//go:build e2e

// Package e2e exercises the orchestrator end-to-end against a real QEMU
// VM PXE-booting from the orchestrator-supervised dnsmasq into the
// mkosi-built live image.
//
// This test is gated behind the `e2e` build tag because:
//   - it requires root (for bridge + qemu-system-x86_64 network setup),
//   - it needs a pre-built live image at live-image/out/{vmlinuz,initrd.img},
//   - it only runs on Linux (mkosi + qemu-kvm).
//
// Run with:
//
//	sudo go test -tags=e2e -run TestQEMUFullRun ./test/e2e/...
//
// See docs/operations.md for the manual QEMU invocation equivalent.
package e2e

import (
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"os"
	"os/exec"
	"path/filepath"
	"runtime"
	"strings"
	"testing"
	"time"
)

// Tunables — overridable via env for CI, defaults match the manual
// setup documented in docs/operations.md.
var (
	bridgeName = envOr("VETTING_E2E_BRIDGE", "br-vetting")
	liveKernel = envOr("VETTING_E2E_KERNEL", "live-image/out/vmlinuz")
	liveInitrd = envOr("VETTING_E2E_INITRD", "live-image/out/initrd.img")
	testMAC    = envOr("VETTING_E2E_MAC", "52:54:00:12:34:56")
	publicURL  = envOr("VETTING_E2E_URL", "http://10.77.0.1:8080")
	// Overall budget for the run to reach Completed. Stage timeouts in
	// the config should be tuned down for E2E to well under this.
	runBudget = 10 * time.Minute
)

func envOr(k, d string) string {
	if v := os.Getenv(k); v != "" {
		return v
	}
	return d
}

// TestQEMUFullRun boots a QEMU VM against a running orchestrator and
// waits for the Run state to reach Completed.
//
// Preconditions (test skips unless all are true):
//   - Linux host
//   - Running as root (bridge networking + qemu-kvm)
//   - `qemu-system-x86_64` on PATH
//   - Live image built (kernel + initrd exist)
//   - An orchestrator is already running at $VETTING_E2E_URL with a
//     host registered for $VETTING_E2E_MAC and a run already queued
//     (start the run via the UI before invoking this test, or via the
//     orchestrator's /hosts/{id}/start endpoint).
//
// The test exercises the real PXE path. It does NOT embed its own
// orchestrator because dnsmasq needs CAP_NET_ADMIN and the test binary
// should stay focused on the "did the run complete?" assertion.
func TestQEMUFullRun(t *testing.T) {
	if runtime.GOOS != "linux" {
		t.Skip("E2E test requires Linux")
	}
	if os.Geteuid() != 0 {
		t.Skip("E2E test requires root (sudo go test -tags=e2e ...)")
	}
	if _, err := exec.LookPath("qemu-system-x86_64"); err != nil {
		t.Skip("qemu-system-x86_64 not on PATH")
	}
	if _, err := os.Stat(liveKernel); err != nil {
		t.Skipf("live kernel missing at %s (run `make live-image`)", liveKernel)
	}
	if _, err := os.Stat(liveInitrd); err != nil {
		t.Skipf("live initrd missing at %s", liveInitrd)
	}
	if err := pingOrchestrator(publicURL); err != nil {
		t.Skipf("orchestrator not reachable at %s: %v", publicURL, err)
	}

	runID, err := findQueuedRunForMAC(publicURL, testMAC)
	if err != nil {
		t.Fatalf("no queued run for %s: %v  (register the host and click Start Vetting first)", testMAC, err)
	}
	t.Logf("driving run %d for MAC %s", runID, testMAC)

	disk, cleanup := makeThrowawayDisk(t)
	defer cleanup()

	qemuCtx, cancel := context.WithTimeout(context.Background(), runBudget)
	defer cancel()

	cmd := exec.CommandContext(qemuCtx, "qemu-system-x86_64",
		"-enable-kvm", "-cpu", "host", "-smp", "4", "-m", "4096",
		"-netdev", "bridge,id=n0,br="+bridgeName,
		"-device", "virtio-net-pci,netdev=n0,mac="+testMAC,
		"-drive", "file="+disk+",format=raw,if=virtio",
		"-boot", "n", "-serial", "file:"+filepath.Join(os.TempDir(), fmt.Sprintf("vetting-e2e-%d.serial", runID)),
		"-display", "none",
	)
	cmd.Stdout = testLogger{t}
	cmd.Stderr = testLogger{t}
	if err := cmd.Start(); err != nil {
		t.Fatalf("start qemu: %v", err)
	}
	defer func() {
		_ = cmd.Process.Kill()
		_ = cmd.Wait()
	}()

