/*
*   This file is part of Luma3DS
*   Copyright (C) 2016-2020 Aurora Wright, TuxSH
*
*   This program is free software: you can redistribute it and/or modify
*   it under the terms of the GNU General Public License as published by
*   the Free Software Foundation, either version 3 of the License, or
*   (at your option) any later version.
*
*   This program 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 General Public License for more details.
*
*   You should have received a copy of the GNU General Public License
*   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*
*   Additional Terms 7.b and 7.c of GPLv3 apply to this file:
*       * Requiring preservation of specified reasonable legal notices or
*         author attributions in that material or in the Appropriate Legal
*         Notices displayed by works containing it.
*       * Prohibiting misrepresentation of the origin of that material,
*         or requiring that modified versions of such material be marked in
*         reasonable ways as different from the original version.
*/

#include <3ds.h>
#include <stdarg.h>
#include "fmt.h"
#include "draw.h"
#include "font.h"
#include "memory.h"
#include "menu.h"
#include "utils.h"
#include "csvc.h"

#define KERNPA2VA(a)            ((a) + (GET_VERSION_MINOR(osGetKernelVersion()) < 44 ? 0xD0000000 : 0xC0000000))

static u32 gpuSavedFramebufferAddr1, gpuSavedFramebufferAddr2, gpuSavedFramebufferFormat, gpuSavedFramebufferStride, gpuSavedFillColor;
static u32 framebufferCacheSize;
static void *framebufferCache;
static RecursiveLock lock;

void Draw_Init(void)
{
    RecursiveLock_Init(&lock);
}

void Draw_Lock(void)
{
    RecursiveLock_Lock(&lock);
}

void Draw_Unlock(void)
{
    RecursiveLock_Unlock(&lock);
}

void Draw_DrawCharacter(u32 posX, u32 posY, u32 color, char character)
{
    u16 *const fb = (u16 *)FB_BOTTOM_VRAM_ADDR;

    s32 y;
    for(y = 0; y < 10; y++)
    {
        char charPos = font[character * 10 + y];

        s32 x;
        for(x = 6; x >= 1; x--)
        {
            u32 screenPos = (posX * SCREEN_BOT_HEIGHT * 2 + (SCREEN_BOT_HEIGHT - y - posY - 1) * 2) + (5 - x) * 2 * SCREEN_BOT_HEIGHT;
            u32 pixelColor = ((charPos >> x) & 1) ? color : COLOR_BLACK;
            fb[screenPos / 2] = pixelColor;
        }
    }
}


u32 Draw_DrawString(u32 posX, u32 posY, u32 color, const char *string)
{
    for(u32 i = 0, line_i = 0; i < strlen(string); i++)
        switch(string[i])
        {
            case '\n':
                posY += SPACING_Y;
                line_i = 0;
                break;

            case '\t':
                line_i += 2;
                break;

            default:
                //Make sure we never get out of the screen
                if(line_i >= ((SCREEN_BOT_WIDTH) - posX) / SPACING_X)
                {
                    posY += SPACING_Y;
                    line_i = 1; //Little offset so we know the same string continues
                    if(string[i] == ' ') break; //Spaces at the start look weird
                }

                Draw_DrawCharacter(posX + line_i * SPACING_X, posY, color, string[i]);

                line_i++;
                break;
        }

    return posY;
}

u32 Draw_DrawFormattedString(u32 posX, u32 posY, u32 color, const char *fmt, ...)
{
    char buf[DRAW_MAX_FORMATTED_STRING_SIZE + 1];
    va_list args;
    va_start(args, fmt);
    vsprintf(buf, fmt, args);
    va_end(args);

    return Draw_DrawString(posX, posY, color, buf);
}

void Draw_FillFramebuffer(u32 value)
{
    memset(FB_BOTTOM_VRAM_ADDR, value, FB_BOTTOM_SIZE);
}

void Draw_ClearFramebuffer(void)
{
    Draw_FillFramebuffer(0);
}

Result Draw_AllocateFramebufferCache(u32 size)
{
    // Can't use fbs in FCRAM when Home Menu is active (AXI config related maybe?)
    u32 addr = 0x0D000000;
    u32 tmp;

    size = (size + 0xFFF) >> 12 << 12; // round-up

    if (framebufferCache != NULL)
        __builtin_trap();

