CoopAllTheThings/hook/src/ipc_client.hpp

// Hook-side view of the shared-memory IPC channel. The host creates the section
// (named by the target game's pid); we open it from inside the game and read the
// forwarded pad state the host publishes each frame.
#pragma once

#include <atomic>
#include <cstdint>

#include <windows.h>

#include "coop/protocol.hpp"
#include "coop/shared_memory.hpp"

namespace coop::hook
{

class IpcClient
{
public:
	// Tries to open the section a few times: the host may inject us slightly
	// before (or after) it creates the mapping. Returns true once connected.
	bool connect(int attempts, int delay_ms)
	{
		const std::wstring name = shared_memory_name(GetCurrentProcessId());
		for (int i = 0; i < attempts; ++i)
		{
			if (shm_.open(name, sizeof(SharedBlock)))
			{
				auto* block = shm_.as<SharedBlock>();
				if (block->magic == kProtocolMagic && block->version == kProtocolVersion)
				{
					block_ = block;
					return true;
				}
				shm_.reset(); // present but not a contract we understand; retry
			}
			Sleep(static_cast<DWORD>(delay_ms));
		}
		return false;
	}

	[[nodiscard]] bool connected() const
	{
		return block_ != nullptr;
	}

	// Host-requested install state for a subsystem (default = install, since the
	// mapping is zero-filled and 0 means "disabled flag clear" = install).
	[[nodiscard]] bool subsystem_install_requested(std::uint32_t subsystem) const
	{
		if (block_ == nullptr || subsystem >= HookSubsys_Count)
		{
			return true;
		}
		return block_->control.subsystem_disabled[subsystem].load(std::memory_order_acquire) == 0;
	}

	// Whether the game is allowed to clip/position the cursor (false = release it,
	// the default). Drives the Focus subsystem's ClipCursor/SetCursorPos hooks.
	[[nodiscard]] bool cursor_clip_allowed() const
	{
		return block_ != nullptr && block_->control.allow_cursor_clip.load(std::memory_order_acquire) != 0;
	}

	// Copies a torn-free snapshot of all slots. Returns false only if the host
	// was mid-write for the whole spin window (caller should reuse its cache).
	bool snapshot(CoopPadState (&out)[kMaxPads], std::uint32_t& count) const
	{
		if (block_ == nullptr)
		{
			return false;
		}
		return read_pads(*block_, out, count);
	}

	// --- Status back-channel (hook -> host diagnostics) --------------------

	// Record that the game queried a controller slot via XInputGetState/Ex.
	void note_state_query(std::uint32_t user_index)
	{
		if (block_ != nullptr && user_index < kMaxPads)
		{
			block_->status.get_state_calls[user_index].fetch_add(1, std::memory_order_relaxed);
		}
	}

	void note_caps_query(std::uint32_t user_index)
	{
		if (block_ != nullptr && user_index < kMaxPads)
		{
			block_->status.get_caps_calls[user_index].fetch_add(1, std::memory_order_relaxed);
		}
	}

	void note_focus_query(FocusApi which)
	{
		if (block_ != nullptr && which < FocusApi_Count)
		{
			block_->status.focus_query_calls[which].fetch_add(1, std::memory_order_relaxed);
		}
	}

	void mark_attached()
	{
		if (block_ != nullptr)
		{
			block_->status.game_pid = GetCurrentProcessId();
			block_->status.attached = 1;
		}
	}

