package block

import (
	"context"
	"fmt"
	"io/ioutil"
	"os"
	"reflect"
	"sort"
	"testing"

	"github.com/kopia/kopia/internal/storagetesting"
	"github.com/kopia/kopia/storage"
)

func newUnderlyingStorageForBlockCacheTesting() storage.Storage {
	ctx := context.Background()
	data := map[string][]byte{}
	st := storagetesting.NewMapStorage(data, nil, nil)
	st.PutBlock(ctx, "block-1", []byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 10})
	return st
}

func TestInMemoryBlockCache(t *testing.T) {
	cacheData := map[string][]byte{}
	cacheStorage := storagetesting.NewMapStorage(cacheData, nil, nil)

	cache, err := newBlockCacheWithCacheStorage(context.Background(), newUnderlyingStorageForBlockCacheTesting(), cacheStorage, CachingOptions{
		MaxCacheSizeBytes: 10000,
	})
	if err != nil {
		t.Fatalf("err: %v", err)
	}
	verifyBlockCache(t, cache)
}

func TestDiskBlockCache(t *testing.T) {
	ctx := context.Background()

	tmpDir, err := ioutil.TempDir("", "kopia")
	if err != nil {
		t.Fatalf("error getting temp dir: %v", err)
	}
	defer os.RemoveAll(tmpDir)

	cache, err := newBlockCache(ctx, newUnderlyingStorageForBlockCacheTesting(), CachingOptions{
		MaxCacheSizeBytes: 10000,
		CacheDirectory:    tmpDir,
	})

	if err != nil {
		t.Fatalf("err: %v", err)
	}
	verifyBlockCache(t, cache)
}
func verifyBlockCache(t *testing.T, cache *blockCache) {
	ctx := context.Background()
	defer cache.close()

	t.Run("GetContentBlock", func(t *testing.T) {
		cases := []struct {
			cacheKey        string
			physicalBlockID string
			offset          int64
			length          int64

			expected []byte
			err      error
		}{
			{"xf0f0f1", "block-1", 1, 5, []byte{2, 3, 4, 5, 6}, nil},
			{"xf0f0f2", "block-1", 0, -1, []byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}, nil},
			{"xf0f0f1", "block-1", 1, 5, []byte{2, 3, 4, 5, 6}, nil},
			{"xf0f0f2", "block-1", 0, -1, []byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}, nil},
			{"xf0f0f3", "no-such-block", 0, -1, nil, storage.ErrBlockNotFound},
			{"xf0f0f4", "no-such-block", 10, 5, nil, storage.ErrBlockNotFound},
			{"f0f0f5", "block-1", 7, 10, []byte{8, 9, 10}, nil},
			{"xf0f0f6", "block-1", 11, 10, nil, fmt.Errorf("invalid offset")},
			{"xf0f0f6", "block-1", -1, 5, nil, fmt.Errorf("invalid offset")},
		}

		for _, tc := range cases {
			v, err := cache.getContentBlock(ctx, tc.cacheKey, tc.physicalBlockID, tc.offset, tc.length)
			if !reflect.DeepEqual(err, tc.err) {
				t.Errorf("unexpected error for %v: %+v, wanted %+v", tc.cacheKey, err, tc.err)
			}
			if !reflect.DeepEqual(v, tc.expected) {
				t.Errorf("unexpected data for %v: %x, wanted %x", tc.cacheKey, v, tc.expected)
			}
		}

		verifyStorageBlockList(t, cache.cacheStorage, "f0f0f1x", "f0f0f2x", "f0f0f5")
	})

	t.Run("DataCorruption", func(t *testing.T) {
		cacheKey := "f0f0f1x"
		d, err := cache.cacheStorage.GetBlock(ctx, cacheKey, 0, -1)
		if err != nil {
			t.Fatalf("unable to retrieve data from cache: %v", err)
		}

		// corrupt the data and write back
		d[0] ^= 1

		if err := cache.cacheStorage.PutBlock(ctx, cacheKey, d); err != nil {
			t.Fatalf("unable to write corrupted block: %v", err)
		}

		v, err := cache.getContentBlock(ctx, "xf0f0f1", "block-1", 1, 5)
		if err != nil {
			t.Fatalf("error in getContentBlock: %v", err)
		}
		if got, want := v, []byte{2, 3, 4, 5, 6}; !reflect.DeepEqual(v, want) {
			t.Errorf("invalid result when reading corrupted data: %v, wanted %v", got, want)
		}
	})
}

func verifyStorageBlockList(t *testing.T, st storage.Storage, expectedBlocks ...string) {
	t.Helper()
	var foundBlocks []string
	st.ListBlocks(context.Background(), "", func(bm storage.BlockMetadata) error {
		foundBlocks = append(foundBlocks, bm.BlockID)
		return nil
	})

	sort.Strings(foundBlocks)
	if !reflect.DeepEqual(foundBlocks, expectedBlocks) {
		t.Errorf("unexpected block list: %v, wanted %v", foundBlocks, expectedBlocks)
	}
}