astmap-core 0.0.1

// Line-level diff: maps changed line ranges to affected symbols.

use serde::Serialize;

use crate::error::DiffError;
use crate::model::{FileChangeStatus, ImpactEntry, SymbolResult, VcsFileChange};
use crate::port::{DiffStore, VcsProvider};

#[derive(Debug, Serialize)]
pub struct DiffResult {
    pub changed_files: Vec<ChangedFile>,
    pub unindexed_files: Vec<String>,
    pub impact: Vec<ImpactEntry>,
    pub summary: DiffSummary,
}

#[derive(Debug, Serialize)]
pub struct ChangedFile {
    pub path: String,
    pub status: FileChangeStatus,
    pub affected_symbols: Vec<SymbolResult>,
}

#[derive(Debug, Serialize)]
pub struct DiffSummary {
    pub changed_files: usize,
    pub affected_symbols: usize,
    pub impacted_symbols: usize,
    pub unindexed: usize,
}

/// Map working tree diff (uncommitted changes) to affected symbols.
pub fn diff_working_tree(
    vcs: &dyn VcsProvider,
    db: &dyn DiffStore,
    impact_depth: i64,
    supported_ext: &[&str],
) -> Result<DiffResult, DiffError> {
    let changes = vcs.working_tree_changes(None)?;
    process_diff(db, &changes, impact_depth, supported_ext)
}

/// Map diff against a base branch/commit to affected symbols.
pub fn diff_against_base(
    vcs: &dyn VcsProvider,
    base: &str,
    db: &dyn DiffStore,
    impact_depth: i64,
    supported_ext: &[&str],
) -> Result<DiffResult, DiffError> {
    let changes = vcs.changes_between_refs(base, "HEAD")?;
    process_diff(db, &changes, impact_depth, supported_ext)
}

/// Process VCS file changes into a DiffResult with symbol lookups and impact analysis.
fn process_diff(
    db: &dyn DiffStore,
    changes: &[VcsFileChange],
    impact_depth: i64,
    supported_ext: &[&str],
) -> Result<DiffResult, DiffError> {
    let mut changed_files = Vec::new();
    let mut unindexed_files = Vec::new();
    let mut all_affected_symbol_ids = Vec::new();

    for change in changes {
        // Filter by supported extensions
        let is_supported = std::path::Path::new(&change.path)
            .extension()
            .and_then(|e| e.to_str())
            .is_some_and(|ext| supported_ext.contains(&ext));
        if !is_supported {
            continue;
        }

        // Check if file is indexed
        let file_id = db.get_file_id(&change.path)?;
        if file_id.is_none() && change.status != FileChangeStatus::Deleted {
            unindexed_files.push(change.path.clone());
            continue;
        }

        match change.status {
            FileChangeStatus::Deleted => {
                changed_files.push(ChangedFile {
                    path: change.path.clone(),
                    status: change.status,
                    affected_symbols: vec![],
                });
            }
            FileChangeStatus::Added => {
                // Added file — all symbols affected
                let symbols = db.symbols_in_line_range(&change.path, 1, i64::MAX)?;
                for s in &symbols {
                    all_affected_symbol_ids.push(s.id);
                }
                changed_files.push(ChangedFile {
                    path: change.path.clone(),
                    status: change.status,
                    affected_symbols: symbols,
                });
            }
            FileChangeStatus::Modified | FileChangeStatus::Renamed => {
                // Modified/Renamed file — find symbols overlapping changed lines
                if change.changed_lines.is_empty() {
                    // No line-level info; treat as entire file changed
                    let symbols = db.symbols_in_line_range(&change.path, 1, i64::MAX)?;
                    for s in &symbols {
                        all_affected_symbol_ids.push(s.id);
                    }
                    changed_files.push(ChangedFile {
                        path: change.path.clone(),
                        status: change.status,
                        affected_symbols: symbols,
                    });
                } else {
                    let mut affected = Vec::new();
                    for (start, end) in &change.changed_lines {
                        let symbols = db.symbols_in_line_range(&change.path, *start, *end)?;
                        for s in symbols {
                            if !affected.iter().any(|a: &SymbolResult| a.id == s.id) {
                                all_affected_symbol_ids.push(s.id);
                                affected.push(s);
                            }
                        }
                    }
                    changed_files.push(ChangedFile {
                        path: change.path.clone(),
                        status: change.status,
                        affected_symbols: affected,
                    });
                }
            }
        }
    }

