// Copyright 2017-2018 ccls Authors
// SPDX-License-Identifier: Apache-2.0

#pragma once

#include "maybe.hh"

#include <llvm/Support/Compiler.h>

#include <macro_map.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;
}

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

struct JsonNull {};

class Reader {
public:
  virtual ~Reader();
  virtual SerializeFormat Format() const = 0;

  virtual bool IsBool() = 0;
  virtual bool IsNull() = 0;
  virtual bool IsInt() = 0;
  virtual bool IsInt64() = 0;
  virtual bool IsUInt64() = 0;
  virtual bool IsDouble() = 0;
  virtual bool IsString() = 0;

  virtual void GetNull() = 0;
  virtual bool GetBool() = 0;
  virtual uint8_t GetUInt8() = 0;
  virtual int GetInt() = 0;
  virtual uint32_t GetUInt32() = 0;
  virtual int64_t GetInt64() = 0;
  virtual uint64_t GetUInt64() = 0;
  virtual double GetDouble() = 0;
  virtual const char *GetString() = 0;

  virtual bool HasMember(const char *x) = 0;
  virtual std::unique_ptr<Reader> operator[](const char *x) = 0;

  virtual void IterArray(std::function<void(Reader &)> fn) = 0;
  virtual void Member(const char *name, std::function<void()> fn) = 0;
};

class Writer {
public:
  virtual ~Writer();
  virtual SerializeFormat Format() const = 0;

  virtual void Null() = 0;
  virtual void Bool(bool x) = 0;
  virtual void Int(int x) = 0;
  virtual void Int64(int64_t x) = 0;
  virtual void UInt8(uint8_t x) = 0;
  virtual void UInt32(uint32_t x) = 0;
  virtual void UInt64(uint64_t x) = 0;
  virtual void Double(double x) = 0;
  virtual void String(const char *x) = 0;
  virtual void String(const char *x, size_t len) = 0;
  virtual void StartArray(size_t) = 0;
  virtual void EndArray() = 0;
  virtual void StartObject() = 0;
  virtual void EndObject() = 0;
  virtual void Key(const char *name) = 0;
};

struct IndexFile;

#define REFLECT_MEMBER_START() ReflectMemberStart(visitor)
#define REFLECT_MEMBER_END() ReflectMemberEnd(visitor);
#define REFLECT_MEMBER(name) ReflectMember(visitor, #name, value.name)
#define REFLECT_MEMBER2(name, value) ReflectMember(visitor, name, value)

#define MAKE_REFLECT_TYPE_PROXY(type_name)                                     \
  MAKE_REFLECT_TYPE_PROXY2(type_name, std::underlying_type_t<type_name>)
#define MAKE_REFLECT_TYPE_PROXY2(type, as_type)                                \
  LLVM_ATTRIBUTE_UNUSED inline void Reflect(Reader &visitor, type &value) {    \
    as_type value0;                                                            \
    ::ccls::Reflect(visitor, value0);                                          \
    value = static_cast<type>(value0);                                         \
  }                                                                            \
  LLVM_ATTRIBUTE_UNUSED inline void Reflect(Writer &visitor, type &value) {    \
    auto value0 = static_cast<as_type>(value);                                 \
    ::ccls::Reflect(visitor, value0);                                          \
  }

#define _MAPPABLE_REFLECT_MEMBER(name) REFLECT_MEMBER(name);

#define MAKE_REFLECT_EMPTY_STRUCT(type, ...)                                   \
  template <typename TVisitor> void Reflect(TVisitor &visitor, type &value) {  \
    REFLECT_MEMBER_START();                                                    \
    REFLECT_MEMBER_END();                                                      \
  }

#define MAKE_REFLECT_STRUCT(type, ...)                                         \
  template <typename TVisitor> void Reflect(TVisitor &visitor, type &value) {  \
    REFLECT_MEMBER_START();                                                    \
    MACRO_MAP(_MAPPABLE_REFLECT_MEMBER, __VA_ARGS__)                           \
    REFLECT_MEMBER_END();                                                      \
  }

// clang-format off
// Config has many fields, we need to support at least its number of fields.
#define NUM_VA_ARGS_IMPL(_1,_2,_3,_4,_5,_6,_7,_8,_9,_10,_11,_12,_13,_14,_15,_16,_17,_18,_19,_20,_21,_22,_23,_24,_25,_26,_27,_28,_29,_30,N,...) N
#define NUM_VA_ARGS(...) NUM_VA_ARGS_IMPL(__VA_ARGS__,30,29,28,27,26,25,24,23,22,21,20,19,18,17,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1)
// clang-format on

#define _MAPPABLE_REFLECT_ARRAY(name) Reflect(visitor, value.name);

