/*
   3ds81 - Nintendo 3DS ZX81 emulator.

   Copyright (C) 2021  Ian Cowburn <ianc@noddybox.co.uk>
   
   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/>
  
   $Id: main.c 77 2010-11-23 08:10:25Z ianc $
*/

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <3ds.h>

#include "framebuffer.h"
#include "gui.h"
#include "keyboard.h"
#include "z80.h"
#include "zx81.h"
#include "tapes.h"
#include "config.h"
#include "snapshot.h"
#include "debug.h"

#ifndef DS81_VERSION
#define DS81_VERSION "DEV " __TIME__ "/" __DATE__
#endif

#ifndef TRUE
#define TRUE 1
#endif

#ifndef FALSE
#define FALSE 0
#endif

/* Macro for PRINT AT in the upper framebuffer
*/
#define AT(x,y) (x)*8,upper.height-1-(y)*8

/* ---------------------------------------- STATIC DATA
*/
static const char *main_menu[]=
	{
	    "Reset ZX81",
	    "Select Tape",
	    "Configure",
	    "Map Joypad to Keys",
	    "Save Memory Snapshot",
	    "Load Memory Snapshot",
	    "Save Joypad/Key State",
	    "Load Joypad/Key State",
            "Help",
            "Debug",
	    "Exit 3DS81",
	    "Cancel",
	    NULL
	};

typedef enum
{
    MenuReset,
    MenuSelectTape,
    MenuConfigure,
    MenuMapJoypad,
    MenuSaveSnapshot,
    MenuLoadSnapshot,
    MenuSaveMappings,
    MenuLoadMappings,
    MenuHelp,
    MenuDebug,
    MenuExit
} MenuOpt;

static const char *debug_menu[]=
	{
	    "Enable Debug Output",
	    "Disable Debug Output",
            "Disassembler",
            "Memory Viewer",
            "CPU Info",
            "Cancel",
	    NULL
	};

typedef enum
{
    DebugMenuEnableOutput,
    DebugMenuDisableOutput,
    DebugMenuDisassembler,
    DebugMenuMemoryView,
    DebugMenuCPUInfo,
} DebugMenuOpt;


/* ---------------------------------------- DISPLAY FUNCS
*/
static void Splash(void)
{
    static char scroller[]=
    {
    	"                   "
	"Welcome to 3DS81, a ZX81 emulator for the Ninetendo 3DS.  "
	"You can safely ignore this message.  I was just bored for half an "
	"hour.  And no retro game is complete without a side-scroller...  "
	"Thanks to Slay Radio, Ladytron, the Genki Rockets, the High "
	"Voltage SID Collection, The Prodigy, Paradise Lost and "
        "Retro Gamer for coding fuel."
    };

    static const char *text[]=
    {
    	"3DS81 \177 2021 Ian Cowburn",
	" ",
	"ZX81 ROM \177 1981",
	"Nine Tiles Networks LTD",
	" ",
	"PRESS A TO CONTINUE",
	" ",
	"https://noddybox.co.uk/",
	" ",
        "If you place .P tape files in",
        "the top directory or ZX81",
        "then you should be able to load",
        "GAME.P with the command",
        "LOAD \"GAME\"",
	NULL
    };

    int f;
    int y;
    int scr_x = 0;
    int scr_y = 240;
    Framebuffer upper;
    Framebuffer lower;

    ZX81EnableFileSystem(TRUE);
    SNAP_Enable(TRUE);

    while(!(hidKeysDown() & KEY_A))
    {
        FB_StartFrame(&upper, &lower);

        FB_Clear(&upper, COL_BLACK);
        FB_Clear(&lower, COL_BLACK);

        FB_Blit(&upper, IMG_SPLASH, 0, scr_y);

        FB_Print(&upper, "10 REM VERSION \001" DS81_VERSION "\001\n"
                         "20 PRINT \"\001THE ZX81 IS ACE\001\"\n"
                         "30 GOTO 20", 
                 0, 230, COL_WHITE, COL_TRANSPARENT);

