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

int btn_pressed(const App* a, Btn btn) {
	return a->btn_states[btn] & btn_state_pressed;
}

int btn_just_pressed(const App* a, Btn btn) {
	return a->btn_states[btn] & btn_state_just_pressed;
}

int btn_just_released(const App* a, Btn btn) {
	return a->btn_states[btn] & btn_state_just_released;
}

typedef struct {
	int x, y, w, h;
	unsigned col;
} Debug_Rect;

#define max_debug_rects 128
Debug_Rect debug_rects[max_debug_rects];
int debug_rect_count;

void ren_debug_rect(
	int x,
	int y,
	int w,
	int h,
	unsigned colour
) {
	Debug_Rect* r = &debug_rects[debug_rect_count++];
	assert(debug_rect_count < max_debug_rects);
	r->x = x;
	r->y = y;
	r->w = w;
	r->h = h;
	r->col = colour;
}

#ifdef plat_posix
#define _POSIX_SOURCE
#define _GNU_SOURCE

#include <fcntl.h>
#include <stdlib.h>
#include <sys/time.h>
#include <time.h>
#include <stdarg.h>
#include <stdio.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
}

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);
}

extern int prog_init(Arena* m);
extern int prog_update(void);
extern int prog_deinit(void);

int main(int argc, const char** argv) {
	Arena a;
	void* mem = malloc(memory_size);
	int r;
	(void)argc;
	(void)argv;
	if (!mem) {
		print_err("Out of memory.\n");
		return error_out_of_memory;
	}
	init_timer();
	init_arena(
		&a,
		mem,
		memory_size
	);
	if ((r = prog_init(&a))) return r;
	for (r = 1; r; r = prog_update());
	prog_deinit();
	return error_none;
}

#endif


#ifdef plat_x11

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

typedef struct {
	unsigned char r, g, b, a;
} Colour;

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;
	int w = max_pc_window_w;
	int h = max_pc_window_h;
	a->fb = heap_alloc(
		a->heap,
		(viewport_w * viewport_h + 32) / 32 * sizeof *a->fb
	);
	p = malloc(sizeof *p * w * h);
	if (!p || !a->fb) {
		print_err("Out of memory.\n");
		pbreak(error_out_of_memory);
	}
	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,
		viewport_w * default_scale,
		viewport_h * default_scale,
		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);
	i->w = wa.width;
	i->h = wa.height;
}

Btn btn_from_xkey(unsigned key) {
	switch (key) {
		case XK_Up:     return btn_up;
		case XK_Down:   return btn_down;
		case XK_Left:   return btn_left;
		case XK_Right:  return btn_right;
		case 0x78:      return btn_shoot;
		case 0x7a:      return btn_jump;
		case 0x63:      return btn_special;
		case XK_Return: return btn_start;
		default:        return btn_unknown;
	}
}

App* new_app(Heap* mem, 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;
	i->d = XOpenDisplay(0);
	i->omx = i->omy = 0;
	i->ms = 1;
	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;
	int j;
	i->begin = get_timer();
	for (j = 0; j < btn_count; j++)
		a->btn_states[j] &= ~(
			btn_state_just_pressed | btn_state_just_released
		);
	while (XPending(d)) {
		XEvent e;
		XWindowAttributes wa;
		KeySym sym;
		Btn btn;
		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);
				i->w = mini(wa.width,  max_pc_window_w);
				i->h = mini(wa.height, max_pc_window_h);
				break;
			case KeyPress:
				sym = XLookupKeysym(&e.xkey, 0);
				btn = btn_from_xkey(sym);
				a->btn_states[btn] |=
					btn_state_pressed |
					btn_state_just_pressed;
				break;
			case KeyRelease:
				sym = XLookupKeysym(&e.xkey, 0);
				btn = btn_from_xkey(sym);
				a->btn_states[btn] &= ~btn_state_pressed;
				a->btn_states[btn] |= btn_state_just_released;
				break;
			default:
				break;
		}
	}
}