// Reflects the struct so it is serialized as an array instead of an object.
// This currently only supports writers.
#define MAKE_REFLECT_STRUCT_WRITER_AS_ARRAY(type, ...)                         \
  inline void Reflect(Writer &visitor, type &value) {                          \
    visitor.StartArray(NUM_VA_ARGS(__VA_ARGS__));                              \
    MACRO_MAP(_MAPPABLE_REFLECT_ARRAY, __VA_ARGS__)                            \
    visitor.EndArray();                                                        \
  }

//// Elementary types

void Reflect(Reader &visitor, uint8_t &value);
void Reflect(Writer &visitor, uint8_t &value);

void Reflect(Reader &visitor, short &value);
void Reflect(Writer &visitor, short &value);

void Reflect(Reader &visitor, unsigned short &value);
void Reflect(Writer &visitor, unsigned short &value);

void Reflect(Reader &visitor, int &value);
void Reflect(Writer &visitor, int &value);

void Reflect(Reader &visitor, unsigned &value);
void Reflect(Writer &visitor, unsigned &value);

void Reflect(Reader &visitor, long &value);
void Reflect(Writer &visitor, long &value);

void Reflect(Reader &visitor, unsigned long &value);
void Reflect(Writer &visitor, unsigned long &value);

void Reflect(Reader &visitor, long long &value);
void Reflect(Writer &visitor, long long &value);

void Reflect(Reader &visitor, unsigned long long &value);
void Reflect(Writer &visitor, unsigned long long &value);

void Reflect(Reader &visitor, double &value);
void Reflect(Writer &visitor, double &value);

void Reflect(Reader &visitor, bool &value);
void Reflect(Writer &visitor, bool &value);

void Reflect(Reader &visitor, std::string &value);
void Reflect(Writer &visitor, std::string &value);

void Reflect(Reader &visitor, std::string_view &view);
void Reflect(Writer &visitor, std::string_view &view);

void Reflect(Reader &vis, const char *&v);
void Reflect(Writer &vis, const char *&v);

void Reflect(Reader &visitor, JsonNull &value);
void Reflect(Writer &visitor, JsonNull &value);

void Reflect(Reader &visitor, SerializeFormat &value);
void Reflect(Writer &visitor, SerializeFormat &value);

//// 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(Reader &visitor, std::optional<T> &value) {
  if (visitor.IsNull()) {
    visitor.GetNull();
    return;
  }
  T real_value;
  Reflect(visitor, real_value);
  value = std::move(real_value);
}
template <typename T> void Reflect(Writer &visitor, std::optional<T> &value) {
  if (value) {
    if (visitor.Format() != SerializeFormat::Json)
      visitor.UInt8(1);
    Reflect(visitor, *value);
  } else
    visitor.Null();
}

// The same as std::optional
template <typename T> void Reflect(Reader &visitor, Maybe<T> &value) {
  if (visitor.IsNull()) {
    visitor.GetNull();
    return;
  }
  T real_value;
  Reflect(visitor, real_value);
  value = std::move(real_value);
}
template <typename T> void Reflect(Writer &visitor, Maybe<T> &value) {
  if (value) {
    if (visitor.Format() != SerializeFormat::Json)
      visitor.UInt8(1);
    Reflect(visitor, *value);
  } else
    visitor.Null();
}

template <typename T>
void ReflectMember(Writer &visitor, const char *name, std::optional<T> &value) {
  // 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 (value || visitor.Format() != SerializeFormat::Json) {
    visitor.Key(name);
    Reflect(visitor, value);
  }
}

// The same as std::optional
template <typename T>
void ReflectMember(Writer &visitor, const char *name, Maybe<T> &value) {
  if (value.Valid() || visitor.Format() != SerializeFormat::Json) {
    visitor.Key(name);
    Reflect(visitor, value);
  }
}

template <typename L, typename R>
void Reflect(Reader &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(Writer &vis, std::pair<L, R> &v) {
  vis.StartObject();
  ReflectMember(vis, "L", v.first);
  ReflectMember(vis, "R", v.second);
  vis.EndObject();
}

// std::vector
template <typename T> void Reflect(Reader &visitor, std::vector<T> &values) {
  visitor.IterArray([&](Reader &entry) {
    T entry_value;
    Reflect(entry, entry_value);
    values.push_back(std::move(entry_value));
  });
}
template <typename T> void Reflect(Writer &visitor, std::vector<T> &values) {
  visitor.StartArray(values.size());
  for (auto &value : values)
    Reflect(visitor, value);
  visitor.EndArray();
}

// ReflectMember

inline bool ReflectMemberStart(Reader &vis) { return false; }
inline bool ReflectMemberStart(Writer &vis) {
  vis.StartObject();
  return true;
}

inline void ReflectMemberEnd(Reader &vis) {}
inline void ReflectMemberEnd(Writer &vis) { vis.EndObject(); }

template <typename T> void ReflectMember(Reader &vis, const char *name, T &v) {
  vis.Member(name, [&]() { Reflect(vis, v); });
}
template <typename T> void ReflectMember(Writer &vis, const char *name, T &v) {
  vis.Key(name);
  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