package task

// 任务状态
const (
	Draft        = "draft"
	PendingReview = "pending_review"
	Rejected     = "rejected"
	Queued       = "queued"
	Dispatched   = "dispatched"
	Running      = "running"
	Success      = "success"
	Failed       = "failed"
	Suspended    = "suspended"
	Cancelled    = "cancelled"
)

// 动作
type Action string

const (
	ActionSubmit   Action = "submit"
	ActionApprove  Action = "approve"
	ActionReject   Action = "reject"
	ActionResubmit Action = "resubmit"
	ActionDispatch Action = "dispatch"
	ActionStart    Action = "start"
	ActionSuccess  Action = "success"
	ActionFail     Action = "fail"
	ActionRetry    Action = "retry"
	ActionSuspend  Action = "suspend"
	ActionResume   Action = "resume"
	ActionCancel   Action = "cancel"
)

// transitions 状态转移表
var transitions = map[string]map[Action]string{
	Draft: {
		ActionSubmit: PendingReview,
		ActionCancel: Cancelled,
	},
	PendingReview: {
		ActionApprove: Queued,
		ActionReject:  Rejected,
		ActionCancel:  Cancelled,
	},
	Rejected: {
		ActionResubmit: PendingReview,
		ActionCancel:   Cancelled,
	},
	Queued: {
		ActionDispatch: Dispatched,
		ActionCancel:   Cancelled,
	},
	Dispatched: {
		ActionStart:  Running,
		ActionFail:   Failed,
		ActionCancel: Cancelled,
	},
	Running: {
		ActionSuccess: Success,
		ActionFail:    Failed,
		ActionSuspend: Suspended,
		ActionCancel:  Cancelled,
	},
	Failed: {
		ActionRetry:  Queued,
		ActionCancel: Cancelled,
	},
	Suspended: {
		ActionResume: Queued,
		ActionCancel: Cancelled,
	},
	Success:   {},
	Cancelled: {},
}

// Next 校验并返回下一状态；非法转移返回 ok=false
func Next(current string, a Action) (string, bool) {
	next, ok := transitions[current][a]
	return next, ok
}

// Can 当前状态是否接受该动作
func Can(current string, a Action) bool {
	_, ok := transitions[current][a]
	return ok
}