/* Copyright 2017-2018 ccls Authors

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

  http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
==============================================================================*/

#pragma once

#include "utils.hh"

#include <llvm/Support/Compiler.h>

#include <macro_map.h>
#include <rapidjson/fwd.h>

#include <cassert>
#include <functional>
#include <memory>
#include <optional>
#include <string>
#include <string_view>
#include <type_traits>
#include <vector>

namespace llvm {
class CachedHashStringRef;
class StringRef;
template <typename Fn> class function_ref;
} // namespace llvm

namespace ccls {
enum class SerializeFormat { Binary, Json };

struct JsonNull {};

struct JsonReader {
  rapidjson::Value *m;
  std::vector<const char *> path_;

  JsonReader(rapidjson::Value *m) : m(m) {}
  void startObject() {}
  void endObject() {}
  void iterArray(llvm::function_ref<void()> fn);
  void member(const char *name, llvm::function_ref<void()> fn);
  bool isNull();
  std::string getString();
  std::string getPath() const;
};

struct JsonWriter {
  using W =
      rapidjson::Writer<rapidjson::StringBuffer, rapidjson::UTF8<char>,
                        rapidjson::UTF8<char>, rapidjson::CrtAllocator, 0>;

  W *m;

  JsonWriter(W *m) : m(m) {}
  void startArray();
  void endArray();
  void startObject();
  void endObject();
  void key(const char *name);
  void null_();
  void int64(int64_t v);
  void string(const char *s);
  void string(const char *s, size_t len);
};

struct BinaryReader {
  const char *p_;

  BinaryReader(std::string_view buf) : p_(buf.data()) {}
  template <typename T> T get() {
    T ret;
    memcpy(&ret, p_, sizeof(T));
    p_ += sizeof(T);
    return ret;
  }
  uint64_t varUInt() {
    auto x = *reinterpret_cast<const uint8_t *>(p_++);
    if (x < 253)
      return x;
    if (x == 253)
      return get<uint16_t>();
    if (x == 254)
      return get<uint32_t>();
    return get<uint64_t>();
  }
  int64_t varInt() {
    uint64_t x = varUInt();
    return int64_t(x >> 1 ^ -(x & 1));
  }
  const char *getString() {
    const char *ret = p_;
    while (*p_)
      p_++;
    p_++;
    return ret;
  }
};

struct BinaryWriter {
  std::string buf_;

  template <typename T> void pack(T x) {
    auto i = buf_.size();
    buf_.resize(i + sizeof(x));
    memcpy(buf_.data() + i, &x, sizeof(x));
  }

  void varUInt(uint64_t n) {
    if (n < 253)
      pack<uint8_t>(n);
    else if (n < 65536) {
      pack<uint8_t>(253);
      pack<uint16_t>(n);
    } else if (n < 4294967296) {
      pack<uint8_t>(254);
      pack<uint32_t>(n);
    } else {
      pack<uint8_t>(255);
      pack<uint64_t>(n);
    }
  }
  void varInt(int64_t n) { varUInt(uint64_t(n) << 1 ^ n >> 63); }
  std::string take() { return std::move(buf_); }

  void string(const char *x) { string(x, strlen(x)); }
  void string(const char *x, size_t len) {
    auto i = buf_.size();
    buf_.resize(i + len + 1);
    memcpy(buf_.data() + i, x, len);
  }
};

struct IndexFile;

#define REFLECT_MEMBER(name) reflectMember(vis, #name, v.name)
#define REFLECT_MEMBER2(name, v) reflectMember(vis, name, v)

#define REFLECT_UNDERLYING(T)                                                  \
  LLVM_ATTRIBUTE_UNUSED inline void reflect(JsonReader &vis, T &v) {           \
    std::underlying_type_t<T> v0;                                              \
    ::ccls::reflect(vis, v0);                                                  \
    v = static_cast<T>(v0);                                                    \
  }                                                                            \
  LLVM_ATTRIBUTE_UNUSED inline void reflect(JsonWriter &vis, T &v) {           \
    auto v0 = static_cast<std::underlying_type_t<T>>(v);                       \
    ::ccls::reflect(vis, v0);                                                  \
  }

#define REFLECT_UNDERLYING_B(T)                                                \
  REFLECT_UNDERLYING(T)                                                        \
  LLVM_ATTRIBUTE_UNUSED inline void reflect(BinaryReader &vis, T &v) {         \
    std::underlying_type_t<T> v0;                                              \
    ::ccls::reflect(vis, v0);                                                  \
    v = static_cast<T>(v0);                                                    \
  }                                                                            \
  LLVM_ATTRIBUTE_UNUSED inline void reflect(BinaryWriter &vis, T &v) {         \
    auto v0 = static_cast<std::underlying_type_t<T>>(v);                       \
    ::ccls::reflect(vis, v0);                                                  \
  }

