package flatten

import (
	"context"
	"fmt"
	"log"

	v1 "github.com/google/go-containerregistry/pkg/v1"

	"edge-infra.dev/pkg/f8n/warehouse"
	"edge-infra.dev/pkg/f8n/warehouse/lift"
	"edge-infra.dev/pkg/f8n/warehouse/lift/cmd/internal"
	"edge-infra.dev/pkg/f8n/warehouse/oci"
	"edge-infra.dev/pkg/f8n/warehouse/oci/layout"
	"edge-infra.dev/pkg/f8n/warehouse/oci/mutate"
	"edge-infra.dev/pkg/f8n/warehouse/oci/name"
	"edge-infra.dev/pkg/lib/cli/rags"
	"edge-infra.dev/pkg/lib/cli/sink"
)

// TODO(aw185176): allow overriding tag?

func New(cfg lift.Config) *sink.Command {
	var (
		packer = internal.NewPacker(cfg)
		push   bool
	)

	cmd := &sink.Command{
		Use:   "flatten [flags] <artifact>",
		Short: "flatten a package by removing composite packages",
		Flags: []*rags.Rag{
			{
				Name:  "push",
				Usage: "push flattened pallet to configured Warehouse registry",
				Value: &rags.Bool{Var: &push},
				Short: "p",
			},
		},
		Extensions: []sink.Extension{packer},
		Exec: func(_ context.Context, r sink.Run) error {
			switch len(r.Args()) {
			case 0:
				return fmt.Errorf("error: a package to flatten is required")
			case 1:
				// only valid number of r.Args()
			default:
				return fmt.Errorf("error: only one package can be provided")
			}

			if push && cfg.Repo == "" {
				return fmt.Errorf("error: oci repo is required for pushing\n" +
					"set one via the --warehouse-oci-repo flag or setting the " +
					"WAREHOUSE_OCI_REPO environment variable")
			}

			artifact, err := internal.ResolveArtifact(packer, r.Args()[0])
			if err != nil {
				return err
			}

			if a, ok := artifact.(oci.Unwrapper); ok {
				artifact = a.Unwrap()
			}

			mt, err := artifact.MediaType()
			if err != nil {
				return err
			}
			if mt.IsImage() {
				log.Println("input is Image, which can't be flattened")
				return nil
			}

			// TODO(aw185176): smooth out these APIs
			idx, err := mutate.Flatten(artifact.(v1.ImageIndex))
			if err != nil {
				return err
			}
			annos, err := oci.Annotations(idx)
			if err != nil {
				return err
			}

			ref, err := name.Tag(fmt.Sprintf("%s:squashed", annos[warehouse.AnnotationName]))
			if err != nil {
				return fmt.Errorf("failed to parse reference for flattened index: %w", err)
			}
			l, err := layout.New(cfg.Cache)
			if err != nil {
				return err
			}
			if err := l.Append(ref, idx); err != nil {
				return err
			}
			d, err := idx.Digest()
			if err != nil {
				return err
			}

			log.Printf("%s:squashed (%s)", annos[warehouse.AnnotationName], d)

			return nil
		},
	}

	return cmd
}