#include "config.h"
#include "error.h"
#include "maths.h"
#include "memory.h"
#include "plat.h"

#ifdef plat_posix

#define _POSIX_SOURCE
#define _GNU_SOURCE
#include <fcntl.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h>
#include <time.h>
#include <unistd.h>

extern int isatty(int);
extern int fileno(FILE*);

int imp_assert(
	int val,
	const char* expr,
	const char* file,
	int line
) {
	if (!val) {
		print_err(
			"%d:%s: Assertion failed: %s.\n",
			line,
			file,
			expr
		);
		pbreak(error_assertion_failed);
		return 0;
	}
	return 1;
}

void print(const char* fmt, ...) {
	va_list args;
	va_start(args, fmt);
	vfprintf(stdout, fmt, args);
	va_end(args);
}

void print_err(const char* fmt, ...) {
	va_list args;
	va_start(args, fmt);

	if (isatty(fileno(stderr))) {
		fprintf(stderr, "\033[31;31m");
	}

	vfprintf(stderr, fmt, args);

	if (isatty(fileno(stderr))) {
		fprintf(stderr, "\033[0m");
	}

	va_end(args);
}

void print_war(const char* fmt, ...) {
	va_list args;
	va_start(args, fmt);

	if (isatty(fileno(stderr))) {
		fprintf(stderr, "\033[31;35m");
	}

	vfprintf(stderr, fmt, args);

	if (isatty(fileno(stderr))) {
		fprintf(stderr, "\033[0m");
	}

	va_end(args);
}

void pbreak(Error code) {
#if defined(DEBUG) && defined(plat_x86)
	__asm__("int3;");
	(void)code;
#else
	exit(code);
#endif
}

struct File {
	int handle;
	int cursor;
	int size;
};

File* file_open(const char* name, File_Flags flags) {
	File* file;
	int handle, f = 0;
	struct stat info;

	if (flags & file_flags_write) {
		f |= O_WRONLY | O_TRUNC;
	}

	if (flags & file_flags_read) {
		f |= O_RDONLY;
	}

	if (flags & file_flags_read_write) {
		f |= O_RDWR;
	}

	if (stat(name, &info) < 0) {
		info.st_size = 0;
		if (flags & file_flags_create) {
			f |= O_CREAT | S_IRUSR | S_IWUSR;
		}
	}

	handle = open(name, f);
	if (handle < 0) {
		return 0;
	}

	file = (File*)malloc(sizeof *file);
	file->handle = handle;
	file->cursor = 0;
	file->size = (int)info.st_size;

	return file;
}

void file_close(File* file) {
	close(file->handle);
	free(file);
}

void file_read(File* file, void* buffer, int size) {
	lseek(file->handle, (off_t)file->cursor, SEEK_SET);
	read(file->handle, buffer, size);
	file->cursor += size;
}

void file_write(File* file, const void* buffer, int size) {
	lseek(file->handle, (off_t)file->cursor, SEEK_SET);
	write(file->handle, buffer, size);
	file->cursor += size;
}

void file_seek(File* file, int offset, File_Whence whence) {
	switch (whence) {
		case file_whence_begin:
			file->cursor = offset;
			break;
		case file_whence_end:
			file->cursor = file->size - offset;
			break;
		case file_whence_cur:
			file->cursor += offset;
			break;
	}
}

int file_size(File* file) {
	return file->size;
}

int file_exists(const char* name) {
	struct stat info;
	return stat(name, &info) == 0;
}


static clockid_t global_clock;
static unsigned long global_freq;

void init_timer(void) {
	struct timespec ts;
	global_clock = CLOCK_REALTIME;
	global_freq = 1000000000;
#if defined(_POSIX_MONOTONIC_CLOCK)
	if (clock_gettime(CLOCK_MONOTONIC, &ts) == 0) {
		global_clock = CLOCK_MONOTONIC;
	}
#else
	(void)ts;
#endif
}

unsigned long get_timer(void) {
	struct timespec ts;
	clock_gettime(global_clock, &ts);
	return
		(unsigned long)ts.tv_sec * global_freq +
		(unsigned long)ts.tv_nsec;
}

void sleep_ns(unsigned long ns) {
	struct timespec t = { 0 };
	t.tv_nsec = ns;
	nanosleep(&t, &t);
}

void init_fps(FPS* f, int mpf) {
	f->now = get_timer();
	f->next = f->now;
	f->mpf = mpf;
	f->pt = 0;
	f->ct = -1;
}

void fps_begin(FPS* f) {
	f->now = get_timer();
}

void fps_end(FPS* f) {
	unsigned long ts = f->next - f->now;
	if (ts > 0) {
		sleep_ns(ts);
	}
}

void fps_update(FPS* f) {
	f->next += f->mpf * 1000000;
	f->pt = f->ct;
	f->ct = get_timer();
	f->fps = 1000000000 / (f->ct - f->pt);
}