void app_rencpy(
	App* a,
	App_Internal* i,
	int sx,
	int sy,
	int s
) {
	const Colour white = { 0xff, 0xff, 0xff, 0xff };
	const Colour black = { 0x00, 0x00, 0x00, 0xff };
	int x, y, sj = 0;
	int w = viewport_w * s;
	int h = viewport_h * s;
	int ex = sx + w;
	int ey = sy + h;
	for (y = sy; y < ey; y++, sj++) {
		int sy = sj / s;
		int si = 0;
		for (x = sx; x < ex; x++, si++) {
			int sx = si / s;
			int idx = sx + sy * viewport_w;
			int bit = 1 << (idx  & 0x1f);
			bit &= a->fb[idx >> 5];
			i->bbp[x + y * max_pc_window_w] = bit? white: black;
		}
	}
	XPutImage(
		i->d,
		i->wi,
		i->gc,
		i->bb,
		0,  0,
		sx, sy,
		w,  h
	);
#ifdef DEBUG
	for (sj = 0; sj < debug_rect_count; sj++) {
		const Debug_Rect* dr = &debug_rects[sj];
		XSetForeground(i->d, i->gc, dr->col);
		XFillRectangle(
			i->d,
			i->wi,
			i->gc,
			dr->x * s,
			dr->y * s,
		  dr->w * s,
		  dr->h * s
		 );
	}
#endif
	debug_rect_count = 0;
}

void app_end(App* a) {
	int s = 1;
	int m1, m2;
	App_Internal* i = (App_Internal*)(&a[1]);
	if (i->w < i->h) {
		m1 = i->w;
		m2 = viewport_w;
	} else {
		m1 = i->h;
		m2 = viewport_h;
	}
	while (m2 * s < m1) s++; /* lol */
	s = maxi(1, s - 1);
	app_rencpy(a, i, 0, 0, s);
	i->end = get_timer();
	a->fps = 1000000000 / (i->end - i->begin);
}

#endif


#ifdef plat_pulse
#include "maths.h"
#define inline /* erm sir we are using C90 here... */
#include <stdlib.h>
#include <math.h>
#include <pulse/simple.h>
#include <pthread.h>

struct {
	short* buf;
	pa_simple* dev;
	int r, play, time;
	pthread_t worker;
	pthread_mutex_t mutex;
} audio;

void* audio_worker(void* arg) {
	const int s = audio_buffer_size;
	int i, c = 1;
	short* buf = audio.buf;
	pa_simple* dev = audio.dev;
	(void)arg;
	while (c) {
		pthread_mutex_lock(&audio.mutex);
		if (!audio.r) c = 0;
		for (
			i = 0;
			i < s && audio.play;
			i++, audio.play--, audio.time++
		) buf[i] = (short)(sin((double)audio.time / 0.05) * 16000.0);
		pthread_mutex_unlock(&audio.mutex);
		for (; i < s; i++) {
			buf[i] = 0;
		}
		pa_simple_write(dev, buf, s * sizeof(short), 0);
	}
	return 0;
}

void init_audio(void) {
	pa_sample_spec sp = { 0 };
	sp.format = PA_SAMPLE_S16LE;
	sp.channels = 1;
	sp.rate = audio_sample_rate;
	audio.dev = pa_simple_new(
		0,
		game_name,
		PA_STREAM_PLAYBACK,
		0,
		"Game Audio",
		&sp,
		0,
		0,
		0
	);
	audio.r = 0;
	audio.play = 0;
	if (!audio.dev) {
		print_err("Failed to create audio device.\n");
		print_war("Running without audio.\n");
		return;
	}
	audio.r = 1;
	audio.buf = malloc(
		audio_buffer_size *
		sizeof *audio.buf
	);
	pthread_mutex_init(&audio.mutex, 0);
	pthread_create(
		&audio.worker,
		0,
		audio_worker,
		0
	);
}

void deinit_audio(void) {
	if (audio.dev) {
		pthread_mutex_lock(&audio.mutex);
		audio.r = 0;
		pthread_mutex_unlock(&audio.mutex);
		pthread_mutex_destroy(&audio.mutex);
		pthread_join(audio.worker, 0);
		pa_simple_drain(audio.dev, 0);
		pa_simple_free(audio.dev);
		free(audio.buf);
	}
}

void play_sound(int len) {
	pthread_mutex_lock(&audio.mutex);
	audio.play += len;
	pthread_mutex_unlock(&audio.mutex);
}

