/*
 * Simple REPL for the calc evaluator.
 * Build: clang main.c -o calc -lm
 * @author Abner Coimbre <abner@terminal.click>
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <assert.h>
#include <ctype.h>

/* Macros expected by tc_calc.h / tc_calc.c */
#define function static
#define global   static
#define cast(T)  (T)

#ifndef TC_CALC_FORMAT_BUFFER_SIZE
#define TC_CALC_FORMAT_BUFFER_SIZE 256
#endif

#include "tc_calc.h"
#include "tc_calc.c"

#define INPUT_MAX 1024

int main(int argc, char **argv)
{
    char buf[INPUT_MAX];
    calc_FormatKind fmt = CALC_FORMAT_DECIMAL;

    // -e "expr": evaluate a single expression and exit
    if (argc == 3 && strcmp(argv[1], "-e") == 0) {
        double result = calc_eval(argv[2]);
        if (isnan(result)) {
            fprintf(stderr, "error: invalid expression\n");
            return 1;
        }
        printf("%s\n", calc_format_result(result, fmt));
        return 0;
    }

    printf("calc> ");
    fflush(stdout);

    while (fgets(buf, sizeof buf, stdin)) {
        /* strip trailing newline */
        buf[strcspn(buf, "\n")] = '\0';

        /* skip blank lines */
        if (buf[0] == '\0') {
            printf("calc> ");
            fflush(stdout);
            continue;
        }

        /* format switching commands */
        if (strcmp(buf, ":dec") == 0) {
            fmt = CALC_FORMAT_DECIMAL;
            printf("  format: decimal\n");
        } else if (strcmp(buf, ":hex") == 0) {
            fmt = CALC_FORMAT_HEX;
            printf("  format: hex\n");
        } else if (strcmp(buf, ":bin") == 0) {
            fmt = CALC_FORMAT_BINARY;
            printf("  format: binary\n");
        } else {
            double result = calc_eval(buf);

            if (isnan(result))
                printf("  error: invalid expression\n");
            else
                printf("  %s\n", calc_format_result(result, fmt));
        }

        printf("calc> ");
        fflush(stdout);
    }

    putchar('\n');
    return 0;
}