//go:build integration

package kvm

// Integration test against a real libvirt/KVM hypervisor. It deviates from
// the repo's testcontainers convention on purpose: libvirt needs /dev/kvm
// and a bridge, neither of which a container provides, so this runs
// against whatever host the KVM_TEST_* variables name. It creates one VM
// from a stock cloud image, waits for it to report an address, deletes it,
// and checks the pool afterwards. The base image stays cached on the host.
//
// Required:
//
//	KVM_TEST_HOST       SSH endpoint, host:port
//	KVM_TEST_USER       SSH user (member of the libvirt group)
//	KVM_TEST_SSH_KEY    path to the private key
//	KVM_TEST_BRIDGE     host bridge for the VM's NIC
//	KVM_TEST_IMAGE_URL  cloud image to fetch (http/https)
//
// Optional:
//
//	KVM_TEST_KNOWN_HOSTS   known_hosts file; without it host keys are NOT verified
//	KVM_TEST_IMAGE_SHA256  expected digest of the image
//	KVM_TEST_POOL          storage pool (default "default")
//	KVM_TEST_SOCKET        libvirt socket path on the host
//	KVM_TEST_TIMEOUT       overall budget incl. the image download (default 20m)
//	KVM_TEST_KEEP          set to anything to leave the VM behind for inspection

import (
	"context"
	"crypto/rand"
	"encoding/hex"
	"errors"
	"fmt"
	"net"
	"os"
	"testing"
	"time"

	libvirt "github.com/digitalocean/go-libvirt"
	"k8s.io/apimachinery/pkg/types"

	"gitea.home.hrajfrisbee.cz/kacerr/egress-proxies-operator/internal/provider"
)

const (
	integrationHostName = "kvm-test"
	integrationImageKey = "test-image"
	integrationPoll     = 5 * time.Second
)

type integrationEnv struct {
	cfg     provider.ProviderConfig
	timeout time.Duration
	keep    bool
}

func loadIntegrationEnv(t *testing.T) integrationEnv {
	t.Helper()
	if testing.Short() {
		t.Skip("integration test skipped under -short")
	}
	required := map[string]string{}
	for _, key := range []string{"KVM_TEST_HOST", "KVM_TEST_USER", "KVM_TEST_SSH_KEY", "KVM_TEST_BRIDGE", "KVM_TEST_IMAGE_URL"} {
		v := os.Getenv(key)
		if v == "" {
			t.Skipf("%s not set; skipping KVM integration test", key)
		}
		required[key] = v
	}
	cfg := &provider.KVMConfig{
		SSHKeyFile:     required["KVM_TEST_SSH_KEY"],
		KnownHostsFile: os.Getenv("KVM_TEST_KNOWN_HOSTS"),
		Images: map[string]provider.KVMImage{
			integrationImageKey: {URL: required["KVM_TEST_IMAGE_URL"], SHA256: os.Getenv("KVM_TEST_IMAGE_SHA256")},
		},
		MachineTypes: map[string]provider.KVMMachineType{"small": {VCPUs: 1, MemoryMiB: 1024}},
		Hosts: []provider.KVMHost{{
			Name:    integrationHostName,
			Address: required["KVM_TEST_HOST"],
			User:    required["KVM_TEST_USER"],
			Socket:  os.Getenv("KVM_TEST_SOCKET"),
			Pool:    os.Getenv("KVM_TEST_POOL"),
			Bridge:  required["KVM_TEST_BRIDGE"],
		}},
	}
	if cfg.KnownHostsFile == "" {
		cfg.InsecureIgnoreHostKey = true
		t.Log("KVM_TEST_KNOWN_HOSTS not set: host key verification disabled for this run")
	}
	pc := provider.ProviderConfig{Name: "kvm-integration", Type: "kvm", KVM: cfg}
	timeout := 20 * time.Minute
	if v := os.Getenv("KVM_TEST_TIMEOUT"); v != "" {
		d, err := time.ParseDuration(v)
		if err != nil {
			t.Fatalf("KVM_TEST_TIMEOUT: %v", err)
		}
		timeout = d
	}
	return integrationEnv{cfg: pc, timeout: timeout, keep: os.Getenv("KVM_TEST_KEEP") != ""}
}

func randomUID(t *testing.T) string {
	t.Helper()
	var b [16]byte
	if _, err := rand.Read(b[:]); err != nil {
		t.Fatal(err)
	}
	h := hex.EncodeToString(b[:])
	return fmt.Sprintf("%s-%s-%s-%s-%s", h[0:8], h[8:12], h[12:16], h[16:20], h[20:32])
}

// TestKVM_lifecycle is one sequential story, not parallel subtests: each
// stage depends on the state the previous one left on the hypervisor.
func TestKVM_lifecycle(t *testing.T) {
	env := loadIntegrationEnv(t)
	ctx, cancel := context.WithTimeout(context.Background(), env.timeout)
	defer cancel()

	prov, err := New(ctx, env.cfg)
	if err != nil {
		t.Fatalf("New: %v", err)
	}
	p := prov.(*Provider)
	host := p.cfg.Hosts[0]

	uid := randomUID(t)
	req := provider.CreateRequest{
		Name:      provider.NameFromUID(types.UID(uid)),
		UID:       uid,
		Namespace: "integration",
		ProxyName: "kvm-integration",
		Placement: provider.Placement{Zone: integrationHostName, MachineType: "small", Image: integrationImageKey},
		CloudInit: "#cloud-config\n",
		Port:      3128,
	}
	t.Logf("host %s (%s), pool %q, bridge %s, domain %s", host.Name, host.Address, host.Pool, host.Bridge, req.Name)