        FB_printf(&lower, scr_x, 8, COL_WHITE, COL_TRANSPARENT,
                  "%-42.42s",scroller);

        y = lower.height - 20;

        for(f=0;text[f];f++)
        {
            FB_Centre(&lower, text[f], y, COL_WHITE, COL_TRANSPARENT);
            y -= 8;
        }

	FB_EndFrame();

        if (scr_y > 0)
        {
            scr_y--;
        }

	if (--scr_x == -8)
	{
	    size_t l = sizeof scroller;
	    char c;

	    scr_x = 0;

	    c = scroller[0];
	    memmove(scroller, scroller+1, l-2);
	    scroller[l-2] = c;
	}
    }
}


/* ---------------------------------------- HELP
*/
static void ShowHelp(void)
{
    struct
    {
        FB_Colour col;
        const char *text;
    }
    help[] =
    {
        {COL_RED, "KEYBOARD"},
        {COL_BLACK, "Use the touchscreen to press keys on the computer."},
        {COL_BLACK, "The ZX81 had a keyword entry system, so when the"},
        {COL_BLACK, "cursor is an inverse K then the keyword printed"},
        {COL_BLACK, "at the top of the key is displayed.  Therefore"},
        {COL_BLACK, "to load a tape press the J key, then the SHIFT"},
        {COL_BLACK, "key (which by default stays pressed until you"},
        {COL_BLACK, "click it again) and press the P key to enter a"},
        {COL_BLACK, "quote, press the SHIFT key to stop pressing it,"}, 
        {COL_BLACK, "type the name of the .P file and close it with"},
        {COL_BLACK, "another quote, then press ENTER"},
        {COL_TRANSPARENT, ""},
        {COL_RED, "LOADING TAPES"},
        {COL_BLACK, "There are two ways of loading tapes in the"},
        {COL_BLACK, "simulator.  The first is to put .P files in"},
        {COL_BLACK, "either the root directory of the SD card"},
        {COL_BLACK, "or a directory called ZX81.  Files from"},
        {COL_BLACK, "either place can be loaded by typing"},
        {COL_BLACK, "LOAD \"GAME\" to load GAME.P.  Alternatively"},
        {COL_BLACK, "you can type LOAD \"*\" to display a file"},
        {COL_BLACK, "selector that allows you to select the tape"},
        {COL_BLACK, "to load.  LOAD \"\" can be used to load an"},
        {COL_BLACK, "internal tape image once it has been selected."},
        {COL_TRANSPARENT, NULL}
    };

    int done = FALSE;
    u32 key;
    Framebuffer upper;
    Framebuffer lower;

    while(!done)
    {
        int f;

        FB_StartFrame(&upper, &lower);

        FB_Clear(&upper, COL_WHITE);
        FB_Clear(&lower, COL_BLACK);

        for(f = 0; help[f].text; f++)
        {
            FB_Print(&upper, help[f].text, 0, upper.height - f * 8,
                     help[f].col,COL_TRANSPARENT);
        }

        FB_Print(&lower, "Scroll around help by using the\n"
                         "control pad\n"
		         "Press A to finish.",
                         0, lower.height - 40, COL_YELLOW,COL_TRANSPARENT);

        FB_EndFrame();

        key = hidKeysDown();

        if (key & KEY_A)
        {
            done = TRUE;
        }
    }
}


/* ---------------------------------------- JOYPAD MAPPING
*/
static void MapJoypad(void)
{
    SoftKeyEvent ev;
    SoftKey pad = NUM_SOFT_KEYS;
    int done = FALSE;
    Framebuffer upper;
    Framebuffer lower;

    while(!done)
    {
        FB_StartFrame(&upper, &lower);

        SK_DisplayKeyboard();

        FB_Clear(&upper, COL_WHITE);