	// XInput hooks were removed (host unhooked input): clear the attached flag so
	// the Controllers panel stops showing stale poll rates.
	void mark_detached()
	{
		if (block_ != nullptr)
		{
			block_->status.attached = 0;
		}
	}

	void mark_focus_spoof(bool active, std::uint64_t game_hwnd)
	{
		if (block_ != nullptr)
		{
			block_->status.focus_spoof = active ? 1u : 0u;
			block_->status.game_hwnd = game_hwnd;
		}
	}

	void set_input_diagnostics(bool raw_registered, bool raw_gamepad, bool raw_gamepad_sink, bool dinput)
	{
		if (block_ != nullptr)
		{
			block_->status.raw_input_registered = raw_registered ? 1u : 0u;
			block_->status.raw_input_gamepad = raw_gamepad ? 1u : 0u;
			block_->status.raw_input_gamepad_sink = raw_gamepad_sink ? 1u : 0u;
			block_->status.dinput_loaded = dinput ? 1u : 0u;
		}
	}

	void heartbeat()
	{
		if (block_ != nullptr)
		{
			block_->status.heartbeat.fetch_add(1, std::memory_order_relaxed);
		}
	}

	// Record the rumble the game requested for a slot (so the host can forward it to
	// the guest's controller). Plain stores; the hook is the sole writer.
	void note_rumble(std::uint32_t slot, std::uint16_t left, std::uint16_t right)
	{
		if (block_ != nullptr && slot < kMaxPads)
		{
			block_->status.rumble_left[slot] = left;
			block_->status.rumble_right[slot] = right;
		}
	}

	// Record the state the hook just returned to the game for a slot (round-trip view).
	void note_read_state(std::uint32_t slot, const CoopPadState& state)
	{
		if (block_ != nullptr && slot < kMaxPads)
		{
			block_->status.read_state[slot] = state;
		}
	}

	// --- Audio render-hook diagnostics -------------------------------------

	// Total distinct render streams the audio hook has observed.
	void set_audio_streams_seen(std::uint32_t count)
	{
		if (block_ != nullptr)
		{
			block_->status.audio_streams_seen = count;
		}
	}

	// Publish a tracked stream's format/role into its debug slot.
	void publish_audio_stream(std::uint32_t slot, const AudioStreamInfo& info)
	{
		if (block_ != nullptr && slot < kMaxAudioStreams)
		{
			block_->status.audio_streams[slot] = info;
		}
	}

	// Update a tracked stream's cumulative frame count (host derives live/idle).
	void note_audio_frames(std::uint32_t slot, std::uint64_t frames)
	{
		if (block_ != nullptr && slot < kMaxAudioStreams)
		{
			block_->status.audio_streams[slot].frames_rendered = frames;
		}
	}

	// --- Present-hook video channel ----------------------------------------

	// Record that the game's Present() ran (diagnostic counter, hook is sole writer).
	void note_present()
	{
		if (block_ != nullptr)
		{
			block_->video.present_calls += 1;
		}
	}

	// Publish that a fresh backbuffer copy is in the shared texture (named
	// coop_video_<pid>) with these dimensions/format; bumps the generation the host
	// polls. The texture itself is shared out-of-band by name, not through here.
	void publish_video_frame(std::uint32_t width, std::uint32_t height, std::uint32_t format)
	{
		if (block_ != nullptr)
		{
			block_->video.width = width;
			block_->video.height = height;
			block_->video.format = format;
			block_->video.generation.fetch_add(1, std::memory_order_release);
		}
	}

	// --- Mouse + keyboard forwarding ---------------------------------------

	// The host's MKB event queue (nullptr if not connected). The MKB subsystem
	// drains it; the host is the sole producer.
	[[nodiscard]] MkbRing* mkb_ring()
	{
		return block_ != nullptr ? &block_->mkb : nullptr;
	}

	// --- Hook registry -----------------------------------------------------

	// Publish the installed-hooks table (name / subsystem / installed / calls).
	void publish_hook_entries(const HookEntry* entries, std::uint32_t count)
	{
		if (block_ == nullptr)
		{
			return;
		}
		if (count > kMaxHookEntries)
		{
			count = kMaxHookEntries;
		}
		for (std::uint32_t i = 0; i < count; ++i)
		{
			block_->status.hook_entries[i] = entries[i];
		}
		block_->status.hook_entry_count = count;
	}

private:
	SharedMemory shm_;
	SharedBlock* block_ = nullptr;
};

} // namespace coop::hook