/* *****************************************************************************
 * usage/getscreen.c -- receive the streamed screen from the calculator.
 * Copyright (C) 2016-2017 Thomas "Cakeisalie5" Touhey <thomas@touhey.fr>
 *
 * This file is part of libp7.
 * libp7 is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 3.0 of the License,
 * or (at your option) any later version.
 *
 * libp7 is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with libp7; if not, see <http://www.gnu.org/licenses/>.
 * ************************************************************************** */
#include <libp7/internals.h>
#define makepixel(R, G, B) (((R) << 16) | ((G) << 8) | (B))

/**
 *	p7_getscreen_adapt:
 *	Adapts the pixels from the received VRAM.
 *
 *	@arg	pixels		the pixels matrix
 *	@arg	w			pointer to the width var
 *	@arg	h			pointer to the height var
 *	@arg	scrtype		the VRAM type
 *	@arg	vram		the VRAM data
 */

static void p7_getscreen_adapt(uint32_t **pixels, p7_packet_t *resp)
{
	uint8_t *vram = resp->p7_seven_packet_vram; int msk;
	uint32_t prizm_gray_colors[] = {0xFFFFFF, 0xAAAAAA, 0x777777, 0x000000};

	switch (resp->p7_seven_packet_pictype) {
	/* monochrome */
	case p7_pictype_1bit:
		msk = 0x80;
		for (unsigned int y = 0; y < resp->p7_seven_packet_height; y++)
		  for (unsigned int x = 0; x < resp->p7_seven_packet_width; x++) {
			/* get pixel */
			pixels[y][x] = (*vram & msk) ? 0x000000 : 0xFFFFFF;

			/* go to next bit */
			vram += msk & 1;
			msk = (msk >> 1) | ((msk & 1) << 7);
		}
		break;

	/* 2-bit (Prizm's encoding) */
	case p7_pictype_2bit:
		msk = 0x80; uint8_t *v2 = &vram[resp->p7_seven_packet_height
			* resp->p7_seven_packet_width / 8];
		for (unsigned int y = 0; y < resp->p7_seven_packet_height; y++)
		  for (unsigned int x = 0; x < resp->p7_seven_packet_width; x++) {
			/* get pixel */
			uint32_t val = (!!(*vram & msk) << 1) | !!(*v2 & msk);
			pixels[y][x] = prizm_gray_colors[val];

			/* go to next */
			vram += msk & 1; v2 += msk & 1;
			msk = (msk >> 1) | ((msk & 1) << 7);
		}
		break;

	/* 3-bit */
	case p7_pictype_3bit:
		msk = 0xF0;
		for (unsigned int y = resp->p7_seven_packet_height - 1;
		 y != (unsigned int)-1; y--)
		  for (unsigned int x = resp->p7_seven_packet_width - 1;
		   x != (unsigned int)-1; x--) {
			/* get pixel */
			uint32_t val = *vram & msk; val = val | (val >> 4);
			uint32_t px = 0;
			if (px & 8) px |= 0xFF0000;
			if (px & 4) px |= 0x00FF00;
			if (px & 2) px |= 0x0000FF;
			pixels[y][x] = px;

			/* go to next */
			vram += msk & 1;
			msk = ~msk & 0xFF;
		}
		break;

	/* 16-bit */
	case p7_pictype_16bit:
		for (unsigned int y = 0; y < resp->p7_seven_packet_height; y++)
		  for (unsigned int x = 0; x < resp->p7_seven_packet_width; x++) {
			/* get pixel */
			uint32_t o = vram[0], t = vram[1];
			pixels[y][x] = (o >> 3) << (16 + 3);
			pixels[y][x] |= (((o &  7) << 3) | (t >> 5)) << (8 + 2);
			pixels[y][x] |= (t & 31) << (0 + 3);

			/* go to next */
			vram += 2;
		}
		break;
	}
}

/**
 *	p7_getscreen:
 *	Get the screen.
 *
 *	@arg	handle		the libp7 handle
 *	@arg	callback	the main callback for the function.
 *						for each correctly received frame, the function will
 *						be called with the dimensions (w, h) and the pixels
 *						matrix.
 *						if it returns 0, the function stops.
 *	@return				if it worked
 */

p7_define_ufunc(p7_getscreen, p7_attrs_getscreen,
	p7_handle_t *handle, p7_screenfunc_t *callback)
{
	int err;
	/* make checks */
	chk_handle(handle);
	chk_seven(handle);
	chk_passive(handle);

	/* allocate pixels */
	uint32_t **pixels = malloc(sizeof(uint32_t*) * MAX_VRAM_HEIGHT
		+ sizeof(uint32_t) * MAX_VRAM_WIDTH * MAX_VRAM_HEIGHT);
	if (!pixels) return (p7_error_alloc);

	/* prepare pixels */
	int y = MAX_VRAM_HEIGHT;
	uint32_t *base = (uint32_t*)(pixels + MAX_VRAM_HEIGHT);
	while (y--) pixels[y] = base + y * MAX_VRAM_WIDTH;

	/* main loop */
	handle->_flags |= p7_intflag_adjscreen;
	while (1) {
		/* get packet */
		if ((err = p7_seven_recv(handle, 0)))
			return (err);
		if (response.p7_seven_packet_type != p7_seven_type_ohp)
			return (p7_error_unknown);

		/* convert */
		if (response.p7_seven_packet_pictype) {
			p7_getscreen_adapt(pixels, &response);

			/* then call back the callback */
			if (!(*callback)(response.p7_seven_packet_width,
			  response.p7_seven_packet_height, pixels))
				break;
		}
	}

	/* stop */
	free(pixels);
	return (0);
}