api: Begin implementing an API

internal/dis/component/server/home/api.go

@@ -0,0 +1,64 @@
+package home
+
+import (
+	"context"
+	"net/http"
+	"time"
+
+	"github.com/FAU-CDI/wisski-distillery/internal/dis/component"
+	"github.com/FAU-CDI/wisski-distillery/internal/status"
+	"github.com/tkw1536/pkglib/httpx"
+)
+
+type API struct {
+	component.Base
+
+	Dependencies struct {
+		Home *Home
+	}
+}
+
+var (
+	_ component.Routeable = (*API)(nil)
+)
+
+func (api *API) Routes() component.Routes {
+	return component.Routes{
+		Prefix:    "/api/v1/systems",
+		Exact:     true,
+		Decorator: api.Config.HTTP.APIDecorator("GET"),
+	}
+}
+
+type APISystemInfo struct {
+	Slug    string
+	URL     string
+	Tagline string
+
+	EntityCount int
+	BundleCount int
+	LastEdit    time.Time
+}
+
+func (api *API) HandleRoute(ctx context.Context, path string) (http.Handler, error) {
+	return httpx.JSON(func(r *http.Request) ([]APISystemInfo, error) {
+		var statuses []status.WissKI
+		if api.Dependencies.Home.ShouldShowList(r) {
+			statuses = api.Dependencies.Home.homeInstances.Get(nil)
+		}
+
+		if len(statuses) == 0 {
+			return []APISystemInfo{}, nil
+		}
+
+		infos := make([]APISystemInfo, len(statuses))
+		for i, status := range statuses {
+			infos[i].Slug = status.Slug
+			infos[i].URL = status.URL
+			infos[i].EntityCount = status.Statistics.Bundles.TotalCount()
+			infos[i].BundleCount = status.Statistics.Bundles.TotalBundles
+			infos[i].LastEdit = status.Statistics.Bundles.LastEdit().Time
+		}
+		return infos, nil
+	}), nil
+}