ryo-analysis 0.1.0

//! Registry update operations for delta-based mutation execution.
//!
//! # Overview
//!
//! During parallel Mutation execution, SymbolRegistry changes are managed as deltas.
//! Each Mutation shares Registry as read-only and returns changes as `RegistryUpdate`.
//! All deltas are applied at Tick end.
//!
//! # Design
//!
//! ```text
//! 1 Tick flow:
//! ┌─────────────────────────────────────────────────────┐
//! │  Mutation A (modify X)  ──┐                         │
//! │  Mutation B (modify Y)  ──┼─→ Collect deltas → Apply to Registry
//! │  Mutation C (modify Z)  ──┘                         │
//! └─────────────────────────────────────────────────────┘
//! ```
//!
//! See `docs/parallel-execution-design.md` for full design details.

use super::{
    FileSpan, InvalidSymbolId, RegistrationError, RenameError, SymbolId, SymbolKind, SymbolPath,
    SymbolRegistry, Visibility,
};
use serde::Serialize;

/// Registry change request (delta).
///
/// Represents a single atomic change to the SymbolRegistry.
/// Collected during Mutation execution and applied at Tick end.
///
/// NOTE: Deserialize is NOT derived because FileSpan contains WorkspaceFilePath
/// which requires context during deserialization.
#[derive(Debug, Clone, PartialEq, Eq, Serialize)]
pub enum RegistryUpdate {
    /// Add a new symbol.
    Add {
        /// Canonical SymbolPath of the new symbol.
        path: SymbolPath,
        /// Kind classification (struct / fn / trait / ...).
        kind: SymbolKind,
        /// Source-file span where the symbol is declared.
        span: FileSpan,
    },

    /// Remove an existing symbol.
    Remove {
        /// Target symbol to remove.
        id: SymbolId,
    },

    /// Rename a symbol (change its path).
    Rename {
        /// Target symbol to rename.
        id: SymbolId,
        /// New canonical SymbolPath to assign.
        new_path: SymbolPath,
    },

    /// Update symbol's file span (position changed).
    UpdateSpan {
        /// Target symbol whose span is being updated.
        id: SymbolId,
        /// Replacement file span.
        new_span: FileSpan,
    },

    /// Update symbol's visibility.
    UpdateVisibility {
        /// Target symbol whose visibility is being updated.
        id: SymbolId,
        /// Replacement visibility value.
        new_visibility: Visibility,
    },

    /// Update symbol's kind.
    UpdateKind {
        /// Target symbol whose kind is being updated.
        id: SymbolId,
        /// Replacement kind classification.
        new_kind: SymbolKind,
    },
}

impl RegistryUpdate {
    /// Get the target SymbolId if this update modifies an existing symbol.
    ///
    /// Returns `None` for `Add` operations (no existing symbol).
    pub fn target_id(&self) -> Option<SymbolId> {
        match self {
            RegistryUpdate::Add { .. } => None,
            RegistryUpdate::Remove { id }
            | RegistryUpdate::Rename { id, .. }
            | RegistryUpdate::UpdateSpan { id, .. }
            | RegistryUpdate::UpdateVisibility { id, .. }
            | RegistryUpdate::UpdateKind { id, .. } => Some(*id),
        }
    }

    /// Check if this update is a destructive operation.
    ///
    /// Destructive operations (Remove, Rename) require special handling
    /// for conflict detection.
    pub fn is_destructive(&self) -> bool {
        matches!(
            self,
            RegistryUpdate::Remove { .. } | RegistryUpdate::Rename { .. }
        )
    }
}

/// Batch of registry updates from a single Mutation.
#[derive(Debug, Clone, Default)]
pub struct RegistryUpdateBatch {
    updates: Vec<RegistryUpdate>,
}

impl RegistryUpdateBatch {
    /// Create an empty batch.
    pub fn new() -> Self {
        Self::default()
    }

    /// Create a batch with pre-allocated capacity.
    pub fn with_capacity(capacity: usize) -> Self {
        Self {
            updates: Vec::with_capacity(capacity),
        }
    }

    /// Add an update to the batch.
    pub fn push(&mut self, update: RegistryUpdate) {
        self.updates.push(update);
    }

    /// Add a symbol addition.
    pub fn add_symbol(&mut self, path: SymbolPath, kind: SymbolKind, span: FileSpan) {
        self.push(RegistryUpdate::Add { path, kind, span });
    }

