mtgodot-poc/extension/src/net/classic/classic_parser.h

#pragma once
// ClassicParser — 40250 GC packet bodies -> shared world model (EntityStore via
// its protocol-neutral mut_* API) + login/char-list state.
// Counterpart of EntityStore::apply() for MT_PROTOCOL=classic.
// See docs/CLIENT-40250-PORT.md §4 / §5.
//
// `body` is the bytes AFTER the 1-byte header (for dynamic packets: after the
// [header][uint16 size] prefix); `len` its length — i.e. exactly what
// ClassicStream::on_packet delivers.

#include "npc_names.h"
#include "wire_classic.h"

#include "../entity_store.h"

#include <cstdint>
#include <functional>
#include <string>
#include <unordered_map>
#include <vector>

namespace mtnet::classic {

struct CharSlot {
	uint32_t id = 0;
	std::string name;
	uint8_t job = 0;
	uint8_t level = 0;
	uint8_t st = 0, ht = 0, dx = 0, iq = 0;
	uint32_t play_minutes = 0;
	int32_t x = 0, y = 0;
	int32_t addr = 0;
	uint16_t port = 0;
	uint16_t main_part = 0, hair_part = 0;
	uint8_t skill_group = 0;
	// Server requires this character to be renamed before entering the game.
	bool change_name = false;
	uint32_t guild_id = 0;
	std::string guild_name;
	bool empty() const { return id == 0 && name.empty(); }
};

class ClassicParser {
public:
	struct CharEvent {
		enum Kind { CreateOk, CreateFail, DeleteOk, DeleteFail } kind;
		int slot = -1;
		int fail_type = 0;
	};
	struct NameEvent {
		uint32_t pid = 0;
		std::string name;
	};

	explicit ClassicParser(EntityStore &world) : m_world(world) {}

	// one GC packet. returns false to abort the connection.
	bool on_gc(uint8_t header, const uint8_t *body, uint32_t len);

	// --- login / select state ---
	const std::vector<CharSlot> &char_slots() const { return m_slots; }
	int slot_count() const { return m_slot_count; }        // 3 or 4
	uint32_t handle() const { return m_handle; }
	uint32_t random_key() const { return m_random_key; }
	bool char_list_ready() const { return m_char_list_ready; }
	const std::string &login_failure() const { return m_login_failure; }
	uint32_t login_key() const { return m_login_key; }     // GC_LOGIN_KEY (auth path)
	uint8_t empire() const { return m_empire; }
	void set_phase_name(const std::string &name) { m_phase_name = name; }
	const std::string &last_error() const { return m_last_error; }
	// §2.2: path to root/npclist.txt (race -> model-code table). Used to name
	// monster / stone / object spawns, mirroring CPythonNonPlayer::GetName().
	// Empty path -> names resolve to "" (permitted). Falls back to
	// $MT_ASSETS / $M2_ASSETS when never set.
	// TODO(W0): M2Client should call
	//   parser().set_npclist_path(AssetRoot::path("root/npclist.txt"))
	void set_npclist_path(std::string path);
	// §2.2 test hook: number of GC_CHARACTER_ADD records awaiting their
	// GC_CHAR_ADDITIONAL_INFO merge.
	size_t pending_actor_count() const { return m_pending_actor.size(); }
	std::vector<uint8_t> drain_unhandled_headers() {
		auto v = std::move(m_unhandled_headers);
		m_unhandled_headers.clear();
		return v;
	}
	std::vector<CharEvent> drain_char_events() {
		auto v = std::move(m_char_events);
		m_char_events.clear();
		return v;
	}
	std::vector<NameEvent> drain_name_events() {
		auto v = std::move(m_name_events);
		m_name_events.clear();
		return v;
	}
	int drain_guild_make_requests() {
		int count = m_guild_make_requests;
		m_guild_make_requests = 0;
		return count;
	}

private:
	template <class T>
	static bool fill(T &t, uint8_t header, const uint8_t *body, uint32_t len) {
		if (len + 1u < sizeof(T)) {
			return false;
		}
		t.header = header;
		std::memcpy(reinterpret_cast<uint8_t *>(&t) + 1, body, sizeof(T) - 1);
		return true;
	}
	void parse_login_success(const SimplePlayer *players, const uint32_t *guild_id,
			const char (*guild_name)[GUILD_NAME_MAX_LEN + 1], int n, uint32_t handle,
			uint32_t rkey);
	// Lazily loads npclist.txt on first use; returns "" for an unknown race or
	// when no list is available.
	const std::string &npc_name_for(uint16_t race);

	EntityStore &m_world;
	// §2.2 two-packet PC/NPC merge: GC_CHARACTER_ADD stages a bare Entity here
	// keyed by vid; GC_CHAR_ADDITIONAL_INFO merges its fields and flushes the
	// combined record via m_world.mut_spawn_full(). W1 owns the merge logic.
	std::unordered_map<uint32_t, Entity> m_pending_actor;
	std::string m_npclist_path;
	std::unordered_map<uint32_t, std::string> m_npc_names;
	bool m_npc_names_loaded = false;
	std::vector<CharSlot> m_slots;
	int m_slot_count = 0;
	uint32_t m_handle = 0;
	uint32_t m_random_key = 0;
	uint32_t m_login_key = 0;
	uint8_t m_empire = 0;
	std::vector<CharEvent> m_char_events;
	std::vector<NameEvent> m_name_events;
	int m_guild_make_requests = 0;
	bool m_char_list_ready = false;
	std::string m_login_failure;
	std::string m_phase_name = "Offline";
	std::string m_last_error;
	std::vector<uint8_t> m_unhandled_headers;
};

} // namespace mtnet::classic