/*****************************************************************************

Copyright (c) 2025 Jaroslav Hensl <emulator@emulace.cz>

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.

*****************************************************************************/

#include "winhack.h"
#include "vmm.h"
#include "vxd.h"

#include "vxd_lib.h"
#include "3d_accel.h"
#include "vxd_halloc.h"

#include "code32.h"

#include "wram.h"

wram_t *wram = NULL;

BOOL wram_init(DWORD bytes)
{
	DWORD x;
	DWORD pages = RoundToPages(bytes);

	if(pages < 16) return FALSE;

	wram = (wram_t*)_PageAllocate(pages, PG_SYS, 0, 0, PAGE_ALLOC_MIN, PAGE_ALLOC_MAX, NULL, PAGEFIXED|PAGEUSEALIGN);

	if(wram == NULL)
	{
		dbg_printf("wram_init: _PageAllocate FAILURE\n");
		return FALSE;
	}

	memset(wram, 0, WRAM_FB_TOP); // clear first 3 pages
	
	for(x = 0; x < 256; x++)
	{
		wram->gamma.red[x]   = x;
		wram->gamma.green[x] = x;
		wram->gamma.blue[x]  = x;
		wram->palette[x].dw  = ((x << 16) | (x << 8) | x);
	}

	/* default screen */
	wram->regs.s.fbstart = WRAM_FB_TOP;
	wram->regs.s.size    = bytes;
	wram->regs.s.width   = 640;
	wram->regs.s.height  = 480;
	wram->regs.s.mode    = MODE_32;
	wram->regs.s.pitch   = wram->regs.s.width*4;
	wram->regs.s.cursor_visible = 0;
	wram->regs.s.cursor_x = 0;
	wram->regs.s.cursor_y = 0;
	wram->regs.s.cursor_w = 0;
	wram->regs.s.cursor_h = 0;
	wram->regs.s.gamma_enable = 0;
	wram->regs.s.fbmin    = WRAM_FB_TOP;
	wram->regs.s.fbmax    = pages * P_SIZE;

	dbg_printf("WRAM init SUCCESS (regs.s.size=%ld)\n", wram->regs.s.size);

	return TRUE;
}

static DWORD readpx8(DWORD x, DWORD y)
{
	BYTE index = ((BYTE*)wram)[wram->regs.s.fbstart + wram->regs.s.pitch*y + x];
	return wram->palette[index].dw;
}

static DWORD readpx32(DWORD x, DWORD y)
{
	DWORD *ptr32 = (DWORD*)(&(((BYTE*)wram)[wram->regs.s.fbstart + wram->regs.s.pitch*y]));
	return ptr32[x];
}

static DWORD readpx24(DWORD x, DWORD y)
{
	DWORD *ptr32 = (DWORD*)(&(((BYTE*)wram)[wram->regs.s.fbstart + wram->regs.s.pitch*y + x*3]));
	return (*ptr32) & 0x00FFFFFF; /* little endian only */
}

static DWORD readpx16(DWORD x, DWORD y)
{
	WORD px16 = ((WORD*)(&(((BYTE*)wram)[wram->regs.s.fbstart + wram->regs.s.pitch*y])))[x];
	return ((px16 & 0xF800) << 8) | ((px16 & 0x07E0) << 5) | ((px16 & 0x001F) << 3);
}

static DWORD readpx15(DWORD x, DWORD y)
{
	WORD px16 = ((WORD*)(&(((BYTE*)wram)[wram->regs.s.fbstart + wram->regs.s.pitch*y])))[x];
	return ((px16 & 0x7C00) << 9) | ((px16 & 0x03E0) << 6) | ((px16 & 0x001F) << 3);
}

static void writepx32(blit_t *blit, DWORD x, DWORD y, DWORD px32)
{
	((DWORD*)&(blit->dst[0].px8[blit->dst_pitch * y]))[x] = px32;
}

static void writepx16(blit_t *blit, DWORD x, DWORD y, DWORD px32)
{
	WORD px16 = ((px32 & 0xF80000) >> 8) | ((px32 & 0xFC00) >> 5) | ((px32 & 0xF8) >> 3);
	((WORD*)&(blit->dst[0].px8[blit->dst_pitch * y]))[x] = px16;
}

static void writepx15(blit_t *blit, DWORD x, DWORD y, DWORD px32)
{
	WORD px15 = ((px32 & 0xF80000) >> 9) | ((px32 & 0xF800) >> 6) | ((px32 & 0xF8) >> 3);
	((WORD*)&(blit->dst[0].px8[blit->dst_pitch * y]))[x] = px15;
}

static void writepx24(blit_t *blit, DWORD x, DWORD y, DWORD px32)
{
	BYTE *ptr8 = &blit->dst[0].px8[blit->dst_pitch * y + x];
	ptr8[0] = px32 >> 16;
	ptr8[1] = px32 >> 8;
	ptr8[2] = px32;
}

typedef DWORD (*readfn_h)(DWORD x, DWORD y);
typedef void (*writefn_h)(blit_t *blit, DWORD x, DWORD y, DWORD px32);

