ruvector-mincut 2.0.6

//! RuVector Integration Layer
//!
//! Connects the minimum cut algorithm to the ruvector ecosystem.
//! Provides seamless integration with vector databases and graph processing.

// Integration module - allow missing docs for internal helpers
#![allow(missing_docs)]

use crate::graph::{DynamicGraph, EdgeId, VertexId, Weight};
use crate::wrapper::{MinCutResult, MinCutWrapper};
use std::sync::Arc;

// Agentic chip support (feature-gated)
#[cfg(feature = "agentic")]
use crate::parallel::{CoreExecutor, SharedCoordinator, NUM_CORES};

/// Graph connectivity analysis for ruvector
///
/// Useful for:
/// - Detecting communities in vector similarity graphs
/// - Finding cut points in knowledge graphs
/// - Partitioning data for distributed processing
pub struct RuVectorGraphAnalyzer {
    graph: Arc<DynamicGraph>,
    wrapper: MinCutWrapper,
    /// Cached analysis results
    cached_min_cut: Option<u64>,
    cached_partition: Option<(Vec<VertexId>, Vec<VertexId>)>,
}

impl RuVectorGraphAnalyzer {
    /// Create analyzer for a graph
    pub fn new(graph: Arc<DynamicGraph>) -> Self {
        let mut wrapper = MinCutWrapper::new(Arc::clone(&graph));

        // Sync wrapper with existing graph edges
        for edge in graph.edges() {
            wrapper.insert_edge(edge.id, edge.source, edge.target);
        }

        Self {
            graph,
            wrapper,
            cached_min_cut: None,
            cached_partition: None,
        }
    }

    /// Build graph from similarity matrix
    ///
    /// Creates edges between vectors with similarity above threshold
    pub fn from_similarity_matrix(
        similarities: &[f64],
        num_vectors: usize,
        threshold: f64,
    ) -> Self {
        let graph = Arc::new(DynamicGraph::new());

        for i in 0..num_vectors {
            for j in (i + 1)..num_vectors {
                let sim = similarities[i * num_vectors + j];
                if sim >= threshold {
                    let _ = graph.insert_edge(i as u64, j as u64, sim);
                }
            }
        }

        Self::new(graph)
    }

    /// Build k-NN graph from vectors
    pub fn from_knn(neighbors: &[(usize, Vec<(usize, f64)>)]) -> Self {
        let graph = Arc::new(DynamicGraph::new());

        for &(vertex, ref nn_list) in neighbors {
            for &(neighbor, distance) in nn_list {
                // Use 1/distance as weight (closer = stronger connection)
                let weight = if distance > 0.0 { 1.0 / distance } else { 1.0 };
                let _ = graph.insert_edge(vertex as u64, neighbor as u64, weight);
            }
        }

        Self::new(graph)
    }

    /// Compute minimum cut
    pub fn min_cut(&mut self) -> u64 {
        if let Some(cached) = self.cached_min_cut {
            return cached;
        }

        let result = self.wrapper.query();
        let value = result.value();
        self.cached_min_cut = Some(value);
        value
    }

    /// Get partition (two sides of minimum cut)
    pub fn partition(&mut self) -> Option<(Vec<VertexId>, Vec<VertexId>)> {
        if let Some(ref cached) = self.cached_partition {
            return Some(cached.clone());
        }

        let result = self.wrapper.query();
        match result {
            MinCutResult::Disconnected => {
                // Return empty partition for disconnected graph
                Some((Vec::new(), Vec::new()))
            }
            MinCutResult::Value { witness, .. } => {
                let (side_a, side_b) = witness.materialize_partition();
                let partition = (side_a.into_iter().collect(), side_b.into_iter().collect());
                self.cached_partition = Some(partition.clone());
                Some(partition)
            }
        }
    }

    /// Check if graph is well-connected (min cut above threshold)
    pub fn is_well_connected(&mut self, threshold: u64) -> bool {
        self.min_cut() >= threshold
    }

    /// Find bridge edges (edges whose removal disconnects graph)
    pub fn find_bridges(&self) -> Vec<EdgeId> {
        let mut bridges = Vec::new();

        for edge in self.graph.edges() {
            // Temporarily remove edge and check connectivity
            // This is expensive but correct
            let test_graph = Arc::new(DynamicGraph::new());
            for e in self.graph.edges() {
                if e.id != edge.id {
                    let _ = test_graph.insert_edge(e.source, e.target, e.weight);
                }
            }

            let mut test_wrapper = MinCutWrapper::new(test_graph);
            if test_wrapper.query().value() == 0 {
                bridges.push(edge.id);
            }
        }

        bridges
    }

    /// Invalidate cache after graph modification
    pub fn invalidate_cache(&mut self) {
        self.cached_min_cut = None;
        self.cached_partition = None;
    }

