/*
 * Copyright © 2022 Michael Smith <mikesmiffy128@gmail.com>
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED “AS IS” AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
 * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */

#include <stdbool.h>
#include <string.h>

#include "con_.h"
#include "engineapi.h"
#include "extmalloc.h"
#include "gametype.h"
#include "hook.h"
#include "intdefs.h"
#include "mem.h"
#include "os.h"
#include "ppmagic.h"
#include "vcall.h"

// It's like the thing Portal Tools does, but at runtime!

DEF_CVAR(sst_portal_colour0, "Crosshair colour for gravity beam (hex)",
		"F2CAA7", CON_ARCHIVE | CON_HIDDEN)
DEF_CVAR(sst_portal_colour1, "Crosshair colour for left portal (hex)",
		"40A0FF", CON_ARCHIVE | CON_HIDDEN)
DEF_CVAR(sst_portal_colour2, "Crosshair colour for right portal (hex)",
		"FFA020", CON_ARCHIVE | CON_HIDDEN)
// XXX: bit weird that this is still con_colour. should we move it back out to
// engineapi as a general colour struct??
static struct con_colour colours[3] = {
		{242, 202, 167, 255}, {64, 160, 255, 255}, {255, 160, 32, 255}};

static void hexparse(uchar out[static 4], const char *s) {
	const char *p = s;
	for (uchar *q = out; q - out < 3; ++q) {
		if (*p >= '0' && *p <= '9') {
			*q = *p++ - '0' << 4;
		}
		else if ((*p | 32) >= 'a' && (*p | 32) <= 'f') {
			*q = 10 + (*p++ | 32) - 'a' << 4;
		}
		else {
			// screw it, just fall back on white, I guess.
			// note: this also handles *p == '\0' so we don't overrun the string
			memset(out, 255, 4); // write 4 rather than 3, prolly faster?
			return;
		}
		// repetitive unrolled nonsense
		if (*p >= '0' && *p <= '9') {
			*q |= *p++ - '0';
		}
		else if ((*p | 32) >= 'a' && (*p | 32) <= 'f') {
			*q |= 10 + (*p++ | 32) - 'a';
		}
		else {
			memset(out, 255, 4);
			return;
		}
	}
	//out[3] = 255; // never changes!
}

static void colourcb(struct con_var *v) {
	// this is stupid and ugly and has no friends, too bad!
	if (v == sst_portal_colour0) {
		hexparse(colours[0].bytes, con_getvarstr(v));
	}
	else if (v == sst_portal_colour1) {
		hexparse(colours[1].bytes, con_getvarstr(v));
	}
	else /* sst_portal_colour2 */ {
		hexparse(colours[2].bytes, con_getvarstr(v));
	}
}

// Original sig is the following but we wanna avoid calling convention weirdness
//typedef struct con_colour (*UTIL_Portal_Color_func)(int);
typedef void (*UTIL_Portal_Color_func)(struct con_colour *out, int portal);
static UTIL_Portal_Color_func orig_UTIL_Portal_Color;
static void hook_UTIL_Portal_Color(struct con_colour *out, int portal) {
	if (portal < 0 || portal > 2) *out = (struct con_colour){255, 255, 255, 255};
	else *out = colours[portal];
}

// TODO(compat): would like to do the usual pointer-chasing business instead of
// using hardcoded offsets, but that's pretty hard here. Would probably have to
// do the entprops stuff for ClientClass, get at the portalgun factory, get a
// vtable, find ViewModelDrawn or something, chase through another 4 or 5 call
// offsets to find something that calls UTIL_Portal_Color... that or dig through
// vgui/hud entries, find the crosshair drawing...
//
// For now we do this!

static bool find_UTIL_Portal_Color(void *base) {
	static const uchar x[] = HEXBYTES(8B, 44, 24, 08, 83, E8, 00, 74, 37, 83,
			E8, 01, B1, FF, 74, 1E, 83, E8, 01, 8B, 44, 24, 04, 88);
	// 5135
	orig_UTIL_Portal_Color = (UTIL_Portal_Color_func)mem_offset(base, 0x1BF090);
	if (!memcmp((void *)orig_UTIL_Portal_Color, x, sizeof(x))) return true;
	// 3420
	orig_UTIL_Portal_Color = (UTIL_Portal_Color_func)mem_offset(base, 0x1AA810);
	if (!memcmp((void *)orig_UTIL_Portal_Color, x, sizeof(x))) return true;
	return false;
}

bool portalcolours_init(void *clientlib) { // ... should libs be globals?
	if (!GAMETYPE_MATCHES(Portal)) return false;
#ifdef _WIN32
	if (!find_UTIL_Portal_Color(clientlib)) {
		con_warn("portalcolours: error: couldn't find UTIL_Portal_Color\n");
		return false;
	}
	orig_UTIL_Portal_Color = (UTIL_Portal_Color_func)hook_inline(
			(void *)orig_UTIL_Portal_Color, (void *)&hook_UTIL_Portal_Color);
	if (!orig_UTIL_Portal_Color) {
		con_warn("portalcolours: error: couldn't hook UTIL_Portal_Color\n");
		return false;
	}
	sst_portal_colour0->base.flags &= ~CON_HIDDEN;
	sst_portal_colour0->cb = &colourcb;
	sst_portal_colour1->base.flags &= ~CON_HIDDEN;
	sst_portal_colour1->cb = &colourcb;
	sst_portal_colour2->base.flags &= ~CON_HIDDEN;
	sst_portal_colour2->cb = &colourcb;
	return true;
#else
#warning TODO(linux): yet more stuff!
	return false;
#endif
}

void portalcolours_end(void) {
	unhook_inline((void *)orig_UTIL_Portal_Color);
}

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