        FB_Print(&upper, "Press the joypad button you want\n"
                         "to define and then the ZX81 key\n"
                         "you want to use.\n\n"
		         "Press CONFIG to finish.",
                         0, upper.height - 40, COL_BLACK,COL_TRANSPARENT);

        if (pad != NUM_SOFT_KEYS)
        {
            FB_printf(&upper, 0, 80, COL_BLACK, COL_TRANSPARENT,
                        "defining\n  \001%s\001",SK_KeyName(pad));
        }

        FB_EndFrame();

	while(SK_GetBareEvent(&ev))
	{
	    if (ev.pressed)
	    {
	    	if (ev.key==SK_ABOUT || ev.key==SK_CONFIG)
		{
		    done = true;
		}
	    }
	    else
	    {
		if (ev.key>=SK_PAD_UP && ev.key<=SK_PAD_SELECT)
		{
		    pad = ev.key;
		}

		if (ev.key<=SK_SPACE && pad!=NUM_SOFT_KEYS)
		{
		    SK_DefinePad(pad,ev.key);
		    pad = NUM_SOFT_KEYS;
		}
	    }
	}
    }
}


/* ---------------------------------------- DEBUG FUNCTIONS
*/
static void DebugDisassembler(Z80 *cpu)
{
    static Z80Word addr = 0;
    int done = FALSE;
    Z80Word curr_addr = 0;
    Framebuffer upper;
    Framebuffer lower;
    SoftKeyEvent ev;
    int f;

    while(!done && aptMainLoop())
    {
        FB_StartFrame(&upper, &lower);

        SK_DisplayKeyboard();

        curr_addr = addr;

        FB_Clear(&upper, COL_WHITE);

        for(f=upper.height - 1; f > 0; f -= 8)
        {
            FB_printf(&upper, 0, f, COL_RED, COL_TRANSPARENT, 
                      "%4.4x:", (unsigned)curr_addr);
            FB_printf(&upper, 6*8, f, COL_BLACK, COL_TRANSPARENT,
                      "%s", Z80Disassemble(cpu, &curr_addr));
        }

        FB_EndFrame();

	while(SK_GetBareEvent(&ev))
	{
	    if (ev.pressed)
	    {
                switch(ev.key)
                {
                    case SK_PAD_UP:
                        addr--;
                        break;

                    case SK_PAD_DOWN:
                        addr++;
                        break;

                    case SK_PAD_R:
                        addr = curr_addr;
                        break;

                    case SK_PAD_L:
                        addr -= 20;
                        break;

                    case SK_PAD_START:
                        done = TRUE;
                        break;

                    case SK_PAD_B:
                    {
                        char addrstr[32] = {0};

                        if (GUI_Input("Enter address", addrstr, 31))
                        {
                            addr = (Z80Word)strtoul(addrstr, NULL, 0);
                        }

                        break;
                    }

                    default:
                        break;
                }
	    }
	}
    }
}

static void DebugMemory(Z80 *cpu)
{
    static Z80Word addr = 0;
    int done = FALSE;
    Z80Word curr_addr = 0;
    Framebuffer upper;
    Framebuffer lower;
    SoftKeyEvent ev;
    int f;
    int r;
    int rows;

    while(!done && aptMainLoop())
    {
        FB_StartFrame(&upper, &lower);

        SK_DisplayKeyboard();

        curr_addr = addr;

        FB_Clear(&upper, COL_WHITE);

        rows = 0;

        for(f=upper.height - 1; f > 0; f -= 8)
        {
            FB_printf(&upper, 0, f, COL_RED, COL_TRANSPARENT, 
                      "%4.4x:", (unsigned)curr_addr);

            for(r=0; r < 8; r++)
            {
                char c = '.';
                unsigned b;

                b = ZX81ReadDisassem(cpu, curr_addr);

