// Copyright 2016 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <memory>

#include <lib/callback/capture.h>
#include <lib/callback/set_when_called.h>
#include <lib/fxl/files/directory.h>
#include <lib/fxl/files/path.h>
#include <lib/fxl/macros.h>
#include <lib/fxl/strings/string_number_conversions.h>

#include "gtest/gtest.h"
#include "peridot/bin/ledger/filesystem/detached_path.h"
#include "peridot/bin/ledger/storage/impl/leveldb_factory.h"
#include "peridot/bin/ledger/testing/test_with_environment.h"
#include "peridot/lib/scoped_tmpfs/scoped_tmpfs.h"

namespace storage {
namespace {

class LevelDbFactoryTest : public ledger::TestWithEnvironment {
 public:
  LevelDbFactoryTest()
      : base_path_(tmpfs_.root_fd()),
        cache_path_(base_path_.SubPath("cache")),
        db_path_(base_path_.SubPath("databases")),
        db_factory_(&environment_, cache_path_) {}

  ~LevelDbFactoryTest() override {}

  // ledger::TestWithEnvironment:
  void SetUp() override {
    ledger::TestWithEnvironment::SetUp();

    ASSERT_TRUE(
        files::CreateDirectoryAt(cache_path_.root_fd(), cache_path_.path()));
    ASSERT_TRUE(files::CreateDirectoryAt(db_path_.root_fd(), db_path_.path()));

    db_factory_.Init();
    RunLoopUntilIdle();
  }

 private:
  scoped_tmpfs::ScopedTmpFS tmpfs_;
  ledger::DetachedPath base_path_;

 protected:
  ledger::DetachedPath cache_path_;
  ledger::DetachedPath db_path_;
  LevelDbFactory db_factory_;

  FXL_DISALLOW_COPY_AND_ASSIGN(LevelDbFactoryTest);
};

TEST_F(LevelDbFactoryTest, GetOrCreateDb) {
  // Create a new instance.
  Status status;
  std::unique_ptr<Db> db;
  bool called;
  db_factory_.GetOrCreateDb(
      db_path_.SubPath("db"), DbFactory::OnDbNotFound::CREATE,
      callback::Capture(callback::SetWhenCalled(&called), &status, &db));
  RunLoopUntilIdle();
  ASSERT_TRUE(called);
  EXPECT_EQ(Status::OK, status);
  EXPECT_NE(nullptr, db);
  // Write one key-value pair.
  RunInCoroutine([&](coroutine::CoroutineHandler* handler) {
    std::unique_ptr<Db::Batch> batch;
    EXPECT_EQ(Status::OK, db->StartBatch(handler, &batch));
    EXPECT_EQ(Status::OK, batch->Put(handler, "key", "value"));
    EXPECT_EQ(Status::OK, batch->Execute(handler));
  });

  // Close the previous instance and open it again.
  db.reset();
  db_factory_.GetOrCreateDb(
      db_path_.SubPath("db"), DbFactory::OnDbNotFound::RETURN,
      callback::Capture(callback::SetWhenCalled(&called), &status, &db));
  RunLoopUntilIdle();
  ASSERT_TRUE(called);
  EXPECT_EQ(Status::OK, status);
  EXPECT_NE(nullptr, db);
  // Expect to find the previously written key-value pair.
  RunInCoroutine([&](coroutine::CoroutineHandler* handler) {
    std::string value;
    EXPECT_EQ(Status::OK, db->Get(handler, "key", &value));
    EXPECT_EQ("value", value);
  });
}

TEST_F(LevelDbFactoryTest, GetDbOnNotFound) {
  // Try to get a non existing Db and expect a |NOT_FOUND| status.
  Status status;
  std::unique_ptr<Db> db;
  bool called;
  db_factory_.GetOrCreateDb(
      db_path_.SubPath("db"), DbFactory::OnDbNotFound::RETURN,
      callback::Capture(callback::SetWhenCalled(&called), &status, &db));
  RunLoopUntilIdle();
  ASSERT_TRUE(called);
  EXPECT_EQ(Status::NOT_FOUND, status);
  EXPECT_EQ(nullptr, db);
}

TEST_F(LevelDbFactoryTest, CreateMultipleDbs) {
  int N = 5;
  Status status;
  std::unique_ptr<Db> db;
  bool called;

