package replays

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

// **The catalogue's bed** (novox/hq ADR 0240 rule 7, to-be 48 §8, Phase D): every long-running resource whose
// declared `health` or image the change touches is started alone and its check must see the program within
// its grace. Run by every merge check of the catalogue on the build seat, with the change's catalogue at
// MESH_REPLAY_CATALOGUE; by hand against the catalogue beside the lab. What changed is against
// MESH_BED_BASE (origin/main by default) in that checkout.
func TestBedProvesEveryChangedHealthCheck(t *testing.T) {
	root := orDefault(os.Getenv("MESH_REPLAY_CATALOGUE"), filepath.Join("..", "..", "mesh-catalog"))
	if _, err := os.Stat(filepath.Join(root, "modules")); err != nil {
		t.Skipf("no catalogue at %s (MESH_REPLAY_CATALOGUE names it)", root)
	}
	base := orDefault(os.Getenv("MESH_BED_BASE"), "origin/main")
	show := func(ref, path string) ([]byte, error) {
		return exec.Command("git", "-c", "safe.directory=*", "-C", root, "show", ref+":"+path).Output()
	}
	if _, err := exec.Command("git", "-c", "safe.directory=*", "-C", root, "rev-parse", "--verify", base).Output(); err != nil {
		// What changed cannot be told, so every declared check is proved: the bed never passes what it did
		// not look at.
		t.Logf("%s is not in the catalogue at %s (%v): every declared check is proved", base, root, err)
	}
	changed, err := ChangedHealth(root, base, show)
	if err != nil {
		t.Fatal(err)
	}
	if len(changed) == 0 {
		t.Logf("no declared check or image of a long-running resource changed against %s: nothing to prove", base)
		return
	}
	docker, ok := DockerFromEnv()
	if !ok {
		t.Fatalf("%d changed check(s) and no container runtime to prove them on", len(changed))
	}
	ctx, cancel := context.WithTimeout(t.Context(), 30*time.Minute)
	defer cancel()
	for _, r := range changed {
		manifest, _ := os.ReadFile(filepath.Join(root, "modules", r.Module, "module.json"))
		v := docker.Prove(ctx, r, FilesOf(manifest))
		switch {
		case v.Failed:
			t.Errorf("FAILS ON THE BED: %s", v.Said)
		case v.Proved:
			t.Logf("proved: %s", v.Said)
		default:
			t.Logf("NOT PROVED HERE: %s", v.Said)
		}
	}
}

// **R-studio — a check that asks an address the program does not bind fails the bed, not a machine**
// (novox/hq ADR 0240 Phase D, done when). The hosted database suite's studio binds the address the runtime
// puts in HOSTNAME, so it answered only on its network address while its image's own check asked localhost:
// unhealthy for ever while working, until the module set HOSTNAME=0.0.0.0. Adopted by name without proof, it
// would have put back a good build.
//
// The replay is that image in miniature: a web server that binds $HOSTNAME's address, and an image check that
// asks localhost. Adopted as the module declared it before the fix, the bed fails it; with the fix, it proves
// it. The image is built here and removed after, with everything the bed made.
func TestBedFailsTheStudiosFalseUnhealthy(t *testing.T) {
	docker, ok := DockerFromEnv()
	if !ok {
		t.Skip("no container runtime: the studio is a container")
	}
	ctx, cancel := context.WithTimeout(t.Context(), 5*time.Minute)
	defer cancel()
	if err := docker.Pull(ctx, "busybox:1.36"); err != nil {
		t.Fatal(err)
	}
	tag := fmt.Sprintf("mesh-replay-studio:%d", time.Now().UnixNano())
	if err := docker.Build(ctx, tag, StudioDockerfile); err != nil {
		t.Fatal(err)
	}
	defer docker.RemoveImage(context.Background(), tag)
	was := BedFloor
	BedFloor = 15 * time.Second
	defer func() { BedFloor = was }()