    // Transitive impact analysis
    let mut impact = Vec::new();
    let mut seen_ids = std::collections::HashSet::new();
    for sym_id in &all_affected_symbol_ids {
        seen_ids.insert(*sym_id);
    }
    for sym_id in &all_affected_symbol_ids {
        let entries = db.impact_analysis(*sym_id, impact_depth)?;
        for entry in entries {
            if seen_ids.insert(entry.symbol_id) {
                impact.push(entry);
            }
        }
    }

    let total_affected = all_affected_symbol_ids.len();
    let summary = DiffSummary {
        changed_files: changed_files.len(),
        affected_symbols: total_affected,
        impacted_symbols: impact.len(),
        unindexed: unindexed_files.len(),
    };

    Ok(DiffResult {
        changed_files,
        unindexed_files,
        impact,
        summary,
    })
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::error::{DbError, DiffError};
    use crate::model::{Config, SymbolKind, SymbolWithParent, VcsFileChange};
    use crate::port::VcsProvider;
    use crate::{ConfigStore, SymbolLookup};
    use std::collections::HashMap;
    // --- Mock VcsProvider ---

    struct MockVcs {
        working_changes: Vec<VcsFileChange>,
        between_changes: Vec<VcsFileChange>,
    }

    impl VcsProvider for MockVcs {
        fn working_tree_changes(
            &self,
            _base_ref: Option<&str>,
        ) -> Result<Vec<VcsFileChange>, DiffError> {
            Ok(self.working_changes.clone())
        }
        fn changes_between_refs(
            &self,
            _from: &str,
            _to: &str,
        ) -> Result<Vec<VcsFileChange>, DiffError> {
            Ok(self.between_changes.clone())
        }
        fn read_file_at_ref(&self, _path: &str, _ref: &str) -> Result<Option<String>, DiffError> {
            Ok(None)
        }
        fn commit_count(&self, _from: &str, _to: &str) -> Result<usize, DiffError> {
            Ok(0)
        }
        fn resolve_ref(&self, _refspec: &str) -> Result<bool, DiffError> {
            Ok(false)
        }
        fn head_sha(&self) -> Result<String, DiffError> {
            Ok("abc".to_string())
        }
        fn root_commit_sha(&self) -> Result<Option<String>, DiffError> {
            Ok(None)
        }
    }

    // --- Mock DiffStore ---

    struct MockDiffStore {
        file_ids: HashMap<String, i64>,
        symbols: HashMap<String, Vec<SymbolResult>>,
        impacts: HashMap<i64, Vec<ImpactEntry>>,
    }

    impl MockDiffStore {
        fn new() -> Self {
            Self {
                file_ids: HashMap::new(),
                symbols: HashMap::new(),
                impacts: HashMap::new(),
            }
        }
    }

    impl ConfigStore for MockDiffStore {
        fn config_get(&self, _key: &str) -> Result<Option<String>, DbError> {
            Ok(None)
        }
        fn config_set(&self, _key: &str, _value: &str) -> Result<(), DbError> {
            Ok(())
        }
        fn config_list(&self) -> Result<Vec<Config>, DbError> {
            Ok(vec![])
        }
    }

    impl SymbolLookup for MockDiffStore {
        fn get_file_id(&self, path: &str) -> Result<Option<i64>, DbError> {
            Ok(self.file_ids.get(path).copied())
        }
        fn get_symbol_by_id(&self, _id: i64) -> Result<Option<crate::Symbol>, DbError> {
            Ok(None)
        }
        fn search_symbols_by_name(
            &self,
            _name: &str,
            _limit: i64,
        ) -> Result<Vec<SymbolResult>, DbError> {
            Ok(vec![])
        }
        fn get_symbols_for_file(&self, _file_id: i64) -> Result<Vec<crate::Symbol>, DbError> {
            Ok(vec![])
        }
        fn get_children(&self, _symbol_id: i64) -> Result<Vec<crate::Symbol>, DbError> {
            Ok(vec![])
        }
        fn impact_analysis(&self, id: i64, _depth: i64) -> Result<Vec<ImpactEntry>, DbError> {
            Ok(self.impacts.get(&id).cloned().unwrap_or_default())
        }
        fn stats(&self) -> Result<(i64, i64, i64), DbError> {
            Ok((0, 0, 0))
        }
    }

