// Copyright 2010 Dolphin Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later

#pragma once

#include <array>
#include <filesystem>
#include <fmt/format.h>
#include <map>
#include <memory>
#include <optional>
#include <string>
#include <string_view>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <vector>

#include "Common/BitSet.h"
#include "Common/CommonTypes.h"
#include "Common/Flag.h"
#include "Common/MathUtil.h"

#include "VideoCommon/AbstractTexture.h"
#include "VideoCommon/BPMemory.h"
#include "VideoCommon/TextureConfig.h"
#include "VideoCommon/TextureDecoder.h"
#include "VideoCommon/TextureInfo.h"
#include "VideoCommon/VideoEvents.h"

class AbstractFramebuffer;
class AbstractStagingTexture;
class PointerWrap;
struct VideoConfig;

namespace VideoCommon
{
class CustomTextureData;
class GameTextureAsset;
}  // namespace VideoCommon

constexpr std::string_view EFB_DUMP_PREFIX = "efb1";
constexpr std::string_view XFB_DUMP_PREFIX = "xfb1";

static constexpr int FRAMECOUNT_INVALID = 0;

struct TextureAndTLUTFormat
{
  TextureAndTLUTFormat(TextureFormat texfmt_ = TextureFormat::I4,
                       TLUTFormat tlutfmt_ = TLUTFormat::IA8)
      : texfmt(texfmt_), tlutfmt(tlutfmt_)
  {
  }

  bool operator==(const TextureAndTLUTFormat& other) const
  {
    if (IsColorIndexed(texfmt))
      return texfmt == other.texfmt && tlutfmt == other.tlutfmt;

    return texfmt == other.texfmt;
  }

  bool operator!=(const TextureAndTLUTFormat& other) const { return !operator==(other); }
  TextureFormat texfmt;
  TLUTFormat tlutfmt;
};

struct EFBCopyParams
{
  EFBCopyParams(PixelFormat efb_format_, EFBCopyFormat copy_format_, bool depth_, bool yuv_,
                bool all_copy_filter_coefs_needed_, bool copy_filter_can_overflow_,
                bool apply_gamma_)
      : efb_format(efb_format_), copy_format(copy_format_), depth(depth_), yuv(yuv_),
        all_copy_filter_coefs_needed(all_copy_filter_coefs_needed_),
        copy_filter_can_overflow(copy_filter_can_overflow_), apply_gamma(apply_gamma_)
  {
  }

  bool operator<(const EFBCopyParams& rhs) const
  {
    return std::tie(efb_format, copy_format, depth, yuv, all_copy_filter_coefs_needed,
                    copy_filter_can_overflow,
                    apply_gamma) < std::tie(rhs.efb_format, rhs.copy_format, rhs.depth, rhs.yuv,
                                            rhs.all_copy_filter_coefs_needed,
                                            rhs.copy_filter_can_overflow, rhs.apply_gamma);
  }

  PixelFormat efb_format;
  EFBCopyFormat copy_format;
  bool depth;
  bool yuv;
  bool all_copy_filter_coefs_needed;
  bool copy_filter_can_overflow;
  bool apply_gamma;
};

template <>
struct fmt::formatter<EFBCopyParams>
{
  std::shared_ptr<int> state;
  constexpr auto parse(format_parse_context& ctx) { return ctx.begin(); }
  template <typename FormatContext>
  auto format(const EFBCopyParams& uid, FormatContext& ctx) const
  {
    std::string copy_format;
    if (uid.copy_format == EFBCopyFormat::XFB)
      copy_format = "XFB";
    else
      copy_format = fmt::to_string(uid.copy_format);
    return fmt::format_to(ctx.out(),
                          "format: {}, copy format: {}, depth: {}, yuv: {}, apply_gamma: {}, "
                          "all_copy_filter_coefs_needed: {}, copy_filter_can_overflow: {}",
                          uid.efb_format, copy_format, uid.depth, uid.yuv, uid.apply_gamma,
                          uid.all_copy_filter_coefs_needed, uid.copy_filter_can_overflow);
  }
};

struct CachedTextureAsset
{
  std::shared_ptr<VideoCommon::GameTextureAsset> m_asset;
  std::optional<std::filesystem::file_time_type> m_last_write_time;
};

struct TCacheEntry
{
  // common members
  std::unique_ptr<AbstractTexture> texture;
  std::unique_ptr<AbstractFramebuffer> framebuffer;
  u32 addr = 0;
  u32 size_in_bytes = 0;
  u64 base_hash = 0;
  u64 hash = 0;  // for paletted textures, hash = base_hash ^ palette_hash
  TextureAndTLUTFormat format;
  u32 memory_stride = 0;
  bool is_efb_copy = false;
  bool is_custom_tex = false;
  bool may_have_overlapping_textures = true;
  // indicates that the mips in this texture are arbitrary content, aren't just downscaled
  bool has_arbitrary_mips = false;
  bool should_force_safe_hashing = false;  // for XFB
  bool is_xfb_copy = false;
  bool is_xfb_container = false;
  u64 id = 0;
  u32 content_semaphore = 0;  // Counts up

