#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include <sysexits.h>

#include <readline/readline.h>
#include <readline/history.h>

#include "dcpu16.h"

/*
 *  cli driver for dcpu16 core
 *  
 *  Justin Wind <justin.wind@gmail.com>
 *    2012 04 10 - implementation started
 *
 */

static const char * const src_id_ = "$Id$";

/* global invocation options */
struct options {
    unsigned int verbose;
} opt_ = {
    .verbose = 0,
};

#define VERBOSE_PRINTF(...) do { if (opt_.verbose) printf(__VA_ARGS__); } while (0)

static void usage_(char *prog, unsigned int full) {
    FILE *f = full ? stdout : stderr;
    char *x = strrchr(prog, '/');

    if (x && *(x + 1))
        prog = x + 1;

    if (full)
        fprintf(f, "%s -- \n\n",
                prog);

    fprintf(f, "Usage: %s [file]\n",
            prog);

    if (full) {
        fprintf(f, "\nOptions:\n"
                "\t [file] -- ram image to load initially\n"
                "\t -h -- this screen\n"
                "\t -v -- verbose execution tracing\n");

        fprintf(f, "\n%78s\n", src_id_);
    }
}

static
int file_load_(struct dcpu16 *vm, char *filename) {
    FILE *f;
    size_t r;

    f = fopen(filename, "rb");
    if (f == NULL) {
        fprintf(stderr, "%s('%s'):%s\n", "fopen", filename, strerror(errno));
        return -1;
    }

    r = fread(vm->ram, sizeof(DCPU16_WORD), DCPU16_RAM, f);
    VERBOSE_PRINTF("read %zu words", r);

    if (ferror(f))
        fprintf(stderr, "%s('%s'):%s\n", "fread", filename, strerror(errno));

    fclose(f);
    return 0;
}

int main(int argc, char **argv) {
    int c;
    char *command;
    char *prompt = "dcpu16> ";
    struct dcpu16 *vm;

    while ( (c = getopt(argc, argv, "hv")) != EOF) {
        switch (c) {
            case 'v':
                opt_.verbose++;
                break;

            case 'h':
                usage_(argv[0], 1);
                exit(EX_OK);

            default:
                usage_(argv[0], 0);
                exit(EX_USAGE);
        }
    }
    if (opt_.verbose < 1) {
        dcpu16_warn_cb_set(NULL);
        dcpu16_trace_cb_set(NULL);
    } else if (opt_.verbose < 2) {
        dcpu16_trace_cb_set(NULL);
    }
    argc -= optind;
    argv += optind;

    if ((vm = dcpu16_new()) == NULL) {
        fprintf(stderr, "could not allocate new dcpu instance\n");
        exit(EX_UNAVAILABLE);
    }

    if (argc) {
        file_load_(vm, *argv);
    }

    dcpu16_state_print(vm);
    dcpu16_disassemble_print(vm, vm->pc);
    while ( (command = readline(prompt)) ) {
        if (strcasecmp(command, "quit") == 0)
            break;

        dcpu16_step(vm);
        dcpu16_state_print(vm);
        dcpu16_disassemble_print(vm, vm->pc);
    }

    printf("finished\n");

    dcpu16_delete(&vm);

    exit(EX_OK);
}