                FB_printf(&upper, 6*8 + r*24, f, COL_BLACK, COL_TRANSPARENT,
                          "%2.2x", b);

                if (b >= 32 && b < 128)
                {
                    c = b;
                }

                FB_printf(&upper, 31*8 + r*8, f, COL_BLUE, COL_TRANSPARENT,
                          "%c", c);

                curr_addr++;
            }

            rows++;
        }

        FB_EndFrame();

	while(SK_GetBareEvent(&ev))
	{
	    if (ev.pressed)
	    {
                switch(ev.key)
                {
                    case SK_PAD_UP:
                        addr--;
                        break;

                    case SK_PAD_DOWN:
                        addr++;
                        break;

                    case SK_PAD_R:
                        addr += rows * 8;
                        break;

                    case SK_PAD_L:
                        addr -= rows * 8;
                        break;

                    case SK_PAD_START:
                        done = TRUE;
                        break;

                    case SK_PAD_B:
                    {
                        char addrstr[32] = {0};

                        if (GUI_Input("Enter address", addrstr, 31))
                        {
                            addr = (Z80Word)strtoul(addrstr, NULL, 0);
                        }

                        break;
                    }

                    default:
                        break;
                }
	    }
	}
    }
}

static void DebugCPU(Z80 *cpu)
{
    static enum
    {
        AddrPC,
        AddrSP,
        AddrHL,
        AddrBC,
        AddrDE,
        AddrIX,
        AddrIY,
        NumAddr
    } addr_type = AddrPC;

    const char *addr_text[]=
    {
        "PC", "SP", "HL", "BC", "DE", "IX", "IY"
    };

    int done = FALSE;
    Framebuffer upper;
    Framebuffer lower;
    SoftKeyEvent ev;
    Z80Word addr;
    Z80Word base;
    int f;

    while(!done && aptMainLoop())
    {
        FB_StartFrame(&upper, &lower);

        SK_DisplayKeyboard();

        FB_Clear(&upper, COL_WHITE);

        addr = cpu->PC;

        FB_printf(&upper, AT(0,0), COL_BLACK, COL_TRANSPARENT,
                  "PC: %4.4x %s", (unsigned)cpu->PC,
                                  Z80Disassemble(cpu, &addr));

        FB_printf(&upper, AT(0,2), COL_BLACK, COL_TRANSPARENT,
                  "AF: %4.4x", (unsigned)cpu->AF.w);

        FB_printf(&upper, AT(0,3), COL_BLACK, COL_TRANSPARENT,
                  "BC: %4.4x", (unsigned)cpu->BC.w);

        FB_printf(&upper, AT(0,4), COL_BLACK, COL_TRANSPARENT,
                  "DE: %4.4x", (unsigned)cpu->DE.w);

        FB_printf(&upper, AT(0,5), COL_BLACK, COL_TRANSPARENT,
                  "HL: %4.4x", (unsigned)cpu->HL.w);

        FB_printf(&upper, AT(0,6), COL_BLACK, COL_TRANSPARENT,
                  "IX: %4.4x", (unsigned)cpu->IX.w);

        FB_printf(&upper, AT(0,7), COL_BLACK, COL_TRANSPARENT,
                  "IY: %4.4x", (unsigned)cpu->IX.w);

        FB_printf(&upper, AT(9,2), COL_BLACK, COL_TRANSPARENT,
                  "AF': %4.4x", (unsigned)cpu->AF_);

        FB_printf(&upper, AT(9,3), COL_BLACK, COL_TRANSPARENT,
                  "BC': %4.4x", (unsigned)cpu->BC_);

        FB_printf(&upper, AT(9,4), COL_BLACK, COL_TRANSPARENT,
                  "DE': %4.4x", (unsigned)cpu->DE_);