    Result res = svcControlMemoryEx(&tmp, addr, 0, size, MEMOP_ALLOC | MEMOP_REGION_SYSTEM, MEMPERM_READWRITE, true);
    if (R_FAILED(res))
    {
        framebufferCache = NULL;
        framebufferCacheSize = 0;
    }
    else
    {
        framebufferCache = (u32 *)addr;
        framebufferCacheSize = size;
    }

    return res;
}

Result Draw_AllocateFramebufferCacheForScreenshot(u32 size)
{
    u32 remaining = (u32)osGetMemRegionFree(MEMREGION_SYSTEM);
    u32 sz = remaining < size ? remaining : size;
    return Draw_AllocateFramebufferCache(sz);
}

void Draw_FreeFramebufferCache(void)
{
    u32 tmp;
    if (framebufferCache != NULL)
        svcControlMemory(&tmp, (u32)framebufferCache, 0, framebufferCacheSize, MEMOP_FREE, 0);
    framebufferCacheSize = 0;
    framebufferCache = NULL;
}

void *Draw_GetFramebufferCache(void)
{
    return framebufferCache;
}

u32 Draw_GetFramebufferCacheSize(void)
{
    return framebufferCacheSize;
}

u32 Draw_SetupFramebuffer(void)
{
    while((GPU_PSC0_CNT | GPU_PSC1_CNT | GPU_TRANSFER_CNT | GPU_CMDLIST_CNT) & 1);

    Draw_FlushFramebuffer();
    memcpy(framebufferCache, FB_BOTTOM_VRAM_ADDR, FB_BOTTOM_SIZE);
    Draw_ClearFramebuffer();
    Draw_FlushFramebuffer();

    u32 format = GPU_FB_BOTTOM_FMT;

    gpuSavedFramebufferAddr1 = GPU_FB_BOTTOM_ADDR_1;
    gpuSavedFramebufferAddr2 = GPU_FB_BOTTOM_ADDR_2;
    gpuSavedFramebufferFormat = format;
    gpuSavedFramebufferStride = GPU_FB_BOTTOM_STRIDE;

    format = (format & ~7) | GSP_RGB565_OES;
    format |= 3 << 8; // set VRAM bits

    GPU_FB_BOTTOM_ADDR_1 = GPU_FB_BOTTOM_ADDR_2 = FB_BOTTOM_VRAM_PA;
    GPU_FB_BOTTOM_FMT = format;
    GPU_FB_BOTTOM_STRIDE = 240 * 2;

    gpuSavedFillColor = LCD_BOT_FILLCOLOR;
    LCD_BOT_FILLCOLOR = 0;

    return framebufferCacheSize;
}

void Draw_RestoreFramebuffer(void)
{
    memcpy(FB_BOTTOM_VRAM_ADDR, framebufferCache, FB_BOTTOM_SIZE);
    Draw_FlushFramebuffer();

    LCD_BOT_FILLCOLOR = gpuSavedFillColor;
    GPU_FB_BOTTOM_ADDR_1 = gpuSavedFramebufferAddr1;
    GPU_FB_BOTTOM_ADDR_2 = gpuSavedFramebufferAddr2;
    GPU_FB_BOTTOM_FMT = gpuSavedFramebufferFormat;
    GPU_FB_BOTTOM_STRIDE = gpuSavedFramebufferStride;
}

void Draw_FlushFramebuffer(void)
{
    svcFlushProcessDataCache(CUR_PROCESS_HANDLE, (u32)FB_BOTTOM_VRAM_ADDR, FB_BOTTOM_SIZE);
}

u32 Draw_GetCurrentFramebufferAddress(bool top, bool left)
{
    if(GPU_FB_BOTTOM_SEL & 1)
    {
        if(left)
            return top ? GPU_FB_TOP_LEFT_ADDR_2 : GPU_FB_BOTTOM_ADDR_2;
        else
            return top ? GPU_FB_TOP_RIGHT_ADDR_2 : GPU_FB_BOTTOM_ADDR_2;
    }
    else
    {
        if(left)
            return top ? GPU_FB_TOP_LEFT_ADDR_1 : GPU_FB_BOTTOM_ADDR_1;
        else
            return top ? GPU_FB_TOP_RIGHT_ADDR_1 : GPU_FB_BOTTOM_ADDR_1;
    }
}

void Draw_GetCurrentScreenInfo(u32 *width, bool *is3d, bool top)
{
    if (top)
    {
        bool isNormal2d = (GPU_FB_TOP_FMT & BIT(6)) != 0;
        *is3d = (GPU_FB_TOP_FMT & BIT(5)) != 0;
        *width = !(*is3d) && !isNormal2d ? 800 : 400;
    }
    else
    {
        *is3d = false;
        *width = 320;
    }
}

static inline void Draw_WriteUnaligned(u8 *dst, u32 tmp, u32 size)
{
    memcpy(dst, &tmp, size);
}

void Draw_CreateBitmapHeader(u8 *dst, u32 width, u32 heigth)
{
    static const u8 bmpHeaderTemplate[54] = {
        // BITMAPFILEHEADER
        0x42, 0x4D, 0xCC, 0xCC, 0xCC, 0xCC, 0x00, 0x00, 0x00, 0x00, 0x40 /* data offset */, 0x00, 0x00, 0x00,