#include <stdlib.h>

extern int entrypoint(int, const char**, Arena*);

int main(int argc, const char** argv) {
	Arena a;
	void* mem = malloc(memory_size);
	if (!mem) {
		print_err("Out of memory.\n");
		return error_out_of_memory;
	}
	init_timer();
	init_arena(
		&a,
		mem,
		memory_size
	);
	return entrypoint(argc, argv, &a);
}

#endif

#ifdef plat_x11

#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <X11/extensions/XInput2.h>

#include <stdlib.h>

typedef struct {
	Display* d;
	Window wi;
	GC gc;
	int w, h;
	int rmx, rmy;
	int omx, omy;
	int ms;
	unsigned long begin, end;
	XImage* bb;
	Colour* bbp;
	Atom wm_delete;
} App_Internal;

void init_rendering(
	App* a,
	App_Internal* i,
	XWindowAttributes* wa
) {
	Colour* p, * fb;
	int w = max_pc_window_w;
	int h = max_pc_window_h;
	int tw = max_vp_w;
	int th = max_vp_h;
	p = malloc(sizeof *p * w * h);
	fb = heap_alloc(a->heap, sizeof *p * tw * th);
	if (!p || !fb) {
		print_err("Out of memory.\n");
		pbreak(error_out_of_memory);
	}
	a->fb = fb;
	i->bb = XCreateImage(
		i->d,
		wa->visual,
		wa->depth,
		ZPixmap,
		0,
		(char*)p,
		w,
		h,
		32,
		w * sizeof *p
	);
	if (!i->bb) {
		print_err("Failed to create X11 backbuffer.\n");
		pbreak(error_platform_error);
	}
	i->bbp = p;
}

void init_window(App* a, App_Internal* i, const char* n) {
	Window root, w;
	Display* d;
	XWindowAttributes wa;
	unsigned rm, bm;
	i->bb = 0;
	i->bbp = 0;
	d = i->d;
	root = DefaultRootWindow(d);
	w = XCreateSimpleWindow(
		d,
		root,
		0,
		0,
		a->w * a->s,
		a->h * a->s,
		0,
		WhitePixel(d, 0),
		BlackPixel(d, 0)
	);
	i->wi = w;
	i->wm_delete = XInternAtom(
		d,
		"WM_DELETE_WINDOW",
		0
	);
	XSetWMProtocols(d, w, &i->wm_delete, 1);
	XStoreName(d, w, n);
	XSelectInput(
		d,
		w,
		ExposureMask      |
		KeyPressMask      |
		KeyReleaseMask    |
		PointerMotionMask |
		ButtonPressMask   |
		ButtonReleaseMask
	);
	XMapRaised(d, w);
	i->gc = XCreateGC(d, w, 0, 0);
	if (!i->gc) {
		print_err("Failed to create X graphics context.\n");
		pbreak(error_platform_error);
	}
	XGetWindowAttributes(d, w, &wa);
	if (wa.depth != 24 && wa.depth != 32) {
		print_err("Only true colour displays are supported.\n");
		pbreak(error_platform_error);
	}
	rm = wa.visual->red_mask  & 0x1000000;
	bm = wa.visual->blue_mask & 0xffffff;
	if ((rm == 0xff && bm == 0xff0000)) {
		print_war("Detected BGR. Colours will look fucked.\n");
	}
	init_rendering(a, i, &wa);
	a->w = (wa.width  + a->s) / a->s;
	a->h = (wa.height + a->s) / a->s;
	i->w = wa.width;
	i->h = wa.height;
}

App* new_app(Heap* mem, int w, int h, const char* n) {
	App* a;
	App_Internal* i;
	a = heap_alloc(mem, sizeof *a + sizeof *i);
	i = (App_Internal*)(&a[1]);
	a->heap = mem;
	a->s = 2;
	a->o = 0;
	a->err = error_none;
	a->w = w;
	a->h = h;
	i->d = XOpenDisplay(0);
	i->omx = i->omy = 0;
	if (!i->d) {
		print_err("Failed to open X11 display.\n");
		pbreak(error_platform_error);
	}
	init_window(a, i, n);
	a->o = 1;
	return a;
}

void deinit_app(App* a) {
	App_Internal* i = (App_Internal*)(&a[1]);
	XDestroyImage(i->bb);
	XFreeGC(i->d, i->gc);
	XDestroyWindow(i->d, i->wi);
	XCloseDisplay(i->d);
	heap_free(a->heap, a);
}