    /// Add a symbol removal.
    pub fn remove_symbol(&mut self, id: SymbolId) {
        self.push(RegistryUpdate::Remove { id });
    }

    /// Add a symbol rename.
    pub fn rename_symbol(&mut self, id: SymbolId, new_path: SymbolPath) {
        self.push(RegistryUpdate::Rename { id, new_path });
    }

    /// Add a span update.
    pub fn update_span(&mut self, id: SymbolId, new_span: FileSpan) {
        self.push(RegistryUpdate::UpdateSpan { id, new_span });
    }

    /// Get the updates.
    pub fn updates(&self) -> &[RegistryUpdate] {
        &self.updates
    }

    /// Consume and return the updates.
    pub fn into_updates(self) -> Vec<RegistryUpdate> {
        self.updates
    }

    /// Check if the batch is empty.
    pub fn is_empty(&self) -> bool {
        self.updates.is_empty()
    }

    /// Get the number of updates.
    pub fn len(&self) -> usize {
        self.updates.len()
    }

    /// Apply all updates to the registry.
    ///
    /// Updates are applied in order. If any update fails, the operation
    /// stops and returns the error. Previously applied updates are NOT
    /// rolled back (partial application).
    ///
    /// # Returns
    /// - `Ok(applied_count)`: Number of successfully applied updates
    /// - `Err(ApplyError)`: First error encountered
    pub fn apply(self, registry: &mut SymbolRegistry) -> Result<usize, ApplyError> {
        let mut applied = 0;

        for update in self.updates {
            update.apply(registry)?;
            applied += 1;
        }

        Ok(applied)
    }
}

/// Error during registry update application.
#[derive(Debug, thiserror::Error)]
pub enum ApplyError {
    /// Symbol registration failed.
    #[error("registration failed: {0}")]
    Registration(#[from] RegistrationError),

    /// Invalid symbol ID.
    #[error("invalid symbol id: {0}")]
    InvalidId(#[from] InvalidSymbolId),

    /// Rename failed.
    #[error("rename failed: {0}")]
    Rename(#[from] RenameError),
}

impl RegistryUpdate {
    /// Apply this update to the registry.
    pub fn apply(self, registry: &mut SymbolRegistry) -> Result<(), ApplyError> {
        match self {
            RegistryUpdate::Add { path, kind, span } => {
                let id = registry.register(path, kind)?;
                registry.set_span(id, span)?;
            }
            RegistryUpdate::Remove { id } => {
                // remove() returns None if not found, but we treat it as success
                // (idempotent deletion)
                let _ = registry.remove(id);
            }
            RegistryUpdate::Rename { id, new_path } => {
                registry.rename(id, new_path)?;
            }
            RegistryUpdate::UpdateSpan { id, new_span } => {
                registry.set_span(id, new_span)?;
            }
            RegistryUpdate::UpdateVisibility { id, new_visibility } => {
                registry.set_visibility(id, new_visibility)?;
            }
            RegistryUpdate::UpdateKind { id, new_kind } => {
                registry.set_kind(id, new_kind)?;
            }
        }
        Ok(())
    }
}

impl IntoIterator for RegistryUpdateBatch {
    type Item = RegistryUpdate;
    type IntoIter = std::vec::IntoIter<RegistryUpdate>;

    fn into_iter(self) -> Self::IntoIter {
        self.updates.into_iter()
    }
}

impl<'a> IntoIterator for &'a RegistryUpdateBatch {
    type Item = &'a RegistryUpdate;
    type IntoIter = std::slice::Iter<'a, RegistryUpdate>;

    fn into_iter(self) -> Self::IntoIter {
        self.updates.iter()
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use ryo_symbol::WorkspaceFilePath;

    /// Create a test FileSpan.
    fn test_span() -> FileSpan {
        FileSpan::new(
            WorkspaceFilePath::new_for_test("test/file.rs", "/", "test"),
            0,
            10,
        )
    }

    #[test]
    fn test_target_id() {
        use slotmap::KeyData;

        let id = SymbolId::from(KeyData::from_ffi(1));
        let path = SymbolPath::parse("foo::bar").unwrap();

        // Add has no target
        let add = RegistryUpdate::Add {
            path: path.clone(),
            kind: SymbolKind::Function,
            span: test_span(),
        };
        assert!(add.target_id().is_none());

        // Remove has target
        let remove = RegistryUpdate::Remove { id };
        assert_eq!(remove.target_id(), Some(id));

