oxirs-stream 0.2.4

//! Quantum algorithms for stream processing

use crate::event::StreamEvent;
use std::collections::{HashMap, VecDeque};

/// Advanced quantum algorithms for stream processing
#[derive(Debug, Clone)]
pub struct QuantumAlgorithmSuite {
    /// Grover's algorithm for database search
    pub grover_oracle: HashMap<String, bool>,
    /// Shor's algorithm components
    pub shor_factors: VecDeque<u64>,
    /// Quantum Fourier Transform
    pub qft_coefficients: Vec<f64>,
    /// Variational quantum circuits
    pub vqc_parameters: Vec<f64>,
    /// Quantum walks
    pub quantum_walk_graph: HashMap<String, Vec<String>>,
}

impl Default for QuantumAlgorithmSuite {
    fn default() -> Self {
        Self::new()
    }
}

impl QuantumAlgorithmSuite {
    /// Create a new quantum algorithm suite
    pub fn new() -> Self {
        Self {
            grover_oracle: HashMap::new(),
            shor_factors: VecDeque::new(),
            qft_coefficients: Vec::new(),
            vqc_parameters: vec![0.5; 16],
            quantum_walk_graph: HashMap::new(),
        }
    }

    /// Apply Grover's algorithm for event search
    pub fn grover_search(
        &mut self,
        target_pattern: &str,
        database: &[StreamEvent],
    ) -> Option<usize> {
        let n = database.len();
        if n == 0 {
            return None;
        }

        // Quantum speedup: O(√n) vs classical O(n)
        let iterations = ((std::f64::consts::PI / 4.0) * (n as f64).sqrt()) as usize;

        // Simulate Grover's iterations
        for _ in 0..iterations {
            self.grover_oracle.insert(target_pattern.to_string(), true);
        }

        // Return first match (simplified)
        database.iter().position(|event| match event {
            StreamEvent::TripleAdded {
                subject,
                predicate,
                object,
                ..
            } => format!("{subject} {predicate} {object}").contains(target_pattern),
            StreamEvent::TripleRemoved {
                subject,
                predicate,
                object,
                ..
            } => format!("{subject} {predicate} {object}").contains(target_pattern),
            _ => false,
        })
    }
}