Initial commit

brittle-core/src/error.rs

@@ -0,0 +1,104 @@
+use std::path::PathBuf;
+use thiserror::Error;
+
+/// Top-level error returned from all public Brittle API methods.
+#[derive(Debug, Error)]
+pub enum BrittleError {
+    #[error("{0}")]
+    Store(#[from] StoreError),
+
+    #[error("{0}")]
+    Validation(#[from] ValidationError),
+
+    #[error("{0}")]
+    BibTeX(#[from] BibtexError),
+}
+
+/// Errors from the storage layer.
+#[derive(Debug, Error)]
+pub enum StoreError {
+    #[error("{entity_type} not found: {id}")]
+    NotFound { entity_type: EntityType, id: String },
+
+    #[error("I/O error: {0}")]
+    Io(#[from] std::io::Error),
+
+    #[error("serialization error: {message}")]
+    Serialization { message: String },
+
+    #[error("deserialization error for {path}: {message}")]
+    Deserialization { path: PathBuf, message: String },
+
+    #[error("git error: {0}")]
+    Git(#[from] git2::Error),
+
+    #[error("repository not found at {path}")]
+    RepoNotFound { path: PathBuf },
+
+    #[error("repository already exists at {path}")]
+    RepoAlreadyExists { path: PathBuf },
+}
+
+/// The kind of entity involved in a not-found error.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum EntityType {
+    Reference,
+    Library,
+    Annotation,
+    Snapshot,
+}
+
+impl std::fmt::Display for EntityType {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            EntityType::Reference => write!(f, "Reference"),
+            EntityType::Library => write!(f, "Library"),
+            EntityType::Annotation => write!(f, "Annotation"),
+            EntityType::Snapshot => write!(f, "Snapshot"),
+        }
+    }
+}
+
+/// Business logic validation errors.
+#[derive(Debug, Error)]
+pub enum ValidationError {
+    #[error(
+        "library cycle detected: moving library {library_id} under {parent_id} would create a cycle"
+    )]
+    LibraryCycle {
+        library_id: String,
+        parent_id: String,
+    },
+
+    #[error("library {id} has children and cannot be deleted; delete or move children first")]
+    LibraryHasChildren { id: String },
+
+    #[error("cite key already exists: {cite_key}")]
+    DuplicateCiteKey { cite_key: String },
+
+    #[error("cite key cannot be empty")]
+    EmptyCiteKey,
+
+    #[error("library name cannot be empty")]
+    EmptyLibraryName,
+
+    #[error("reference {reference_id} has no PDF attached")]
+    NoPdfAttached { reference_id: String },
+
+    #[error("PDF file not found: {path}")]
+    PdfNotFound { path: PathBuf },
+
+    #[error("there are uncommitted changes; create a snapshot or call discard_changes() first")]
+    UncommittedChanges,
+}
+
+/// Errors specific to BibTeX export.
+#[derive(Debug, Error)]
+pub enum BibtexError {
+    #[error("reference '{cite_key}' ({entry_type}): missing required field '{field}'")]
+    MissingRequiredField {
+        cite_key: String,
+        entry_type: String,
+        field: String,
+    },
+}