#include "pez.h"
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <readline/readline.h>
#include <readline/history.h>

#define CHECK(x) do {                            \
    if (!(x)) {                                  \
        fprintf(stderr, "%s\n", pez_geterr(cx)); \
        assert(!#x);                             \
    }                                            \
} while (0)

static bool
printtop(PezContext *cx)
{
    assert(pez_top(cx) >= 2);
    return
        pez_push(cx, 0) // printf was stored here
     && pez_pushstring(cx, "%a", 2)
     && pez_push(cx, -3)
     && pez_apply(cx, 2)
     && (pez_pop(cx), pez_pop(cx), 1);
}

static void
help(void)
{
    printf("Usage: pez [OPTION]... [FILE] [ARG]...\n"
           "With no FILE, enter repl.\n"
           "\n"
           "  -h, --help    show this help message\n"
           "  -db           debug: print bytecode\n"
           "  -dG           debug: stress GC\n"
           "  -dg           debug: print GC info\n"
           "\n");    
}

int
main(int argc, char **argv) {
    PezContext *cx = pez_new(NULL, NULL, 32*1024 /* 32KiB stack */);
    FILE *fp = NULL;
    int i, ret = 0;

    assert(cx != NULL && "no context");

    for (i = 1; i < argc; ++i) {
        const char *arg = argv[i];
        if (*arg == '-') {
            if (!strcmp(arg, "-h") || !strcmp(arg, "--help")) {
                help();
                goto Bye;
            } else if (arg[1] == 'd') {
                pez_debug(cx, arg + 2);
            } else {
                printf("pez: Invalid option '%s'\n", arg);
                help();
                ret = 1;
                goto Bye;
            }
        } else {
            fp = fopen(arg, "r");
            if (!fp) {
                perror(arg);
                ret = 1;
                goto Bye;
            }
            break;
        }
    }

    if (!fp) {
        char *src;
        using_history();
        CHECK(pez_pushglobal(cx, "printf"));

        while ((src = readline("> "))) {
            add_history(src);
            if (!pez_eval_str(cx, "<repl>", src)) {
                fprintf(stderr, "error: %s\n", pez_geterr(cx));
            } else {
                assert(pez_top(cx) == 2);
                CHECK(printtop(cx));
                printf("\n");
            }
            free(src);
        }
    } else {
        if (!pez_eval_file(cx, argv[i], fp)) {
            fprintf(stderr, "error: %s\n", pez_geterr(cx));
            ret = 1;
            goto Bye;
        }
        assert(pez_top(cx) == 1);
    }
Bye:
    if (fp) {
        fclose(fp);
    }
    pez_del(cx); 
    return ret;
}