package osupdate

import (
	"context"
	"crypto/sha256"
	"encoding/base64"
	"encoding/hex"
	"encoding/json"
	"errors"
	"io"
	"net/http"
	"net/http/httptest"
	"os"
	"strings"
	"testing"

	"gitea.dooplex.hu/admin/felhom-agent/internal/reconcile"
	"gitea.dooplex.hu/admin/felhom-agent/internal/signedjobs"
)

// bundleWrapper plays felhom-os-apply for mode "bundle": it records the plan and the bundle file's bytes AT CALL TIME
// (the executor deletes the file afterwards), and answers with rep.
type bundleWrapper struct {
	t      *testing.T
	rep    string
	plans  []map[string]any
	bodies [][]byte
}

func (b *bundleWrapper) Run(_ context.Context, name string, args ...string) ([]byte, []byte, error) {
	if name != WrapperPath || len(args) != 2 || args[0] != "--plan" {
		b.t.Fatalf("unexpected command %s %v", name, args)
	}
	raw, err := os.ReadFile(args[1])
	if err != nil {
		b.t.Fatal(err)
	}
	var plan map[string]any
	_ = json.Unmarshal(raw, &plan)
	b.plans = append(b.plans, plan)
	body, _ := os.ReadFile(plan["bundle"].(string))
	b.bodies = append(b.bodies, body)
	return []byte("OSAPPLY-REPORT " + b.rep + "\n"), nil, nil
}

func serveBundle(t *testing.T, body []byte) (*httptest.Server, string) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != "/felhom-agent/0.143.0/"+BundleFileName {
			http.NotFound(w, r)
			return
		}
		_, _ = w.Write(body)
	}))
	t.Cleanup(srv.Close)
	sum := sha256.Sum256(body)
	return srv, hex.EncodeToString(sum[:])
}

func bundleExec(t *testing.T, w *bundleWrapper, srvURL string) (ConfigUpdateExecutor, *bool) {
	l, _ := newLeg(t, &fakeWrapper{t: t}, nil)
	l.Runner = w
	called := false
	return ConfigUpdateExecutor{Leg: l, URLTemplate: srvURL + "/felhom-agent/{version}/felhom-agent",
		AfterInstall: func(context.Context) { called = true }}, &called
}

func signedCtx() context.Context {
	return signedjobs.WithSignedOp(context.Background(), &reconcile.SignedOp{Blob: []byte(`{"op":"agent_config_update"}`), Sig: []byte("SIG")})
}

func params(v, sha string) json.RawMessage {
	p, _ := json.Marshal(ConfigUpdateParams{AgentVersion: v, BundleSHA256: sha})
	return p
}

// The courier hands the wrapper the bundle bytes it downloaded and the RAW signed envelope (the wrapper verifies both
// itself), then runs the capability probe. Red-proof: drop "signed" from the plan → the plan check below fails.
func TestConfigUpdate_PassesBundleAndEnvelopeToTheWrapper(t *testing.T) {
	body := []byte(`{"format":1,"agent_version":"0.143.0","files":[]}`)
	srv, sha := serveBundle(t, body)
	w := &bundleWrapper{t: t, rep: `{"mode":"bundle","bundle":{"agent_version":"0.143.0","written":["/etc/sudoers.d/felhom-agent"]}}`}
	e, called := bundleExec(t, w, srv.URL)
	if err := e.Execute(signedCtx(), OpConfigUpdate, params("0.143.0", sha)); err != nil {
		t.Fatal(err)
	}
	p := w.plans[0]
	sg, _ := p["signed"].(map[string]any)
	if p["mode"] != "bundle" || p["layer"] != "host" || sg == nil || sg["sig"] != "SIG" ||
		sg["blob_b64"] != base64.StdEncoding.EncodeToString([]byte(`{"op":"agent_config_update"}`)) {
		t.Fatalf("plan = %v", p)
	}
	if string(w.bodies[0]) != string(body) || !strings.HasSuffix(p["bundle"].(string), "/bundle-0.143.0.json") {
		t.Fatalf("the wrapper got %q at %v", w.bodies[0], p["bundle"])
	}
	if !*called {
		t.Fatal("the capability probe must run after an install")
	}
	if _, err := os.Stat(p["bundle"].(string)); !os.IsNotExist(err) {
		t.Fatal("the downloaded bundle must be removed after the call")
	}
}

func TestConfigUpdate_WrongShaNeverReachesTheWrapper(t *testing.T) {
	srv, _ := serveBundle(t, []byte("tampered"))
	w := &bundleWrapper{t: t}
	e, called := bundleExec(t, w, srv.URL)
	err := e.Execute(signedCtx(), OpConfigUpdate, params("0.143.0", strings.Repeat("a", 64)))
	if err == nil || len(w.plans) != 0 || *called {
		t.Fatalf("err=%v plans=%d", err, len(w.plans))
	}
}

func TestConfigUpdate_RefusedAndFailedAreErrors(t *testing.T) {
	for _, rep := range []string{`{"refused":{"code":"R17","reason":"trust root"}}`, `{"failed":{"rc":3},"bundle":{"rolled_back":["/x"]}}`} {
		srv, sha := serveBundle(t, []byte("{}"))
		w := &bundleWrapper{t: t, rep: rep}
		e, called := bundleExec(t, w, srv.URL)
		if err := e.Execute(signedCtx(), OpConfigUpdate, params("0.143.0", sha)); err == nil || *called {
			t.Fatalf("%s: err=%v called=%v", rep, err, *called)
		}
	}
}

func TestConfigUpdate_GuardsBeforeAnyDownload(t *testing.T) {
	w := &bundleWrapper{t: t}
	e, _ := bundleExec(t, w, "http://127.0.0.1:1")
	if err := e.Execute(signedCtx(), "agent_update", nil); !errors.Is(err, signedjobs.ErrNoExecutor) {
		t.Fatalf("another op must pass through the chain: %v", err)
	}
	if err := e.Execute(context.Background(), OpConfigUpdate, params("0.143.0", strings.Repeat("a", 64))); err == nil {
		t.Fatal("no envelope must refuse")
	}
	for _, p := range []json.RawMessage{params("0.143", strings.Repeat("a", 64)), params("0.143.0", "ABC"), json.RawMessage(`nope`)} {
		if err := e.Execute(signedCtx(), OpConfigUpdate, p); err == nil {
			t.Fatalf("bad params %s must refuse", p)
		}
	}
	if len(w.plans) != 0 {
		t.Fatal("no wrapper call on a refusal")
	}
}

func TestBundleURL(t *testing.T) {
	u, err := BundleURL("https://gitea.dooplex.hu/api/packages/admin/generic/felhom-agent/{version}/felhom-agent", "0.143.0")
	if err != nil || u != "https://gitea.dooplex.hu/api/packages/admin/generic/felhom-agent/0.143.0/felhom-config-bundle.json" {
		t.Fatalf("%s %v", u, err)
	}
	if _, err := BundleURL("https://example/felhom-agent-{version}.bin", "0.143.0"); err == nil {
		t.Fatal("an underivable template must refuse")
	}
}

func (b *bundleWrapper) RunStdin(ctx context.Context, _ io.Reader, name string, args ...string) ([]byte, []byte, error) {
	return b.Run(ctx, name, args...)
}