//! Quantum-inspired FFT optimizer

use super::types::*;
use crate::error::FFTResult;
use scirs2_core::ndarray::Array2;
use scirs2_core::numeric::{Complex, Float};
use std::collections::VecDeque;
use std::fmt::Debug;
use std::time::Instant;

/// Quantum-inspired FFT optimizer
#[derive(Debug)]
#[allow(dead_code)]
pub struct QuantumInspiredFftOptimizer<F: Float + Debug> {
    /// Quantum state representation
    pub(crate) quantum_state: QuantumState<F>,
    /// Quantum gates for optimization
    pub(crate) quantum_gates: Vec<QuantumGate<F>>,
    /// Quantum annealing parameters
    pub(crate) annealing_params: AnnealingParameters<F>,
    /// Quantum measurement system
    pub(crate) measurement_system: QuantumMeasurement<F>,
}

/// Quantum state for optimization
#[derive(Debug, Clone)]
pub struct QuantumState<F: Float> {
    /// State amplitudes
    pub amplitudes: Vec<Complex<F>>,
    /// State phases
    pub phases: Vec<F>,
    /// Entanglement information
    pub entanglement: EntanglementInfo,
}

/// Entanglement information
#[derive(Debug, Clone)]
pub struct EntanglementInfo {
    /// Entangled qubit pairs
    pub entangled_pairs: Vec<(usize, usize)>,
    /// Entanglement strength
    pub entanglement_strength: f64,
}

impl Default for EntanglementInfo {
    fn default() -> Self {
        Self {
            entangled_pairs: Vec::new(),
            entanglement_strength: 0.0,
        }
    }
}

/// Quantum annealing parameters
#[derive(Debug, Clone)]
pub struct AnnealingParameters<F: Float> {
    /// Initial temperature
    pub initial_temperature: F,
    /// Final temperature
    pub final_temperature: F,
    /// Annealing schedule
    pub annealing_schedule: AnnealingSchedule<F>,
    /// Number of annealing steps
    pub num_steps: usize,
}

impl<F: Float> Default for AnnealingParameters<F> {
    fn default() -> Self {
        Self {
            initial_temperature: F::from(1.0).expect("Failed to convert constant to float"),
            final_temperature: F::from(0.01).expect("Failed to convert constant to float"),
            annealing_schedule: AnnealingSchedule::Linear,
            num_steps: 1000,
        }
    }
}

/// Quantum measurement system
#[derive(Debug)]
#[allow(dead_code)]
pub struct QuantumMeasurement<F: Float> {
    /// Measurement operators
    pub(crate) measurement_operators: Vec<MeasurementOperator<F>>,
    /// Measurement results history
    pub(crate) measurement_history: VecDeque<MeasurementResult<F>>,
}

/// Measurement operator
#[derive(Debug, Clone)]
pub struct MeasurementOperator<F: Float> {
    /// Operator name
    pub name: String,
    /// Operator matrix
    pub operator: Array2<Complex<F>>,
    /// Expected value
    pub expected_value: Option<F>,
}

/// Measurement result
#[derive(Debug, Clone)]
pub struct MeasurementResult<F: Float> {
    /// Measured value
    pub value: F,
    /// Measurement uncertainty
    pub uncertainty: F,
    /// Measurement time
    pub timestamp: Instant,
}

impl<F: Float + Debug> QuantumInspiredFftOptimizer<F> {
    pub fn new() -> FFTResult<Self> {
        Ok(Self {
            quantum_state: QuantumState::new()?,
            quantum_gates: Vec::new(),
            annealing_params: AnnealingParameters::default(),
            measurement_system: QuantumMeasurement::new()?,
        })
    }
}

impl<F: Float> QuantumState<F> {
    pub fn new() -> FFTResult<Self> {
        Ok(Self {
            amplitudes: Vec::new(),
            phases: Vec::new(),
            entanglement: EntanglementInfo::default(),
        })
    }
}

impl<F: Float> QuantumMeasurement<F> {
    pub fn new() -> FFTResult<Self> {
        Ok(Self {
            measurement_operators: Vec::new(),
            measurement_history: VecDeque::new(),
        })
    }
}
