// ncurses.c
// Implements interface.h
// Provides an in-terminal interface to the emulator.

#include<ncurses.h>
#include"interface.h"
#include"../apple.h"
#include"../cpu/6502.h"


int TermX = 0;
int TermY = 0;

WINDOW *AppleWindow;


byte* VRAM;

int vPosition = 0;

int vOffset = 0;


void PrintInfo()
{
	mvprintw(2, 43, " acc  : %02x", acc);
	mvprintw(3, 43, "  X   : %02x",  X );
	mvprintw(4, 43, "  Y   : %02x",  Y );
	mvprintw(5, 43, "  PC  : %04x", PC);
	mvprintw(6, 43, "  S   : %02x",  S );
	mvprintw(7, 43, "Flags : %c%c_%c%c%c%c%c",
		getFlag(flag_N) ? 'N':'.' ,
		getFlag(flag_V) ? 'V':'.' ,
		getFlag(flag_B) ? 'B':'.' ,
		getFlag(flag_D) ? 'D':'.' ,
		getFlag(flag_I) ? 'I':'.' ,
		getFlag(flag_Z) ? 'Z':'.' ,
		getFlag(flag_C) ? 'C':'.'
	);
	mvprintw(2, 65, "Stack");
	int count = 3;
	for (int i = 0x1ff; i > 0x1e8; i--) {
		if (i == (0x1ff-S)) // Indicate the stack pointer!
			attron(A_REVERSE);
		mvprintw(count, 65, "%x : %x", i, GetMemory(i));
		attroff(A_REVERSE);
		count++;
	}
	refresh();
}



void DisplayInit()
{
	// ncurses initialization functions.
    initscr();
    cbreak();
    noecho();
    curs_set(0);
    keypad(stdscr, TRUE);

    // Draw decorative border.
    attron(A_REVERSE);
    move(0, 0);
    printw("                                          ");
    for (int i = 1; i <= 24; i++)
    {
        mvaddch(i,  0, ' ');
        mvaddch(i, 41, ' ');
    }
    mvprintw(25, 0, " ~                                        ");
    mvprintw(26, 0, "             Alekseis Apple I             ");
    mvprintw(27, 0, "                                          ");
    attroff(A_REVERSE);

	// Create seperate Apple screen window.
    AppleWindow = newwin(24, 40, 1, 1);
	
	// @ prompt.
    mvwaddch(AppleWindow, TermY, TermX, '@' | A_BLINK);

	// Initialize the terminal shift register variables.
    VRAM = (byte*)malloc(960);

    refresh();
}



void DisplayClose()
{
    free(VRAM);
	curs_set(1);
    endwin();
}



void DisplayInput(byte n)
{
	if (n == BS) {
		return;
	}

	// Clear @
    mvwaddch(AppleWindow, TermY, TermX, ' ');

	if (n == CR) {
		// Add spacing characters into VRAM
		do {
			VRAM[vPosition] = ' ';
			vPosition++;
		} while ((vPosition % 40) > 0);

		// Set display to next line
		TermX = 0;
		TermY++;
	}
	else {
		// Place character
		mvwaddch(AppleWindow, TermY, TermX, n & 0x7F);
	
		// Add character to VRAM
		VRAM[vPosition] = n & 0x7f;
		vPosition++;

		// Set display to next character/next line
		TermX++;
		if (TermX >= 40) {
			TermX = 0;
			TermY++;
		}
	}

	// Reset VRAM_Position if it's value is too great.
	if (vPosition >= 960)
        vPosition -= 960;
    
	// If Y is past height..
    if (TermY >= 24) {
		
		//.. discard the first line..
		vOffset += 40;

        //.. then, for every cell of the screen except the last line, fill with VRAM..
        for (int i = 0; i < 23; i++) {
        for (int j = 0; j < 40; j++) {
            mvwaddch(AppleWindow, i, j, VRAM[vOffset++ % 960] );
        }}

		// ..and move offset up to next line.
		vOffset += 40;
		
		// Visually set to start of final line, and clear line.
        TermY = 23;
        TermX = 0;
        mvwprintw(AppleWindow, TermY, TermX,
			"                                        ");
    }

	// Place @
    mvwaddch(AppleWindow, TermY, TermX, '@' | A_BLINK);
    wrefresh(AppleWindow);
}