/* SPDX-License-Identifier: Unlicense
 */

#include "bus.hpp"
#include "musashi-m68k/m68k.h"

#include <cstdio>
#include <cstdlib>
#include <cstdarg>
#include <ctime>

#if !defined(DEBUG_TRACE_INSTRUCTIONS)
#   define DEBUG_TRACE_INSTRUCTIONS 0
#endif

static void exit_error(const char* fmt, ...)
{
    va_list args;
    va_start(args, fmt);
    vfprintf(stderr, fmt, args);
    va_end(args);
    fprintf(stderr, "\n");
    exit(EXIT_FAILURE);
}

/* Called when the CPU pulses the RESET line */
void m68k_reset_callback(void)
{
    // TODO
}

/* Called when the CPU acknowledges an interrupt */
int m68k_irq_ack(int level)
{
    (void) level;
    // TODO
    exit_error("IRQ ack");
    return M68K_INT_ACK_SPURIOUS;
}

static void make_hex(char* buff, unsigned int pc, unsigned int length)
{
    char* ptr = buff;

    for (;length>0;length -= 2)
    {
        sprintf(ptr, "%04x", m68k_read_disassembler_16(pc));
        pc += 2;
        ptr += 4;
        if (length > 2)
            *ptr++ = ' ';
    }
}

void m68k_instr_callback(int pc)
{
    if (!DEBUG_TRACE_INSTRUCTIONS)
        return;
    char buff[100];
    unsigned int instr_size =
        m68k_disassemble(buff, pc, M68K_CPU_TYPE_68000);
    char buff2[100];
    make_hex(buff2, pc, instr_size);
    printf("E %08X: %-20s: %s\n", pc, buff2, buff);
    fflush(stdout);
}

int main(int argc, char* argv[])
{
    if (argc != 2)
    {
        printf("Usage: sim <program file>\n");
        exit(-1);
    }

    FILE* const fhandle = fopen(argv[1], "rb");

    if (fhandle == NULL)
        exit_error("Unable to open %s", argv[1]);

    const size_t fread_ret = fread(g_rom, 1, ROM_SIZE, fhandle);
    if (fread_ret <= 0)
        exit_error("Error reading %s", argv[1]);
    printf("Read into ROM %zu bytes\n", fread_ret);

    m68k_init();
    m68k_set_cpu_type(M68K_CPU_TYPE_68000);
    m68k_pulse_reset();

    while (1)
    {
        // Values to execute determine the interleave rate.
        // Smaller values allow for more accurate interleaving with multiple
        // devices/CPUs but is more processor intensive.
        // 100000 is usually a good value to start at, then work from there.

        // Note that I am not emulating the correct clock speed!
        m68k_execute(100000);
    }

    return 0;
}