package bootstrap

import (
	"context"
	"fmt"
	"net/http"
	"os"
	"path/filepath"
	"strings"
	"testing"
	"time"
)

// Step 7 installs the one module whose image can never come from the mesh's own registry, because
// it IS the mesh's own registry (novox/hq 04-ISSUES/029). These tests defend that, and defend the
// distinction the whole verify layer of this program is built on: a container that is up is not a
// service that answers.

// catalogueWith writes a fake catalogue checkout holding one module's manifest.
//
// A fixture here rather than the real catalogue, unlike the substrate example the rewrite tests
// use: the catalogue is a different repository on a different branch, and a test that read it
// would pass or fail according to what somebody else had checked out.
func catalogueWith(t *testing.T, module, manifest string) string {
	t.Helper()
	root := t.TempDir()
	dir := filepath.Join(root, catalogueDir, module)
	if err := os.MkdirAll(dir, 0o755); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(dir, "module.json"), []byte(manifest), 0o644); err != nil {
		t.Fatal(err)
	}
	return root
}

const upstreamRegistryManifest = `{
  "module": "registry",
  "version": "1",
  "provides": [{"name": "artifact-store", "scope": "mesh"}],
  "capabilities": ["container-runtime"],
  "resources": [
    {"id": "state", "type": "directory", "path": "/var/lib/mesh/registry", "mode": "0700"},
    {"id": "store", "type": "container", "name": "mesh-registry",
     "image": "registry@sha256:a3d8aaa63ed8681a604f1dea0aa03f100d5895b6a58ace528858a7b332415373",
     "ports": ["5000:5000"]}
  ]
}`

// aMeshThatAgrees answers every command the installer issues at steps 7 and 9 the way a working
// mesh would, except for whatever a test overrides.
func aMeshThatAgrees(answers map[string]string) func(string, []string) (string, error) {
	return func(name string, args []string) (string, error) {
		joined := strings.Join(args, " ")
		for fragment, said := range answers {
			if strings.Contains(joined, fragment) {
				return said, nil
			}
		}
		switch {
		case name != "docker":
			return "", fmt.Errorf("unexpected program %q", name)
		case args[0] == "cp":
			return "", nil
		case args[0] == "inspect":
			return "true running\n", nil
		case args[0] == "exec":
			return "", nil
		}
		return "", fmt.Errorf("unexpected: %v", args)
	}
}

func installing(t *testing.T, catalogue string) Options {
	t.Helper()
	return Options{
		Node:      "anchor",
		Catalogue: catalogue,
		Registry:  "127.0.0.1:5000",
		Timeout:   time.Second,
		Wait:      0,
	}
}

// A container that is up is not a registry that serves. `/v2/` is the registry API's own "yes, I
// am one and I am ready", and the step after this pushes to it — so it is refused here rather than
// discovered inside a `docker push`.
func TestARegistryContainerThatIsUpIsNotARegistryThatServes(t *testing.T) {
	previous := answerEvery
	answerEvery = time.Millisecond
	defer func() { answerEvery = previous }()

	runtime := &asked{answer: aMeshThatAgrees(nil)}
	deps := Deps{
		Run: runtime.run,
		Fetch: func(context.Context, string) (int, string, error) {
			return http.StatusInternalServerError, "", nil
		},
	}

	_, err := InstallRegistry(context.Background(),
		installing(t, catalogueWith(t, RegistryModule, upstreamRegistryManifest)),
		deps, controlPlane{container: "temp-mesh-control", run: runtime.run, timeout: time.Second},
		func(string) {})
	if err == nil {
		t.Fatal("a registry whose container is up and which answers 500 was accepted")
	}
	for _, wanted := range []string{"/v2/", "Running is not serving"} {
		if !strings.Contains(err.Error(), wanted) {
			t.Errorf("the refusal does not mention %q:\n%v", wanted, err)
		}
	}
}

