#include "zxscreen.h"
#include "z80.h"
#include <SDL2/SDL.h>

namespace zxscreen
{
    uint32_t palette[16] = {
        0x000000, 0x000080, 0x800000, 0x800080, 0x008000, 0x008080, 0x808000, 0x808080,
        0x000000, 0x0000FF, 0xFF0000, 0xFF00FF, 0x00FF00, 0x00FFFF, 0xFFFF00, 0xFFFFFF
    };
    SDL_Window *win = nullptr;
    SDL_Renderer *ren = nullptr;
    SDL_Texture *tex = nullptr;

    void show()
    {
        if (win) return;
        win = SDL_CreateWindow("ZX Spectrum Screen", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 352, 288, SDL_WINDOW_RESIZABLE);
        ren = SDL_CreateRenderer(win, -1, 0);
        tex = SDL_CreateTexture(ren, SDL_PIXELFORMAT_ARGB8888, SDL_TEXTUREACCESS_STREAMING, 352, 288);
        refresh();
    }

    void refresh()
    {
        const uint8_t* memory = z80::getMem();
        //memory+=0x4000;

        Uint32* pixels;
        int pitch;
        SDL_LockTexture(tex, NULL, (void**)&pixels, &pitch);

        // Upper border
        for (int i=0; i<352*48;++i) *(pixels++) = palette[7];

        // scanlines
        for (uint8_t y=0; y<192; ++y)
        {
            // Left border
            for (int j=0;j<48;++j) *(pixels++) = palette[7];

            // Actual screen
            for (uint8_t x=0;x<32;++x)
            {
                uint16_t address = 0x4000 | (x&0x1f) | ((y&0x7)<<8) | ((y&0x38)<<2) | ((y&0xc0)<<5);
                uint8_t block = memory[address];
                for (int i=0;i<8;++i)
                {
                    *(pixels++)=(block&0x80) ? palette[7] : palette[0];
                    block = block<<1;
                }
            }

            // Right border
            for (int j=0;j<48;++j) *(pixels++) = palette[7];
        }

        // Lower border
        for (int i=0; i<352*48;++i) *(pixels++)=palette[7];

        SDL_UnlockTexture(tex);
        SDL_RenderCopy(ren, tex, NULL, NULL);
        SDL_RenderPresent(ren);
    }
}