        FB_printf(&upper, AT(9,5), COL_BLACK, COL_TRANSPARENT,
                  "HL': %4.4x", (unsigned)cpu->HL_);

        switch(addr_type)
        {
            case AddrPC:
                addr = cpu->PC;
                break;
            case AddrSP:
                addr = cpu->SP;
                break;
            case AddrHL:
                addr = cpu->HL.w;
                break;
            case AddrBC:
                addr = cpu->BC.w;
                break;
            case AddrDE:
                addr = cpu->DE.w;
                break;
            case AddrIX:
                addr = cpu->IX.w;
                break;
            case AddrIY:
                addr = cpu->IY.w;
                break;
            default:
                break;
        }

        base = addr;
        addr -= 5;

        for(f=0; f < 11; f++)
        {
            if (addr == base)
            {
                FB_printf(&upper, AT(0,9+f), COL_BLACK, COL_LIGHTGREY,
                            "%s %4.4x: %2.2x",
                                addr_text[addr_type],
                                (unsigned)addr,
                                (unsigned)ZX81ReadDisassem(cpu, addr));
            }
            else
            {
                FB_printf(&upper, AT(3,9+f), COL_BLACK, COL_TRANSPARENT,
                            "%4.4x: %2.2x",
                                (unsigned)addr,
                                (unsigned)ZX81ReadDisassem(cpu, addr));
            }

            addr++;
        }

        FB_printf(&upper, AT(0,21), COL_BLACK, COL_TRANSPARENT,
                    "IFF1: %2.2x IFF2: %2.2x IM: %2.2x I:%2.2x R:%2.2x",
                        (unsigned)cpu->IFF1,
                        (unsigned)cpu->IFF2,
                        (unsigned)cpu->IM,
                        (unsigned)cpu->I,
                        (unsigned)cpu->R);

        FB_printf(&upper, AT(0,23), COL_BLACK, COL_TRANSPARENT,
                    "Flags: SZ5H3PNC");

        FB_printf(&upper, AT(7,24), COL_BLACK, 
                    cpu->AF.b.lo & eZ80_Sign ? COL_GREEN : COL_RED, " ");

        FB_printf(&upper, AT(8,24), COL_BLACK, 
                    cpu->AF.b.lo & eZ80_Zero ? COL_GREEN : COL_RED, " ");

        FB_printf(&upper, AT(9,24), COL_BLACK, 
                    cpu->AF.b.lo & eZ80_Hidden5 ? COL_GREEN : COL_RED, " ");

        FB_printf(&upper, AT(10,24), COL_BLACK, 
                    cpu->AF.b.lo & eZ80_HalfCarry ? COL_GREEN : COL_RED, " ");

        FB_printf(&upper, AT(11,24), COL_BLACK, 
                    cpu->AF.b.lo & eZ80_Hidden3 ? COL_GREEN : COL_RED, " ");

        FB_printf(&upper, AT(12,24), COL_BLACK, 
                    cpu->AF.b.lo & eZ80_PV ? COL_GREEN : COL_RED, " ");

        FB_printf(&upper, AT(13,24), COL_BLACK, 
                    cpu->AF.b.lo & eZ80_Neg ? COL_GREEN : COL_RED, " ");

        FB_printf(&upper, AT(14,24), COL_BLACK, 
                    cpu->AF.b.lo & eZ80_Carry ? COL_GREEN : COL_RED, " ");

        FB_EndFrame();

        if (SK_KeyPressed(SK_PAD_X))
        {
            Z80SingleStep(cpu);
        }

	while(SK_GetBareEvent(&ev))
	{
	    if (ev.pressed)
	    {
                switch(ev.key)
                {
                    case SK_PAD_L:
                        if (addr_type == AddrPC)
                        {
                            addr_type = AddrIY;
                        }
                        else
                        {
                            addr_type--;
                        }
                        break;

                    case SK_PAD_R:
                        addr_type = (addr_type + 1) % NumAddr;
                        break;

                    case SK_PAD_START:
                        done = TRUE;
                        break;

                    case SK_PAD_B:
                        Z80SingleStep(cpu);
                        break;

                    default:
                        break;
                }
	    }
	}
    }
}

static void DebugMenu(Z80 *cpu)
{
    switch(GUI_Menu(debug_menu))
    {
        case DebugMenuEnableOutput:
        {
            char host[32] = {0};
            char port[32] = {0};

            debug_enabled = TRUE;

