/*
 * Attempt to implement picture viewer XCB with kbd and pointer grabbing, fullscreen
 *
 * Author: Peter Wu <lekensteyn@gmail.com>
 * Date: 2012-09-24
 * gcc -o xcbviewfs xcbviewfs.c -lxcb-image -lxcb-shm -lxcb
 */

#include <xcb/xcb.h>
#include <xcb/xcb_image.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <stdint.h>
#include <X11/xpm.h>

/* defined in colorlookup.c which is generated by colorlookupgen.c */
extern int color_lookup(char *name, uint8_t color[3]);

#define bail(lbl, msg) do { \
	fprintf(stderr, msg); \
	goto lbl; \
} while (0)

static unsigned char empty_cursor_data[32];
static int load_xpm_image(char *filename, unsigned char **data,
	unsigned int *len, unsigned int *width, unsigned int *height);

int main(int argc, char **argv) {
	xcb_connection_t *c;
	xcb_screen_t *screen;
	xcb_window_t win;
	xcb_cursor_t cursor;

	char *filename;
	unsigned char *image_data;
	unsigned int image_data_len;
	unsigned int image_width, image_height;
	xcb_pixmap_t pmap = 0;
	xcb_gcontext_t gc = 0;

	/* options */
	int grab_pointer = 0;
	int hide_cursor  = 0;
	int grab_kbd     = 0;
	int fullscreen   = 0;
	int draw_picture = 0;
	//grab_kbd = !(fullscreen = grab_pointer = hide_cursor = 0 );
	draw_picture = grab_kbd = fullscreen = grab_pointer = hide_cursor = 1;
	xcb_keycode_t magic_keys[] = {40, 31, 26}; /* DIE */

	if (argc < 2) {
		fprintf(stderr, "Usage: %s filename\n", *argv);
		return 1;
	}
	filename = argv[1];

	c = xcb_connect(NULL, NULL);
	if (!c) {
		fprintf(stderr, "Cannot open display\n");
		return 1;
	}

	if (!load_xpm_image(filename, &image_data, &image_data_len,
		&image_width, &image_height))
		bail(disconnect, "Failed to load XPM image\n");

	screen = xcb_setup_roots_iterator(xcb_get_setup(c)).data;
	win = xcb_generate_id(c);
	/* For each mask, need to add valwin item in order as defined by the
	 * enum, see See http://xcb.freedesktop.org/tutorial/events/ */
	uint32_t mask = XCB_CW_BACK_PIXEL | XCB_CW_EVENT_MASK;
	uint32_t valwin[] = {
		screen->black_pixel,
		XCB_EVENT_MASK_EXPOSURE | XCB_EVENT_MASK_KEY_PRESS,
	};
	xcb_create_window(c, 0, win, /* conn, depth, WinID */
		screen->root, /* parent */
		0, 0, /* x y */
		screen->width_in_pixels, screen->height_in_pixels,
		0, /* border_width */
		XCB_WINDOW_CLASS_INPUT_OUTPUT, /* class */
		screen->root_visual,
		mask, valwin);

	if (hide_cursor) {
		xcb_pixmap_t cp = xcb_create_pixmap_from_bitmap_data(c, win,
			empty_cursor_data, 16, 16, 1, 0, 0, 0);

		cursor = xcb_generate_id(c);
		xcb_create_cursor(c, cursor, cp, cp, 0, 0, 0, 0xFFFF, 0xFFFF, 0xFFFF, 8, 8);
		xcb_free_pixmap(c, cp);
		/* pointer is already changed by xcb_grab_pointer */
		if (!grab_pointer) {
			xcb_change_window_attributes(c, win, XCB_CW_CURSOR, &cursor);
			xcb_flush(c);
		}
	}
	if (grab_pointer) {
		xcb_grab_pointer_cookie_t cookie;
		xcb_grab_pointer_reply_t *reply;
		cookie = xcb_grab_pointer(c, 1, screen->root, XCB_NONE,
			XCB_GRAB_MODE_ASYNC, XCB_GRAB_MODE_ASYNC,
			XCB_NONE, hide_cursor ? cursor : XCB_NONE,
			XCB_CURRENT_TIME);
		if (!(reply = xcb_grab_pointer_reply(c, cookie, NULL))) {
			bail(disconnect, "No pointer grab reply\n");
		}
		if (reply->status != XCB_GRAB_STATUS_SUCCESS) {
			bail(disconnect, "Grab pointer FAILED\n");
		}
		free(reply);
	}
	if (hide_cursor) xcb_free_cursor(c, cursor);
	if (grab_kbd) {
		xcb_grab_keyboard_cookie_t cookie;
		xcb_grab_keyboard_reply_t *reply;
		cookie = xcb_grab_keyboard(c, 1, screen->root, XCB_CURRENT_TIME,
			XCB_GRAB_MODE_ASYNC, XCB_GRAB_MODE_ASYNC);
		if (!(reply = xcb_grab_keyboard_reply(c, cookie, NULL))) {
			bail(ungrab_pointer, "No kbd grab reply\n");
		}
		if (reply->status != XCB_GRAB_STATUS_SUCCESS) {
			bail(ungrab_pointer, "Grab kbd FAILED\n");
		}
		free(reply);
	}
	if (fullscreen) {
		xcb_intern_atom_cookie_t cookie;
		xcb_intern_atom_reply_t *reply;
		xcb_atom_t property, data;