// The whole of step 7, against a mesh that agrees: registered, assigned, pushed, up, and answering.
func TestARegistryThatAnswersIsAccepted(t *testing.T) {
	runtime := &asked{answer: aMeshThatAgrees(nil)}
	deps := Deps{
		Run: runtime.run,
		Fetch: func(context.Context, string) (int, string, error) {
			return http.StatusOK, "{}", nil
		},
	}

	out, err := InstallRegistry(context.Background(),
		installing(t, catalogueWith(t, RegistryModule, upstreamRegistryManifest)),
		deps, controlPlane{container: "temp-mesh-control", run: runtime.run, timeout: time.Second},
		func(string) {})
	if err != nil {
		t.Fatal(err)
	}
	if out.Container != "mesh-registry" {
		t.Errorf("the registry's container is %q", out.Container)
	}
	if out.Answered != http.StatusOK {
		t.Errorf("the registry answered %d", out.Answered)
	}
	// Registered, assigned and pushed, through the same three commands a person types.
	for _, wanted := range []string{
		"module add /registry-module.json",
		"assign anchor registry",
		"push anchor",
	} {
		if !runtime.ran(wanted) {
			t.Errorf("the installer never ran %q: %v", wanted, runtime.commands)
		}
	}
}

// **The registry's image is upstream and it is never built.** A manifest carrying the catalogue's
// placeholder digest would mean somebody had made this module buildable — which is the cycle
// novox/hq 04-ISSUES/029 settled: a module that provides the artifact store cannot be delivered
// through the artifact store.
func TestARegistryManifestThatWantsBuildingIsRefused(t *testing.T) {
	wants := strings.Replace(upstreamRegistryManifest,
		"registry@sha256:a3d8aaa63ed8681a604f1dea0aa03f100d5895b6a58ace528858a7b332415373",
		"mesh-runtime-registry@"+placeholderDigest, 1)

	runtime := &asked{answer: aMeshThatAgrees(nil)}
	_, err := InstallRegistry(context.Background(),
		installing(t, catalogueWith(t, RegistryModule, wants)),
		Deps{Run: runtime.run}, controlPlane{container: "temp-mesh-control", run: runtime.run},
		func(string) {})
	if err == nil {
		t.Fatal("a registry manifest naming an image the mesh would have to build was accepted")
	}
	if !strings.Contains(err.Error(), "04-ISSUES/029") {
		t.Errorf("the refusal does not name the decision it rests on: %v", err)
	}
	if runtime.ran("module add") {
		t.Error("it was registered anyway")
	}
}

// A catalogue that is not there is said plainly, with what --catalog is. This is the most likely
// mistake anybody makes at this step and the least interesting to debug.
func TestACatalogueThatIsNotThereIsSaidPlainly(t *testing.T) {
	runtime := &asked{answer: aMeshThatAgrees(nil)}
	_, err := InstallRegistry(context.Background(),
		installing(t, filepath.Join(t.TempDir(), "nowhere")),
		Deps{Run: runtime.run}, controlPlane{container: "temp-mesh-control", run: runtime.run},
		func(string) {})
	if err == nil {
		t.Fatal("a catalogue that does not exist was accepted")
	}
	if !strings.Contains(err.Error(), "--catalog") {
		t.Errorf("the refusal does not say what to fix: %v", err)
	}
}

// A refusal from the control plane is repeated verbatim. mesh-control refuses in paragraphs —
// "nothing provides route, wanted by registry" — and an installer that reported "exit status 1"
// would throw away the only thing a person can act on.
func TestWhatTheMeshRefusedIsRepeated(t *testing.T) {
	refusal := "nothing provides \"route\", wanted by registry"
	runtime := &asked{answer: func(name string, args []string) (string, error) {
		if strings.Contains(strings.Join(args, " "), "push") {
			return refusal, fmt.Errorf("exit status 1")
		}
		return aMeshThatAgrees(nil)(name, args)
	}}

	_, err := InstallRegistry(context.Background(),
		installing(t, catalogueWith(t, RegistryModule, upstreamRegistryManifest)),
		Deps{Run: runtime.run}, controlPlane{container: "temp-mesh-control", run: runtime.run,
			timeout: time.Second}, func(string) {})
	if err == nil {
		t.Fatal("a push the mesh refused was reported as successful")
	}
	if !strings.Contains(err.Error(), refusal) {
		t.Errorf("what the mesh said is not in the failure:\n%v", err)
	}
	if !strings.Contains(err.Error(), "run this installer again") {
		t.Errorf("the failure does not say a re-run continues from here:\n%v", err)
	}
}