        // Rename has target
        let rename = RegistryUpdate::Rename { id, new_path: path };
        assert_eq!(rename.target_id(), Some(id));
    }

    #[test]
    fn test_is_destructive() {
        use slotmap::KeyData;

        let id = SymbolId::from(KeyData::from_ffi(1));
        let path = SymbolPath::parse("foo::bar").unwrap();

        assert!(!RegistryUpdate::Add {
            path: path.clone(),
            kind: SymbolKind::Function,
            span: test_span(),
        }
        .is_destructive());

        assert!(RegistryUpdate::Remove { id }.is_destructive());
        assert!(RegistryUpdate::Rename { id, new_path: path }.is_destructive());

        assert!(!RegistryUpdate::UpdateSpan {
            id,
            new_span: test_span()
        }
        .is_destructive());
    }

    #[test]
    fn test_batch_builder() {
        use slotmap::KeyData;

        let id = SymbolId::from(KeyData::from_ffi(1));
        let path = SymbolPath::parse("foo::bar").unwrap();

        let mut batch = RegistryUpdateBatch::new();
        assert!(batch.is_empty());

        batch.add_symbol(path.clone(), SymbolKind::Function, test_span());
        batch.remove_symbol(id);

        assert_eq!(batch.len(), 2);
        assert!(!batch.is_empty());
    }

    #[test]
    fn test_batch_apply_add() {
        let mut registry = SymbolRegistry::new();
        let path = SymbolPath::parse("test::NewSymbol").unwrap();

        let mut batch = RegistryUpdateBatch::new();
        batch.add_symbol(path.clone(), SymbolKind::Function, test_span());

        let applied = batch.apply(&mut registry).unwrap();
        assert_eq!(applied, 1);

        // Verify symbol was added
        let id = registry.lookup(&path).expect("symbol should exist");
        assert_eq!(registry.kind(id), Some(SymbolKind::Function));
        assert!(registry.span(id).is_some());
    }

    #[test]
    fn test_batch_apply_remove() {
        let mut registry = SymbolRegistry::new();
        let path = SymbolPath::parse("test::ToRemove").unwrap();
        let id = registry.register(path.clone(), SymbolKind::Struct).unwrap();

        let mut batch = RegistryUpdateBatch::new();
        batch.remove_symbol(id);

        let applied = batch.apply(&mut registry).unwrap();
        assert_eq!(applied, 1);

        // Verify symbol was removed
        assert!(registry.lookup(&path).is_none());
        assert!(!registry.contains(id));
    }

    #[test]
    fn test_batch_apply_rename() {
        let mut registry = SymbolRegistry::new();
        let old_path = SymbolPath::parse("test::OldName").unwrap();
        let new_path = SymbolPath::parse("test::NewName").unwrap();
        let id = registry
            .register(old_path.clone(), SymbolKind::Struct)
            .unwrap();

        let mut batch = RegistryUpdateBatch::new();
        batch.rename_symbol(id, new_path.clone());

        let applied = batch.apply(&mut registry).unwrap();
        assert_eq!(applied, 1);

        // Verify rename
        assert!(registry.lookup(&old_path).is_none());
        assert_eq!(registry.lookup(&new_path), Some(id));
    }

    #[test]
    fn test_batch_apply_multiple() {
        use super::Visibility;

        let mut registry = SymbolRegistry::new();
        let path1 = SymbolPath::parse("test::First").unwrap();
        let path2 = SymbolPath::parse("test::Second").unwrap();

        let id1 = registry
            .register(path1.clone(), SymbolKind::Struct)
            .unwrap();

        let mut batch = RegistryUpdateBatch::new();
        batch.add_symbol(path2.clone(), SymbolKind::Function, test_span());
        batch.push(RegistryUpdate::UpdateVisibility {
            id: id1,
            new_visibility: Visibility::Public,
        });

        let applied = batch.apply(&mut registry).unwrap();
        assert_eq!(applied, 2);

        // Verify both operations
        assert!(registry.lookup(&path2).is_some());
        assert_eq!(registry.visibility(id1), Some(&Visibility::Public));
    }

    #[test]
    fn test_batch_apply_empty() {
        let mut registry = SymbolRegistry::new();
        let batch = RegistryUpdateBatch::new();

        let applied = batch.apply(&mut registry).unwrap();
        assert_eq!(applied, 0);
    }
}