package store

import "lindenii.org/go/furgit/object/id"

// Batch stages reference operations for one non-atomic apply.
//
// Unlike Transaction,
// Batch may reject some queued operations
// while still applying others successfully when Apply runs.
//
// Labels: MT-Unsafe.
type Batch interface {
	// Create creates one direct reference,
	// requiring that the logical reference does not already exist.
	Create(name string, newID id.ObjectID) error

	// Update updates one direct reference,
	// requiring that the current logical reference value matches oldID.
	Update(name string, newID, oldID id.ObjectID) error

	// Delete deletes one direct reference,
	// requiring that the current logical reference value matches oldID.
	Delete(name string, oldID id.ObjectID) error

	// Verify verifies that the current logical reference value matches oldID.
	Verify(name string, oldID id.ObjectID) error

	// CreateSymbolic creates one symbolic reference,
	// requiring that the named reference does not already exist.
	CreateSymbolic(name, newTarget string) error

	// UpdateSymbolic updates one symbolic reference directly,
	// requiring that its current target matches oldTarget.
	UpdateSymbolic(name, newTarget, oldTarget string) error

	// DeleteSymbolic deletes one symbolic reference directly,
	// requiring that its current target matches oldTarget.
	DeleteSymbolic(name, oldTarget string) error

	// VerifySymbolic verifies that the named symbolic reference
	// currently points at oldTarget.
	VerifySymbolic(name, oldTarget string) error

	// Apply validates and applies queued operations,
	// returning one result per queued operation in order.
	// Fatal backend failures are returned separately.
	//
	// Malformed operations are rejected by the queueing methods above
	// and do not enter the batch.
	//
	// Apply invalidates the receiver.
	Apply() ([]BatchResult, error)

	// Abort abandons the batch and releases any resources it holds.
	//
	// Abort invalidates the receiver.
	Abort() error
}

// BatchStatus reports the outcome for one queued batch operation.
type BatchStatus uint8

const (
	// BatchStatusApplied indicates that the operation was applied.
	BatchStatusApplied BatchStatus = iota

	// BatchStatusRejected indicates that the operation was rejected
	// without aborting the rest of the batch.
	BatchStatusRejected

	// BatchStatusFatal indicates that the operation triggered a fatal failure.
	BatchStatusFatal

	// BatchStatusNotAttempted indicates that the operation was not attempted
	// because an earlier operation failed fatally.
	BatchStatusNotAttempted
)

// BatchResult reports the outcome for one queued batch operation.
type BatchResult struct {
	Name   string
	Status BatchStatus
	Error  error //exhaustruct:optional
}