package entity

import "time"

const (
	RelationNone   = 0
	RelationFriend = 1
	RelationBlock  = 2
)

const (
	ListDefault = 20
	ListMax     = 100
)

// Relation is a bidirectional friendship. Natural key (user_small, user_big).
type Relation struct {
	UserSmall int64
	UserBig   int64
	CreatedAt time.Time
}

func NewRelation(a, b int64, at time.Time) *Relation {
	small, big := OrderUsers(a, b)
	return &Relation{UserSmall: small, UserBig: big, CreatedAt: at}
}

func (r *Relation) Other(me int64) int64 {
	if r == nil {
		return 0
	}
	if r.UserSmall == me {
		return r.UserBig
	}
	if r.UserBig == me {
		return r.UserSmall
	}
	return 0
}

func ClampLimit(limit int) int {
	if limit <= 0 {
		return ListDefault
	}
	if limit > ListMax {
		return ListMax
	}
	return limit
}

// ViewStatus is the viewer-centric relation: friend, blocked-by-me, or none.
func ViewStatus(friend, blockedByMe bool) int {
	if blockedByMe {
		return RelationBlock
	}
	if friend {
		return RelationFriend
	}
	return RelationNone
}