package patch

import (
	"context"

	"sigs.k8s.io/controller-runtime/pkg/client"
)

// SerialPatcher provides serial patching of object using the patch helper. It
// remembers the state of the last patched object and uses that to calculate
// the patch against a new object.
type SerialPatcher struct {
	client       client.Client
	beforeObject client.Object
}

// NewSerialPatcher returns a SerialPatcher with the given object as the initial
// base object for the patching operations.
func NewSerialPatcher(obj client.Object, c client.Client) *SerialPatcher {
	return &SerialPatcher{
		client:       c,
		beforeObject: obj.DeepCopyObject().(client.Object),
	}
}

// Patch performs patching operation of the SerialPatcher and updates the
// beforeObject after a successful patch for subsequent patching.
func (sp *SerialPatcher) Patch(ctx context.Context, obj client.Object, options ...Option) error {
	// Create a new patch helper with the before object.
	patcher, err := NewHelper(sp.beforeObject, sp.client)
	if err != nil {
		return err
	}

	// Patch with the changes from the new object.
	if err := patcher.Patch(ctx, obj, options...); err != nil {
		return err
	}

	// Update the before object for next patch.
	sp.beforeObject = obj.DeepCopyObject().(client.Object)

	return nil
}