/*
 *  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 (
	"errors"
	"sync"
)

type idCacheMap map[Identifier]([]*Object)
type idCache struct {
	l *sync.Mutex
	m idCacheMap
}

func (ic *idCache) add(id Identifier, a *Object, wg *sync.WaitGroup) {
	ic.l.Lock()
	defer ic.l.Unlock()
	defer wg.Done()

	ic.m[id] = append(ic.m[id], a) // We don't care if we got a actual existing object or not
}

func (ic *idCache) Query(id Identifier) (o []*Object, err error) {
	if ic.l == nil {
		err = errors.New("Cache hasn't been initialised")
		return
	}
	ic.l.Lock()
	defer ic.l.Unlock()

	o, ok := ic.m[id]
	if !ok {
		err = errors.New("Object not found")
		return
	}
	return
}

func (d *DependencyGraph) BuildCache() {
	d.ic.l = new(sync.Mutex)
	d.ic.m = make(idCacheMap)

	wg := new(sync.WaitGroup)
	for oi, ov := range d.ol {
		for _, lid := range ov.Id {
			wg.Add(1)
			go d.ic.add(lid, &d.ol[oi], wg)
		}
	}
	wg.Wait()
}