/*

    casm - Simple, portable assembler

    Copyright (C) 2003-2015  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/>.

    -------------------------------------------------------------------------

    Commodore T64 tape output handler.

*/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include "global.h"
#include "codepage.h"
#include "prgout.h"
#include "expr.h"


/* ---------------------------------------- MACROS & TYPES
*/

/* ---------------------------------------- PRIVATE TYPES AND VARS
*/
enum option_t
{
    OPT_START_ADDR
};

static const ValueTable option_set[]=
{
    {"prg-start", OPT_START_ADDR},
    {NULL}
};

typedef struct
{
    int		start_addr;
} Options;

static Options options =
{
    -1
};


/* ---------------------------------------- PRIVATE FUNCTIONS
*/

static int PokeB(Byte *mem, int addr, Byte b)
{
    mem[addr++] = b;
    return (addr % 0x10000);
}


static int PokeW(Byte *mem, int addr, int w)
{
    addr = PokeB(mem, addr, w & 0xff);
    return PokeB(mem, addr, (w & 0xff00) >> 8);
}


static int PokeS(Byte *mem, int addr, const char *str)
{
    while(*str)
    {
        addr = PokeB(mem, addr, CodeFromNative(CP_CBM, *str++));
    }

    return addr;
}


static void WriteByte(FILE *fp, Byte b)
{
    putc(b, fp);
}


static void WriteWord(FILE *fp, int w)
{
    WriteByte(fp, w & 0xff);
    WriteByte(fp, (w & 0xff00) >> 8);
}


/* ---------------------------------------- INTERFACES
*/
const ValueTable *PRGOutputOptions(void)
{
    return option_set;
}

CommandStatus PRGOutputSetOption(int opt, int argc, char *argv[],
                                 int quoted[], char *err, size_t errsize)
{
    CommandStatus stat = CMD_OK;

    CMD_ARGC_CHECK(1);

    switch(opt)
    {
        case OPT_START_ADDR:
            CMD_EXPR(argv[0], options.start_addr);
            break;

        default:
            break;
    }

    return stat;
}

int PRGOutput(const char *filename, const char *filename_bank,
              MemoryBank **bank, int count, char *error, size_t error_size)
{
    int f;

    for(f = 0; f < count; f++)
    {
        FILE *fp;
        char buff[4096];
        const char *name;
        Byte *mem;
        int min, max, len;
        char sys[16];
        int addr = 0x803;
        int next;

        if (count == 1)
        {
            name = filename;
        }
        else
        {
            snprintf(buff, sizeof buff, filename_bank, bank[f]->number);
            name = buff;
        }

        if (!(fp = fopen(name, "wb")))
        {
            snprintf(error, error_size, "Failed to open %s", name);
            return FALSE;
        }

        mem = bank[f]->memory;
        min = bank[f]->min_address_used;
        max = bank[f]->max_address_used;

        /* We're going to prepend some BASIC
        */
        if (min < 0x810)
        {
            snprintf(error, error_size, "Bank starts below a safe "
                                        "area to add BASIC loader");

            return FALSE;
        }

        if (options.start_addr == -1)
        {
            snprintf(sys, sizeof sys, "%d", bank[f]->min_address_used);
        }
        else
        {
            snprintf(sys, sizeof sys, "%d", options.start_addr);
        }

        addr = PokeW(mem, addr, 10);
        addr = PokeB(mem, addr, 0x9e);
        addr = PokeS(mem, addr, sys);
        addr = PokeB(mem, addr, 0x00);

        next = addr;

        addr = PokeW(mem, addr, 0x00);

        PokeW(mem, 0x801, next);

        min = 0x801;        /* Start of BASIC */

        len = max - min + 1;

        /* Output PRG file
        */
        WriteWord(fp, min);
        fwrite(mem + min, len, 1, fp);

        fclose(fp);
    }

    return TRUE;
}


/*
vim: ai sw=4 ts=8 expandtab
*/