#endif

#ifdef plat_sdl2

#if defined(plat_ems)
#include <emscripten.h>
#endif

#include <SDL2/SDL.h>
#include <stdio.h>
#include <string.h>

void print(const char* fmt, ...) {
	va_list a;
	va_start(a, fmt);
	SDL_LogMessageV(0, SDL_LOG_PRIORITY_INFO, fmt, a);
	va_end(a);
}

void print_err(const char* fmt, ...) {
	va_list a;
	va_start(a, fmt);
	SDL_LogMessageV(0, SDL_LOG_PRIORITY_ERROR, fmt, a);
	va_end(a);
}

void print_war(const char* fmt, ...) {
	va_list a;
	va_start(a, fmt);
	SDL_LogMessageV(0, SDL_LOG_PRIORITY_WARN, fmt, a);
	va_end(a);
}

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 pbreak(Error code) {
	(void)code;
	SDL_TriggerBreakpoint();
}

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

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

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

void fps_update(FPS* f) {
	f->next += f->mpf;
	f->pt = f->ct;
	f->ct = SDL_GetTicks();
	f->fps = 1000 / (f->ct - f->pt);
}

extern int prog_init(Arena* m);
extern int prog_update(void);
extern void prog_deinit(void);

static void main_loop(void) {
#ifdef plat_ems
	prog_update();
#else
	int r;
	for (r = 1; r; r = prog_update());
	SDL_Quit();
#endif
}

int main(int argc, const char** argv) {
	Arena a;
	void* mem = malloc(memory_size);
	int r;
	(void)argc;
	(void)argv;
	if (!mem) {
		print_err("Out of memory.\n");
		return error_out_of_memory;
	}
	init_arena(
		&a,
		mem,
		memory_size
	);
	if ((r = prog_init(&a))) return r;
#ifdef plat_ems
	emscripten_set_main_loop(main_loop, 0, 1);
#else
	main_loop();
#endif
	prog_deinit();
	return 0;
}

Btn sdl_to_btn(const SDL_Event* e) {
	switch (e->key.keysym.sym) {
		case SDLK_z:
		case SDLK_RETURN:
			return btn_jump;
		case SDLK_x:
			return btn_shoot;
		case SDLK_c:
			return btn_special;
		case SDLK_LEFT:
		case SDLK_h:
			return btn_left;
		case SDLK_RIGHT:
		case SDLK_l:
			return btn_right;
		case SDLK_UP:
		case SDLK_k:
			return btn_up;
		case SDLK_DOWN:
		case SDLK_j:
			return btn_down;
		default: return btn_unknown;
	}
}

typedef struct {
	SDL_Window* wi;
	SDL_Renderer* re;
	SDL_Texture* bb;
	unsigned* bbp;
	int w, h;
} App_Internal;

void init_window(App* a, App_Internal* i, const char* n) {
	int flag = 0;
#ifndef plat_ems
	flag = SDL_WINDOW_RESIZABLE;
#endif
	SDL_CreateWindowAndRenderer(
		viewport_w * 2,
		viewport_h * 2,
		flag,
		&i->wi,
		&i->re
	);
	i->w = viewport_w * 2;
	i->h = viewport_h * 2;
	SDL_SetWindowTitle(i->wi, n);
	i->bb = SDL_CreateTexture(
		i->re,
		SDL_PIXELFORMAT_ABGR8888,
		SDL_TEXTUREACCESS_STREAMING,
		viewport_w,
		viewport_h
	);
	a->fb = heap_alloc(
		a->heap,
		(viewport_w * viewport_h + 32) / 32 * sizeof *a->fb
	);
}

