#![allow(dead_code)]

use super::perpetual::{
    lollipops_decomposed_named,
    lollipops_named,
    lollipops_only_loop_decomposed,
    lollipops_only_loop_decomposed_named,
    lollipops_prefix_len_loop_decomposed,
    lollipops_prefix_len_loop_decomposed_named
};
use super::structure::{RSenvironment, RSreaction, RSset};
use super::translator::IdType;
use std::cmp;
use std::collections::HashSet;


// see confluent, confluents
pub fn confluent(
    delta: &RSenvironment,
    reaction_rules: &[RSreaction],
    entities: &[RSset],
) -> Option<(usize, usize, Vec<RSset>)> {

    let all_loops = lollipops_prefix_len_loop_decomposed(delta,
							 reaction_rules,
							 entities.first()?);
    let (prefix_len, hoop) = all_loops.first()?.clone();
    let dimension = hoop.len();
    let mut max_distance = prefix_len;

    for available_entities in entities.iter().skip(1) {
	let all_loops = lollipops_prefix_len_loop_decomposed(delta,
							     reaction_rules,
							     available_entities);
        // FIXME we take just the first? do we compare all?
        let (prefix_len, new_hoop) = all_loops.first()?;

        if new_hoop.len() != dimension || !hoop.contains(new_hoop.first()?) {
            return None;
        }
        max_distance = cmp::max(max_distance, *prefix_len);
    }
    Some((max_distance, dimension, hoop))
}


// see confluent, confluents
pub fn confluent_named(
    delta: &RSenvironment,
    reaction_rules: &[RSreaction],
    entities: &[RSset],
    symb: IdType
) -> Option<(usize, usize, Vec<RSset>)> {
    let (prefix_len, first_hoop) =
	lollipops_prefix_len_loop_decomposed_named(delta,
						   reaction_rules,
						   entities.first()?,
						   symb)?;
    let dimension = first_hoop.len();
    let mut max_distance = prefix_len;
    let hoop = first_hoop;

    for available_entities in entities.iter().skip(1) {
        let (prefix_len, new_hoop) =
            lollipops_prefix_len_loop_decomposed_named(delta,
						       reaction_rules,
						       available_entities,
						       symb)?;

        if new_hoop.len() != dimension || !hoop.contains(new_hoop.first()?) {
            return None;
        }
        max_distance = cmp::max(max_distance, prefix_len);
    }
    Some((max_distance, dimension, hoop))
}

// -----------------------------------------------------------------------------

// see invariant
pub fn invariant_named(
    delta: &RSenvironment,
    reaction_rules: &[RSreaction],
    entities: &[RSset],
    symb: IdType
) -> Option<(Vec<RSset>, Vec<RSset>)> {
    let (prefix, hoop) = lollipops_decomposed_named(delta,
					  reaction_rules,
					  entities.first()?,
					  symb)?;
    let mut invariant = vec![];
    invariant.append(&mut prefix.clone());
    invariant.append(&mut hoop.clone());
    let dimension = hoop.len();

    for available_entities in entities {
	let (new_prefix, new_hoop) = lollipops_decomposed_named(delta,
							reaction_rules,
							available_entities,
							symb)?;
	if new_hoop.len() != dimension || !hoop.contains(new_hoop.first()?) {
	    return None
	}
	invariant.append(&mut new_prefix.clone());
    }
    // remove duplicates, maybe better with sorting?
    invariant =
	invariant
	.iter()
	.cloned()
	.collect::<HashSet<_>>()
	.iter()
	.cloned()
	.collect::<Vec<_>>();
    Some((invariant, hoop))
}

// -----------------------------------------------------------------------------

// see loop_confluent
pub fn loop_confluent_named(
    deltas: &[RSenvironment],
    reaction_rules: &[RSreaction],
    entities: &[RSset],
    symb: IdType
) -> Option<Vec<(usize, usize, Vec<RSset>)>> {
    deltas.iter()
	.map(|q| confluent_named(q, reaction_rules, entities, symb))
	.collect::<Option<Vec<_>>>()
}

// see strong_confluent
#[allow(clippy::type_complexity)]
pub fn strong_confluent_named(
    deltas: &[RSenvironment],
    reaction_rules: &[RSreaction],
    entities: &[RSset],
    symb: IdType
) -> Option<Vec<(Vec<RSset>, usize, Vec<RSset>)>> {
    deltas.iter()
        .map(|q| {
	    let (invariant, hoop) = invariant_named(q,
						    reaction_rules,
						    entities,
						    symb)?;
	    let length = invariant.len();
	    Some((invariant, length, hoop)) }
	)
        .collect::<Option<Vec<_>>>()
}