package localapi

import (
	"context"
	"io"
	"os"
	"path/filepath"
	"testing"
)

// R-861 (agent v0.146.0): the shared-parent boot script and unit arrive with the signed config bundle; the agent never
// installs them. It checks them and enables the unit when nothing has.
//
// RED-PROOF (audits/hub-safety-2026-10-05/partF/red-proof.txt): put the old installSharedParentUnit call back (an
// `install` of a /tmp file) → TestSharedParentBoot_NeverInstalls fails.

type callRecorder struct{ calls [][]string }

func (r *callRecorder) Run(_ context.Context, name string, args ...string) ([]byte, []byte, error) {
	r.calls = append(r.calls, append([]string{name}, args...))
	return nil, nil, nil
}

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

func bootFiles(t *testing.T, script, unit string) (string, string, string) {
	t.Helper()
	d := t.TempDir()
	sp, up := filepath.Join(d, "felhom-shared-parent.sh"), filepath.Join(d, "felhom-shared-parent.service")
	if script != "" {
		_ = os.WriteFile(sp, []byte(script), 0o755)
	}
	if unit != "" {
		_ = os.WriteFile(up, []byte(unit), 0o644)
	}
	return sp, up, filepath.Join(d, "wants-link")
}

func TestSharedParentBoot_NeverInstalls(t *testing.T) {
	for _, c := range []struct{ name, script, unit string }{
		{"both missing", "", ""},
		{"script differs", "#!/bin/sh\necho old\n", sharedParentUnit},
		{"unit missing", sharedParentScript, ""},
	} {
		r := &callRecorder{}
		b := NewGuestBinder(r, nil)
		sp, up, link := bootFiles(t, c.script, c.unit)
		if err := b.ensureSharedParentBoot(context.Background(), up, sp, link); err == nil {
			t.Errorf("%s: no error — the operator would not learn the bundle is missing", c.name)
		}
		if len(r.calls) != 0 {
			t.Errorf("%s: the agent ran %v — it must install nothing (R-861)", c.name, r.calls)
		}
	}
}

func TestSharedParentBoot_EnablesOnceTheBundleBroughtTheFiles(t *testing.T) {
	r := &callRecorder{}
	b := NewGuestBinder(r, nil)
	sp, up, link := bootFiles(t, sharedParentScript, sharedParentUnit)
	if err := b.ensureSharedParentBoot(context.Background(), up, sp, link); err != nil {
		t.Fatal(err)
	}
	if len(r.calls) != 1 || len(r.calls[0]) != 3 || r.calls[0][0] != "systemctl" || r.calls[0][1] != "enable" ||
		r.calls[0][2] != "felhom-shared-parent.service" {
		t.Fatalf("want exactly `systemctl enable felhom-shared-parent.service`, got %v", r.calls)
	}
	_ = os.Symlink(up, link)
	r.calls = nil
	if err := b.ensureSharedParentBoot(context.Background(), up, sp, link); err != nil || len(r.calls) != 0 {
		t.Fatalf("already enabled: want no calls, got %v (%v)", r.calls, err)
	}
}

// The bundle's copies are byte-identical to the constants the agent compares against.
func TestSharedParentFilesEqualTheBundle(t *testing.T) {
	for file, want := range map[string]string{"felhom-shared-parent.sh": sharedParentScript, "felhom-shared-parent.service": sharedParentUnit} {
		got, err := os.ReadFile(filepath.Join("..", "..", "configs", file))
		if err != nil || string(got) != want {
			t.Errorf("configs/%s differs from the agent's constant (err %v)", file, err)
		}
	}
}