App* new_app(struct Heap* mem, 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;
	init_window(a, i, n);
	a->o = 1;
	return a;
}

void deinit_app(App* a) {

}

void app_begin(App* a) {
	App_Internal* i = (App_Internal*)(&a[1]);
	SDL_Event e;
	int j;
	Btn btn;
	for (j = 0; j < btn_count; j++)
		a->btn_states[j] &= ~(
			btn_state_just_pressed | btn_state_just_released
		);
	while (SDL_PollEvent(&e)) {
		switch (e.type) {
			case SDL_QUIT:
				a->o = 0;
				break;
			case SDL_KEYDOWN:
				btn = sdl_to_btn(&e);
				a->btn_states[btn] |=
					btn_state_pressed |
					btn_state_just_pressed;
				break;
			case SDL_KEYUP:
				btn = sdl_to_btn(&e);
				a->btn_states[btn] &= ~btn_state_pressed;
				a->btn_states[btn] |= btn_state_just_released;
				break;
			case SDL_WINDOWEVENT:
				switch (e.window.event) {
					case SDL_WINDOWEVENT_RESIZED:
						i->w = e.window.data1;
						i->h = e.window.data2;
						break;
				}
				break;
			default: break;
		}
	}
}

void rencpy(App* a, unsigned* t, int p) {
	const unsigned white = 0xffffffff;
	const unsigned black = 0x00000000;
	int x, y, i = 0;
	p /= 4;
	for (y = 0; y < viewport_h; y++) {
		for (x = 0; x < viewport_w; x++, i++) {
			int bit = 1 << (i & 0x1f);
			bit &= a->fb[i >> 5];
			t[x + y * p] = bit? white: black;
		}
	}
}

void fit_dr(App_Internal* i, SDL_Rect* r) {
	int w = viewport_w, h = viewport_h, s;
	for (s = 1; w * s <= i->w && h * s <= i->h; s++);
	if (s > 1) s--;
	r->w = viewport_w * s;
	r->h = viewport_h * s;
	r->x = i->w / 2 - r->w / 2;
	r->y = i->h / 2 - r->h / 2;
}

void app_end(App* a) {
	App_Internal* i = (App_Internal*)(&a[1]);
	unsigned* target;
	SDL_Rect sr = { 0, 0, viewport_w, viewport_h };
	SDL_Rect dr = sr;
	int pitch;
	fit_dr((App_Internal*)&a[1], &dr);
	SDL_LockTexture(
		i->bb,
		0,
		(void**)&target,
		&pitch
	);
	rencpy(a, target, pitch);
	SDL_UnlockTexture(i->bb);
	SDL_RenderClear(i->re);
	SDL_RenderCopy(
		i->re,
		i->bb,
		&sr,
		&dr
	);
	SDL_RenderPresent(i->re);
}

static SDL_AudioSpec aud_spec;
int audio_len, audio_time;

void fill_audio(void *udata, Uint8 *stream, int len) {
	int i;
	int16_t* pcm = (int16_t*)stream;
	len /= 2;
	for (
		i = 0;
		i < len && audio_len;
		i++, audio_len--, audio_time++
	) pcm[i] = (int16_t)(sin((double)audio_time / 0.05) * 16000.0);
	for (; i < len; i++)
		pcm[i] = 0;
}

void init_audio(void) {
	audio_len = 0;
	audio_time = 0;
	aud_spec.freq = audio_sample_rate;
	aud_spec.format = AUDIO_S16;
	aud_spec.channels = 1;
#ifndef plat_ems
	aud_spec.samples = audio_buffer_size;
#else
	/* websites are retarded */
	aud_spec.samples = 1024;
#endif
	aud_spec.callback = fill_audio;
	aud_spec.userdata = 0;
	SDL_OpenAudio(&aud_spec, 0);
	SDL_PauseAudio(0);
}

void deinit_audio(void) {
	SDL_CloseAudio();
}

void play_sound(int len) {
	audio_len += len;
}

#endif