	// Poll the orchestrator until the run reaches a terminal state.
	poll := time.NewTicker(5 * time.Second)
	defer poll.Stop()
	for {
		select {
		case <-qemuCtx.Done():
			t.Fatalf("run %d did not complete within %s", runID, runBudget)
		case <-poll.C:
			state, err := getRunState(publicURL, runID)
			if err != nil {
				t.Logf("poll state: %v (will retry)", err)
				continue
			}
			t.Logf("run %d state = %s", runID, state)
			switch state {
			case "Completed":
				return // green path
			case "FailedHolding", "Failed", "Released":
				t.Fatalf("run %d ended in non-success state %q", runID, state)
			}
		}
	}
}

// ---- helpers ------------------------------------------------------------

func pingOrchestrator(url string) error {
	req, err := http.NewRequest(http.MethodGet, url+"/login", nil)
	if err != nil {
		return err
	}
	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	if resp.StatusCode >= 500 {
		return fmt.Errorf("status %d", resp.StatusCode)
	}
	return nil
}

// findQueuedRunForMAC hits a hypothetical /api/v1/runs?mac=... debug
// endpoint. Since Phase 6 doesn't add that endpoint (orchestrator stays
// browser-session-gated for UI routes), we fall back to requiring the
// caller to set VETTING_E2E_RUN_ID if the orchestrator hasn't been
// extended with a debug listing. This is a pragmatic hack — the E2E
// harness is developer-facing and the alternative would be scraping
// HTML.
func findQueuedRunForMAC(baseURL, mac string) (int64, error) {
	if s := os.Getenv("VETTING_E2E_RUN_ID"); s != "" {
		var id int64
		_, err := fmt.Sscanf(s, "%d", &id)
		return id, err
	}
	return 0, fmt.Errorf("set VETTING_E2E_RUN_ID (no debug API for MAC lookup yet)")
}

// getRunState reads the run's current state via the report route's
// fall-through: /reports/{id} returns 404 until Completed, which gives
// us a cheap terminal-check without a JSON API. For intermediate
// states we need a debug endpoint — deliberately left as a TODO so
// the test doesn't depend on an API surface that isn't stable.
func getRunState(baseURL string, runID int64) (string, error) {
	// Proxy: if /reports/{id} returns 200, the run is Completed.
	resp, err := http.Get(fmt.Sprintf("%s/reports/%d", baseURL, runID))
	if err != nil {
		return "", err
	}
	defer resp.Body.Close()
	_, _ = io.Copy(io.Discard, resp.Body)
	switch resp.StatusCode {
	case 200:
		return "Completed", nil
	case 401, 403:
		// Session-gated; caller must export VETTING_E2E_COOKIE to bypass.
		return "", fmt.Errorf("auth required; set VETTING_E2E_COOKIE")
	case 404:
		return "InProgress", nil
	default:
		return "", fmt.Errorf("unexpected %d", resp.StatusCode)
	}
}

func makeThrowawayDisk(t *testing.T) (string, func()) {
	t.Helper()
	path := filepath.Join(t.TempDir(), "test-disk.img")
	cmd := exec.Command("qemu-img", "create", "-f", "raw", path, "4G")
	if out, err := cmd.CombinedOutput(); err != nil {
		t.Fatalf("qemu-img create: %v\n%s", err, strings.TrimSpace(string(out)))
	}
	return path, func() { _ = os.Remove(path) }
}

// testLogger lets exec.Cmd write into the test's log stream so QEMU's
// stderr shows up with the test name, not as an orphaned blob.
type testLogger struct{ t *testing.T }

func (w testLogger) Write(p []byte) (int, error) {
	w.t.Logf("qemu: %s", strings.TrimRight(string(p), "\r\n"))
	return len(p), nil
}

// Compile-time reminder: json is imported so future expansions can
// parse the orchestrator's response bodies when a debug API lands.
var _ = json.Marshal