package testsuite

import (
	"context"
	"fmt"
	"io/ioutil"
	"os"
	"path/filepath"
	"testing"
	"time"

	"github.com/containerd/containerd/errdefs"
	"github.com/containerd/containerd/fs/fstest"
	"github.com/containerd/containerd/mount"
	"github.com/containerd/containerd/namespaces"
	"github.com/containerd/containerd/snapshot"
	"github.com/containerd/containerd/testutil"
	"github.com/stretchr/testify/assert"
)

// SnapshotterSuite runs a test suite on the snapshotter given a factory function.
func SnapshotterSuite(t *testing.T, name string, snapshotterFn func(ctx context.Context, root string) (snapshot.Snapshotter, func(), error)) {
	t.Parallel()

	t.Run("Basic", makeTest(name, snapshotterFn, checkSnapshotterBasic))
	t.Run("StatActive", makeTest(name, snapshotterFn, checkSnapshotterStatActive))
	t.Run("StatComitted", makeTest(name, snapshotterFn, checkSnapshotterStatCommitted))
	t.Run("TransitivityTest", makeTest(name, snapshotterFn, checkSnapshotterTransitivity))
	t.Run("PreareViewFailingtest", makeTest(name, snapshotterFn, checkSnapshotterPrepareView))
	t.Run("Update", makeTest(name, snapshotterFn, checkUpdate))
	t.Run("Remove", makeTest(name, snapshotterFn, checkRemove))

	t.Run("LayerFileupdate", makeTest(name, snapshotterFn, checkLayerFileUpdate))
	t.Run("RemoveDirectoryInLowerLayer", makeTest(name, snapshotterFn, checkRemoveDirectoryInLowerLayer))
	t.Run("Chown", makeTest(name, snapshotterFn, checkChown))
	t.Run("DirectoryPermissionOnCommit", makeTest(name, snapshotterFn, checkDirectoryPermissionOnCommit))

	// Rename test still fails on some kernels with overlay
	//t.Run("Rename", makeTest(name, snapshotterFn, checkRename))
}

func makeTest(name string, snapshotterFn func(ctx context.Context, root string) (snapshot.Snapshotter, func(), error), fn func(ctx context.Context, t *testing.T, snapshotter snapshot.Snapshotter, work string)) func(t *testing.T) {
	return func(t *testing.T) {
		ctx := context.Background()
		ctx = namespaces.WithNamespace(ctx, "testsuite")
		restoreMask := clearMask()
		defer restoreMask()
		// Make two directories: a snapshotter root and a play area for the tests:
		//
		// 	/tmp
		// 		work/ -> passed to test functions
		// 		root/ -> passed to snapshotter
		//
		tmpDir, err := ioutil.TempDir("", "snapshot-suite-"+name+"-")
		if err != nil {
			t.Fatal(err)
		}
		defer os.RemoveAll(tmpDir)

		root := filepath.Join(tmpDir, "root")
		if err := os.MkdirAll(root, 0777); err != nil {
			t.Fatal(err)
		}

		snapshotter, cleanup, err := snapshotterFn(ctx, root)
		if err != nil {
			t.Fatal(err)
		}
		defer cleanup()

		work := filepath.Join(tmpDir, "work")
		if err := os.MkdirAll(work, 0777); err != nil {
			t.Fatal(err)
		}

		defer testutil.DumpDir(t, tmpDir)
		fn(ctx, t, snapshotter, work)
	}
}

// checkSnapshotterBasic tests the basic workflow of a snapshot snapshotter.
func checkSnapshotterBasic(ctx context.Context, t *testing.T, snapshotter snapshot.Snapshotter, work string) {
	// TODO: this always fails when run in parallel, why?
	//	t.Parallel()

	initialApplier := fstest.Apply(
		fstest.CreateFile("/foo", []byte("foo\n"), 0777),
		fstest.CreateDir("/a", 0755),
		fstest.CreateDir("/a/b", 0755),
		fstest.CreateDir("/a/b/c", 0755),
	)

	diffApplier := fstest.Apply(
		fstest.CreateFile("/bar", []byte("bar\n"), 0777),
		// also, change content of foo to bar
		fstest.CreateFile("/foo", []byte("bar\n"), 0777),
		fstest.RemoveAll("/a/b"),
	)

	preparing := filepath.Join(work, "preparing")
	if err := os.MkdirAll(preparing, 0777); err != nil {
		t.Fatalf("failure reason: %+v", err)
	}

	mounts, err := snapshotter.Prepare(ctx, preparing, "")
	if err != nil {
		t.Fatalf("failure reason: %+v", err)
	}