		cookie = xcb_intern_atom(c, 0, 13, "_NET_WM_STATE");
		if (!(reply = xcb_intern_atom_reply(c, cookie, 0))) {
			bail(ungrab_kbd, "Failed to get _NET_WM_STATE atom\n");
		}
		property = reply->atom;
		free(reply);

		cookie = xcb_intern_atom(c, 0, 24, "_NET_WM_STATE_FULLSCREEN");
		if (!(reply = xcb_intern_atom_reply(c, cookie, 0))) {
			bail(ungrab_kbd, "Failed to get _NET_WM_STATE_FULLSCREEN atom\n");
		}
		data = reply->atom;
		free(reply);

		xcb_change_property(c, XCB_PROP_MODE_REPLACE, win,
			property, XCB_ATOM_ATOM, 32, 1, &data);
		xcb_flush(c);
	}
	if (draw_picture) {
		/**
		 * X-Bitmap, XY-Pixmap or Z-Pixmap? See
		 * http://www.linux.ie/old-list/23540.html
		 */
		xcb_image_t *img;
		img = xcb_image_create_native(c, image_width, image_height,
			XCB_IMAGE_FORMAT_Z_PIXMAP,
			24, /* depth */
			image_data,
			image_data_len,
			image_data);

		pmap = xcb_generate_id(c);
		xcb_create_pixmap(c, 24, pmap, win, image_width, image_height);

		gc = xcb_generate_id(c);
		xcb_create_gc(c, gc, pmap, 0, NULL);

		xcb_image_put(c, pmap, gc, img, 0, 0, 0);
		xcb_flush(c);

		xcb_image_destroy(img);
	}

	xcb_map_window(c, win);
	xcb_flush(c);

	size_t magic_level = 0;
	size_t magic_len = sizeof(magic_keys)/sizeof(*magic_keys);

	xcb_generic_event_t *e;
	int running = 1;
	while (running && (e = xcb_wait_for_event(c))) {
		switch (e->response_type) {
		case XCB_EXPOSE:
			if (!draw_picture) break;
			xcb_expose_event_t *ee = (xcb_expose_event_t *)e;
			xcb_copy_area(c, pmap, win, gc,
				ee->x, ee->y,
				ee->x, ee->y,
				ee->width,
				ee->height);
			xcb_flush(c);
			break;
		case XCB_KEY_PRESS: ;
			xcb_button_press_event_t *press = (xcb_button_press_event_t *)e;
			xcb_keycode_t key = press->detail;
			if (magic_keys[magic_level] == key) {
				if (++magic_level >= magic_len)
					running = 0;
			} else {
				magic_level = 0;
			}
			break;
		}
		free(e);
	}
	if (pmap) xcb_free_pixmap(c, pmap);
	/* if closed normally */
	if (running) xcb_destroy_window(c, win);
ungrab_kbd:
	xcb_ungrab_keyboard(c, XCB_CURRENT_TIME);
ungrab_pointer:
	xcb_ungrab_pointer(c, XCB_CURRENT_TIME);
disconnect:
	if (!draw_picture) free(image_data); /* TODO: check other error paths */
	xcb_disconnect(c);
	return 0;
}