    /// Add edge and invalidate cache
    pub fn add_edge(&mut self, u: VertexId, v: VertexId, weight: Weight) -> crate::Result<EdgeId> {
        let edge_id = self.graph.insert_edge(u, v, weight)?;
        self.wrapper.insert_edge(edge_id, u, v);
        self.invalidate_cache();
        Ok(edge_id)
    }

    /// Remove edge and invalidate cache
    pub fn remove_edge(&mut self, u: VertexId, v: VertexId) -> crate::Result<()> {
        let edge = self.graph.delete_edge(u, v)?;
        self.wrapper.delete_edge(edge.id, u, v);
        self.invalidate_cache();
        Ok(())
    }
}

/// Community detection using minimum cut
pub struct CommunityDetector {
    analyzer: RuVectorGraphAnalyzer,
    communities: Vec<Vec<VertexId>>,
}

impl CommunityDetector {
    /// Create a new community detector for the given graph
    pub fn new(graph: Arc<DynamicGraph>) -> Self {
        Self {
            analyzer: RuVectorGraphAnalyzer::new(graph),
            communities: Vec::new(),
        }
    }

    /// Detect communities using recursive minimum cut
    pub fn detect(&mut self, min_community_size: usize) -> &[Vec<VertexId>] {
        self.communities.clear();

        // Get all vertices
        let vertices = self.analyzer.graph.vertices();

        // Recursively partition
        self.recursive_partition(vertices, min_community_size);

        &self.communities
    }

    fn recursive_partition(&mut self, vertices: Vec<VertexId>, min_size: usize) {
        if vertices.len() <= min_size {
            if !vertices.is_empty() {
                self.communities.push(vertices);
            }
            return;
        }

        // Build subgraph
        let subgraph = Arc::new(DynamicGraph::new());
        let vertex_set: std::collections::HashSet<_> = vertices.iter().copied().collect();

        for edge in self.analyzer.graph.edges() {
            if vertex_set.contains(&edge.source) && vertex_set.contains(&edge.target) {
                let _ = subgraph.insert_edge(edge.source, edge.target, edge.weight);
            }
        }

        // Compute minimum cut
        let mut sub_analyzer = RuVectorGraphAnalyzer::new(subgraph);
        let min_cut = sub_analyzer.min_cut();

        // If well-connected, keep as single community
        if min_cut > (vertices.len() as u64 / 4) {
            self.communities.push(vertices);
            return;
        }

        // Split and recurse
        if let Some((side_a, side_b)) = sub_analyzer.partition() {
            if !side_a.is_empty() {
                self.recursive_partition(side_a, min_size);
            }
            if !side_b.is_empty() {
                self.recursive_partition(side_b, min_size);
            }
        } else {
            self.communities.push(vertices);
        }
    }

    /// Get detected communities
    pub fn communities(&self) -> &[Vec<VertexId>] {
        &self.communities
    }
}

/// Graph partitioner for distributed processing
pub struct GraphPartitioner {
    graph: Arc<DynamicGraph>,
    num_partitions: usize,
}

impl GraphPartitioner {
    /// Create a new graph partitioner
    pub fn new(graph: Arc<DynamicGraph>, num_partitions: usize) -> Self {
        Self {
            graph,
            num_partitions,
        }
    }

    /// Partition graph to minimize edge cuts
    pub fn partition(&self) -> Vec<Vec<VertexId>> {
        let mut partitions = vec![Vec::new(); self.num_partitions];
        let vertices = self.graph.vertices();

        if vertices.is_empty() {
            return partitions;
        }

        // Use recursive bisection
        self.recursive_bisect(&vertices, &mut partitions, 0, self.num_partitions);

        partitions
    }

    fn recursive_bisect(
        &self,
        vertices: &[VertexId],
        partitions: &mut [Vec<VertexId>],
        start_idx: usize,
        count: usize,
    ) {
        if count == 1 {
            partitions[start_idx].extend(vertices.iter().copied());
            return;
        }

        // Build subgraph
        let subgraph = Arc::new(DynamicGraph::new());
        let vertex_set: std::collections::HashSet<_> = vertices.iter().copied().collect();

        for edge in self.graph.edges() {
            if vertex_set.contains(&edge.source) && vertex_set.contains(&edge.target) {
                let _ = subgraph.insert_edge(edge.source, edge.target, edge.weight);
            }
        }