	if len(mounts) < 1 {
		t.Fatal("expected mounts to have entries")
	}

	if err := mount.MountAll(mounts, preparing); err != nil {
		t.Fatalf("failure reason: %+v", err)
	}
	defer testutil.Unmount(t, preparing)

	if err := initialApplier.Apply(preparing); err != nil {
		t.Fatalf("failure reason: %+v", err)
	}

	committed := filepath.Join(work, "committed")
	if err := snapshotter.Commit(ctx, committed, preparing); err != nil {
		t.Fatalf("failure reason: %+v", err)
	}

	si, err := snapshotter.Stat(ctx, committed)
	if err != nil {
		t.Fatalf("failure reason: %+v", err)
	}

	assert.Equal(t, "", si.Parent)
	assert.Equal(t, snapshot.KindCommitted, si.Kind)

	next := filepath.Join(work, "nextlayer")
	if err := os.MkdirAll(next, 0777); err != nil {
		t.Fatalf("failure reason: %+v", err)
	}

	mounts, err = snapshotter.Prepare(ctx, next, committed)
	if err != nil {
		t.Fatalf("failure reason: %+v", err)
	}
	if err := mount.MountAll(mounts, next); err != nil {
		t.Fatalf("failure reason: %+v", err)
	}
	defer testutil.Unmount(t, next)

	if err := fstest.CheckDirectoryEqualWithApplier(next, initialApplier); err != nil {
		t.Fatalf("failure reason: %+v", err)
	}

	if err := diffApplier.Apply(next); err != nil {
		t.Fatalf("failure reason: %+v", err)
	}

	ni, err := snapshotter.Stat(ctx, next)
	if err != nil {
		t.Fatal(err)
	}

	assert.Equal(t, committed, ni.Parent)
	assert.Equal(t, snapshot.KindActive, ni.Kind)

	nextCommitted := filepath.Join(work, "committed-next")
	if err := snapshotter.Commit(ctx, nextCommitted, next); err != nil {
		t.Fatalf("failure reason: %+v", err)
	}

	si2, err := snapshotter.Stat(ctx, nextCommitted)
	if err != nil {
		t.Fatalf("failure reason: %+v", err)
	}

	assert.Equal(t, committed, si2.Parent)
	assert.Equal(t, snapshot.KindCommitted, si2.Kind)

	expected := map[string]snapshot.Info{
		si.Name:  si,
		si2.Name: si2,
	}
	walked := map[string]snapshot.Info{} // walk is not ordered
	assert.NoError(t, snapshotter.Walk(ctx, func(ctx context.Context, si snapshot.Info) error {
		walked[si.Name] = si
		return nil
	}))

	assert.Equal(t, expected, walked)

	nextnext := filepath.Join(work, "nextnextlayer")
	if err := os.MkdirAll(nextnext, 0777); err != nil {
		t.Fatalf("failure reason: %+v", err)
	}

	mounts, err = snapshotter.View(ctx, nextnext, nextCommitted)
	if err != nil {
		t.Fatalf("failure reason: %+v", err)
	}
	if err := mount.MountAll(mounts, nextnext); err != nil {
		t.Fatalf("failure reason: %+v", err)
	}

	if err := fstest.CheckDirectoryEqualWithApplier(nextnext,
		fstest.Apply(initialApplier, diffApplier)); err != nil {
		testutil.Unmount(t, nextnext)
		t.Fatalf("failure reason: %+v", err)
	}

	testutil.Unmount(t, nextnext)
	assert.NoError(t, snapshotter.Remove(ctx, nextnext))
	assert.Error(t, snapshotter.Remove(ctx, committed))
	assert.NoError(t, snapshotter.Remove(ctx, nextCommitted))
	assert.NoError(t, snapshotter.Remove(ctx, committed))
}

// Create a New Layer on top of base layer with Prepare, Stat on new layer, should return Active layer.
func checkSnapshotterStatActive(ctx context.Context, t *testing.T, snapshotter snapshot.Snapshotter, work string) {
	t.Parallel()

	preparing := filepath.Join(work, "preparing")
	if err := os.MkdirAll(preparing, 0777); err != nil {
		t.Fatal(err)
	}

	mounts, err := snapshotter.Prepare(ctx, preparing, "")
	if err != nil {
		t.Fatal(err)
	}

	if len(mounts) < 1 {
		t.Fatal("expected mounts to have entries")
	}

	if err = mount.MountAll(mounts, preparing); err != nil {
		t.Fatal(err)
	}
	defer testutil.Unmount(t, preparing)

	if err = ioutil.WriteFile(filepath.Join(preparing, "foo"), []byte("foo\n"), 0777); err != nil {
		t.Fatal(err)
	}

	si, err := snapshotter.Stat(ctx, preparing)
	if err != nil {
		t.Fatal(err)
	}
	assert.Equal(t, si.Name, preparing)
	assert.Equal(t, snapshot.KindActive, si.Kind)
	assert.Equal(t, "", si.Parent)
}

