package domain

import (
	"errors"
	"time"
)

var ErrInvalidAuthorizationTransition = errors.New("invalid authorization status transition")

type AuthorizationStatus string

const (
	AuthorizationStatusPendingDelivery AuthorizationStatus = "PENDING_DELIVERY"
	AuthorizationStatusDelivered       AuthorizationStatus = "DELIVERED"
	AuthorizationStatusAcknowledged    AuthorizationStatus = "ACKNOWLEDGED"
	AuthorizationStatusExecuting       AuthorizationStatus = "EXECUTING"
	AuthorizationStatusFenced          AuthorizationStatus = "FENCED"
	AuthorizationStatusConsumed        AuthorizationStatus = "CONSUMED"
	AuthorizationStatusSuperseded      AuthorizationStatus = "SUPERSEDED"
	AuthorizationStatusExpired         AuthorizationStatus = "EXPIRED"
)

type OrderAuthorization struct {
	ID                  string
	TaskID              string
	SpecTrialID         string
	Version             int
	GoodsID             string
	SKUColor            string
	SKUSize             string
	Quantity            int
	AuthorizedUnitPrice string
	TotalPriceCap       string
	Note                *string
	Status              AuthorizationStatus
	CreatedBy           string
	CreatedAt           time.Time
	ExpiresAt           time.Time
}

// CanTransitionTo 围栏后的授权只能消费，不能回到可领取或可过期状态，以防重复采购。
func (status AuthorizationStatus) CanTransitionTo(next AuthorizationStatus) bool {
	_, allowed := authorizationTransitions[status][next]
	return allowed
}

// TransitionAuthorization 返回下一状态；未定义的授权状态转移一律失败。
func TransitionAuthorization(current, next AuthorizationStatus) (AuthorizationStatus, error) {
	if !current.CanTransitionTo(next) {
		return current, ErrInvalidAuthorizationTransition
	}

	return next, nil
}

var authorizationTransitions = map[AuthorizationStatus]map[AuthorizationStatus]struct{}{
	AuthorizationStatusPendingDelivery: {
		AuthorizationStatusDelivered:  {},
		AuthorizationStatusSuperseded: {},
		AuthorizationStatusExpired:    {},
	},
	AuthorizationStatusDelivered: {
		AuthorizationStatusAcknowledged: {},
		AuthorizationStatusSuperseded:   {},
		AuthorizationStatusExpired:      {},
	},
	AuthorizationStatusAcknowledged: {
		AuthorizationStatusExecuting:  {},
		AuthorizationStatusSuperseded: {},
		AuthorizationStatusExpired:    {},
	},
	AuthorizationStatusExecuting: {
		AuthorizationStatusFenced:     {},
		AuthorizationStatusSuperseded: {},
		AuthorizationStatusExpired:    {},
	},
	AuthorizationStatusFenced: {
		AuthorizationStatusConsumed: {},
	},
}