void app_begin(App* a) {
	App_Internal* i = (App_Internal*)(&a[1]);
	Display* d = i->d;
	Window w = i->wi;
	i->begin = get_timer();
	while (XPending(d)) {
		XEvent e;
		XWindowAttributes wa;
		XNextEvent(d, &e);
		switch (e.type) {
			case ClientMessage:
				if (
					(Atom)e.xclient.data.l[0] ==
					i->wm_delete
				) {
					a->o = 0;
				}
				break;
			case Expose:
				XGetWindowAttributes(d, w, &wa);
				a->w = (wa.width  + a->s) / a->s;
				a->h = (wa.height + a->s) / a->s;
				a->w = mini(a->w, max_vp_w);
				a->h = mini(a->h, max_vp_w);
				i->w = mini(wa.width,  max_pc_window_w);
				i->h = mini(wa.height, max_pc_window_h);
				break;
			case MotionNotify:
				if (i->ms) {
					a->mx = e.xmotion.x / a->s;
					a->my = e.xmotion.y / a->s;
				}
				break;
			case GenericEvent:
				if (!i->ms) {
					if (
						XGetEventData(d, &e.xcookie) &&
						e.xcookie.evtype == XI_RawMotion
					) {
						XIRawEvent* re = e.xcookie.data;
						if (re->valuators.mask_len) {
							const double* values = re->raw_values;
							if (XIMaskIsSet(re->valuators.mask, 0)) {
								i->rmx += (int)values[0];
							}
							if (XIMaskIsSet(re->valuators.mask, 1)) {
								i->rmy += (int)values[1];
							}
							a->mx = i->rmx / a->s;
							a->my = i->rmy / a->s;
						}
						XFreeEventData(d, &e.xcookie);
					}
				}
				break;
			default:
				break;
		}
	}
	a->dmx = a->mx - i->omx;
	a->dmy = a->my - i->omy;
	i->omx = a->mx;
	i->omy = a->my;
}

void app_rencpy(
	App* a,
	App_Internal* i,
	int x,
	int y,
	int w,
	int h
) {
	int rat_x,  rat_y;
	int rrat_x, rrat_y;
	int sx, sy;
	int ix, iy, sw, sh, dw, dh;
	int dsx, dsy;
	int dex, dey;
	int pidx;
	Colour* dst;
	const Colour* src;
	unsigned char t;
	sw = a->w;
	sh = a->h;
	dw = i->w;
	dh = i->h;
	rat_x  = (sw << fbits * 2) / (dw << fbits);
	rat_y  = (sh << fbits * 2) / (dh << fbits);
	rrat_x = (dw << fbits * 2) / (sw << fbits);
	rrat_y = (dh << fbits * 2) / (sh << fbits);
	dsx = (x       * rrat_x) >> fbits;
	dsy = (y       * rrat_y) >> fbits;
	dex = ((x + w) * rrat_x) >> fbits;
	dey = ((y + h) * rrat_y) >> fbits;
	dst = i->bbp;
	src = a->fb;
	for (iy = dsy; iy < dey; iy++) {
		sy = (rat_y * (iy << fbits)) >> (fbits * 2);
		for (ix = dsx; ix < dex; ix++) {
			sx = (rat_x * (ix << fbits)) >> (fbits * 2);
			pidx = sx + sy * sw;
			dst = &i->bbp[ix + iy * max_pc_window_w];
			*dst = src[pidx];
			t = dst->r;
			dst->r = dst->b;
			dst->b = t;
		}
	}
	XPutImage(
		i->d,
		i->wi,
		i->gc,
		i->bb,
		dsx, dsy,
		dsx, dsy,
		dex - dsx, dey - dsy
	);
}

void app_end(App* a) {
	App_Internal* i = (App_Internal*)(&a[1]);
	app_rencpy(a, i, 0, 0, a->w, a->h);
	i->end = get_timer();
	a->fps = 1000000000 / (i->end - i->begin);
}

void cfg_mouse(App* a, int show) {
	App_Internal* i = (App_Internal*)(&a[1]);
	Display* d = i->d;
	Window w = i->wi;
	i->ms = show;
	if (show) {
		XUndefineCursor(d, w);
		XUngrabPointer(d, CurrentTime);
	} else {
		XColor c;
		char bd[1] = { 0 };
		Pixmap b = XCreateBitmapFromData(d, w, bd, 1, 1);
		Cursor cur = XCreatePixmapCursor(d, b, b, &c, &c, 0, 0);
		XIEventMask em;
		unsigned char mask[XIMaskLen(XI_RawMotion)] = { 0 };
		XDefineCursor(d, w, cur);
		XGrabPointer(
			d,
			w,
			1,
			ButtonPressMask |
			ButtonReleaseMask |
			PointerMotionMask,
			GrabModeAsync,
			GrabModeAsync,
			w,
			None,
			CurrentTime
		);
		em.deviceid = XIAllMasterDevices;
		em.mask_len = sizeof(mask);
		em.mask = mask;
		XISetMask(mask, XI_RawMotion);
		XISelectEvents(d, DefaultRootWindow(d), &em, 1);
		i->rmx = a->mx;
		i->rmy = a->my;
	}
}

#endif