// Package fluxcd provides access to the embedded vendored manifests for
// installing FluxCD to K8s clusters. This package only provides a single
// function for loading the embedded manifests, and all other functionality
// should be implemented in the appropriate `pkg/` directory.
package fluxcd

import (
	"embed"
	"fmt"

	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
	"sigs.k8s.io/kustomize/api/krusty"
	ktypes "sigs.k8s.io/kustomize/api/types"

	"edge-infra.dev/pkg/k8s/decoder"
	"edge-infra.dev/pkg/k8s/kustomize"
)

//go:embed manifests/*.yaml
//go:embed base/**/*.yaml
//go:embed base/*.yaml
//go:embed kustomize-helm-controllers/*.yaml
var fluxcdManifests embed.FS

// private rendering options struct.  rendering options should be set by passing
// public Options to `LoadManifests()`
type options struct {
	// what would typically be passed to `kustomize build`
	kustomizeBuildTarget string
}

// Option is the public functional option interface
type Option func(*options)

// OnlyKustomizeController will cause only fluxcd/kustomize-controller and
// its dependencies to be rendered.
func OnlyKustomizeController() func(*options) {
	return func(o *options) {
		o.kustomizeBuildTarget = "kustomize-controller"
	}
}

// LoadManifests reads the manifests from the embedded byte mapping containing
// vendored FluxCD installation manifests and our Kustomize patches + targets,
// runs 'kustomize build' based on the provided options and then decodes the
// data into K8s objects that can be applied to the K8s API using controller-runtime's
// client.
// If no options are provided, it will render the fluxcd/helm-controller and
// fluxcd/kustomize-controller and their dependencies, as they are the only
// FluxCD components used in Edge.
func LoadManifests(opts ...Option) ([]*unstructured.Unstructured, error) {
	o := &options{kustomizeBuildTarget: "kustomize-helm-controllers"}
	for _, opt := range opts {
		opt(o)
	}

	ops := krusty.MakeDefaultOptions()
	ops.LoadRestrictions = ktypes.LoadRestrictionsNone
	k := krusty.MakeKustomizer(
		ops,
	)

	m, err := k.Run(&kustomize.FS{FS: fluxcdManifests}, o.kustomizeBuildTarget)
	if err != nil {
		return nil, fmt.Errorf("failed to execute kustomize build: %w", err)
	}

	yaml, err := m.AsYaml()
	if err != nil {
		return nil, fmt.Errorf("failed to convert kustomize build result into bytes: %w", err)
	}

	return decoder.DecodeYAML(yaml)
}