#define _MAPPABLE_REFLECT_MEMBER(name) REFLECT_MEMBER(name);

#define REFLECT_STRUCT(type, ...)                                              \
  template <typename Vis> void reflect(Vis &vis, type &v) {                    \
    reflectMemberStart(vis);                                                   \
    MACRO_MAP(_MAPPABLE_REFLECT_MEMBER, __VA_ARGS__)                           \
    reflectMemberEnd(vis);                                                     \
  }

#define _MAPPABLE_REFLECT_ARRAY(name) reflect(vis, v.name);

void reflect(JsonReader &vis, bool &v);
void reflect(JsonReader &vis, unsigned char &v);
void reflect(JsonReader &vis, short &v);
void reflect(JsonReader &vis, unsigned short &v);
void reflect(JsonReader &vis, int &v);
void reflect(JsonReader &vis, unsigned &v);
void reflect(JsonReader &vis, long &v);
void reflect(JsonReader &vis, unsigned long &v);
void reflect(JsonReader &vis, long long &v);
void reflect(JsonReader &vis, unsigned long long &v);
void reflect(JsonReader &vis, double &v);
void reflect(JsonReader &vis, const char *&v);
void reflect(JsonReader &vis, std::string &v);

void reflect(JsonWriter &vis, bool &v);
void reflect(JsonWriter &vis, unsigned char &v);
void reflect(JsonWriter &vis, short &v);
void reflect(JsonWriter &vis, unsigned short &v);
void reflect(JsonWriter &vis, int &v);
void reflect(JsonWriter &vis, unsigned &v);
void reflect(JsonWriter &vis, long &v);
void reflect(JsonWriter &vis, unsigned long &v);
void reflect(JsonWriter &vis, long long &v);
void reflect(JsonWriter &vis, unsigned long long &v);
void reflect(JsonWriter &vis, double &v);
void reflect(JsonWriter &vis, const char *&v);
void reflect(JsonWriter &vis, std::string &v);

void reflect(BinaryReader &vis, bool &v);
void reflect(BinaryReader &vis, unsigned char &v);
void reflect(BinaryReader &vis, short &v);
void reflect(BinaryReader &vis, unsigned short &v);
void reflect(BinaryReader &vis, int &v);
void reflect(BinaryReader &vis, unsigned &v);
void reflect(BinaryReader &vis, long &v);
void reflect(BinaryReader &vis, unsigned long &v);
void reflect(BinaryReader &vis, long long &v);
void reflect(BinaryReader &vis, unsigned long long &v);
void reflect(BinaryReader &vis, double &v);
void reflect(BinaryReader &vis, const char *&v);
void reflect(BinaryReader &vis, std::string &v);

void reflect(BinaryWriter &vis, bool &v);
void reflect(BinaryWriter &vis, unsigned char &v);
void reflect(BinaryWriter &vis, short &v);
void reflect(BinaryWriter &vis, unsigned short &v);
void reflect(BinaryWriter &vis, int &v);
void reflect(BinaryWriter &vis, unsigned &v);
void reflect(BinaryWriter &vis, long &v);
void reflect(BinaryWriter &vis, unsigned long &v);
void reflect(BinaryWriter &vis, long long &v);
void reflect(BinaryWriter &vis, unsigned long long &v);
void reflect(BinaryWriter &vis, double &v);
void reflect(BinaryWriter &vis, const char *&v);
void reflect(BinaryWriter &vis, std::string &v);

void reflect(JsonReader &vis, JsonNull &v);
void reflect(JsonWriter &vis, JsonNull &v);

void reflect(JsonReader &vis, SerializeFormat &v);
void reflect(JsonWriter &vis, SerializeFormat &v);

void reflect(JsonWriter &vis, std::string_view &v);

//// Type constructors

// reflectMember std::optional<T> is used to represent TypeScript optional
// properties (in `key: value` context). reflect std::optional<T> is used for a
// different purpose, whether an object is nullable (possibly in `value`
// context).
template <typename T> void reflect(JsonReader &vis, std::optional<T> &v) {
  if (!vis.isNull()) {
    v.emplace();
    reflect(vis, *v);
  }
}
template <typename T> void reflect(JsonWriter &vis, std::optional<T> &v) {
  if (v)
    reflect(vis, *v);
  else
    vis.null_();
}
template <typename T> void reflect(BinaryReader &vis, std::optional<T> &v) {
  if (*vis.p_++) {
    v.emplace();
    reflect(vis, *v);
  }
}
template <typename T> void reflect(BinaryWriter &vis, std::optional<T> &v) {
  if (v) {
    vis.pack<unsigned char>(1);
    reflect(vis, *v);
  } else {
    vis.pack<unsigned char>(0);
  }
}

