/*
 * Copyright (c) 2008 Martin Decky
 * Copyright (c) 2006 Ondrej Palkovsky
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup kernel_genarch
 * @{
 */
/** @file
 */

#include <assert.h>
#include <debug.h>
#include <genarch/fb/font-8x16.h>
#include <genarch/fb/fb.h>
#include <console/chardev.h>
#include <console/console.h>
#include <sysinfo/sysinfo.h>
#include <mm/km.h>
#include <stdlib.h>
#include <align.h>
#include <panic.h>
#include <memw.h>
#include <config.h>
#include <bitops.h>
#include <str.h>
#include <ddi/ddi.h>
#include <typedefs.h>
#include <byteorder.h>

#define BG_COLOR     0x001620
#define FG_COLOR     0xf3cf65
#define INV_COLOR    0xaaaaaa

#define FB_PAGES  8

#define RED(x, bits)    (((x) >> (8 + 8 + 8 - (bits))) & ((1 << (bits)) - 1))
#define GREEN(x, bits)  (((x) >> (8 + 8 - (bits))) & ((1 << (bits)) - 1))
#define BLUE(x, bits)   (((x) >> (8 - (bits))) & ((1 << (bits)) - 1))

#define COL2X(col)  ((col) * FONT_WIDTH)
#define ROW2Y(row)  ((row) * FONT_SCANLINES)

#define X2COL(x)  ((x) / FONT_WIDTH)
#define Y2ROW(y)  ((y) / FONT_SCANLINES)

#define FB_POS(instance, x, y) \
	((y) * (instance)->scanline + (x) * (instance)->pixelbytes)

#define BB_POS(instance, col, row) \
	((((instance)->start_row + (row)) % (instance)->rows) * \
	    (instance)->cols + (col))

#define BB_NEXT_COL(pos) (++(pos))

#define GLYPH_POS(instance, glyph, y) \
	((glyph) * (instance)->glyphbytes + (y) * (instance)->glyphscanline)

#define TAB_WIDTH 8

typedef void (*rgb_conv_t)(void *, uint32_t);

typedef struct {
	SPINLOCK_DECLARE(lock);

	parea_t parea;

	uint8_t *addr;
	uint16_t *backbuf;
	uint8_t *glyphs;
	uint8_t *bgscan;

	rgb_conv_t rgb_conv;

	unsigned int xres;
	unsigned int yres;

	/** Number of rows that fit on framebuffer */
	unsigned int screen_rows;

	unsigned int scanline;
	unsigned int glyphscanline;

	unsigned int pixelbytes;
	unsigned int glyphbytes;
	unsigned int bgscanbytes;

	/** Number of columns in the backbuffer */
	unsigned int cols;
	/** Number of rows in the backbuffer */
	unsigned int rows;

	/** Starting row in the cyclic backbuffer */
	unsigned int start_row;

	/** Top-most visible row (relative to start_row) */
	unsigned int offset_row;

	/** Current backbuffer position */
	unsigned int position;

	/** Partial character between writes */
	mbstate_t mbstate;

	unsigned int row;
	unsigned int column;
} fb_instance_t;

static void fb_write(outdev_t *, const char *, size_t);
static void fb_redraw(outdev_t *);
static void fb_scroll_up(outdev_t *);
static void fb_scroll_down(outdev_t *);

static outdev_operations_t fbdev_ops = {
	.write = fb_write,
	.redraw = fb_redraw,
	.scroll_up = fb_scroll_up,
	.scroll_down = fb_scroll_down
};

/*
 * RGB conversion functions.
 *
 * These functions write an RGB value to some memory in some predefined format.
 * The naming convention corresponds to the format created by these functions.
 * The functions use the so called network order (i.e. big endian) with respect
 * to their names.
 */

static void rgb_0888(void *dst, uint32_t rgb)
{
	*((uint32_t *) dst) = host2uint32_t_be((0 << 24) |
	    (RED(rgb, 8) << 16) | (GREEN(rgb, 8) << 8) | (BLUE(rgb, 8)));
}

static void bgr_0888(void *dst, uint32_t rgb)
{
	*((uint32_t *) dst) = host2uint32_t_be((0 << 24) |
	    (BLUE(rgb, 8) << 16) | (GREEN(rgb, 8) << 8) | (RED(rgb, 8)));
}

static void rgb_8880(void *dst, uint32_t rgb)
{
	*((uint32_t *) dst) = host2uint32_t_be((RED(rgb, 8) << 24) |
	    (GREEN(rgb,	8) << 16) | (BLUE(rgb, 8) << 8) | 0);
}

