// Copyright 2018 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.

#ifndef ZIRCON_SYSTEM_ULIB_BLOBFS_TEST_UNIT_UTILS_H_
#define ZIRCON_SYSTEM_ULIB_BLOBFS_TEST_UNIT_UTILS_H_

#include <memory>
#include <optional>

#include <block-client/cpp/block-device.h>
#include <fbl/auto_lock.h>
#include <fbl/vector.h>
#include <zxtest/zxtest.h>

#include "allocator/allocator.h"
#include "transaction-manager.h"

namespace blobfs {

constexpr uint32_t kBlockSize = kBlobfsBlockSize;
constexpr groupid_t kGroupID = 2;
constexpr size_t kWritebackCapacity = 8;
constexpr uint32_t kDeviceBlockSize = 1024;
constexpr uint32_t kDiskBlockRatio = kBlockSize / kDeviceBlockSize;

// Callback for MockTransactionManager to invoke on calls to Transaction(). |request| is performed
// on the provided |vmo|.
using TransactionCallback =
    fbl::Function<zx_status_t(const block_fifo_request_t& request, const zx::vmo& vmo)>;

using block_client::BlockDevice;

// A simplified TransactionManager to be used when unit testing structures which require one (e.g.
// WritebackQueue, Journal). Allows vmos to be attached/detached and a customized callback to be
// invoked on transaction completion.
// This class is thread-safe.
class MockTransactionManager : public TransactionManager {
 public:
  MockTransactionManager() = default;
  ~MockTransactionManager() = default;

  // Sets the |callback| to be invoked for each request on calls to Transaction().
  void SetTransactionCallback(TransactionCallback callback) {
    fbl::AutoLock lock(&lock_);
    transaction_callback_ = std::move(callback);
  }

  uint32_t FsBlockSize() const final { return kBlockSize; }

  uint32_t DeviceBlockSize() const final { return kBlockSize; }

  uint64_t BlockNumberToDevice(uint64_t block_num) const final { return block_num; }

  block_client::BlockDevice* GetDevice() final { return nullptr; }

  zx_status_t RunOperation(const storage::Operation& operation,
                           storage::BlockBuffer* buffer) final {
    return ZX_OK;
  }

  zx_status_t Transaction(block_fifo_request_t* requests, size_t count) override;

  const Superblock& Info() const final { return superblock_; }

  Superblock& MutableInfo() { return superblock_; }

  zx_status_t AddInodes(Allocator*) final { return ZX_ERR_NOT_SUPPORTED; }

  zx_status_t AddBlocks(size_t nblocks, RawBitmap* map) final { return ZX_ERR_NOT_SUPPORTED; }

  zx_status_t BlockAttachVmo(const zx::vmo& vmo, storage::Vmoid* out) final;

  zx_status_t BlockDetachVmo(storage::Vmoid vmoid) final;

  BlobfsMetrics* Metrics() final { return &metrics_; }

  size_t WritebackCapacity() const final { return kWritebackCapacity; }

  fs::Journal* journal() final {
    ZX_ASSERT(false);
    return nullptr;
  }

 private:
  BlobfsMetrics metrics_{};
  Superblock superblock_{};
  fbl::Vector<std::optional<zx::vmo>> attached_vmos_ __TA_GUARDED(lock_);
  TransactionCallback transaction_callback_ __TA_GUARDED(lock_);
  fbl::Mutex lock_;
};

// A trivial space manager, incapable of resizing.
class MockSpaceManager : public SpaceManager {
 public:
  Superblock& MutableInfo() { return superblock_; }

  const Superblock& Info() const final { return superblock_; }
  zx_status_t AddInodes(Allocator*) final { return ZX_ERR_NOT_SUPPORTED; }
  zx_status_t AddBlocks(size_t nblocks, RawBitmap* map) final { return ZX_ERR_NOT_SUPPORTED; }
  zx_status_t BlockAttachVmo(const zx::vmo& vmo, storage::Vmoid* out) final { return ZX_ERR_NOT_SUPPORTED; }
  zx_status_t BlockDetachVmo(storage::Vmoid vmoid) final { return ZX_ERR_NOT_SUPPORTED; }

 private:
  Superblock superblock_{};
};

// Create a block and node map of the requested size, update the superblock of
// the |space_manager|, and create an allocator from this provided info.
void InitializeAllocator(size_t blocks, size_t nodes, MockSpaceManager* space_manager,
                         std::unique_ptr<Allocator>* out);

// Force the allocator to become maximally fragmented by allocating
// every-other block within up to |blocks|.
void ForceFragmentation(Allocator* allocator, size_t blocks);

// Save the extents within |in| in a non-reserved vector |out|.
void CopyExtents(const fbl::Vector<ReservedExtent>& in, fbl::Vector<Extent>* out);

// Save the nodes within |in| in a non-reserved vector |out|.
void CopyNodes(const fbl::Vector<ReservedNode>& in, fbl::Vector<uint32_t>* out);

// Reads |size| bytes from the |device| at byte offset |dev_offset| into |buf|.
// Expects |size| and |dev_offset| to be multiple of |device| block size.
void DeviceBlockRead(BlockDevice* device, void* buf, size_t size, uint64_t dev_offset);

// Writes |size| bytes from the |buf| to the |device| at offset |dev_offset|.
// Expects |size| and |dev_offset| to be multiple of |device| block size.
void DeviceBlockWrite(BlockDevice* device, const void* buf, size_t size, uint64_t dev_offset);

}  // namespace blobfs

#endif  // ZIRCON_SYSTEM_ULIB_BLOBFS_TEST_UNIT_UTILS_H_