// Commit a New Layer on top of base layer with Prepare & Commit , Stat on new layer, should return Committed layer.
func checkSnapshotterStatCommitted(ctx context.Context, t *testing.T, snapshotter snapshot.Snapshotter, work string) {
	t.Parallel()

	preparing := filepath.Join(work, "preparing")
	if err := os.MkdirAll(preparing, 0777); err != nil {
		t.Fatal(err)
	}

	mounts, err := snapshotter.Prepare(ctx, preparing, "")
	if err != nil {
		t.Fatal(err)
	}

	if len(mounts) < 1 {
		t.Fatal("expected mounts to have entries")
	}

	if err = mount.MountAll(mounts, preparing); err != nil {
		t.Fatal(err)
	}
	defer testutil.Unmount(t, preparing)

	if err = ioutil.WriteFile(filepath.Join(preparing, "foo"), []byte("foo\n"), 0777); err != nil {
		t.Fatal(err)
	}

	committed := filepath.Join(work, "committed")
	if err = snapshotter.Commit(ctx, committed, preparing); err != nil {
		t.Fatal(err)
	}

	si, err := snapshotter.Stat(ctx, committed)
	if err != nil {
		t.Fatal(err)
	}
	assert.Equal(t, si.Name, committed)
	assert.Equal(t, snapshot.KindCommitted, si.Kind)
	assert.Equal(t, "", si.Parent)

}

func snapshotterPrepareMount(ctx context.Context, snapshotter snapshot.Snapshotter, diffPathName string, parent string, work string) (string, error) {
	preparing := filepath.Join(work, diffPathName)
	if err := os.MkdirAll(preparing, 0777); err != nil {
		return "", err
	}

	mounts, err := snapshotter.Prepare(ctx, preparing, parent)
	if err != nil {
		return "", err
	}

	if len(mounts) < 1 {
		return "", fmt.Errorf("expected mounts to have entries")
	}

	if err = mount.MountAll(mounts, preparing); err != nil {
		return "", err
	}
	return preparing, nil
}

// Given A <- B <- C, B is the parent of C and A is a transitive parent of C (in this case, a "grandparent")
func checkSnapshotterTransitivity(ctx context.Context, t *testing.T, snapshotter snapshot.Snapshotter, work string) {
	t.Parallel()

	preparing, err := snapshotterPrepareMount(ctx, snapshotter, "preparing", "", work)
	if err != nil {
		t.Fatal(err)
	}
	defer testutil.Unmount(t, preparing)

	if err = ioutil.WriteFile(filepath.Join(preparing, "foo"), []byte("foo\n"), 0777); err != nil {
		t.Fatal(err)
	}

	snapA := filepath.Join(work, "snapA")
	if err = snapshotter.Commit(ctx, snapA, preparing); err != nil {
		t.Fatal(err)
	}

	next, err := snapshotterPrepareMount(ctx, snapshotter, "next", snapA, work)
	if err != nil {
		t.Fatal(err)
	}
	defer testutil.Unmount(t, next)

	if err = ioutil.WriteFile(filepath.Join(next, "foo"), []byte("foo bar\n"), 0777); err != nil {
		t.Fatal(err)
	}

	snapB := filepath.Join(work, "snapB")
	if err = snapshotter.Commit(ctx, snapB, next); err != nil {
		t.Fatal(err)
	}

	siA, err := snapshotter.Stat(ctx, snapA)
	if err != nil {
		t.Fatal(err)
	}

	siB, err := snapshotter.Stat(ctx, snapB)
	if err != nil {
		t.Fatal(err)
	}

	siParentB, err := snapshotter.Stat(ctx, siB.Parent)
	if err != nil {
		t.Fatal(err)
	}

	// Test the transivity
	assert.Equal(t, "", siA.Parent)
	assert.Equal(t, snapA, siB.Parent)
	assert.Equal(t, "", siParentB.Parent)

}

// Creating two layers with Prepare or View with same key must fail.
func checkSnapshotterPrepareView(ctx context.Context, t *testing.T, snapshotter snapshot.Snapshotter, work string) {
	t.Parallel()

	preparing, err := snapshotterPrepareMount(ctx, snapshotter, "preparing", "", work)
	if err != nil {
		t.Fatal(err)
	}
	defer testutil.Unmount(t, preparing)

	snapA := filepath.Join(work, "snapA")
	if err = snapshotter.Commit(ctx, snapA, preparing); err != nil {
		t.Fatal(err)
	}