// The same as std::optional
template <typename T> void reflect(JsonReader &vis, Maybe<T> &v) {
  if (!vis.isNull())
    reflect(vis, *v);
}
template <typename T> void reflect(JsonWriter &vis, Maybe<T> &v) {
  if (v)
    reflect(vis, *v);
  else
    vis.null_();
}
template <typename T> void reflect(BinaryReader &vis, Maybe<T> &v) {
  if (*vis.p_++)
    reflect(vis, *v);
}
template <typename T> void reflect(BinaryWriter &vis, Maybe<T> &v) {
  if (v) {
    vis.pack<unsigned char>(1);
    reflect(vis, *v);
  } else {
    vis.pack<unsigned char>(0);
  }
}

template <typename T>
void reflectMember(JsonWriter &vis, const char *name, std::optional<T> &v) {
  // For TypeScript std::optional property key?: value in the spec,
  // We omit both key and value if value is std::nullopt (null) for JsonWriter
  // to reduce output. But keep it for other serialization formats.
  if (v) {
    vis.key(name);
    reflect(vis, *v);
  }
}
template <typename T>
void reflectMember(BinaryWriter &vis, const char *, std::optional<T> &v) {
  reflect(vis, v);
}

// The same as std::optional
template <typename T>
void reflectMember(JsonWriter &vis, const char *name, Maybe<T> &v) {
  if (v.valid()) {
    vis.key(name);
    reflect(vis, v);
  }
}
template <typename T>
void reflectMember(BinaryWriter &vis, const char *, Maybe<T> &v) {
  reflect(vis, v);
}

template <typename L, typename R>
void reflect(JsonReader &vis, std::pair<L, R> &v) {
  vis.member("L", [&]() { reflect(vis, v.first); });
  vis.member("R", [&]() { reflect(vis, v.second); });
}
template <typename L, typename R>
void reflect(JsonWriter &vis, std::pair<L, R> &v) {
  vis.startObject();
  reflectMember(vis, "L", v.first);
  reflectMember(vis, "R", v.second);
  vis.endObject();
}
template <typename L, typename R>
void reflect(BinaryReader &vis, std::pair<L, R> &v) {
  reflect(vis, v.first);
  reflect(vis, v.second);
}
template <typename L, typename R>
void reflect(BinaryWriter &vis, std::pair<L, R> &v) {
  reflect(vis, v.first);
  reflect(vis, v.second);
}

// std::vector
template <typename T> void reflect(JsonReader &vis, std::vector<T> &v) {
  vis.iterArray([&]() {
    v.emplace_back();
    reflect(vis, v.back());
  });
}
template <typename T> void reflect(JsonWriter &vis, std::vector<T> &v) {
  vis.startArray();
  for (auto &it : v)
    reflect(vis, it);
  vis.endArray();
}
template <typename T> void reflect(BinaryReader &vis, std::vector<T> &v) {
  for (auto n = vis.varUInt(); n; n--) {
    v.emplace_back();
    reflect(vis, v.back());
  }
}
template <typename T> void reflect(BinaryWriter &vis, std::vector<T> &v) {
  vis.varUInt(v.size());
  for (auto &it : v)
    reflect(vis, it);
}

// reflectMember

void reflectMemberStart(JsonReader &);
template <typename T> void reflectMemberStart(T &) {}
inline void reflectMemberStart(JsonWriter &vis) { vis.startObject(); }

template <typename T> void reflectMemberEnd(T &) {}
inline void reflectMemberEnd(JsonWriter &vis) { vis.endObject(); }

template <typename T>
void reflectMember(JsonReader &vis, const char *name, T &v) {
  vis.member(name, [&]() { reflect(vis, v); });
}
template <typename T>
void reflectMember(JsonWriter &vis, const char *name, T &v) {
  vis.key(name);
  reflect(vis, v);
}
template <typename T>
void reflectMember(BinaryReader &vis, const char *, T &v) {
  reflect(vis, v);
}
template <typename T>
void reflectMember(BinaryWriter &vis, const char *, T &v) {
  reflect(vis, v);
}

// API

const char *intern(llvm::StringRef str);
llvm::CachedHashStringRef internH(llvm::StringRef str);
std::string serialize(SerializeFormat format, IndexFile &file);
std::unique_ptr<IndexFile>
deserialize(SerializeFormat format, const std::string &path,
            const std::string &serialized_index_content,
            const std::string &file_content,
            std::optional<int> expected_version);
} // namespace ccls