/*
 *  This file is part of solvar. (https://git.redxen.eu/caskd/solvar)
 *  Copyright (c) 2022 Alex-David Denes
 *
 *  solvar is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  any later version.
 *
 *  solvar is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with solvar.  If not, see <https://www.gnu.org/licenses/>.
 */

package solvar

import (
	"golang.org/x/exp/slices"
)

type internalRelation struct {
	o *internalObject
	t RelationType
}
type RelationType uint

const (
	RelationTypeNeed RelationType = iota
	RelationTypeReject
)

type Relation struct {
	Id Identifier
	T  RelationType
}

func (d *DependencyGraph) solveRelation(np *[]*Object, rel *Relation, cb chan callbackSolver) {
	var err error
	var rio []*internalObject

	// Setup deferred callback
	defer func(e *error, i *[]*internalObject, cbc chan callbackSolver) {
		cbc <- callbackSolver{e: *e, io: *i}
	}(&err, &rio, cb)

	var obs []*Object
	if obs, err = d.ic.Query(rel.Id); err != nil {
		return
	}

	var tmp []*Object
	for _, obv := range obs {
		// Remove already visited objects
		if !slices.Contains(*np, obv) {
			tmp = append(tmp, obv)
		}
	}
	obs = tmp

	if rel.T == RelationTypeNeed {
		lcb := make(chan callbackSolver, len(obs))
		for _, ob := range obs {
			go d.solveObject(np, ob, rel.T, lcb)
		}
		for range obs {
			cb := <-lcb
			if cb.e != nil {
				return
			}
			rio = append(rio, cb.io...)
		}
	} else {
		rio = append(rio, &internalObject{r: obs})
	}
}