package paths

import (
	"encoding/json"
	"os"
	"path/filepath"
	"testing"

	"banger/internal/runtimebundle"
)

func TestResolveRuntimeDirPrefersEnv(t *testing.T) {
	t.Setenv("BANGER_RUNTIME_DIR", "/env/runtime")

	if got := ResolveRuntimeDir("/config/runtime", "/deprecated/repo"); got != "/env/runtime" {
		t.Fatalf("ResolveRuntimeDir() = %q, want /env/runtime", got)
	}
}

func TestResolveRuntimeDirUsesInstalledLayout(t *testing.T) {
	root := t.TempDir()
	runtimeDir := filepath.Join(root, "lib", "banger")
	createRuntimeBundle(t, runtimeDir)

	origExecutablePath := executablePath
	executablePath = func() (string, error) {
		return filepath.Join(root, "bin", "banger"), nil
	}
	t.Cleanup(func() {
		executablePath = origExecutablePath
	})

	if got := ResolveRuntimeDir("", ""); got != runtimeDir {
		t.Fatalf("ResolveRuntimeDir() = %q, want %q", got, runtimeDir)
	}
}

func TestResolveRuntimeDirUsesBuildRuntimeForSourceCheckoutBinary(t *testing.T) {
	root := t.TempDir()
	runtimeDir := filepath.Join(root, "build", "runtime")
	createRuntimeBundle(t, runtimeDir)

	origExecutablePath := executablePath
	executablePath = func() (string, error) {
		return filepath.Join(root, "banger"), nil
	}
	t.Cleanup(func() {
		executablePath = origExecutablePath
	})

	if got := ResolveRuntimeDir("", ""); got != runtimeDir {
		t.Fatalf("ResolveRuntimeDir() = %q, want %q", got, runtimeDir)
	}
}

func TestResolveRuntimeDirUsesBuildRuntimeForBuildBinExecutable(t *testing.T) {
	root := t.TempDir()
	runtimeDir := filepath.Join(root, "build", "runtime")
	createRuntimeBundle(t, runtimeDir)

	origExecutablePath := executablePath
	executablePath = func() (string, error) {
		return filepath.Join(root, "build", "bin", "banger"), nil
	}
	t.Cleanup(func() {
		executablePath = origExecutablePath
	})

	if got := ResolveRuntimeDir("", ""); got != runtimeDir {
		t.Fatalf("ResolveRuntimeDir() = %q, want %q", got, runtimeDir)
	}
}

func createRuntimeBundle(t *testing.T, runtimeDir string) {
	t.Helper()
	metadata := runtimebundle.BundleMetadata{
		FirecrackerBin:  "bin/firecracker",
		SSHKeyPath:      "keys/id_ed25519",
		NamegenPath:     "bin/namegen",
		CustomizeScript: "scripts/customize.sh",
		VSockAgentPath:  "bin/banger-vsock-agent",
		DefaultPackages: "config/packages.apt",
		DefaultRootfs:   "images/rootfs-docker.ext4",
		DefaultKernel:   "kernels/vmlinux",
	}
	for _, rel := range []string{
		metadata.FirecrackerBin,
		metadata.SSHKeyPath,
		metadata.NamegenPath,
		metadata.CustomizeScript,
		metadata.VSockAgentPath,
		metadata.DefaultPackages,
		metadata.DefaultRootfs,
		metadata.DefaultKernel,
	} {
		path := filepath.Join(runtimeDir, rel)
		if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
			t.Fatalf("mkdir %s: %v", filepath.Dir(path), err)
		}
		if err := os.WriteFile(path, []byte("test"), 0o644); err != nil {
			t.Fatalf("write %s: %v", path, err)
		}
	}
	data, err := json.Marshal(metadata)
	if err != nil {
		t.Fatalf("Marshal: %v", err)
	}
	if err := os.WriteFile(filepath.Join(runtimeDir, runtimebundle.BundleMetadataFile), data, 0o644); err != nil {
		t.Fatalf("write bundle metadata: %v", err)
	}
}