static void bgr_8880(void *dst, uint32_t rgb)
{
	*((uint32_t *) dst) = host2uint32_t_be((BLUE(rgb, 8) << 24) |
	    (GREEN(rgb,	8) << 16) | (RED(rgb, 8) << 8) | 0);
}

static void rgb_888(void *dst, uint32_t rgb)
{
	((uint8_t *) dst)[0] = RED(rgb, 8);
	((uint8_t *) dst)[1] = GREEN(rgb, 8);
	((uint8_t *) dst)[2] = BLUE(rgb, 8);
}

static void bgr_888(void *dst, uint32_t rgb)
{
	((uint8_t *) dst)[0] = BLUE(rgb, 8);
	((uint8_t *) dst)[1] = GREEN(rgb, 8);
	((uint8_t *) dst)[2] = RED(rgb, 8);
}

static void rgb_555_be(void *dst, uint32_t rgb)
{
	*((uint16_t *) dst) = host2uint16_t_be(RED(rgb, 5) << 10 |
	    GREEN(rgb, 5) << 5 | BLUE(rgb, 5));
}

static void rgb_555_le(void *dst, uint32_t rgb)
{
	*((uint16_t *) dst) = host2uint16_t_le(RED(rgb, 5) << 10 |
	    GREEN(rgb, 5) << 5 | BLUE(rgb, 5));
}

static void rgb_565_be(void *dst, uint32_t rgb)
{
	*((uint16_t *) dst) = host2uint16_t_be(RED(rgb, 5) << 11 |
	    GREEN(rgb, 6) << 5 | BLUE(rgb, 5));
}

static void rgb_565_le(void *dst, uint32_t rgb)
{
	*((uint16_t *) dst) = host2uint16_t_le(RED(rgb, 5) << 11 |
	    GREEN(rgb, 6) << 5 | BLUE(rgb, 5));
}

/** BGR 3:2:3
 *
 * Even though we try 3:2:3 color scheme here, an 8-bit framebuffer
 * will most likely use a color palette. The color appearance
 * will be pretty random and depend on the default installed
 * palette. This could be fixed by supporting custom palette
 * and setting it to simulate the 8-bit truecolor.
 *
 * Currently we set the palette on the ia32, amd64, ppc32 and sparc64 port.
 *
 * Note that the byte is being inverted by this function. The reason is
 * that we would like to use a color palette where the white color code
 * is 0 and the black color code is 255, as some machines (Sun Blade 1500)
 * use these codes for black and white and prevent to set codes
 * 0 and 255 to other colors.
 *
 */
static void bgr_323(void *dst, uint32_t rgb)
{
	*((uint8_t *) dst) =
	    ~((RED(rgb, 3) << 5) | (GREEN(rgb, 2) << 3) | BLUE(rgb, 3));
}

/** Draw character at given position
 *
 */
static void glyph_draw(fb_instance_t *instance, uint16_t glyph,
    unsigned int col, unsigned int row, bool overlay)
{
	if (!overlay)
		instance->backbuf[BB_POS(instance, col, row)] = glyph;

	/* Do not output if the framebuffer is used by user space */
	if ((instance->parea.mapped) && (!console_override))
		return;

	/* Check whether the glyph should be visible */
	if (row < instance->offset_row)
		return;

	unsigned int rel_row = row - instance->offset_row;
	if (rel_row >= instance->screen_rows)
		return;

	unsigned int x = COL2X(col);
	unsigned int y = ROW2Y(rel_row);

	for (unsigned int yd = 0; yd < FONT_SCANLINES; yd++)
		memcpy(&instance->addr[FB_POS(instance, x, y + yd)],
		    &instance->glyphs[GLYPH_POS(instance, glyph, yd)],
		    instance->glyphscanline);
}