    impl DiffStore for MockDiffStore {
        fn symbols_in_line_range(
            &self,
            path: &str,
            start: i64,
            end: i64,
        ) -> Result<Vec<SymbolResult>, DbError> {
            Ok(self
                .symbols
                .get(path)
                .map(|syms| {
                    syms.iter()
                        .filter(|s| s.start_line <= end && s.end_line >= start)
                        .cloned()
                        .collect()
                })
                .unwrap_or_default())
        }
        fn all_symbols_for_file(&self, _path: &str) -> Result<Vec<SymbolWithParent>, DbError> {
            Ok(vec![])
        }
    }

    fn make_sym(id: i64, name: &str, path: &str, start: i64, end: i64) -> SymbolResult {
        SymbolResult {
            id,
            name: name.to_string(),
            kind: SymbolKind::Function,
            file_path: path.to_string(),
            start_line: start,
            end_line: end,
            signature: None,
            summary: None,
        }
    }

    fn make_impact(id: i64, name: &str, path: &str, depth: i64) -> ImpactEntry {
        ImpactEntry {
            symbol_id: id,
            symbol_name: name.to_string(),
            symbol_kind: SymbolKind::Function,
            file_path: path.to_string(),
            depth,
            dep_type: crate::model::DepType::Calls,
        }
    }

    #[test]
    fn test_process_diff_deleted_file() {
        let db = MockDiffStore::new();
        let changes = vec![VcsFileChange {
            path: "src/old.rs".to_string(),
            old_path: None,
            status: FileChangeStatus::Deleted,
            changed_lines: vec![],
        }];

        let result = process_diff(&db, &changes, 3, &["rs"]).unwrap();
        assert_eq!(result.changed_files.len(), 1);
        assert_eq!(result.changed_files[0].status, FileChangeStatus::Deleted);
        assert!(result.changed_files[0].affected_symbols.is_empty());
    }

    #[test]
    fn test_process_diff_added_file() {
        let mut db = MockDiffStore::new();
        db.file_ids.insert("src/new.rs".to_string(), 1);
        db.symbols.insert(
            "src/new.rs".to_string(),
            vec![make_sym(10, "new_fn", "src/new.rs", 1, 10)],
        );
        let changes = vec![VcsFileChange {
            path: "src/new.rs".to_string(),
            old_path: None,
            status: FileChangeStatus::Added,
            changed_lines: vec![],
        }];

        let result = process_diff(&db, &changes, 3, &["rs"]).unwrap();
        assert_eq!(result.changed_files.len(), 1);
        assert_eq!(result.changed_files[0].status, FileChangeStatus::Added);
        assert_eq!(result.changed_files[0].affected_symbols.len(), 1);
        assert_eq!(result.summary.affected_symbols, 1);
    }

    #[test]
    fn test_process_diff_modified_with_lines() {
        let mut db = MockDiffStore::new();
        db.file_ids.insert("src/lib.rs".to_string(), 1);
        db.symbols.insert(
            "src/lib.rs".to_string(),
            vec![
                make_sym(10, "foo", "src/lib.rs", 1, 10),
                make_sym(11, "bar", "src/lib.rs", 20, 30),
            ],
        );
        let changes = vec![VcsFileChange {
            path: "src/lib.rs".to_string(),
            old_path: None,
            status: FileChangeStatus::Modified,
            changed_lines: vec![(5, 7)],
        }];

        let result = process_diff(&db, &changes, 3, &["rs"]).unwrap();
        assert_eq!(result.changed_files.len(), 1);
        assert_eq!(result.changed_files[0].affected_symbols.len(), 1);
        assert_eq!(result.changed_files[0].affected_symbols[0].name, "foo");
    }

    #[test]
    fn test_process_diff_modified_no_lines() {
        let mut db = MockDiffStore::new();
        db.file_ids.insert("src/lib.rs".to_string(), 1);
        db.symbols.insert(
            "src/lib.rs".to_string(),
            vec![make_sym(10, "foo", "src/lib.rs", 1, 10)],
        );
        let changes = vec![VcsFileChange {
            path: "src/lib.rs".to_string(),
            old_path: None,
            status: FileChangeStatus::Modified,
            changed_lines: vec![],
        }];

        let result = process_diff(&db, &changes, 3, &["rs"]).unwrap();
        assert_eq!(result.changed_files[0].affected_symbols.len(), 1);
    }