	// Prepare & View with same key
	newLayer := filepath.Join(work, "newlayer")
	if err = os.MkdirAll(preparing, 0777); err != nil {
		t.Fatal(err)
	}

	// Prepare & View with same key
	_, err = snapshotter.Prepare(ctx, newLayer, snapA)
	if err != nil {
		t.Fatal(err)
	}

	_, err = snapshotter.View(ctx, newLayer, snapA)
	//must be err != nil
	assert.NotNil(t, err)

	// Two Prepare with same key
	prepLayer := filepath.Join(work, "prepLayer")
	if err = os.MkdirAll(preparing, 0777); err != nil {
		t.Fatal(err)
	}

	_, err = snapshotter.Prepare(ctx, prepLayer, snapA)
	if err != nil {
		t.Fatal(err)
	}

	_, err = snapshotter.Prepare(ctx, prepLayer, snapA)
	//must be err != nil
	assert.NotNil(t, err)

	// Two View with same key
	viewLayer := filepath.Join(work, "viewLayer")
	if err = os.MkdirAll(preparing, 0777); err != nil {
		t.Fatal(err)
	}

	_, err = snapshotter.View(ctx, viewLayer, snapA)
	if err != nil {
		t.Fatal(err)
	}

	_, err = snapshotter.View(ctx, viewLayer, snapA)
	//must be err != nil
	assert.NotNil(t, err)

}

// baseTestSnapshots creates a base set of snapshots for tests, each snapshot is empty
// Tests snapshots:
//  c1 - committed snapshot, no parent
//  c2 - commited snapshot, c1 is parent
//  a1 - active snapshot, c2 is parent
//  a1 - active snapshot, no parent
//  v1 - view snapshot, v1 is parent
//  v2 - view snapshot, no parent
func baseTestSnapshots(ctx context.Context, snapshotter snapshot.Snapshotter) error {
	if _, err := snapshotter.Prepare(ctx, "c1-a", ""); err != nil {
		return err
	}
	if err := snapshotter.Commit(ctx, "c1", "c1-a"); err != nil {
		return err
	}
	if _, err := snapshotter.Prepare(ctx, "c2-a", "c1"); err != nil {
		return err
	}
	if err := snapshotter.Commit(ctx, "c2", "c2-a"); err != nil {
		return err
	}
	if _, err := snapshotter.Prepare(ctx, "a1", "c2"); err != nil {
		return err
	}
	if _, err := snapshotter.Prepare(ctx, "a2", ""); err != nil {
		return err
	}
	if _, err := snapshotter.View(ctx, "v1", "c2"); err != nil {
		return err
	}
	if _, err := snapshotter.View(ctx, "v2", ""); err != nil {
		return err
	}
	return nil
}

func checkUpdate(ctx context.Context, t *testing.T, snapshotter snapshot.Snapshotter, work string) {
	t.Parallel()

	t1 := time.Now().UTC()
	if err := baseTestSnapshots(ctx, snapshotter); err != nil {
		t.Fatalf("Failed to create base snapshots: %v", err)
	}
	t2 := time.Now().UTC()
	testcases := []struct {
		name   string
		kind   snapshot.Kind
		parent string
	}{
		{
			name: "c1",
			kind: snapshot.KindCommitted,
		},
		{
			name:   "c2",
			kind:   snapshot.KindCommitted,
			parent: "c1",
		},
		{
			name:   "a1",
			kind:   snapshot.KindActive,
			parent: "c2",
		},
		{
			name: "a2",
			kind: snapshot.KindActive,
		},
		{
			name:   "v1",
			kind:   snapshot.KindView,
			parent: "c2",
		},
		{
			name: "v2",
			kind: snapshot.KindView,
		},
	}
	for _, tc := range testcases {
		st, err := snapshotter.Stat(ctx, tc.name)
		if err != nil {
			t.Fatalf("Failed to stat %s: %v", tc.name, err)
		}
		if st.Created.Before(t1) || st.Created.After(t2) {
			t.Errorf("(%s) wrong created time %s: expected between %s and %s", tc.name, st.Created, t1, t2)
			continue
		}
		if st.Created != st.Updated {
			t.Errorf("(%s) unexpected updated time %s: expected %s", tc.name, st.Updated, st.Created)
			continue
		}
		if st.Kind != tc.kind {
			t.Errorf("(%s) unexpected kind %s, expected %s", tc.name, st.Kind, tc.kind)
			continue
		}
		if st.Parent != tc.parent {
			t.Errorf("(%s) unexpected parent %q, expected %q", tc.name, st.Parent, tc.parent)
			continue
		}
		if st.Name != tc.name {
			t.Errorf("(%s) unexpected name %q, expected %q", tc.name, st.Name, tc.name)
			continue
		}