  // Indicates that this TCacheEntry has been invalided from textures_by_address
  bool invalidated = false;

  bool reference_changed = false;  // used by xfb to determine when a reference xfb changed

  // Texture dimensions from the GameCube's point of view
  u32 native_width = 0;
  u32 native_height = 0;
  u32 native_levels = 0;

  // used to delete textures which haven't been used for TEXTURE_KILL_THRESHOLD frames
  int frameCount = FRAMECOUNT_INVALID;

  // Keep an iterator to the entry in textures_by_hash, so it does not need to be searched when
  // removing the cache entry
  std::multimap<u64, std::shared_ptr<TCacheEntry>>::iterator textures_by_hash_iter;

  // This is used to keep track of both:
  //   * efb copies used by this partially updated texture
  //   * partially updated textures which refer to this efb copy
  std::unordered_set<TCacheEntry*> references;

  // Pending EFB copy
  std::unique_ptr<AbstractStagingTexture> pending_efb_copy;
  u32 pending_efb_copy_width = 0;
  u32 pending_efb_copy_height = 0;

  std::string texture_info_name = "";

  CachedTextureAsset linked_asset;

  explicit TCacheEntry(std::unique_ptr<AbstractTexture> tex,
                       std::unique_ptr<AbstractFramebuffer> fb);

  ~TCacheEntry();

  void SetGeneralParameters(u32 _addr, u32 _size, TextureAndTLUTFormat _format,
                            bool force_safe_hashing)
  {
    addr = _addr;
    size_in_bytes = _size;
    format = _format;
    should_force_safe_hashing = force_safe_hashing;
  }

  void SetDimensions(unsigned int _native_width, unsigned int _native_height,
                     unsigned int _native_levels)
  {
    native_width = _native_width;
    native_height = _native_height;
    native_levels = _native_levels;
    memory_stride = _native_width;
  }

  void SetHashes(u64 _base_hash, u64 _hash)
  {
    base_hash = _base_hash;
    hash = _hash;
  }

  // This texture entry is used by the other entry as a sub-texture
  void CreateReference(TCacheEntry* other_entry)
  {
    // References are two-way, so they can easily be destroyed later
    this->references.emplace(other_entry);
    other_entry->references.emplace(this);
  }

  // Acquiring a content lock will lock the current contents and prevent texture cache from
  // reusing the same entry for a newer version of the texture.
  void AcquireContentLock() { content_semaphore++; }
  void ReleaseContentLock() { content_semaphore--; }

  // Can this be mutated?
  bool IsLocked() const { return content_semaphore > 0; }

  void SetXfbCopy(u32 stride);
  void SetEfbCopy(u32 stride);
  void SetNotCopy();

  bool OverlapsMemoryRange(u32 range_address, u32 range_size) const;

  bool IsEfbCopy() const { return is_efb_copy; }
  bool IsCopy() const { return is_xfb_copy || is_efb_copy; }
  u32 NumBlocksX() const;
  u32 NumBlocksY() const;
  u32 BytesPerRow() const;

  u64 CalculateHash() const;

  int HashSampleSize() const;
  u32 GetWidth() const { return texture->GetConfig().width; }
  u32 GetHeight() const { return texture->GetConfig().height; }
  u32 GetNumLevels() const { return texture->GetConfig().levels; }
  u32 GetNumLayers() const { return texture->GetConfig().layers; }
  AbstractTextureFormat GetFormat() const { return texture->GetConfig().format; }
  void DoState(PointerWrap& p);
};

using RcTcacheEntry = std::shared_ptr<TCacheEntry>;

class TextureCacheBase
{
public:
  // Minimal version of TCacheEntry just for TexPool
  struct TexPoolEntry
  {
    std::unique_ptr<AbstractTexture> texture;
    std::unique_ptr<AbstractFramebuffer> framebuffer;
    int frameCount = FRAMECOUNT_INVALID;

    TexPoolEntry(std::unique_ptr<AbstractTexture> tex, std::unique_ptr<AbstractFramebuffer> fb);
  };

  struct TextureCreationInfo
  {
    u64 base_hash;
    u64 full_hash;
    u32 bytes_per_block;
    u32 palette_size;
  };

  TextureCacheBase();
  virtual ~TextureCacheBase();

  bool Initialize();
  void Shutdown();

  void OnConfigChanged(const VideoConfig& config);