    #[test]
    fn test_process_diff_unindexed_file() {
        let db = MockDiffStore::new();
        let changes = vec![VcsFileChange {
            path: "src/unknown.rs".to_string(),
            old_path: None,
            status: FileChangeStatus::Added,
            changed_lines: vec![],
        }];

        let result = process_diff(&db, &changes, 3, &["rs"]).unwrap();
        assert_eq!(result.unindexed_files, vec!["src/unknown.rs"]);
        assert_eq!(result.summary.unindexed, 1);
    }

    #[test]
    fn test_process_diff_filters_unsupported_ext() {
        let db = MockDiffStore::new();
        let changes = vec![VcsFileChange {
            path: "README.md".to_string(),
            old_path: None,
            status: FileChangeStatus::Modified,
            changed_lines: vec![],
        }];

        let result = process_diff(&db, &changes, 3, &["rs"]).unwrap();
        assert!(result.changed_files.is_empty());
    }

    #[test]
    fn test_process_diff_impact_dedup() {
        let mut db = MockDiffStore::new();
        db.file_ids.insert("src/a.rs".to_string(), 1);
        db.symbols.insert(
            "src/a.rs".to_string(),
            vec![
                make_sym(10, "fn_a", "src/a.rs", 1, 5),
                make_sym(11, "fn_b", "src/a.rs", 6, 10),
            ],
        );
        // Both symbols have impact on sym 99
        db.impacts
            .insert(10, vec![make_impact(99, "downstream", "src/b.rs", 1)]);
        db.impacts
            .insert(11, vec![make_impact(99, "downstream", "src/b.rs", 1)]);

        let changes = vec![VcsFileChange {
            path: "src/a.rs".to_string(),
            old_path: None,
            status: FileChangeStatus::Modified,
            changed_lines: vec![(1, 10)],
        }];

        let result = process_diff(&db, &changes, 3, &["rs"]).unwrap();
        // Impact should be deduplicated
        assert_eq!(result.impact.len(), 1);
        assert_eq!(result.impact[0].symbol_name, "downstream");
    }

    #[test]
    fn test_diff_working_tree_delegates() {
        let vcs = MockVcs {
            working_changes: vec![],
            between_changes: vec![],
        };
        let db = MockDiffStore::new();
        let result = diff_working_tree(&vcs, &db, 3, &["rs"]).unwrap();
        assert!(result.changed_files.is_empty());
    }

    #[test]
    fn test_diff_against_base_delegates() {
        let vcs = MockVcs {
            working_changes: vec![],
            between_changes: vec![],
        };
        let db = MockDiffStore::new();
        let result = diff_against_base(&vcs, "main", &db, 3, &["rs"]).unwrap();
        assert!(result.changed_files.is_empty());
    }

    #[test]
    fn test_process_diff_renamed_file() {
        let mut db = MockDiffStore::new();
        db.file_ids.insert("src/renamed.rs".to_string(), 1);
        db.symbols.insert(
            "src/renamed.rs".to_string(),
            vec![make_sym(10, "foo", "src/renamed.rs", 1, 10)],
        );
        let changes = vec![VcsFileChange {
            path: "src/renamed.rs".to_string(),
            old_path: Some("src/old_name.rs".to_string()),
            status: FileChangeStatus::Renamed,
            changed_lines: vec![(1, 5)],
        }];

        let result = process_diff(&db, &changes, 3, &["rs"]).unwrap();
        assert_eq!(result.changed_files.len(), 1);
        assert_eq!(result.changed_files[0].status, FileChangeStatus::Renamed);
        assert_eq!(result.changed_files[0].affected_symbols.len(), 1);
    }

    #[test]
    fn test_process_diff_dedup_symbols_in_overlapping_ranges() {
        let mut db = MockDiffStore::new();
        db.file_ids.insert("src/lib.rs".to_string(), 1);
        db.symbols.insert(
            "src/lib.rs".to_string(),
            vec![make_sym(10, "foo", "src/lib.rs", 1, 20)],
        );

        let changes = vec![VcsFileChange {
            path: "src/lib.rs".to_string(),
            old_path: None,
            status: FileChangeStatus::Modified,
            changed_lines: vec![(3, 5), (10, 15)],
        }];

        let result = process_diff(&db, &changes, 3, &["rs"]).unwrap();
        // Same symbol overlaps both ranges but should only appear once
        assert_eq!(result.changed_files[0].affected_symbols.len(), 1);
        assert_eq!(result.summary.affected_symbols, 1);
    }
}