		createdAt := st.Created
		expected := map[string]string{
			"l1": "v1",
			"l2": "v2",
			"l3": "v3",
		}
		st.Parent = "doesnotexist"
		st.Labels = expected
		u1 := time.Now().UTC()
		st, err = snapshotter.Update(ctx, st)
		if err != nil {
			t.Fatalf("Failed to update %s: %v", tc.name, err)
		}
		u2 := time.Now().UTC()

		if st.Created != createdAt {
			t.Errorf("(%s) wrong created time %s: expected %s", tc.name, st.Created, createdAt)
			continue
		}
		if st.Updated.Before(u1) || st.Updated.After(u2) {
			t.Errorf("(%s) wrong updated time %s: expected between %s and %s", tc.name, st.Updated, u1, u2)
			continue
		}
		if st.Kind != tc.kind {
			t.Errorf("(%s) unexpected kind %s, expected %s", tc.name, st.Kind, tc.kind)
			continue
		}
		if st.Parent != tc.parent {
			t.Errorf("(%s) unexpected parent %q, expected %q", tc.name, st.Parent, tc.parent)
			continue
		}
		if st.Name != tc.name {
			t.Errorf("(%s) unexpected name %q, expected %q", tc.name, st.Name, tc.name)
			continue
		}
		assertLabels(t, st.Labels, expected)

		expected = map[string]string{
			"l1": "updated",
			"l3": "v3",
		}
		st.Labels = map[string]string{
			"l1": "updated",
			"l4": "v4",
		}
		st, err = snapshotter.Update(ctx, st, "labels.l1", "labels.l2")
		if err != nil {
			t.Fatalf("Failed to update %s: %v", tc.name, err)
		}
		assertLabels(t, st.Labels, expected)

		expected = map[string]string{
			"l4": "v4",
		}
		st.Labels = expected
		st, err = snapshotter.Update(ctx, st, "labels")
		if err != nil {
			t.Fatalf("Failed to update %s: %v", tc.name, err)
		}
		assertLabels(t, st.Labels, expected)

		// Test failure received when providing immutable field path
		st.Parent = "doesnotexist"
		st, err = snapshotter.Update(ctx, st, "parent")
		if err == nil {
			t.Errorf("Expected error updating with immutable field path")
		} else if !errdefs.IsInvalidArgument(err) {
			t.Fatalf("Unexpected error updating %s: %+v", tc.name, err)
		}
	}
}

func assertLabels(t *testing.T, actual, expected map[string]string) {
	if len(actual) != len(expected) {
		t.Fatalf("Label size mismatch: %d vs %d\n\tActual: %#v\n\tExpected: %#v", len(actual), len(expected), actual, expected)
	}
	for k, v := range expected {
		if a := actual[k]; v != a {
			t.Errorf("Wrong label value for %s, got %q, expected %q", k, a, v)
		}
	}
	if t.Failed() {
		t.FailNow()
	}
}

func checkRemove(ctx context.Context, t *testing.T, snapshotter snapshot.Snapshotter, work string) {
	t.Parallel()

	if _, err := snapshotter.Prepare(ctx, "committed-a", ""); err != nil {
		t.Fatal(err)
	}
	if err := snapshotter.Commit(ctx, "committed-1", "committed-a"); err != nil {
		t.Fatal(err)
	}
	if _, err := snapshotter.Prepare(ctx, "reuse-1", "committed-1"); err != nil {
		t.Fatal(err)
	}
	if err := snapshotter.Remove(ctx, "reuse-1"); err != nil {
		t.Fatal(err)
	}
	if _, err := snapshotter.View(ctx, "reuse-1", "committed-1"); err != nil {
		t.Fatal(err)
	}
	if err := snapshotter.Remove(ctx, "reuse-1"); err != nil {
		t.Fatal(err)
	}
	if _, err := snapshotter.Prepare(ctx, "reuse-1", ""); err != nil {
		t.Fatal(err)
	}
	if err := snapshotter.Remove(ctx, "committed-1"); err != nil {
		t.Fatal(err)
	}
	if err := snapshotter.Commit(ctx, "commited-1", "reuse-1"); err != nil {
		t.Fatal(err)
	}
}