void wram_blit(blit_t *blit)
{
	readfn_h readfn = NULL;
	writefn_h writefn = NULL;
	DWORD x, y, sx, sy;
	pixel_32_t px;
	LONG cursor_ex = wram->regs.s.cursor_x + wram->regs.s.cursor_w;
	LONG cursor_ey = wram->regs.s.cursor_y + wram->regs.s.cursor_h;
	DWORD scans = blit->dst_scans;

	switch(wram->regs.s.mode)
	{
		case MODE_32: readfn = readpx32; break;
		case MODE_24: readfn = readpx24; break;
		case MODE_16: readfn = readpx16; break;
		case MODE_15: readfn = readpx15; break;
		case MODE_8:  readfn = readpx8;  break;
	}

	switch(blit->dst_mode)
	{
		case MODE_32: writefn = writepx32; break;
		case MODE_24: writefn = writepx24; break;
		case MODE_16: writefn = writepx16; break;
		case MODE_15: writefn = writepx15; break;
	}

	if(readfn == NULL || writefn == NULL) return;

	//dbg_printf("wram_blit, mode=%d -> mode=%d, dst=%lX\n", wram->regs.s.mode, blit->dst_mode, blit->dst[0].flat.dw);

	for(y = blit->src_sy; y < blit->src_ey; y++)
	{
		for(x = blit->src_sx; x < blit->src_ex; x++)
		{
			px.dw = readfn(x, y);
			if(wram->regs.s.gamma_enable)
			{
				px.c.r = wram->gamma.red[px.c.r];
				px.c.g = wram->gamma.green[px.c.g];
				px.c.b = wram->gamma.blue[px.c.b];
			}
			if(wram->regs.s.cursor_visible)
			{
				if((LONG)x >= wram->regs.s.cursor_x && (LONG)x < cursor_ex)
				{
					if((LONG)y >= wram->regs.s.cursor_y && (LONG)y < cursor_ey)
					{
						DWORD cp = ((y - wram->regs.s.cursor_y)*CURSOR_DMAX) + (x - wram->regs.s.cursor_x);
						px.dw &= wram->cursor.andmask[cp];
						px.dw ^= wram->cursor.xormask[cp];
					}
				}
			}

			for(sy = 0; sy < scans; sy++)
			{
				for(sx = 0; sx < scans; sx++)
				{
					writefn(blit,
						blit->dst_padx + x*scans + sx,
						blit->dst_pady + y*scans + sy,
						px.dw);
				}
			}
		}
	}
}

void wram_clear_target(blit_t *blit)
{
	DWORD x, y;
	writefn_h writefn = NULL;

	switch(blit->dst_mode)
	{
		case MODE_32: writefn = writepx32; break;
		case MODE_24: writefn = writepx24; break;
		case MODE_16: writefn = writepx16; break;
		case MODE_15: writefn = writepx15; break;
	}

	if(writefn == NULL) return;

	for(y = 0; y < blit->dst_h; y++)
	{
		for(x = 0; x < blit->dst_w; x++)
		{
			writefn(blit, x, y, 0x00000000);
		}
	}
}

void wram_clear()
{
	BYTE *ptr = &(((BYTE*)wram)[wram->regs.s.fbstart]);	
	memset(ptr, 0, wram->regs.s.pitch * wram->regs.s.height);
}

BOOL wram_swap(void *virtptr, blit_t *blit)
{
	flat_t flat_wram;
	flat_t flat_ptr;

	flat_wram.ptr = wram;
	flat_ptr.ptr = virtptr;

	if(flat_ptr.dw >= (flat_wram.dw + WRAM_FB_TOP) &&
		flat_ptr.dw < (flat_wram.dw + wram->regs.s.size))
	{
		wram->regs.s.fbstart = flat_ptr.dw - flat_wram.dw;
		
		if(blit != NULL)
		{
			blit->num_changes = 1;
			blit->src_sx = 0;
			blit->src_sy = 0;
			blit->src_ex = wram->regs.s.width;
			blit->src_ey = wram->regs.s.height;
		}
		
		return TRUE;
	}

	return FALSE;
}

#define SWAP_DW(_a, _b) do{\
	DWORD swtmp = _a; \
	_a = _b; \
	_b = swtmp;}while(0)

void wram_changes(blit_t *blit, DWORD sx, DWORD sy, DWORD ex, DWORD ey)
{
	if(sx > ex)
	{
		SWAP_DW(sx, ex);
	}

	if(sy > ey)
	{
		SWAP_DW(sy, ey);
	}

	if(blit->num_changes == 0)
	{
		if(sx >= wram->regs.s.width)  sx = wram->regs.s.width-1;
		if(ex >  wram->regs.s.width)  ex = wram->regs.s.width;
		if(sy >= wram->regs.s.height) sy = wram->regs.s.height-1; 
		if(ey >  wram->regs.s.height) ey = wram->regs.s.height;

		blit->src_sx = sx;
		blit->src_ex = ex;
		blit->src_sy = sy;
		blit->src_ey = ey;
	}
	else
	{
		if(ex > wram->regs.s.width)  ex = wram->regs.s.width;
		if(ey > wram->regs.s.height) ey = wram->regs.s.height;

		if(sx < blit->src_sx)	blit->src_sx = sx;
		if(sy < blit->src_sy) blit->src_sy = sy;
		
		if(ex > blit->src_ex) blit->src_ex = ex;
		if(ey > blit->src_ey) blit->src_ey = ey;		
	}
	blit->num_changes++;
}