	// Cleanup runs even when a stage fails, with its own budget: the test
	// ctx may already be spent by then.
	t.Cleanup(func() {
		if env.keep {
			t.Logf("KVM_TEST_KEEP set: leaving domain %s and its volumes on %s", req.Name, host.Address)
			return
		}
		cctx, ccancel := context.WithTimeout(context.Background(), 2*time.Minute)
		defer ccancel()
		if err := p.Delete(cctx, formatProviderID(host.Name, req.Name)); err != nil {
			t.Errorf("cleanup Delete: %v", err)
		}
	})

	// --- create (includes the image fetch on a cold host) ---
	start := time.Now()
	id, err := p.Create(ctx, req)
	if err != nil {
		t.Fatalf("Create: %v", err)
	}
	t.Logf("Create returned %s after %s", id, time.Since(start).Round(time.Second))
	if want := formatProviderID(host.Name, req.Name); id != want {
		t.Fatalf("providerID = %s, want %s", id, want)
	}

	// --- create again: must find what it made, not duplicate it ---
	id2, err := p.Create(ctx, req)
	if err != nil {
		t.Fatalf("second Create: %v", err)
	}
	if id2 != id {
		t.Fatalf("second Create returned %s, want %s", id2, id)
	}

	// --- wait for the guest to come up with an address ---
	inst := waitForRunning(ctx, t, p, id)
	t.Logf("domain Running with IP %s (state reported after %s)", inst.IP, time.Since(start).Round(time.Second))
	if inst.UID != uid {
		t.Errorf("UID read back = %q, want %q (metadata round-trip through libvirt)", inst.UID, uid)
	}
	if age := time.Since(inst.CreatedAt); inst.CreatedAt.IsZero() || age < 0 || age > time.Hour {
		t.Errorf("CreatedAt = %s (age %s), want a recent timestamp", inst.CreatedAt, age)
	}
	if conn, err := net.DialTimeout("tcp", net.JoinHostPort(inst.IP, "22"), 5*time.Second); err != nil {
		t.Logf("note: tcp %s:22 not reachable from this machine (%v); fine if the bridge network is not routed here", inst.IP, err)
	} else {
		conn.Close()
		t.Logf("tcp %s:22 reachable from this machine", inst.IP)
	}

	// --- the GC view must include it ---
	listed, err := p.ListByTag(ctx)
	if err != nil {
		t.Fatalf("ListByTag: %v", err)
	}
	if !containsID(listed, id) {
		t.Errorf("ListByTag = %+v, want it to include %s", listed, id)
	}

	// --- delete, then verify nothing of the VM remains but the base image does ---
	if err := p.Delete(ctx, id); err != nil {
		t.Fatalf("Delete: %v", err)
	}
	if _, err := p.Get(ctx, id); !errors.Is(err, provider.ErrNotFound) {
		t.Errorf("Get after Delete = %v, want ErrNotFound", err)
	}
	if err := p.Delete(ctx, id); err != nil {
		t.Errorf("second Delete: %v, want nil (idempotent)", err)
	}
	listed, err = p.ListByTag(ctx)
	if err != nil {
		t.Fatalf("ListByTag after Delete: %v", err)
	}
	if containsID(listed, id) {
		t.Errorf("ListByTag still includes %s after Delete", id)
	}

	src, err := resolveImage(p.cfg, integrationImageKey)
	if err != nil {
		t.Fatal(err)
	}
	err = p.hosts.call(ctx, host, func(api libvirtAPI) error {
		pool, err := api.StoragePoolLookupByName(host.Pool)
		if err != nil {
			return err
		}
		for _, gone := range []string{overlayVolumeName(req.Name), seedVolumeName(req.Name)} {
			if _, err := api.StorageVolLookupByName(pool, gone); !hasCode(err, libvirt.ErrNoStorageVol) {
				t.Errorf("volume %s after Delete: lookup err = %v, want ErrNoStorageVol", gone, err)
			}
		}
		for _, kept := range []string{src.volumeName(), src.markerName()} {
			if _, err := api.StorageVolLookupByName(pool, kept); err != nil {
				t.Errorf("cached image volume %s: %v, want it kept after Delete", kept, err)
			}
		}
		return nil
	})
	if err != nil {
		t.Fatalf("inspecting pool after Delete: %v", err)
	}
	// KVM_TEST_KEEP is for inspecting a failed run; a passed run has
	// nothing left to keep, so let cleanup's Delete confirm that.
	env.keep = false
}

// waitForRunning polls Get until the instance is Running with an IP or ctx
// ends. Transient errors are retried; anything else fails the test.
func waitForRunning(ctx context.Context, t *testing.T, p *Provider, id string) *provider.Instance {
	t.Helper()
	var last provider.InstanceState
	ticker := time.NewTicker(integrationPoll)
	defer ticker.Stop()
	for {
		inst, err := p.Get(ctx, id)
		switch {
		case err == nil:
			if inst.State != last {
				t.Logf("state %s ip %q", inst.State, inst.IP)
				last = inst.State
			}
			if inst.State == provider.StateRunning {
				return inst
			}
			if inst.State == provider.StateStopped {
				t.Fatalf("domain reported %s while waiting for Running; check `virsh console %s` on the host", inst.State, idName(id))
			}
		case errors.Is(err, provider.ErrTransient):
			t.Logf("Get: transient error, retrying: %v", err)
		default:
			t.Fatalf("Get: %v", err)
		}
		select {
		case <-ctx.Done():
			t.Fatalf("timed out waiting for Running (last state %s): %v", last, ctx.Err())
		case <-ticker.C:
		}
	}
}

func idName(id string) string {
	_, name, _ := parseProviderID(id)
	return name
}

func containsID(list []provider.Instance, id string) bool {
	for _, inst := range list {
		if inst.ID == id {
			return true
		}
	}
	return false
}