            GUI_Input("Enter host", host, 31);
            GUI_Input("Enter port", port, 31);

            if (!host[0])
            {
                strcpy(host, "192.168.0.77");
            }

            if (!port[0])
            {
                strcpy(port, "12345");
            }

            DEBUG_SetAddress(host, port);
            break;
        }

        case DebugMenuDisableOutput:
            debug_enabled = FALSE;
            break;

        case DebugMenuDisassembler:
            DebugDisassembler(cpu);
            break;

        case DebugMenuMemoryView:
            DebugMemory(cpu);
            break;

        case DebugMenuCPUInfo:
            DebugCPU(cpu);
            break;
    }
}

/* ---------------------------------------- MAIN
*/
int main(int argc, char *argv[])
{
    Z80 *z80;
    int quit = FALSE;

    gfxInit(GSP_RGB565_OES, GSP_RGB565_OES, false);

    FB_Init();

    z80 = Z80Init(ZX81ReadMem,
		  ZX81WriteMem,
		  ZX81ReadPort,
		  ZX81WritePort,
		  ZX81ReadDisassem);

    if (!z80)
    {
	GUI_Alert(TRUE,"Failed to initialise\nthe Z80 CPU emulation!");
    }

    ZX81Init(z80);

    Splash();

    LoadConfig();
    ZX81Reconfigure();

    SK_DisplayKeyboard();

    SK_SetSticky(SK_SHIFT,DS81_Config[DS81_STICKY_SHIFT]);

    if (DS81_Config[DS81_LOAD_DEFAULT_SNAPSHOT])
    {
    	SNAP_Load(z80, "AUTO", SNAP_TYPE_FULL);
    }

    while(!quit && aptMainLoop())
    {
	SoftKeyEvent ev;
        Framebuffer upper;
        Framebuffer lower;

        FB_StartFrame(&upper, &lower);

        SK_DisplayKeyboard();

    	Z80Exec(z80);

        ZX81RenderDisplay(&upper, z80);

        FB_EndFrame();

	while(SK_GetEvent(&ev))
	{
	    switch(ev.key)
	    {
	    	case SK_ABOUT:
	    	case SK_CONFIG:
		    if (ev.pressed)
		    {
			switch(GUI_Menu(main_menu))
			{
			    case MenuReset:
				ZX81Reset(z80);
				break;

			    case MenuSelectTape:
			    	SelectTape();
				break;

			    case MenuConfigure:
				GUI_Config();
				SK_SetSticky(SK_SHIFT,
					     DS81_Config[DS81_STICKY_SHIFT]);
				ZX81Reconfigure();
				break;

			    case MenuMapJoypad:
				MapJoypad();
			    	break;

			    case MenuSaveSnapshot:
			    	SNAP_Save(z80, SNAP_TYPE_FULL);
			    	break;

			    case MenuLoadSnapshot:
			    	SNAP_Load(z80, NULL, SNAP_TYPE_FULL);
			    	break;

			    case MenuSaveMappings:
			    	SNAP_Save(z80, SNAP_TYPE_KEYBOARD);
			    	break;

			    case MenuLoadMappings:
			    	SNAP_Load(z80, NULL, SNAP_TYPE_KEYBOARD);
			    	break;

                            case MenuHelp:
                                ShowHelp();
                                break;

                            case MenuDebug:
                                DebugMenu(z80);
                                break;

                            case MenuExit:
                                quit = TRUE;
                                break;
			}
		    }
		    break;

	    	default:
		    ZX81HandleKey(ev.key,ev.pressed);
		    break;
	    }
	}
    }

    gfxExit();

    return 0;
}