#include "forth.h"

// Global variables
int32_t data_stack[DATA_STACK_SIZE];
int sp = -1;
Cell ret_stack[RET_STACK_SIZE];
int rp = -1;
Cell* ip = NULL;

Word dict[DICT_SIZE];
int dict_idx = 0;
Word* dict_head = NULL;
Cell dict_bodies[BODY_SIZE];
int body_idx = 0;

int state = 0;
Cell compile_buf[COMPILE_BUF_SIZE];
int compile_idx = 0;
char compiling_name[MAX_NAME_LEN + 1];

char input_buf[INPUT_BUF_SIZE];
char* input_ptr = NULL;

Cell* compile_stack[COMPILE_STACK_SIZE];
int compile_sp = -1;

int32_t user_mem[USER_MEMORY_SIZE];
int32_t* here = &user_mem[0];

// Stack helpers
void data_push(int32_t val) {
    if (sp < DATA_STACK_SIZE - 1) {
        data_stack[++sp] = val;
    } else {
        printf("Data stack overflow\n");
    }
}

int32_t data_pop(void) {
    if (sp >= 0) {
        return data_stack[sp--];
    } else {
        printf("Data stack underflow\n");
        return 0;
    }
}

void ret_push_ip(Cell* val) {
    if (rp < RET_STACK_SIZE - 1) {
        rp++;
        ret_stack[rp].cell_ptr = val;
    } else {
        printf("Return stack overflow\n");
    }
}

Cell* ret_pop_ip(void) {
    if (rp >= 0) {
        Cell* res = ret_stack[rp].cell_ptr;
        rp--;
        return res;
    } else {
        printf("Return stack underflow\n");
        return NULL;
    }
}

void ret_push_num(int32_t val) {
    if (rp < RET_STACK_SIZE - 1) {
        rp++;
        ret_stack[rp].num = val;
    } else {
        printf("Return stack overflow\n");
    }
}

int32_t ret_pop_num(void) {
    if (rp >= 0) {
        int32_t res = ret_stack[rp].num;
        rp--;
        return res;
    } else {
        printf("Return stack underflow\n");
        return 0;
    }
}

void compile_push(Cell* addr) {
    if (compile_sp < COMPILE_STACK_SIZE - 1) {
        compile_stack[++compile_sp] = addr;
    } else {
        printf("Compile stack overflow\n");
    }
}

Cell* compile_pop(void) {
    if (compile_sp >= 0) {
        return compile_stack[compile_sp--];
    } else {
        printf("Compile stack underflow\n");
        return NULL;
    }
}