package chart

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"os"
	"strings"

	"github.com/containerd/containerd/remotes"
	"github.com/containerd/containerd/remotes/docker"
	"github.com/google/go-containerregistry/pkg/name"
	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
	"helm.sh/helm/v3/pkg/action"
	"helm.sh/helm/v3/pkg/chart/loader"
	"helm.sh/helm/v3/pkg/cli"
	"k8s.io/client-go/util/jsonpath"
	"oras.land/oras-go/pkg/content"
	"oras.land/oras-go/pkg/oras"

	"github.com/rancherfederal/hauler/pkg/apis/hauler.cattle.io/v1alpha1"
	"github.com/rancherfederal/hauler/pkg/log"
)

const (
	// OCIScheme is the URL scheme for OCI-based requests
	OCIScheme = "oci"

	// CredentialsFileBasename is the filename for auth credentials file
	CredentialsFileBasename = "config.json"

	// ConfigMediaType is the reserved media type for the Helm chart manifest config
	ConfigMediaType = "application/vnd.cncf.helm.config.v1+json"

	// ChartLayerMediaType is the reserved media type for Helm chart package content
	ChartLayerMediaType = "application/vnd.cncf.helm.chart.content.v1.tar+gzip"

	// ProvLayerMediaType is the reserved media type for Helm chart provenance files
	ProvLayerMediaType = "application/vnd.cncf.helm.chart.provenance.v1.prov"
)

type Chart struct {
	cfg v1alpha1.Chart

	resolver remotes.Resolver
}

var defaultKnownImagePaths = []string{
	// Deployments & DaemonSets
	"{.spec.template.spec.initContainers[*].image}",
	"{.spec.template.spec.containers[*].image}",

	// Pods
	"{.spec.initContainers[*].image}",
	"{.spec.containers[*].image}",
}

func NewChart(cfg v1alpha1.Chart) Chart {
	return Chart{
		cfg: cfg,

		// TODO:
		resolver: docker.NewResolver(docker.ResolverOptions{}),
	}
}

func (c Chart) Copy(ctx context.Context, registry string) error {
	var (
		s                  = content.NewMemoryStore()
		l                  = log.FromContext(ctx)
		contentDescriptors []ocispec.Descriptor
	)

	chartdata, err := fetch(c.cfg.Name, c.cfg.RepoURL, c.cfg.Version)
	if err != nil {
		return err
	}

	ch, err := loader.LoadArchive(bytes.NewBuffer(chartdata))
	if err != nil {
		return err
	}

	chartDescriptor := s.Add("", ChartLayerMediaType, chartdata)
	contentDescriptors = append(contentDescriptors, chartDescriptor)

	configData, _ := json.Marshal(ch.Metadata)
	configDescriptor := s.Add("", ConfigMediaType, configData)

	// TODO: Clean this up
	ref, err := name.ParseReference(fmt.Sprintf("hauler/%s:%s", c.cfg.Name, c.cfg.Version), name.WithDefaultRegistry(registry))
	if err != nil {
		return err
	}

	l.Infof("Copying chart to: '%s'", ref.Name())
	pushedDesc, err := oras.Push(ctx, c.resolver, ref.Name(), s, contentDescriptors,
		oras.WithConfig(configDescriptor), oras.WithNameValidation(nil))
	if err != nil {
		return err
	}

	l.Debugf("Copied with descriptor: '%s'", pushedDesc.Digest.String())
	return nil
}

func fetch(name, repo, version string) ([]byte, error) {
	cpo := action.ChartPathOptions{
		RepoURL: repo,
		Version: version,
	}

	cp, err := cpo.LocateChart(name, cli.New())
	if err != nil {
		return nil, err
	}

	data, err := os.ReadFile(cp)
	if err != nil {
		return nil, err
	}

	return data, nil
}

func parseJSONPath(data interface{}, parser *jsonpath.JSONPath, template string) ([]string, error) {
	buf := new(bytes.Buffer)
	if err := parser.Parse(template); err != nil {
		return nil, err
	}

	if err := parser.Execute(buf, data); err != nil {
		return nil, err
	}

	f := func(s rune) bool { return s == ' ' }
	r := strings.FieldsFunc(buf.String(), f)
	return r, nil
}