#pragma once

#include <array>
#include <cstddef>
#include <cstdint>
#include <memory>
#include <string>
#include <unordered_map>
#include <vector>

#include <mio/mmap.hpp>
#include <sodium.h>

class CBufferPool;

constexpr std::size_t M2PACK_MAGIC_SIZE = 8;
constexpr std::size_t M2PACK_HASH_SIZE = 32;
constexpr std::size_t M2PACK_SIGNATURE_SIZE = 64;
constexpr std::size_t M2PACK_KEY_SIZE = crypto_aead_xchacha20poly1305_ietf_KEYBYTES;
constexpr std::size_t M2PACK_NONCE_SIZE = crypto_aead_xchacha20poly1305_ietf_NPUBBYTES;
constexpr std::size_t M2PACK_PUBLIC_KEY_SIZE = crypto_sign_PUBLICKEYBYTES;

#pragma pack(push, 1)
struct TM2PackHeader
{
	char magic[M2PACK_MAGIC_SIZE];
	uint32_t version;
	uint32_t flags;
	uint32_t key_id;
	uint64_t manifest_offset;
	uint64_t manifest_size;
	uint8_t manifest_hash[M2PACK_HASH_SIZE];
	uint8_t manifest_signature[M2PACK_SIGNATURE_SIZE];
	uint8_t reserved[60];
};

struct TM2PackManifestHeader
{
	uint32_t entry_count;
	uint32_t flags;
};

struct TM2PackManifestEntryFixed
{
	uint16_t path_size;
	uint8_t compression;
	uint8_t flags;
	uint64_t data_offset;
	uint64_t original_size;
	uint64_t stored_size;
	uint8_t nonce[M2PACK_NONCE_SIZE];
	uint8_t plaintext_hash[M2PACK_HASH_SIZE];
};
#pragma pack(pop)

struct TM2PackEntry
{
	std::string path;
	uint8_t compression = 0;
	uint64_t data_offset = 0;
	uint64_t original_size = 0;
	uint64_t stored_size = 0;
	std::array<uint8_t, M2PACK_NONCE_SIZE> nonce {};
	std::array<uint8_t, M2PACK_HASH_SIZE> plaintext_hash {};
};

class CM2Pack : public std::enable_shared_from_this<CM2Pack>
{
public:
	CM2Pack() = default;
	~CM2Pack() = default;

	bool Load(const std::string& path);
	const std::vector<TM2PackEntry>& GetIndex() const { return m_index; }

	bool GetFile(const TM2PackEntry& entry, std::vector<uint8_t>& result);
	bool GetFileWithPool(const TM2PackEntry& entry, std::vector<uint8_t>& result, CBufferPool* pPool);

private:
	bool ValidateManifest();
	bool DecryptEntryPayload(const TM2PackEntry& entry, std::vector<uint8_t>& decrypted, CBufferPool* pPool);

private:
	TM2PackHeader m_header {};
	std::vector<uint8_t> m_manifest_bytes;
	std::vector<TM2PackEntry> m_index;
	mio::mmap_source m_file;
};

using TM2PackFileMapEntry = std::pair<std::shared_ptr<CM2Pack>, TM2PackEntry>;
using TM2PackFileMap = std::unordered_map<std::string, TM2PackFileMapEntry>;

#include "M2PackKeys.h"