  // Removes textures which aren't used for more than TEXTURE_KILL_THRESHOLD frames,
  // frameCount is the current frame number.
  void Cleanup(int _frameCount);

  void Invalidate();
  void ReleaseToPool(TCacheEntry* entry);

  TCacheEntry* Load(const TextureInfo& texture_info);
  RcTcacheEntry GetTexture(const int textureCacheSafetyColorSampleSize,
                           const TextureInfo& texture_info);
  RcTcacheEntry GetXFBTexture(u32 address, u32 width, u32 height, u32 stride,
                              MathUtil::Rectangle<int>* display_rect);

  virtual void BindTextures(BitSet32 used_textures);
  void CopyRenderTargetToTexture(u32 dstAddr, EFBCopyFormat dstFormat, u32 width, u32 height,
                                 u32 dstStride, bool is_depth_copy,
                                 const MathUtil::Rectangle<int>& srcRect, bool isIntensity,
                                 bool scaleByHalf, float y_scale, float gamma, bool clamp_top,
                                 bool clamp_bottom,
                                 const CopyFilterCoefficients::Values& filter_coefficients);

  void ScaleTextureCacheEntryTo(RcTcacheEntry& entry, u32 new_width, u32 new_height);

  // Flushes all pending EFB copies to emulated RAM.
  void FlushEFBCopies();

  // Flush any Bound textures that can't be reused
  void FlushStaleBinds();

  // Texture Serialization
  void SerializeTexture(AbstractTexture* tex, const TextureConfig& config, PointerWrap& p);
  std::optional<TexPoolEntry> DeserializeTexture(PointerWrap& p);

  // Save States
  void DoState(PointerWrap& p);

  static bool AllCopyFilterCoefsNeeded(const std::array<u32, 3>& coefficients);
  static bool CopyFilterCanOverflow(const std::array<u32, 3>& coefficients);

protected:
  // Decodes the specified data to the GPU texture specified by entry.
  // Returns false if the configuration is not supported.
  // width, height are the size of the image in pixels.
  // aligned_width, aligned_height are the size of the image in pixels, aligned to the block size.
  // row_stride is the number of bytes for a row of blocks, not pixels.
  bool DecodeTextureOnGPU(RcTcacheEntry& entry, u32 dst_level, const u8* data, u32 data_size,
                          TextureFormat format, u32 width, u32 height, u32 aligned_width,
                          u32 aligned_height, u32 row_stride, const u8* palette,
                          TLUTFormat palette_format);

  virtual void CopyEFB(AbstractStagingTexture* dst, const EFBCopyParams& params, u32 native_width,
                       u32 bytes_per_row, u32 num_blocks_y, u32 memory_stride,
                       const MathUtil::Rectangle<int>& src_rect, bool scale_by_half,
                       bool linear_filter, float y_scale, float gamma, bool clamp_top,
                       bool clamp_bottom, const std::array<u32, 3>& filter_coefficients);
  virtual void CopyEFBToCacheEntry(RcTcacheEntry& entry, bool is_depth_copy,
                                   const MathUtil::Rectangle<int>& src_rect, bool scale_by_half,
                                   bool linear_filter, EFBCopyFormat dst_format, bool is_intensity,
                                   float gamma, bool clamp_top, bool clamp_bottom,
                                   const std::array<u32, 3>& filter_coefficients);

  alignas(16) u8* temp = nullptr;
  size_t temp_size = 0;

private:
  using TexAddrCache = std::multimap<u32, RcTcacheEntry>;
  using TexHashCache = std::multimap<u64, RcTcacheEntry>;

  using TexPool = std::unordered_multimap<TextureConfig, TexPoolEntry>;

  static bool DidLinkedAssetsChange(const TCacheEntry& entry);

  TCacheEntry* LoadImpl(const TextureInfo& texture_info, bool force_reload);

  bool CreateUtilityTextures();

  void SetBackupConfig(const VideoConfig& config);

  RcTcacheEntry CreateTextureEntry(const TextureCreationInfo& creation_info,
                                   const TextureInfo& texture_info, int safety_color_sample_size,
                                   const VideoCommon::CustomTextureData* custom_texture_data,
                                   bool custom_arbitrary_mipmaps);

  RcTcacheEntry GetXFBFromCache(u32 address, u32 width, u32 height, u32 stride);

  RcTcacheEntry ApplyPaletteToEntry(RcTcacheEntry& entry, const u8* palette, TLUTFormat tlutfmt);

  RcTcacheEntry ReinterpretEntry(const RcTcacheEntry& existing_entry, TextureFormat new_format);

  RcTcacheEntry DoPartialTextureUpdates(RcTcacheEntry& entry_to_update, const u8* palette,
                                        TLUTFormat tlutfmt);
  void StitchXFBCopy(RcTcacheEntry& entry_to_update);

  void DumpTexture(RcTcacheEntry& entry, std::string basename, unsigned int level,
                   bool is_arbitrary);
  void CheckTempSize(size_t required_size);

