warnings().to_vec(),
+                })
+            }
+        }
+    }
+}

crates/application/src/use_cases/mod.rs

@@ -1,3 +1,4 @@
+pub mod build_code_graph;
 pub mod check_freshness;
 pub mod diff_diagram;
 pub mod generate_diagram;

crates/application/tests/build_code_graph_tests.rs

@@ -0,0 +1,152 @@
+mod fakes;
+
+use std::path::Path;
+
+use archlens_application::use_cases::build_code_graph::BuildCodeGraph;
+use archlens_domain::{
+    AnalysisConfig, AnalysisResult, AnalysisWarning, CodeElement, CodeElementKind, CodeGraph,
+    DiagramLevel, FilePath, Language, SourceFile,
+};
+
+use fakes::{FakeFileDiscovery, FakeProjectAnalyzer, FakeSourceAnalyzer};
+
+#[test]
+fn project_level_returns_project_analyzer_graph() {
+    let mut cg = CodeGraph::new();
+    cg.add_element(
+        CodeElement::new(
+            "MyApp",
+            CodeElementKind::Project,
+            FilePath::new("Cargo.toml").unwrap(),
+            1,
+        )
+        .unwrap(),
+    );
+
+    let use_case = BuildCodeGraph {
+        discovery: FakeFileDiscovery::empty(),
+        source_analyzer: FakeSourceAnalyzer::new(),
+        project_analyzer: Some(Box::new(FakeProjectAnalyzer::new(cg))),
+    };
+
+    let result = use_case
+        .execute(Path::new("."), &AnalysisConfig::default(), DiagramLevel::Project)
+        .unwrap();
+
+    assert_eq!(result.graph.elements().len(), 1);
+    assert_eq!(result.graph.elements()[0].name(), "MyApp");
+    assert!(result.warnings.is_empty());
+}
+
+#[test]
+fn project_level_without_analyzer_returns_error() {
+    let use_case = BuildCodeGraph {
+        discovery: FakeFileDiscovery::empty(),
+        source_analyzer: FakeSourceAnalyzer::new(),
+        project_analyzer: None,
+    };
+
+    let err = use_case
+        .execute(Path::new("."), &AnalysisConfig::default(), DiagramLevel::Project)
+        .unwrap_err();
+
+    assert!(err.to_string().contains("no project analyzer"));
+}
+
+#[test]
+fn type_level_uses_source_analyzer_not_project() {
+    let files = vec![SourceFile::new(
+        FilePath::new("src/order.rs").unwrap(),
+        Language::Rust,
+    )];
+    let discovery = FakeFileDiscovery::new(files);
+    let analyzer = FakeSourceAnalyzer::new().with_result(
+        "src/order.rs",
+        AnalysisResult::new(
+            vec![CodeElement::new(
+                "Order",
+                CodeElementKind::Struct,
+                FilePath::new("src/order.rs").unwrap(),
+                1,
+            )
+            .unwrap()],
+            vec![],
+            vec![],
+        ),
+    );
+
+    let mut project_cg = CodeGraph::new();
+    project_cg.add_element(
+        CodeElement::new(
+            "ProjectElement",
+            CodeElementKind::Project,
+            FilePath::new("Cargo.toml").unwrap(),
+            1,
+        )
+        .unwrap(),
+    );
+
+    let use_case = BuildCodeGraph {
+        discovery,
+        source_analyzer: analyzer,
+        project_analyzer: Some(Box::new(FakeProjectAnalyzer::new(project_cg))),
+    };
+
+    let result = use_case
+        .execute(Path::new("."), &AnalysisConfig::default(), DiagramLevel::Type)
+        .unwrap();
+
+    // Source element present, project element NOT merged (Type level skips merge)
+    assert_eq!(result.graph.elements().len(), 1);
+    assert_eq!(result.graph.elements()[0].name(), "Order");
+}
+
+#[test]
+fn module_level_without_project_analyzer_succeeds() {
+    let use_case = BuildCodeGraph {
+        discovery: FakeFileDiscovery::empty(),
+        source_analyzer: FakeSourceAnalyzer::new(),
+        project_analyzer: None,
+    };
+
+    let result = use_case
+        .execute(Path::new("."), &AnalysisConfig::default(), DiagramLevel::Module)
+        .unwrap();
+
+    assert!(result.graph.elements().is_empty());
+}
+
+#[test]
+fn warnings_from_source_analysis_are_propagated() {
+    let files = vec![SourceFile::new(
+        FilePath::new("src/broken.rs").unwrap(),
+        Language::Rust,
+    )];
+    let discovery = FakeFileDiscovery::new(files);
+    let analyzer = FakeSourceAnalyzer::new().with_result(
+        "src/broken.rs",
+        AnalysisResult::new(
+            vec![],
+            vec![],
+            vec![AnalysisWarning::new(
+                FilePath::new("src/broken.rs").unwrap(),
+                5,
+                "unparseable block",
+            )
+            .unwrap()],
+        ),
+    );
+
+    let use_case = BuildCodeGraph {
+        discovery,
+        source_analyzer: analyzer,
+        project_analyzer: None,
+    };
+
+    let result = use_case
+        .execute(Path::new("."), &AnalysisConfig::default(), DiagramLevel::Module)
+        .unwrap();
+
+    assert_eq!(result.warnings.len(), 1);
+    assert_eq!(result.warnings[0].message(), "unparseable block");
+}