  // Create N LevelDb instances, one after the other. All of them will use the
  // existing cached instance and then, initialize the creation of a new one.
  for (int i = 0; i < N; ++i) {
    ledger::DetachedPath path = db_path_.SubPath(fxl::NumberToString(i));
    EXPECT_FALSE(files::IsDirectoryAt(path.root_fd(), path.path()));

    db_factory_.GetOrCreateDb(
        path, DbFactory::OnDbNotFound::CREATE,
        callback::Capture(callback::SetWhenCalled(&called), &status, &db));
    RunLoopUntilIdle();
    EXPECT_TRUE(called);
    EXPECT_EQ(Status::OK, status);
    EXPECT_NE(nullptr, db);
    // Check that the directory was created.
    EXPECT_TRUE(files::IsDirectoryAt(path.root_fd(), path.path()));
  }
}

TEST_F(LevelDbFactoryTest, CreateMultipleDbsConcurrently) {
  int N = 5;
  Status statuses[N];
  std::unique_ptr<Db> dbs[N];
  bool called[N];

  // Create N LevelDb instances concurrently. The first one will use the cached
  // instance, the 2nd one will be queued up to get the cached one when it's
  // initialized, and all the others will be created directly at the destination
  // directory.
  for (int i = 0; i < N; ++i) {
    ledger::DetachedPath path = db_path_.SubPath(fxl::NumberToString(i));
    EXPECT_FALSE(files::IsDirectoryAt(path.root_fd(), path.path()));

    db_factory_.GetOrCreateDb(
        db_path_.SubPath(fxl::NumberToString(i)),
        DbFactory::OnDbNotFound::CREATE,
        callback::Capture(callback::SetWhenCalled(&called[i]), &statuses[i],
                          &dbs[i]));
  }
  RunLoopUntilIdle();

  for (int i = 0; i < N; ++i) {
    ledger::DetachedPath path = db_path_.SubPath(fxl::NumberToString(i));
    EXPECT_TRUE(called[i]);
    EXPECT_EQ(Status::OK, statuses[i]);
    EXPECT_NE(nullptr, dbs[i]);
    // Check that the directory was created.
    EXPECT_TRUE(files::IsDirectoryAt(path.root_fd(), path.path()));
  }
}

TEST_F(LevelDbFactoryTest, GetOrCreateDbInCallback) {
  bool called1;
  ledger::DetachedPath path1 = db_path_.SubPath("1");

  bool called2;
  ledger::DetachedPath path2 = db_path_.SubPath("2");
  Status status2;
  std::unique_ptr<Db> db2;

  db_factory_.GetOrCreateDb(
      path1, DbFactory::OnDbNotFound::CREATE,
      [&](Status status1, std::unique_ptr<Db> db1) {
        called1 = true;
        EXPECT_EQ(Status::OK, status1);
        EXPECT_NE(nullptr, db1);
        db_factory_.GetOrCreateDb(
            path2, DbFactory::OnDbNotFound::CREATE,
            callback::Capture(callback::SetWhenCalled(&called2), &status2,
                              &db2));
      });
  RunLoopUntilIdle();
  EXPECT_TRUE(called1);
  EXPECT_TRUE(called2);
  EXPECT_EQ(Status::OK, status2);
  EXPECT_NE(nullptr, db2);

  // Check that the directories were created.
  EXPECT_TRUE(files::IsDirectoryAt(path1.root_fd(), path1.path()));
  EXPECT_TRUE(files::IsDirectoryAt(path2.root_fd(), path2.path()));
}

TEST_F(LevelDbFactoryTest, InitWithCachedDbAvailable) {
  // When an empty LevelDb instance is already cached from a previous
  // LevelDbFactory execution, don't create a new instance, but use the existing
  // one directly.
  scoped_tmpfs::ScopedTmpFS tmpfs;
  ledger::DetachedPath cache_path(tmpfs.root_fd(), "cache");
  // Must be the same as |kCachedDbPath| in leveldb_factory.cc.
  ledger::DetachedPath cached_db_path = cache_path.SubPath("cached_db");

  auto db_factory = std::make_unique<LevelDbFactory>(&environment_, cache_path);

  // The cached db directory should not be created, yet.
  EXPECT_FALSE(
      files::IsDirectoryAt(cached_db_path.root_fd(), cached_db_path.path()));

  // Initialize and wait for the cached instance to be created.
  db_factory->Init();
  RunLoopUntilIdle();

  // Close the factory. This will not affect the created cached instance, which
  // was created under |cached_db_path|.
  db_factory.reset();
  EXPECT_TRUE(
      files::IsDirectoryAt(cached_db_path.root_fd(), cached_db_path.path()));

  // Reset and re-initialize the factory object. It should now use the
  // previously created instance.
  db_factory = std::make_unique<LevelDbFactory>(&environment_, cache_path);
  db_factory->Init();
  RunLoopUntilIdle();
}

}  // namespace
}  // namespace storage