	studio := func(env map[string]any) BedResource {
		r := map[string]any{"id": "studio", "type": "container", "name": "supabase-studio", "image": tag,
			"health": map[string]any{"kind": "runtime", "grace": "10s"}}
		if env != nil {
			r["env"] = env
		}
		return BedResource{Module: "supabase", ID: "studio", Resource: r, Listens: map[string]int{}}
	}
	before := docker.Prove(ctx, studio(nil), nil)
	if !before.Failed || !strings.Contains(before.Said, "does not see it") {
		t.Fatalf("the studio's false unhealthy was not failed on the bed: %+v", before)
	}
	t.Logf("before the fix: %s", before.Said)
	after := docker.Prove(ctx, studio(map[string]any{"HOSTNAME": "0.0.0.0"}), nil)
	if !after.Proved {
		t.Fatalf("the studio with HOSTNAME=0.0.0.0 was not proved: %+v", after)
	}
	t.Logf("with the fix: %s", after.Said)
}

// StudioDockerfile is the studio in miniature: it serves on the address HOSTNAME names, and its own check
// asks localhost, as the studio's image does.
const StudioDockerfile = `FROM busybox:1.36
RUN mkdir -p /www && echo studio > /www/index.html
HEALTHCHECK --interval=5s --timeout=2s --retries=2 CMD wget -q -O /dev/null http://localhost:3000/ || exit 1
CMD addr=$(grep -w "$HOSTNAME" /etc/hosts | head -n 1 | cut -f 1); exec httpd -f -p "${addr:-$HOSTNAME}:3000" -h /www
`

// What the bed proves is what the change touches: a long-running container whose declared check or image
// changed, or that is new; never a step, never one left as it was.
func TestTheBedProvesWhatTheChangeTouches(t *testing.T) {
	root := t.TempDir()
	git := func(args ...string) {
		t.Helper()
		cmd := exec.Command("git", append([]string{"-C", root, "-c", "user.email=lab@example", "-c", "user.name=lab"}, args...)...)
		if out, err := cmd.CombinedOutput(); err != nil {
			t.Fatalf("git %v: %v %s", args, err, out)
		}
	}
	write := func(module, body string) {
		t.Helper()
		if err := os.MkdirAll(filepath.Join(root, "modules", module), 0o755); err != nil {
			t.Fatal(err)
		}
		if err := os.WriteFile(filepath.Join(root, "modules", module, "module.json"), []byte(body), 0o644); err != nil {
			t.Fatal(err)
		}
	}
	git("init", "-q", "-b", "main")
	write("web", `{"module":"web","resources":[{"id":"server","type":"container","image":"web@sha256:a","health":{"kind":"runtime"}},
	  {"id":"seed","type":"container","image":"web@sha256:a","run-once":true,"health":{"kind":"runtime"}}]}`)
	write("db", `{"module":"db","resources":[{"id":"server","type":"container","image":"db@sha256:a","health":{"kind":"runtime"}}]}`)
	git("add", "-A")
	git("commit", "-qm", "base")
	write("web", `{"module":"web","resources":[{"id":"server","type":"container","image":"web@sha256:b","health":{"kind":"runtime"}},
	  {"id":"seed","type":"container","image":"web@sha256:b","run-once":true,"health":{"kind":"runtime"}}]}`)
	write("cache", `{"module":"cache","resources":[{"id":"server","type":"container","image":"cache@sha256:a","health":{"kind":"tcp","endpoint":"redis"}},
	  {"id":"plain","type":"container","image":"cache@sha256:a"}]}`)
	show := func(ref, path string) ([]byte, error) {
		return exec.Command("git", "-C", root, "show", ref+":"+path).Output()
	}
	changed, err := ChangedHealth(root, "main", show)
	if err != nil {
		t.Fatal(err)
	}
	var got []string
	for _, r := range changed {
		got = append(got, r.Module+"."+r.ID)
	}
	if strings.Join(got, ",") != "cache.server,web.server" {
		t.Fatalf("the bed would prove %v; want the new module's checked container and the one whose image moved", got)
	}
}