#define _USE_MATH_DEFINES

#include <stdio.h>
#include <stdlib.h>
#include <windows.h>
#include <tlhelp32.h>
#include <math.h>

#include "../mumble_plugin.h"

HANDLE h = NULL;

static DWORD getProcess(const wchar_t *exename) {
	PROCESSENTRY32 pe;
	DWORD pid = 0;

	pe.dwSize = sizeof(pe);
	HANDLE hSnap = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
	if (hSnap != INVALID_HANDLE_VALUE) {
		BOOL ok = Process32First(hSnap, &pe);

		while (ok) {
			if (wcscmp(pe.szExeFile, exename)==0) {
				pid = pe.th32ProcessID;
				break;
			}
			ok = Process32Next(hSnap, &pe);
		}
		CloseHandle(hSnap);
	}
	return pid;
}

static bool peekProc(VOID *base, VOID *dest, SIZE_T len) {
	SIZE_T r;
	BOOL ok=ReadProcessMemory(h, base, dest, len, &r);
	return (ok && (r == len));
}

static void about(HWND h) {
	::MessageBox(h, L"Reads audio position information from Wolfenstein: Enemy Territory (v 2.60b)", L"Mumble W:ET plugin", MB_OK);
}


static int fetch(float *pos, float *front, float *top) {
	float viewHor, viewVer;
	char state;

	for (int i=0;i<3;i++)
		pos[i]=front[i]=top[i]=0.0;

	bool ok;

	/*
		This plugin uses the following Variables:

			Address			Type	Description
			===================================
			0x013F79CC		float	Y-Coordinate
			0x013E8CF4		float	X-Coordinate
			0x013E8CF8		float	Z-Coordinate
			0x013F9E20		float	Horizontal view
			0x013F9E1C		float	Vertical view
			0x013E8D18		byte	Magic value (32 ingame / 0 spectating)
	*/
	ok = peekProc((BYTE *) 0x013E8D18, &state, 1);
	if (! ok)
		return false;

	if (state != 32)
		return true; // If this magic value is !=32 we are spectating, so switch off PA

	ok = peekProc((BYTE *) 0x013F79CC, pos+1, 4) &&	//Y
	     peekProc((BYTE *) 0x013E8CF4, pos, 4) &&	//X
	     peekProc((BYTE *) 0x013E8CF8, pos+2, 4) && //Z
	     peekProc((BYTE *) 0x013F9E20, &viewHor, 4) && //Hor
	     peekProc((BYTE *) 0x013F9E1C, &viewVer, 4); //Ver

	if (! ok)
		return false;

	/*
	   Z-Value is increasing when heading north
				  decreasing when heading south
	   X-Value is increasing when heading east
				  decreasing when heading west
	   Y-Value is increasing when going up
				  decreasing when going down
	   1 unit = 1 meter (not confirmed)
	*/

	// Fake top vector
	top[2] = -1; // Head movement is in front vector
	// Calculate view unit vector
	/*
	   Vertical view 0 when centered
				   -90 when looking up
				   +90 when looking down
	   Increasing when looking down.

	   Horizontal is 90 when facing north
					  0 when facing east
					-90 when facing south
					+/-180 when facing west
	   Increasing when turning left.
	*/
	viewVer *= (float)M_PI/180;
	viewHor *= (float)M_PI/180;

	front[0] = cos(viewVer) * cos(viewHor);
	front[1] = -sin(viewVer);
	front[2] = cos(viewVer) * sin(viewHor);

	return ok;
}

static int trylock() {
	h = NULL;
	DWORD pid=getProcess(L"ET.exe");
	if (!pid)
		return false;

	h=OpenProcess(PROCESS_VM_READ, false, pid);
	if (!h)
		return false;

	float pos[3], front[3], top[3];
	if (fetch(pos, front, top))
		return true;

	CloseHandle(h);
	h = NULL;
	return false;
}

static void unlock() {
	if (h) {
		CloseHandle(h);
		h = NULL;
	}
}

static MumblePlugin wolfetplug = {
	MUMBLE_PLUGIN_MAGIC,
	L"Wolfenstein: Enemy Territory 2.60b",
	L"Wolfenstein: Enemy Territory",
	about,
	NULL,
	trylock,
	unlock,
	fetch
};

extern "C" __declspec(dllexport) MumblePlugin *getMumblePlugin() {
	return &wolfetplug;
}