use crate::binary_string::{BinaryString, Bounds};
use crate::fitness::one_max::OneMax;
use crate::fitness::sphere::Sphere;
use crate::terminating::{AndTerminatingConditions, EqualTerminatingCondition, NoBetterForCyclesTerminatingCondition, TerminatingCondition};
use crate::perturbation::{BinaryStringBitPerturbation, PerturbationOperator};
use crate::comparison::{BetterThanOperator, MinimizingOperator};
use crate::fitness::{FitnessFunction, BinaryFitnessWrapper};

// Functions
#[derive(Debug, Clone, PartialEq)]
pub struct LocalSearchCandidate<T>
    where T: Clone
{
    pub fit: T,
    pub pos: BinaryString,
    pub cycle: usize
}

#[derive(Debug, Clone, PartialEq)]
pub struct LocalSearchResult<T>
    where T: Clone
{
    pub best_candidate: LocalSearchCandidate<T>,

    // How many cycles there were
    pub cycles: usize,

    // statistics
    pub best_candidates: Vec<LocalSearchCandidate<T>>
}

fn local_search_first_improving<
        T, TErr, TFit, TTerminatingCondition, TPerturbationOperator, TBetterThanOperator>(
    fit: &TFit,
    terminating_condition: &mut TTerminatingCondition,
    perturbation_operator: &mut TPerturbationOperator,
    better_than_operator: &TBetterThanOperator,
    initial: &BinaryString
) -> Result<LocalSearchResult<T>, TErr>
where
    T: Clone,
    TFit: FitnessFunction<In = BinaryString, Out = T, Err = TErr>,
    TTerminatingCondition: TerminatingCondition<T>,
    TPerturbationOperator: PerturbationOperator<Chromosome = BinaryString>,
    TBetterThanOperator: BetterThanOperator<T>,
{
    let mut best_candidate = LocalSearchCandidate {
        pos: initial.clone(),
        fit: fit.fit(&initial)?,
        cycle: 0
    };

    let mut stats: Vec<LocalSearchCandidate<T>> = vec![];
    let mut cycle: usize = 0;

    while !terminating_condition.should_terminate(&best_candidate, &stats, cycle) {
        let perturbed = perturbation_operator.perturb(&best_candidate.pos);
        let perturbed_fit = fit.fit(&perturbed)?;

        // Minimize
        if better_than_operator.better_than(&perturbed_fit, &best_candidate.fit) {
            best_candidate = LocalSearchCandidate {
                pos: perturbed.clone(),
                fit: perturbed_fit,
                cycle
            };

            stats.push(best_candidate.clone());
        }

        cycle += 1;
    }

    Ok(LocalSearchResult {
        best_candidate,
        best_candidates: stats,
        cycles: cycle
    })
}

#[test]
fn test_local_search_sphere() {
    let optimum = BinaryString::new(vec![0, 0, 1, 0, 0,
                                         0, 0, 1, 0, 0]);
    let bounds = vec![Bounds::new(0.0, 31.0), Bounds::new(0.0, 31.0)];
    let optimum_real = optimum.to_real(&bounds).unwrap();
    let sphere = Sphere::new(optimum_real);
    let sphere_wrapped = BinaryFitnessWrapper::new(sphere, bounds);

    let result = local_search_first_improving(
        &sphere_wrapped,
        &mut
            AndTerminatingConditions::new(
                vec![
                    &mut EqualTerminatingCondition::new_remembered(optimum.clone()),
                    &mut NoBetterForCyclesTerminatingCondition::new(100)
                ]
            ),
        &mut BinaryStringBitPerturbation::new(0.3),
        &MinimizingOperator::new(),
        &BinaryString::new(vec![1; 10]),
    ).unwrap();

    println!("{:?}", result);

    assert_eq!(
        result.best_candidate.fit,
        0.0
    );

    assert_eq!(
        result.best_candidate.pos,
        optimum
    );
}

#[test]
fn test_local_search_one_max() {
    let one_max = OneMax::new();
    let optimum = BinaryString::new(vec![0; 10]);

    let result = local_search_first_improving(
        &one_max,
        &mut
            AndTerminatingConditions::new(
                vec![
                    &mut EqualTerminatingCondition::new_remembered(optimum.clone()),
                    &mut NoBetterForCyclesTerminatingCondition::new(100)
                ]
            ),
        &mut BinaryStringBitPerturbation::new(0.3),
        &MinimizingOperator::new(),
        &BinaryString::new(vec![1; 10]),
    ).unwrap();

    println!("{:?}", result);

    assert_eq!(
        result.best_candidate.fit,
        0
    );

    assert_eq!(
        result.best_candidate.pos,
        optimum
    );
}