yasshi2525/RushHour

package entities

import (
    "fmt"
)

// Step represents two Relayable is logically connected.
// Step is out of target for persistence because it can derived by other resources.
type Step struct {
    Base
    FromNode Relayable
    ToNode   Relayable
}

// NewStep create new instance and relation to Relayable
func (m *Model) NewStep(f Relayable, t Relayable) *Step {
    s := &Step{
        Base:     m.NewBase(STEP),
        FromNode: f,
        ToNode:   t,
    }
    s.Init(m)
    f.OutSteps()[s.ID] = s
    t.InSteps()[s.ID] = s
    m.Add(s)
    return s
}

// B returns base information of this elements.
func (s *Step) B() *Base {
    return &s.Base
}

// Init do nothing
func (s *Step) Init(m *Model) {
    s.Base.Init(STEP, m)
}

// From returns where Step comes from
func (s *Step) From() Entity {
    return s.FromNode
}

// To returns where Step goes to
func (s *Step) To() Entity {
    return s.ToNode
}

// Cost is calculated by distance
func (s *Step) Cost() float64 {
    return s.FromNode.Pos().Dist(s.ToNode.Pos()) / s.M.conf.Human.Speed
}

// Resolve set reference from id.
func (s *Step) Resolve(args ...Entity) {
}

// CheckDelete check remaining reference.
func (s *Step) CheckDelete() error {
    return nil
}

// BeforeDelete delete selt from related Locationable.
func (s *Step) BeforeDelete() {
    delete(s.FromNode.OutSteps(), s.ID)
    delete(s.ToNode.InSteps(), s.ID)
}

// Delete removes this entity with related ones.
func (s *Step) Delete() {
    s.M.Delete(s)
}

// String represents status
func (s *Step) String() string {
    return fmt.Sprintf("%s(%v):from=%v,to=%v,c=%.2f", s.Type().Short(),
        s.ID, s.FromNode, s.ToNode, s.Cost())
}