#include "forth.h"

// Stack operations
void do_dup(Word* w) {
    if (sp < 0) return;
    int32_t v = data_stack[sp];
    data_push(v);
}

void do_drop(Word* w) {
    data_pop();
}

void do_swap(Word* w) {
    if (sp < 1) return;
    int32_t a = data_stack[sp-1];
    int32_t b = data_stack[sp];
    data_stack[sp-1] = b;
    data_stack[sp] = a;
}

void do_over(Word* w) {
    if (sp < 1) return;
    data_push(data_stack[sp-1]);
}

void do_rot(Word* w) {
    if (sp < 2) return;
    int32_t a = data_stack[sp-2];
    int32_t b = data_stack[sp-1];
    int32_t c = data_stack[sp];
    data_stack[sp-2] = c;
    data_stack[sp-1] = a;
    data_stack[sp] = b;
}

void do_minus_rot(Word* w) {
    if (sp < 2) return;
    int32_t a = data_stack[sp-2];
    int32_t b = data_stack[sp-1];
    int32_t c = data_stack[sp];
    data_stack[sp-2] = b;
    data_stack[sp-1] = c;
    data_stack[sp] = a;
}

void do_nip(Word* w) {
    if (sp < 1) return;
    data_stack[sp-1] = data_stack[sp];
    sp--;
}

void do_tuck(Word* w) {
    if (sp < 1) return;
    int32_t a = data_stack[sp-1];
    int32_t b = data_stack[sp];
    data_push(a);
    data_stack[sp-2] = b;
}

// Arithmetic operations
void do_add(Word* w) {
    if (sp < 1) return;
    int32_t b = data_pop();
    int32_t a = data_pop();
    data_push(a + b);
}

void do_sub(Word* w) {
    if (sp < 1) return;
    int32_t b = data_pop();
    int32_t a = data_pop();
    data_push(a - b);
}

void do_mul(Word* w) {
    if (sp < 1) return;
    int32_t b = data_pop();
    int32_t a = data_pop();
    data_push(a * b);
}

void do_div(Word* w) {
    if (sp < 1) return;
    int32_t b = data_pop();
    int32_t a = data_pop();
    if (b == 0) {
        printf("Division by zero\n");
        data_push(a);
        data_push(b);
        return;
    }
    data_push(a / b);
}

void do_mod(Word* w) {
    if (sp < 1) return;
    int32_t b = data_pop();
    int32_t a = data_pop();
    if (b == 0) {
        printf("Modulo by zero\n");
        data_push(a);
        data_push(b);
        return;
    }
    data_push(a % b);
}

void do_slash_mod(Word* w) {
    if (sp < 1) return;
    int32_t b = data_pop();
    int32_t a = data_pop();
    if (b == 0) {
        printf("Modulo by zero\n");
        data_push(a);
        data_push(b);
        return;
    }
    data_push(a / b);
    data_push(a % b);
}

void do_one_plus(Word* w) {
    if (sp < 0) return;
    data_stack[sp]++;
}

void do_one_minus(Word* w) {
    if (sp < 0) return;
    data_stack[sp]--;
}

void do_two_plus(Word* w) {
    if (sp < 0) return;
    data_stack[sp] += 2;
}

void do_two_minus(Word* w) {
    if (sp < 0) return;
    data_stack[sp] -= 2;
}

void do_negate(Word* w) {
    if (sp < 0) return;
    data_stack[sp] = -data_stack[sp];
}

void do_abs(Word* w) {
    if (sp < 0) return;
    int32_t v = data_pop();
    data_push(v < 0 ? -v : v);
}

void do_min(Word* w) {
    if (sp < 1) return;
    int32_t b = data_pop();
    int32_t a = data_pop();
    data_push(a < b ? a : b);
}

void do_max(Word* w) {
    if (sp < 1) return;
    int32_t b = data_pop();
    int32_t a = data_pop();
    data_push(a > b ? a : b);
}

// Logic operations
void do_and(Word* w) {
    if (sp < 1) return;
    int32_t b = data_pop();
    int32_t a = data_pop();
    data_push(a & b);
}

void do_or(Word* w) {
    if (sp < 1) return;
    int32_t b = data_pop();
    int32_t a = data_pop();
    data_push(a | b);
}

void do_xor(Word* w) {
    if (sp < 1) return;
    int32_t b = data_pop();
    int32_t a = data_pop();
    data_push(a ^ b);
}

void do_invert(Word* w) {
    if (sp < 0) return;
    data_stack[sp] = ~data_stack[sp];
}

void do_lshift(Word* w) {
    if (sp < 1) return;
    int32_t b = data_pop();
    int32_t a = data_pop();
    data_push(a << b);
}

void do_rshift(Word* w) {
    if (sp < 1) return;
    int32_t b = data_pop();
    int32_t a = data_pop();
    data_push((int32_t)((uint32_t)a >> b));
}

// Comparison operations
void do_eq(Word* w) {
    if (sp < 1) return;
    int32_t b = data_pop();
    int32_t a = data_pop();
    data_push(a == b ? -1 : 0); // Forth uses -1 for true, 0 for false
}

void do_neq(Word* w) {
    if (sp < 1) return;
    int32_t b = data_pop();
    int32_t a = data_pop();
    data_push(a != b ? -1 : 0);
}

void do_lt(Word* w) {
    if (sp < 1) return;
    int32_t b = data_pop();
    int32_t a = data_pop();
    data_push(a < b ? -1 : 0);
}

void do_gt(Word* w) {
    if (sp < 1) return;
    int32_t b = data_pop();
    int32_t a = data_pop();
    data_push(a > b ? -1 : 0);
}

void do_lte(Word* w) {
    if (sp < 1) return;
    int32_t b = data_pop();
    int32_t a = data_pop();
    data_push(a <= b ? -1 : 0);
}

void do_gte(Word* w) {
    if (sp < 1) return;
    int32_t b = data_pop();
    int32_t a = data_pop();
    data_push(a >= b ? -1 : 0);
}

void do_zero_eq(Word* w) {
    if (sp < 0) return;
    int32_t a = data_pop();
    data_push(a == 0 ? -1 : 0);
}

void do_zero_lt(Word* w) {
    if (sp < 0) return;
    int32_t a = data_pop();
    data_push(a < 0 ? -1 : 0);
}

void do_zero_gt(Word* w) {
    if (sp < 0) return;
    int32_t a = data_pop();
    data_push(a > 0 ? -1 : 0);
}

// I/O operations
void do_dot(Word* w) {
    if (sp < 0) return;
    printf("%d ", data_pop());
    fflush(stdout);
}

void do_cr(Word* w) {
    printf("\n");
    fflush(stdout);
}

void do_emit(Word* w) {
    if (sp < 0) return;
    putchar((char)data_pop());
    fflush(stdout);
}

void do_key(Word* w) {
    int c = getchar();
    data_push(c == EOF ? -1 : c);
}

void do_dot_quote(Word* w) {
    // Immediate word: parse string until " and print/compile
    if (state == 0) { // Interpret mode: print immediately
        //