  RcTcacheEntry AllocateCacheEntry(const TextureConfig& config);
  std::optional<TexPoolEntry> AllocateTexture(const TextureConfig& config);
  TexPool::iterator FindMatchingTextureFromPool(const TextureConfig& config);
  TexAddrCache::iterator GetTexCacheIter(TCacheEntry* entry);

  // Return all possible overlapping textures. As addr+size of the textures is not
  // indexed, this may return false positives.
  std::pair<TexAddrCache::iterator, TexAddrCache::iterator>
  FindOverlappingTextures(u32 addr, u32 size_in_bytes);

  // Removes and unlinks texture from texture cache and returns it to the pool
  TexAddrCache::iterator InvalidateTexture(TexAddrCache::iterator t_iter,
                                           bool discard_pending_efb_copy = false);

  void UninitializeEFBMemory(u8* dst, u32 stride, u32 bytes_per_row, u32 num_blocks_y);
  void UninitializeXFBMemory(u8* dst, u32 stride, u32 bytes_per_row, u32 num_blocks_y);

  // Precomputing the coefficients for the previous, current, and next lines for the copy filter.
  static std::array<u32, 3>
  GetRAMCopyFilterCoefficients(const CopyFilterCoefficients::Values& coefficients);
  static std::array<u32, 3>
  GetVRAMCopyFilterCoefficients(const CopyFilterCoefficients::Values& coefficients);

  // Flushes a pending EFB copy to RAM from the host to the guest RAM.
  void WriteEFBCopyToRAM(u8* dst_ptr, u32 width, u32 height, u32 stride,
                         std::unique_ptr<AbstractStagingTexture> staging_texture);
  void FlushEFBCopy(TCacheEntry* entry);

  // Returns a staging texture of the maximum EFB copy size.
  std::unique_ptr<AbstractStagingTexture> GetEFBCopyStagingTexture();

  // Returns an EFB copy staging texture to the pool, so it can be re-used.
  void ReleaseEFBCopyStagingTexture(std::unique_ptr<AbstractStagingTexture> tex);

  bool CheckReadbackTexture(u32 width, u32 height, AbstractTextureFormat format);
  void DoSaveState(PointerWrap& p);
  void DoLoadState(PointerWrap& p);

  // textures_by_address is the authoritive version of what's actually "in" the texture cache
  // but it's possible for invalidated TCache entries to live on elsewhere
  TexAddrCache textures_by_address;

  // textures_by_hash is an alternative view of the texture cache
  // All textures in here will also be in textures_by_address
  TexHashCache textures_by_hash;

  // bound_textures are actually active in the current draw
  // It's valid for textures to be in here after they've been invalidated
  std::array<RcTcacheEntry, 8> bound_textures{};

  TexPool texture_pool;
  u64 last_entry_id = 0;

  // Backup configuration values
  struct BackupConfig
  {
    int color_samples;
    bool texfmt_overlay;
    bool texfmt_overlay_center;
    bool hires_textures;
    bool cache_hires_textures;
    bool copy_cache_enable;
    bool stereo_3d;
    bool efb_mono_depth;
    bool gpu_texture_decoding;
    bool disable_vram_copies;
    bool arbitrary_mipmap_detection;
    bool graphics_mods;
    u32 graphics_mod_change_count;
  };
  BackupConfig backup_config = {};

  // Encoding texture used for EFB copies to RAM.
  std::unique_ptr<AbstractTexture> m_efb_encoding_texture;
  std::unique_ptr<AbstractFramebuffer> m_efb_encoding_framebuffer;

  // Decoding texture used for GPU texture decoding.
  std::unique_ptr<AbstractTexture> m_decoding_texture;

  // Pool of readback textures used for deferred EFB copies.
  std::vector<std::unique_ptr<AbstractStagingTexture>> m_efb_copy_staging_texture_pool;

  // List of pending EFB copies. It is important that the order is preserved for these,
  // so that overlapping textures are written to guest RAM in the order they are issued.
  // It's valid for textures to live be in here after they've been invalidated
  std::vector<RcTcacheEntry> m_pending_efb_copies;

  // Staging texture used for readbacks.
  // We store this in the class so that the same staging texture can be used for multiple
  // readbacks, saving the overhead of allocating a new buffer every time.
  std::unique_ptr<AbstractStagingTexture> m_readback_texture;

  void OnFrameEnd();

  Common::EventHook m_frame_event =
      AfterFrameEvent::Register([this] { OnFrameEnd(); }, "TextureCache");
};

extern std::unique_ptr<TextureCacheBase> g_texture_cache;