crates/application/tests/fakes/mod.rs

@@ -3,9 +3,11 @@
 mod diagram_renderer;
 mod file_discovery;
 mod output_writer;
+mod project_analyzer;
 mod source_analyzer;
 
 pub use diagram_renderer::FakeDiagramRenderer;
 pub use file_discovery::FakeFileDiscovery;
 pub use output_writer::FakeOutputWriter;
+pub use project_analyzer::FakeProjectAnalyzer;
 pub use source_analyzer::FakeSourceAnalyzer;

crates/application/tests/fakes/project_analyzer.rs

@@ -0,0 +1,23 @@
+use std::path::Path;
+
+use archlens_domain::{CodeGraph, DomainError, ports::ProjectAnalyzer};
+
+pub struct FakeProjectAnalyzer {
+    graph: CodeGraph,
+}
+
+impl FakeProjectAnalyzer {
+    pub fn new(graph: CodeGraph) -> Self {
+        Self { graph }
+    }
+
+    pub fn empty() -> Self {
+        Self { graph: CodeGraph::new() }
+    }
+}
+
+impl ProjectAnalyzer for FakeProjectAnalyzer {
+    fn analyze(&self, _root: &Path) -> Result<CodeGraph, DomainError> {
+        Ok(self.graph.clone())
+    }
+}

crates/presentation/src/lib.rs

@@ -2,8 +2,8 @@ mod cli;
 
 use anyhow::{Result, bail};
 
-use archlens_application::queries::AnalyzeCodebase;
 use archlens_application::use_cases::{
+    build_code_graph::BuildCodeGraph,
     check_freshness::CheckFreshness,
     diff_diagram::DiffDiagram,
     generate_diagram::GenerateDiagram,
@@ -152,23 +152,28 @@ fn build_graph(args: &Cli, level: DiagramLevel) -> Result<NormalizedGraph> {
         analysis_config = analysis_config.with_changed_files(changed);
     }
 
-    if level == DiagramLevel::Project {
+    let project_analyzer: Option<Box<dyn ProjectAnalyzer>> = {
         let cargo_toml = args.path.join("Cargo.toml");
-        let project_graph = if cargo_toml.exists() {
-            CargoWorkspaceAnalyzer::new().analyze(&args.path)?
+        let pyproject = args.path.join("pyproject.toml");
+        if cargo_toml.exists() {
+            Some(Box::new(CargoWorkspaceAnalyzer::new()))
+        } else if pyproject.exists() {
+            Some(Box::new(PythonProjectAnalyzer::new()))
         } else {
-            PythonProjectAnalyzer::new().analyze(&args.path)?
-        };
-        return Ok(NormalizedGraph::from_project(project_graph));
-    }
+            None
+        }
+    };
 
-    let discovery = WalkdirDiscovery::new();
-    let analyzer = TreeSitterAnalyzer::new();
-    let analyze = AnalyzeCodebase::new(discovery, analyzer);
-    let result = analyze.execute(&args.path, &analysis_config)?;
+    let use_case = BuildCodeGraph {
+        discovery: WalkdirDiscovery::new(),
+        source_analyzer: TreeSitterAnalyzer::new(),
+        project_analyzer,
+    };
 
-    if !result.warnings().is_empty() {
-        for warning in result.warnings() {
+    let result = use_case.execute(&args.path, &analysis_config, level)?;
+
+    if !result.warnings.is_empty() {
+        for warning in &result.warnings {
             eprintln!(
                 "WARNING: {}:{} {}",
                 warning.file_path().as_str(),
@@ -179,26 +184,12 @@ fn build_graph(args: &Cli, level: DiagramLevel) -> Result<NormalizedGraph> {
         if args.strict {
             bail!(
                 "analysis produced {} warning(s) in strict mode",
-                result.warnings().len()
+                result.warnings.len()
             );
         }
     }
 
-    let mut graph = result.graph().clone();
-
-    if level == DiagramLevel::Module {
-        let workspace_toml = args.path.join("Cargo.toml");
-        let project_graph = if workspace_toml.exists() {
-            CargoWorkspaceAnalyzer::new().analyze(&args.path).ok()
-        } else {
-            PythonProjectAnalyzer::new().analyze(&args.path).ok()
-        };
-        if let Some(pg) = project_graph {
-            graph.merge_project_edges(&pg);
-        }
-    }
-
-    Ok(graph)
+    Ok(result.graph)
 }
 
 fn create_renderer(