package intentflow

import "errors"

// Sentinel errors use the public API error codes from the design §9.
var (
	ErrPlanNotFoundOrHidden      = errors.New("PLAN_NOT_FOUND_OR_HIDDEN")
	ErrPlanStaleRevision         = errors.New("PLAN_STALE_REVISION")
	ErrPlanExpired               = errors.New("PLAN_EXPIRED")
	ErrPlanDecisionConflict      = errors.New("PLAN_DECISION_CONFLICT")
	ErrPlanDependencyInvalid     = errors.New("PLAN_DEPENDENCY_INVALID")
	ErrPlanActionForbidden       = errors.New("PLAN_ACTION_FORBIDDEN")
	ErrPlanActionVersionConflict = errors.New("PLAN_ACTION_VERSION_CONFLICT")
	ErrUnauthenticated           = errors.New("ERR_UNAUTHENTICATED")
)

var errTurnExists = errors.New("intentflow: turn exists")

// ErrorCode returns the stable machine code for a sentinel, or empty.
func ErrorCode(err error) string {
	switch {
	case errors.Is(err, ErrPlanNotFoundOrHidden):
		return "PLAN_NOT_FOUND_OR_HIDDEN"
	case errors.Is(err, ErrPlanStaleRevision):
		return "PLAN_STALE_REVISION"
	case errors.Is(err, ErrPlanExpired):
		return "PLAN_EXPIRED"
	case errors.Is(err, ErrPlanDecisionConflict):
		return "PLAN_DECISION_CONFLICT"
	case errors.Is(err, ErrPlanDependencyInvalid):
		return "PLAN_DEPENDENCY_INVALID"
	case errors.Is(err, ErrPlanActionForbidden):
		return "PLAN_ACTION_FORBIDDEN"
	case errors.Is(err, ErrPlanActionVersionConflict):
		return "PLAN_ACTION_VERSION_CONFLICT"
	case errors.Is(err, ErrUnauthenticated):
		return "ERR_UNAUTHENTICATED"
	case errors.Is(err, ErrSegmentProposalDisabled):
		return "SEGMENT_PROPOSAL_DISABLED"
	case errors.Is(err, ErrSegmentProposalMalformed):
		return "SEGMENT_PROPOSAL_MALFORMED"
	case errors.Is(err, ErrSegmentProposalTimeout):
		return "SEGMENT_PROPOSAL_TIMEOUT"
	case errors.Is(err, ErrSegmentProposalOutOfBounds):
		return "SEGMENT_PROPOSAL_OUT_OF_BOUNDS"
	default:
		return ""
	}
}