#define print_once(...) do { \
	static int printed = 0; \
	if (!printed) { \
		fprintf(stderr, __VA_ARGS__); \
		printed = 1; \
	} \
} while(0)

static void xpm_parse_color_line(char *line, uint8_t color[3]) {
	int search_color = 0;
	char c = *line;
	while (c) {
		char *next_ws;
		while (c == ' ' || c == '\t')
			c = *++line;

		next_ws = strchr(line, ' ');
		if (!next_ws) next_ws = strchr(line, '\t');
		if (next_ws) *next_ws = 0;

		if (search_color) {
			if (line[0] == '#') {
				unsigned int hex = strtol(line + 1, NULL, 16);
				if (strlen(line) == 4) { /* #RGB */
					color[0] = ((hex >> 2) & 0xF) * 0x11;
					color[1] = ((hex >> 1) & 0xF) * 0x11;
					color[2] = (hex        & 0xF) * 0x11;
				} else { /* assume #RRGGBB */
					color[0] = (hex >>16) & 0xFF;
					color[1] = (hex >> 8) & 0xFF;
					color[2] = hex        & 0xFF;
				}
				return;
			} else if (line[0] == '%') {
				/* HSV not implemented */
				print_once("HSV not implemented\n");
			} else if (strcasecmp("None", line) == 0) {
				/* transparant wut? */
				memset(color, 0, 3);
				return;
			} else if (color_lookup(line, color)) {
				/* TODO: handle colors with whitespace */
				return;
			} else {
				print_once("Color %s unimplemented\n", line);
			}
			search_color = 0;
		} else if (strcmp(line, "c") == 0) {
			search_color = 1;
		} else {
			/* not implemented */
			print_once("Color type not implemented: %s\n", line);
		}
		/* continue searching if there are more tokens */
		if (next_ws) line = next_ws + 1;
		else break;
	}
	color[0] = color[1] = color[2] = 0x42;
	print_once("No color found\n");
}

typedef struct _ColorPair ColorPair;
struct _ColorPair {
	unsigned int key; /* assume that the key has less or equal bytes */
	uint8_t color[3]; /* RGB */
};
int colorpaircmp(const void *a, const void *b) {
	const ColorPair *left = a, *right = b;
	return left->key - right->key;
}

static int load_xpm_image(char *filename, unsigned char **data,
	unsigned int *len, unsigned int *width, unsigned int *height) {
	unsigned int w, h;
	char **xpm_data;
	int error;

	if ((error = XpmReadFileToData(filename, &xpm_data))) {
		fprintf(stderr, "Cannot load image: %s\n", XpmGetErrorString(error));
		return 0;
	}

	/* 1: width height ncolors chars_per_pixel [opt_hotspot_x opt_hotspot_y]
	 * ncolors: char (of len chars_per_pixel) (key color)+
	 *     key m(ono), s(ymbolic name), g(rayscale)4(level), g(rayscale w/
	 *     more than 4 levels), c(color visual). "s None" is transparant
	 * height: width*chars_per_pixels
	 * (ignore Extensions), array size = 1 + ncolors + height
	 * XCB image: width * height * 4 bytes
	 * See also http://www.net.uom.gr/Books/Manuals/xpm-3-paper.pdf
	 */

	unsigned int ncolors, cpp;
	unsigned int i;
	/* assume XPM library is not stupid */
	sscanf(xpm_data[0], "%u %u %u %u", &w, &h, &ncolors, &cpp);
	if (cpp > sizeof(unsigned int)) {
		bail(free_xpm, "CPP does not fit in integer data type\n");
	}
	*width = w; *height = h;
	*len = w * h * 4;

	*data = malloc(w * h * 4);
	if (!data) {
		bail(free_xpm, "Cannot allocate memory for image\n");
	}

	ColorPair *colors = malloc(ncolors * sizeof(ColorPair));
	for (i=1; i<=ncolors; i++) {
		char *line = xpm_data[i];
		ColorPair *color = &colors[i - 1];
		color->key = 0;
		memcpy(&color->key, line, cpp);
		/* skip color key */
		xpm_parse_color_line(line + cpp, color->color);
	}
	qsort(colors, ncolors, sizeof(ColorPair), colorpaircmp);

	/* fill data */
	unsigned int x, y;
	char **all_pixels = &xpm_data[1 + ncolors];
	for (y=0; y<h; ++y) {
		char *pixels = all_pixels[y];
		unsigned char *data_line = *data + 4 * y * w;
		for (x=0; x<w; ++x) {
			ColorPair key;
			ColorPair *color;

			key.key = 0;
			memcpy(&key.key, pixels + cpp * x, cpp);
			color = bsearch(&key, colors, ncolors,
				sizeof(ColorPair), colorpaircmp);

			if (color) {
				uint8_t *c = color->color;
				unsigned char *p = data_line + 4 * x;
				*(p++) = c[2]; /* b */
				*(p++) = c[1]; /* g */
				*(p++) = c[0]; /* r */
			} else {
				fprintf(stderr, "No color found\n");
			}
		}
	}

	error = 1; /* success */

	free(colors);
free_xpm:
	XpmFree(xpm_data);
	return error;
}