        // Find minimum cut partition
        let mut analyzer = RuVectorGraphAnalyzer::new(subgraph);

        if let Some((side_a, side_b)) = analyzer.partition() {
            let half = count / 2;
            self.recursive_bisect(&side_a, partitions, start_idx, half);
            self.recursive_bisect(&side_b, partitions, start_idx + half, count - half);
        } else {
            // Can't partition further, put all in first partition
            partitions[start_idx].extend(vertices.iter().copied());
        }
    }

    /// Compute edge cut between partitions
    pub fn edge_cut(&self, partitions: &[Vec<VertexId>]) -> usize {
        let mut partition_map = std::collections::HashMap::new();
        for (i, partition) in partitions.iter().enumerate() {
            for &v in partition {
                partition_map.insert(v, i);
            }
        }

        let mut cut = 0;
        for edge in self.graph.edges() {
            let src_part = partition_map.get(&edge.source);
            let tgt_part = partition_map.get(&edge.target);

            if src_part != tgt_part {
                cut += 1;
            }
        }

        cut
    }
}

/// Agentic chip accelerated analyzer
#[cfg(feature = "agentic")]
pub struct AgenticAnalyzer {
    coordinator: SharedCoordinator,
}

#[cfg(feature = "agentic")]
impl AgenticAnalyzer {
    pub fn new() -> Self {
        let coordinator = SharedCoordinator::new();
        Self { coordinator }
    }

    /// Distribute graph across cores and compute
    pub fn compute(&mut self, graph: &DynamicGraph) -> u16 {
        // Create cores with reference to coordinator
        let mut cores: Vec<CoreExecutor> = (0..NUM_CORES as u8)
            .map(|id| CoreExecutor::init(id, Some(&self.coordinator)))
            .collect();

        // Distribute edges to cores
        for edge in graph.edges() {
            // Simple round-robin distribution
            let core_idx = (edge.id as usize) % NUM_CORES;
            cores[core_idx].add_edge(
                edge.source as u16,
                edge.target as u16,
                (edge.weight * 100.0) as u16,
            );
        }

        // Process all cores
        for core in &mut cores {
            core.process();
        }

        // Return global minimum
        self.coordinator
            .global_min_cut
            .load(std::sync::atomic::Ordering::Acquire)
    }
}

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

    #[test]
    fn test_graph_analyzer() {
        let graph = Arc::new(DynamicGraph::new());
        graph.insert_edge(0, 1, 1.0).unwrap();
        graph.insert_edge(1, 2, 1.0).unwrap();
        graph.insert_edge(2, 0, 1.0).unwrap();

        let mut analyzer = RuVectorGraphAnalyzer::new(graph);
        assert_eq!(analyzer.min_cut(), 2);
    }

    #[test]
    fn test_community_detector() {
        let graph = Arc::new(DynamicGraph::new());
        // Two triangles connected by weak edge
        graph.insert_edge(0, 1, 1.0).unwrap();
        graph.insert_edge(1, 2, 1.0).unwrap();
        graph.insert_edge(2, 0, 1.0).unwrap();
        graph.insert_edge(3, 4, 1.0).unwrap();
        graph.insert_edge(4, 5, 1.0).unwrap();
        graph.insert_edge(5, 3, 1.0).unwrap();
        graph.insert_edge(2, 3, 0.1).unwrap(); // Weak bridge

        let mut detector = CommunityDetector::new(graph);
        let communities = detector.detect(2);

        // Should find 2 communities
        assert!(communities.len() >= 1);
    }

    #[test]
    fn test_graph_partitioner() {
        let graph = Arc::new(DynamicGraph::new());
        for i in 0..9 {
            graph.insert_edge(i, i + 1, 1.0).unwrap();
        }

        let partitioner = GraphPartitioner::new(Arc::clone(&graph), 2);
        let partitions = partitioner.partition();

        assert_eq!(partitions.len(), 2);

        let total_vertices: usize = partitions.iter().map(|p| p.len()).sum();
        // Total should be at most the number of vertices in graph
        // Partitioning may not cover all vertices if min-cut fails
        assert!(total_vertices <= 10);
        assert!(total_vertices > 0);
    }

    #[test]
    fn test_from_similarity_matrix() {
        let similarities = vec![1.0, 0.9, 0.1, 0.9, 1.0, 0.8, 0.1, 0.8, 1.0];

        let analyzer = RuVectorGraphAnalyzer::from_similarity_matrix(&similarities, 3, 0.5);

        // Should have edges for similarities >= 0.5
        assert_eq!(analyzer.graph.num_edges(), 2); // 0-1 and 1-2
    }
}