//! QATAAUM Phase 4: Quantum Algorithm Breadth Implementation
//!
//! Complete implementation of 7 foundational quantum algorithms from first principles.
//! Includes full mathematical verification, test coverage, and integration with the
//! QATAAUM quantum simulator ecosystem.
//!
//! **Algorithms Implemented:**
//! 1. Hamiltonian Pauli Sums - foundation for VQE/QAOA
//! 2. Variational Quantum Eigensolver (VQE) - hybrid optimization
//! 3. Quantum Approximate Optimization Algorithm (QAOA) - combinatorial optimization
//! 4. Hamiltonian Simulation - time evolution via Trotter-Suzuki
//! 5. Amplitude Estimation - quantum signal processing
//! 6. Quantum Walks - graph exploration and mixing
//! 7. Shor's Algorithm Modular Arithmetic - factoring foundation
//!
//! Clean-room implementation based on standard quantum mechanics and algorithms textbooks.

use num_complex::Complex64;
use std::f64::consts::PI;

pub mod hamiltonian;
pub mod vqe;
pub mod qaoa;
pub mod hamiltonian_sim;
pub mod amplitude_est;
pub mod walks;
pub mod shor;

pub use hamiltonian::*;
pub use vqe::*;
pub use qaoa::*;
pub use hamiltonian_sim::*;
pub use amplitude_est::*;
pub use walks::*;
pub use shor::*;

/// Result type for algorithm operations
pub type AlgorithmResult<T> = Result<T, AlgorithmError>;

/// Algorithm errors
#[derive(Debug, Clone)]
pub enum AlgorithmError {
    /// Invalid parameters
    InvalidParameters(String),

    /// Convergence failed
    ConvergenceFailed(String),

    /// Invalid state or configuration
    InvalidState(String),

    /// Numerical precision error
    NumericalError(String),

    /// Graph structure error
    InvalidGraph(String),

    /// Mathematical error
    MathematicalError(String),
}

impl std::fmt::Display for AlgorithmError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            AlgorithmError::InvalidParameters(msg) => write!(f, "Invalid parameters: {}", msg),
            AlgorithmError::ConvergenceFailed(msg) => write!(f, "Convergence failed: {}", msg),
            AlgorithmError::InvalidState(msg) => write!(f, "Invalid state: {}", msg),
            AlgorithmError::NumericalError(msg) => write!(f, "Numerical error: {}", msg),
            AlgorithmError::InvalidGraph(msg) => write!(f, "Invalid graph: {}", msg),
            AlgorithmError::MathematicalError(msg) => write!(f, "Mathematical error: {}", msg),
        }
    }
}

impl std::error::Error for AlgorithmError {}

// Made with Bob