/** Scroll screen down by one row
 *
 */
static void screen_scroll(fb_instance_t *instance)
{
	if ((!instance->parea.mapped) || (console_override)) {
		for (unsigned int rel_row = 0; rel_row < instance->screen_rows; rel_row++) {
			unsigned int y = ROW2Y(rel_row);
			unsigned int row = rel_row + instance->offset_row;

			for (unsigned int yd = 0; yd < FONT_SCANLINES; yd++) {
				unsigned int x;
				unsigned int col;
				size_t bb_pos = BB_POS(instance, 0, row);
				size_t bb_pos1 = BB_POS(instance, 0, row + 1);

				for (col = 0, x = 0; col < instance->cols;
				    col++, x += FONT_WIDTH) {
					uint16_t glyph;

					if (row < instance->rows - 1) {
						if (instance->backbuf[bb_pos] ==
						    instance->backbuf[bb_pos1])
							goto skip;

						glyph = instance->backbuf[bb_pos1];
					} else
						glyph = 0;

					memcpy(&instance->addr[FB_POS(instance, x, y + yd)],
					    &instance->glyphs[GLYPH_POS(instance, glyph, yd)],
					    instance->glyphscanline);
				skip:
					BB_NEXT_COL(bb_pos);
					BB_NEXT_COL(bb_pos1);
				}
			}
		}
	}

	/*
	 * Implement backbuffer scrolling by wrapping around
	 * the cyclic buffer.
	 */

	instance->start_row++;
	if (instance->start_row == instance->rows)
		instance->start_row = 0;

	memsetw(&instance->backbuf[BB_POS(instance, 0, instance->rows - 1)],
	    instance->cols, 0);
}

static void cursor_put(fb_instance_t *instance)
{
	unsigned int col = instance->column;
	unsigned int row = instance->row;

	glyph_draw(instance, fb_font_glyph(U_CURSOR), col, row, true);
}

static void cursor_remove(fb_instance_t *instance)
{
	unsigned int col = instance->column;
	unsigned int row = instance->row;

	glyph_draw(instance, instance->backbuf[BB_POS(instance, col, row)],
	    col, row, true);
}

/** Render glyphs
 *
 * Convert glyphs from device independent font
 * description to current visual representation.
 *
 */
static void glyphs_render(fb_instance_t *instance)
{
	/* Prerender glyphs */
	uint16_t glyph;

	for (glyph = 0; glyph < FONT_GLYPHS; glyph++) {
		uint32_t fg_color;

		if (glyph == FONT_GLYPHS - 1)
			fg_color = INV_COLOR;
		else
			fg_color = FG_COLOR;

		unsigned int y;

		for (y = 0; y < FONT_SCANLINES; y++) {
			unsigned int x;

			for (x = 0; x < FONT_WIDTH; x++) {
				void *dst =
				    &instance->glyphs[GLYPH_POS(instance, glyph, y) +
				    x * instance->pixelbytes];
				uint32_t rgb = (fb_font[glyph][y] &
				    (1 << (7 - x))) ? fg_color : BG_COLOR;
				instance->rgb_conv(dst, rgb);
			}
		}
	}

	/* Prerender background scanline */
	unsigned int x;

	for (x = 0; x < instance->xres; x++)
		instance->rgb_conv(&instance->bgscan[x * instance->pixelbytes], BG_COLOR);
}

static void fb_redraw_internal(fb_instance_t *instance)
{
	for (unsigned int rel_row = 0; rel_row < instance->screen_rows; rel_row++) {
		unsigned int y = ROW2Y(rel_row);
		unsigned int row = rel_row + instance->offset_row;

		for (unsigned int yd = 0; yd < FONT_SCANLINES; yd++) {
			unsigned int x;
			unsigned int col;
			size_t bb_pos = BB_POS(instance, 0, row);

			for (col = 0, x = 0; col < instance->cols;
			    col++, x += FONT_WIDTH) {
				uint16_t glyph =
				    instance->backbuf[bb_pos];
				void *dst = &instance->addr[FB_POS(instance, x, y + yd)];
				void *src = &instance->glyphs[GLYPH_POS(instance, glyph, yd)];
				memcpy(dst, src, instance->glyphscanline);
				BB_NEXT_COL(bb_pos);
			}
		}
	}

	if (COL2X(instance->cols) < instance->xres) {
		unsigned int y;
		unsigned int size =
		    (instance->xres - COL2X(instance->cols)) * instance->pixelbytes;

		for (y = 0; y < instance->yres; y++)
			memcpy(&instance->addr[FB_POS(instance, COL2X(instance->cols), y)],
			    instance->bgscan, size);
	}

	if (ROW2Y(instance->screen_rows) < instance->yres) {
		unsigned int y;

		for (y = ROW2Y(instance->screen_rows); y < instance->yres; y++)
			memcpy(&instance->addr[FB_POS(instance, 0, y)],
			    instance->bgscan, instance->bgscanbytes);
	}
}

static void _advance_row(fb_instance_t *instance)
{
	instance->column = 0;
	instance->row++;
}

static void _advance_column(fb_instance_t *instance)
{
	instance->column++;
	if (instance->column == instance->cols)
		_advance_row(instance);
}

