package main

// The declared dump, exactly as the backup holder runs it, against the bus's own image.
//
//	docker build --build-arg NATS_BASE=<digest> --build-arg GO_BASE=<digest> -t mesh-nats:check ..
//	MESH_TEST_NATS_IMAGE=mesh-nats:check go test -run TestTheDeclaredDump ./...

import (
	"encoding/json"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"testing"
	"time"

	"github.com/nats-io/nats.go"
)

// manifestOf is the nats module's own definition, beside this program.
func manifestOf(t *testing.T) map[string]any {
	t.Helper()
	raw, err := os.ReadFile("../module.json")
	if err != nil {
		t.Fatal(err)
	}
	var m map[string]any
	if err := json.Unmarshal(raw, &m); err != nil {
		t.Fatal(err)
	}
	return m
}

func declaredDump(t *testing.T, m map[string]any) string {
	t.Helper()
	for _, item := range m["data"].(map[string]any)["own"].([]any) {
		it := item.(map[string]any)
		if it["id"] != "jetstream" {
			continue
		}
		backup, _ := it["backup"].(map[string]any)
		if backup == nil || backup["into"] != "snapshots" {
			t.Fatalf("the bus's streams are not protected by a dump into its snapshots: %v", it["backup"])
		}
		return backup["dump"].(string)
	}
	t.Fatal("the nats module declares no jetstream data item")
	return ""
}

func serverConf(t *testing.T, m map[string]any) string {
	t.Helper()
	for _, r := range m["resources"].([]any) {
		res := r.(map[string]any)
		if res["id"] == "server-conf" {
			return res["content"].(string)
		}
	}
	t.Fatal("the nats module declares no server configuration")
	return ""
}

// The dump is the one the manifest declares, run by `sh -c` as the holder runs it, with the module's
// directories filled in; the server is the module's image with the module's own configuration and a
// user list holding the bus's own module with the controller's grants for it.
func TestTheDeclaredDumpRunsInTheBussImage(t *testing.T) {
	image := os.Getenv("MESH_TEST_NATS_IMAGE")
	if image == "" {
		t.Skip("MESH_TEST_NATS_IMAGE unset: the bus's image, built from ../Dockerfile")
	}
	const name = "mesh-broker-nats" // the container the dump names
	if out, _ := exec.Command("docker", "ps", "-a", "-q", "--filter", "name=^"+name+"$").Output(); len(strings.TrimSpace(string(out))) > 0 {
		t.Skipf("a container called %s already runs here; this test will not touch it", name)
	}
	m := manifestOf(t)
	dump := declaredDump(t, m)

	conf, tlsDir, data, state, snapshots := t.TempDir(), t.TempDir(), t.TempDir(), t.TempDir(), t.TempDir()
	pin := selfSigned(t, tlsDir)
	_ = os.WriteFile(filepath.Join(conf, "nats.conf"), []byte(serverConf(t, m)), 0o644)
	accounts := liveBusConf()
	accounts = accounts[strings.Index(accounts, "accounts {"):]
	_ = os.WriteFile(filepath.Join(conf, "accounts.conf"), []byte(accounts), 0o644)

	docker(t, "run", "-d", "--rm", "--name", name, "--user", owner(), "-p", "127.0.0.1::4222",
		"-v", data+":/data", "-v", conf+":/etc/nats:ro", "-v", tlsDir+":/tls:ro", image)
	t.Cleanup(func() { _ = exec.Command("docker", "rm", "-f", name).Run() })
	_, port, _ := strings.Cut(docker(t, "port", name, "4222/tcp"), ":")

	admin := dial(t, "tls://127.0.0.1:"+port, Credential{Fingerprint: pin, User: "admin", Password: "admin"}, nil)
	js, _ := admin.JetStream()
	kv, err := js.CreateKeyValue(&nats.KeyValueConfig{Bucket: "mesh-controller_hand-acts"})
	if err != nil {
		t.Fatal(err)
	}
	for _, k := range []string{"a", "b", "c"} {
		if _, err := kv.Put(k, []byte("act "+k)); err != nil {
			t.Fatal(err)
		}
	}

	run := func(cred Credential) (string, error) {
		raw, _ := json.Marshal(cred)
		if err := os.WriteFile(filepath.Join(state, "broker"), raw, 0o600); err != nil {
			t.Fatal(err)
		}
		command := strings.NewReplacer("${dir:mesh-state}", state, "${dir:snapshots}", snapshots).Replace(dump)
		out, err := exec.Command("sh", "-c", command).CombinedOutput()
		return string(out), err
	}

	began := time.Now()
	out, err := run(Credential{URL: "nats://bus.example:4222", Fingerprint: pin, User: snapshotUser, Password: "snap"})
	if err != nil {
		t.Fatalf("the declared dump failed: %v\n%s", err, out)
	}
	t.Logf("the declared dump took %s:\n%s", time.Since(began).Round(time.Millisecond), out)
	tarPath := filepath.Join(snapshots, "bus.tar")
	f, err := os.Open(tarPath)
	if err != nil {
		t.Fatalf("the dump left no bus.tar: %v", err)
	}
	a, err := ReadArchive(f, "")
	f.Close()
	if err != nil {
		t.Fatal(err)
	}
	defer a.Close()
	if err := a.Verify(); err != nil {
		t.Fatal(err)
	}
	if len(a.Manifest.Streams) != 1 || a.Manifest.Streams[0].Name != "KV_mesh-controller_hand-acts" || a.Manifest.Streams[0].Messages != 3 {
		t.Fatalf("the snapshot holds %+v", a.Manifest.Streams)
	}
	before, _ := os.ReadFile(tarPath)

	// A night that cannot snapshot fails, says why, and leaves last night's snapshot as it was.
	out, err = run(Credential{Fingerprint: pin, User: snapshotUser, Password: "wrong"})
	if err == nil {
		t.Fatalf("a dump the bus refused succeeded:\n%s", out)
	}
	if !strings.Contains(out, "Authorization Violation") && !strings.Contains(strings.ToLower(out), "authorization") {
		t.Errorf("the failure does not say the bus refused the credential: %s", out)
	}
	after, _ := os.ReadFile(tarPath)
	if string(after) != string(before) {
		t.Error("a failed night replaced the last good snapshot")
	}
	if _, err := os.Stat(tarPath + ".partial"); !os.IsNotExist(err) {
		t.Error("a failed night left its partial file behind")
	}
}