distro: introduce Arch and ImageType interfaces

Objects implementing these interfaces will represent the
architecture support for a given distro and the image type
support for a given architecture distro combination, respectively.

The idea is to always resolve to these objects early, and drop
the equilavent methods from the distro interface. This means that
we convert our input strings to real objects once, and then never
have to verify their correctness again.

Signed-off-by: Tom Gundersen <teg@jklm.no>

internal/distro/fedora31/distro.go

@@ -6,6 +6,7 @@ import (
 	"strconv"
 
 	"github.com/osbuild/osbuild-composer/internal/common"
+	"github.com/osbuild/osbuild-composer/internal/distro"
 	"github.com/osbuild/osbuild-composer/internal/osbuild"
 
 	"github.com/google/uuid"
@@ -15,12 +16,6 @@ import (
 	"github.com/osbuild/osbuild-composer/internal/rpmmd"
 )
 
-type Fedora31 struct {
-	arches        map[string]arch
-	outputs       map[string]output
-	buildPackages []string
-}
-
 type arch struct {
 	Name               string
 	BootloaderPackages []string
@@ -44,6 +39,103 @@ type output struct {
 const Distro = common.Fedora31
 const ModulePlatformID = "platform:f31"
 
+type Fedora31 struct {
+	arches        map[string]arch
+	outputs       map[string]output
+	buildPackages []string
+}
+
+type Fedora31Arch struct {
+	name   string
+	distro *Fedora31
+	arch   *arch
+}
+
+type Fedora31ImageType struct {
+	name   string
+	arch   *Fedora31Arch
+	output *output
+}
+
+func (d *Fedora31) GetArch(arch string) (distro.Arch, error) {
+	a, exists := d.arches[arch]
+	if !exists {
+		return nil, errors.New("invalid architecture: " + arch)
+	}
+
+	return &Fedora31Arch{
+		name:   arch,
+		distro: d,
+		arch:   &a,
+	}, nil
+}
+
+func (a *Fedora31Arch) Name() string {
+	return a.name
+}
+
+func (a *Fedora31Arch) ListImageTypes() []string {
+	return a.distro.ListOutputFormats()
+}
+
+func (a *Fedora31Arch) GetImageType(imageType string) (distro.ImageType, error) {
+	t, exists := a.distro.outputs[imageType]
+	if !exists {
+		return nil, errors.New("invalid image type: " + imageType)
+	}
+
+	return &Fedora31ImageType{
+		name:   imageType,
+		arch:   a,
+		output: &t,
+	}, nil
+}
+
+func (t *Fedora31ImageType) Name() string {
+	return t.name
+}
+
+func (t *Fedora31ImageType) Filename() string {
+	return t.output.Name
+}
+
+func (t *Fedora31ImageType) MIMEType() string {
+	return t.output.MimeType
+}
+
+func (t *Fedora31ImageType) Size(size uint64) uint64 {
+	return t.arch.distro.GetSizeForOutputType(t.name, size)
+}
+
+func (t *Fedora31ImageType) BasePackages() ([]string, []string) {
+	packages := t.output.Packages
+	if t.output.Bootable {
+		packages = append(packages, t.arch.arch.BootloaderPackages...)
+	}
+
+	return packages, t.output.ExcludedPackages
+}
+
+func (t *Fedora31ImageType) BuildPackages() []string {
+	return append(t.arch.distro.buildPackages, t.arch.arch.BuildPackages...)
+}
+
+func (t *Fedora31ImageType) Manifest(c *blueprint.Customizations,
+	repos []rpmmd.RepoConfig,
+	packageSpecs,
+	buildPackageSpecs []rpmmd.PackageSpec,
+	size uint64) (*osbuild.Manifest, error) {
+	pipeline, err := t.arch.distro.pipeline(c, repos, packageSpecs, buildPackageSpecs, t.arch.name, t.name, size)
+	if err != nil {
+		return nil, err
+	}
+
+	return &osbuild.Manifest{
+		Sources:  *t.arch.distro.sources(append(packageSpecs, buildPackageSpecs...)),
+		Pipeline: *pipeline,
+	}, nil
+}
+
 func New() *Fedora31 {
 	const GigaByte = 1024 * 1024 * 1024