/** Print character to screen
 *
 * Emulate basic terminal commands.
 *
 */
static void _putuchar(fb_instance_t *instance, char32_t ch)
{
	switch (ch) {
	case '\n':
		_advance_row(instance);
		break;
	case '\r':
		instance->column = 0;
		break;
	case '\b':
		if (instance->column > 0)
			instance->column--;
		break;
	case '\t':
		do {
			glyph_draw(instance, fb_font_glyph(' '),
			    instance->column,
			    instance->row, false);
			_advance_column(instance);
		} while (instance->column % TAB_WIDTH != 0);
		break;
	default:
		glyph_draw(instance, fb_font_glyph(ch),
		    instance->column,
		    instance->row, false);
		_advance_column(instance);
	}

	while (instance->row >= instance->rows) {
		instance->row--;
		screen_scroll(instance);
	}
}

static void fb_write(outdev_t *dev, const char *s, size_t n)
{
	fb_instance_t *instance = (fb_instance_t *) dev->data;

	spinlock_lock(&instance->lock);
	cursor_remove(instance);

	size_t offset = 0;
	char32_t ch;

	while ((ch = str_decode_r(s, &offset, n, U_SPECIAL, &instance->mbstate)))
		_putuchar(instance, ch);

	cursor_put(instance);
	spinlock_unlock(&instance->lock);
}

/** Scroll the framebuffer up
 *
 */
static void fb_scroll_up(outdev_t *dev)
{
	fb_instance_t *instance = (fb_instance_t *) dev->data;
	spinlock_lock(&instance->lock);

	if (instance->offset_row >= instance->screen_rows / 2)
		instance->offset_row -= instance->screen_rows / 2;
	else
		instance->offset_row = 0;

	fb_redraw_internal(instance);
	cursor_put(instance);

	spinlock_unlock(&instance->lock);
}

/** Scroll the framebuffer down
 *
 */
static void fb_scroll_down(outdev_t *dev)
{
	fb_instance_t *instance = (fb_instance_t *) dev->data;
	spinlock_lock(&instance->lock);

	if (instance->offset_row + instance->screen_rows / 2 <=
	    instance->rows - instance->screen_rows)
		instance->offset_row += instance->screen_rows / 2;
	else
		instance->offset_row = instance->rows - instance->screen_rows;

	fb_redraw_internal(instance);
	cursor_put(instance);

	spinlock_unlock(&instance->lock);
}

/** Refresh the screen
 *
 */
static void fb_redraw(outdev_t *dev)
{
	fb_instance_t *instance = (fb_instance_t *) dev->data;

	spinlock_lock(&instance->lock);
	fb_redraw_internal(instance);
	spinlock_unlock(&instance->lock);
}

/** Framebuffer was mapped or unmapped.
 *
 * @param arg Framebuffer instance
 */
static void fb_mapped_changed(void *arg)
{
	fb_instance_t *instance = (fb_instance_t *) arg;

	if (!instance->parea.mapped) {
		spinlock_lock(&instance->lock);
		fb_redraw_internal(instance);
		spinlock_unlock(&instance->lock);
	}
}

/** Initialize framebuffer as a output character device
 *
 */
outdev_t *fb_init(fb_properties_t *props)
{
	assert(props);
	assert(props->x > 0);
	assert(props->y > 0);
	assert(props->scan > 0);

	rgb_conv_t rgb_conv;
	unsigned int pixelbytes;

	switch (props->visual) {
	case VISUAL_INDIRECT_8:
		rgb_conv = bgr_323;
		pixelbytes = 1;
		break;
	case VISUAL_RGB_5_5_5_LE:
		rgb_conv = rgb_555_le;
		pixelbytes = 2;
		break;
	case VISUAL_RGB_5_5_5_BE:
		rgb_conv = rgb_555_be;
		pixelbytes = 2;
		break;
	case VISUAL_RGB_5_6_5_LE:
		rgb_conv = rgb_565_le;
		pixelbytes = 2;
		break;
	case VISUAL_RGB_5_6_5_BE:
		rgb_conv = rgb_565_be;
		pixelbytes = 2;
		break;
	case VISUAL_RGB_8_8_8:
		rgb_conv = rgb_888;
		pixelbytes = 3;
		break;
	case VISUAL_BGR_8_8_8:
		rgb_conv = bgr_888;
		pixelbytes = 3;
		break;
	case VISUAL_RGB_8_8_8_0:
		rgb_conv = rgb_8880;
		pixelbytes = 4;
		break;
	case VISUAL_RGB_0_8_8_8:
		rgb_conv = rgb_0888;
		pixelbytes = 4;
		break;
	case VISUAL_BGR_0_8_8_8:
		rgb_conv = bgr_0888;
		pixelbytes = 4;
		break;
	case VISUAL_BGR_8_8_8_0:
		rgb_conv = bgr_8880;
		pixelbytes = 4;
		break;
	default:
		LOG("Unsupported visual.");
		return NULL;
	}