        // BITMAPINFOHEADER
        0x28, 0x00, 0x00, 0x00, 0xCC, 0xCC, 0xCC, 0xCC, 0xCC, 0xCC, 0xCC, 0xCC, 0x01, 0x00, 0x18, 0x00, 0x00,
        0x00, 0x00, 0x00, 0xCC, 0xCC, 0xCC, 0xCC, 0x12, 0x0B, 0x00, 0x00, 0x12, 0x0B, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00
    };

    memcpy(dst, bmpHeaderTemplate, 54);
    memset(dst + 54, 0, 64 - 54);
    Draw_WriteUnaligned(dst + 2, 64 + 3 * width * heigth, 4);
    Draw_WriteUnaligned(dst + 0x12, width, 4);
    Draw_WriteUnaligned(dst + 0x16, heigth, 4);
    Draw_WriteUnaligned(dst + 0x22, 3 * width * heigth, 4);
}

static inline void Draw_ConvertPixelToBGR8(u8 *dst, const u8 *src, GSPGPU_FramebufferFormat srcFormat)
{
    u8 red, green, blue;
    switch(srcFormat)
    {
        case GSP_RGBA8_OES:
        {
            u32 px = *(u32 *)src;
            dst[0] = (px >>  8) & 0xFF;
            dst[1] = (px >> 16) & 0xFF;
            dst[2] = (px >> 24) & 0xFF;
            break;
        }
        case GSP_BGR8_OES:
        {
            dst[2] = src[2];
            dst[1] = src[1];
            dst[0] = src[0];
            break;
        }
        case GSP_RGB565_OES:
        {
            // thanks neobrain
            u16 px = *(u16 *)src;
            blue = px & 0x1F;
            green = (px >> 5) & 0x3F;
            red = (px >> 11) & 0x1F;

            dst[0] = (blue  << 3) | (blue  >> 2);
            dst[1] = (green << 2) | (green >> 4);
            dst[2] = (red   << 3) | (red   >> 2);

            break;
        }
        case GSP_RGB5_A1_OES:
        {
            u16 px = *(u16 *)src;
            blue = (px >> 1) & 0x1F;
            green = (px >> 6) & 0x1F;
            red = (px >> 11) & 0x1F;

            dst[0] = (blue  << 3) | (blue  >> 2);
            dst[1] = (green << 3) | (green >> 2);
            dst[2] = (red   << 3) | (red   >> 2);

            break;
        }
        case GSP_RGBA4_OES:
        {
            u16 px = *(u32 *)src;
            blue = (px >> 4) & 0xF;
            green = (px >> 8) & 0xF;
            red = (px >> 12) & 0xF;

            dst[0] = (blue  << 4) | (blue  >> 0);
            dst[1] = (green << 4) | (green >> 0);
            dst[2] = (red   << 4) | (red   >> 0);

            break;
        }
        default: break;
    }
}

typedef struct FrameBufferConvertArgs {
    u8 *buf;
    u32 width;
    u8 startingLine;
    u8 numLines;
    u8 scaleFactorY;
    bool top;
    bool left;
} FrameBufferConvertArgs;

static void Draw_ConvertFrameBufferLinesKernel(const FrameBufferConvertArgs *args)
{
    static const u8 formatSizes[] = { 4, 3, 2, 2, 2 };

    GSPGPU_FramebufferFormat fmt = args->top ? (GSPGPU_FramebufferFormat)(GPU_FB_TOP_FMT & 7) : (GSPGPU_FramebufferFormat)(GPU_FB_BOTTOM_FMT & 7);
    u32 width = args->width;
    u32 stride = args->top ? GPU_FB_TOP_STRIDE : GPU_FB_BOTTOM_STRIDE;

    u32 pa = Draw_GetCurrentFramebufferAddress(args->top, args->left);
    u8 *addr = (u8 *)KERNPA2VA(pa);

    for (u32 y = args->startingLine; y < args->startingLine + args->numLines; y++)
    {
        for (u8 i = 0; i < args->scaleFactorY; i++)
        {
            for(u32 x = 0; x < width; x++)
            {
                __builtin_prefetch(addr + x * stride + y * formatSizes[fmt], 0, 3);
                Draw_ConvertPixelToBGR8(args->buf + (x + width * (args->scaleFactorY * y + i)) * 3 , addr + x * stride + y * formatSizes[fmt], fmt);
            }
        }
    }
}

void Draw_ConvertFrameBufferLines(u8 *buf, u32 width, u32 startingLine, u32 numLines, u32 scaleFactorY, bool top, bool left)
{
    FrameBufferConvertArgs args = { buf, width, (u8)startingLine, (u8)numLines, (u8)scaleFactorY, top, left };
    svcCustomBackdoor(Draw_ConvertFrameBufferLinesKernel, &args);
}