	outdev_t *fbdev = malloc(sizeof(outdev_t));
	if (!fbdev)
		return NULL;

	fb_instance_t *instance = malloc(sizeof(fb_instance_t));
	if (!instance) {
		free(fbdev);
		return NULL;
	}

	outdev_initialize("fbdev", fbdev, &fbdev_ops);
	fbdev->data = instance;

	spinlock_initialize(&instance->lock, "*fb.instance.lock");

	instance->rgb_conv = rgb_conv;
	instance->pixelbytes = pixelbytes;
	instance->xres = props->x;
	instance->yres = props->y;
	instance->scanline = props->scan;

	instance->screen_rows = Y2ROW(instance->yres);

	instance->cols = X2COL(instance->xres);
	instance->rows = FB_PAGES * instance->screen_rows;

	instance->start_row = instance->rows - instance->screen_rows;
	instance->offset_row = instance->start_row;
	instance->row = instance->start_row;
	instance->column = 0;

	instance->glyphscanline = FONT_WIDTH * instance->pixelbytes;
	instance->glyphbytes = ROW2Y(instance->glyphscanline);
	instance->bgscanbytes = instance->xres * instance->pixelbytes;

	size_t fbsize = instance->scanline * instance->yres;
	size_t bbsize = instance->cols * instance->rows * sizeof(uint16_t);
	size_t glyphsize = FONT_GLYPHS * instance->glyphbytes;

	instance->addr = (uint8_t *) km_map((uintptr_t) props->addr, fbsize,
	    KM_NATURAL_ALIGNMENT, PAGE_WRITE | PAGE_WRITE_COMBINE);
	if (!instance->addr) {
		LOG("Unable to map framebuffer.");
		free(instance);
		free(fbdev);
		return NULL;
	}

	instance->backbuf = (uint16_t *) malloc(bbsize);
	if (!instance->backbuf) {
		LOG("Unable to allocate backbuffer.");
		free(instance);
		free(fbdev);
		return NULL;
	}

	instance->glyphs = (uint8_t *) malloc(glyphsize);
	if (!instance->glyphs) {
		LOG("Unable to allocate glyphs.");
		free(instance->backbuf);
		free(instance);
		free(fbdev);
		return NULL;
	}

	instance->bgscan = malloc(instance->bgscanbytes);
	if (!instance->bgscan) {
		LOG("Unable to allocate background pixel.");
		free(instance->glyphs);
		free(instance->backbuf);
		free(instance);
		free(fbdev);
		return NULL;
	}

	memsetw(instance->backbuf, instance->cols * instance->rows, 0);
	glyphs_render(instance);

	ddi_parea_init(&instance->parea);
	instance->parea.pbase = props->addr;
	instance->parea.frames = SIZE2FRAMES(fbsize);
	instance->parea.unpriv = false;
	instance->parea.mapped = false;
	instance->parea.mapped_changed = fb_mapped_changed;
	instance->parea.arg = (void *) instance;
	ddi_parea_register(&instance->parea);

	if (!fb_exported) {
		/*
		 * We export the kernel framebuffer for uspace usage.
		 * This is used in the case the uspace framebuffer
		 * driver is not self-sufficient.
		 */
		sysinfo_set_item_val("fb", NULL, true);
		sysinfo_set_item_val("fb.kind", NULL, 1);
		sysinfo_set_item_val("fb.width", NULL, instance->xres);
		sysinfo_set_item_val("fb.height", NULL, instance->yres);
		sysinfo_set_item_val("fb.scanline", NULL, instance->scanline);
		sysinfo_set_item_val("fb.visual", NULL, props->visual);
		sysinfo_set_item_val("fb.address.physical", NULL, props->addr);

		fb_exported = true;
	}

	fb_redraw(fbdev);
	return fbdev;
}

/** @}
 */