#include "forth.h"

// Input tokenizer
char* next_token(void) {
    if (input_ptr == NULL) return NULL;
    while (*input_ptr != '\0' && isspace((unsigned char)*input_ptr)) {
        input_ptr++;
    }
    if (*input_ptr == '\0') return NULL;
    char* start = input_ptr;
    while (*input_ptr != '\0' && !isspace((unsigned char)*input_ptr)) {
        input_ptr++;
    }
    if (*input_ptr != '\0') {
        *input_ptr = '\0';
        input_ptr++;
    }
    return start;
}

// Interpreter functions
void inner_interpreter(void) {
    while (ip != NULL) {
        Cell current = *ip;
        ip++; // Move to next cell
        current.word->code(current.word);
    }
}

void process_token(const char* token) {
    Word* w = lookup_word(token);
    if (w != NULL) {
        if (state == 0) { // Interpret mode
            if (w->code == do_docolon) { // Colon definition
                ret_push_ip(NULL); // Return address to stop interpreter
                ip = w->body;
                inner_interpreter();
            } else { // Primitive word
                w->code(w);
            }
        } else { // Compile mode
            if (w->flags & (1 << 7)) { // Immediate word: execute now
                if (w->code == do_docolon) {
                    ret_push_ip(NULL);
                    ip = w->body;
                    inner_interpreter();
                } else {
                    w->code(w);
                }
            } else { // Normal word: compile into current definition
                if (compile_idx >= COMPILE_BUF_SIZE) {
                    printf("Compile buffer full\n");
                    return;
                }
                compile_buf[compile_idx++] = (Cell){.word = w};
            }
        }
    } else { // Not a known word: try to parse as number
        char* end;
        long v = strtol(token, &end, 10);
        if (end != token && *end == '\0') { // Valid integer
            if (state == 0) { // Interpret mode: push number
                data_push((int32_t)v);
            } else { // Compile mode: compile lit + number
                Word* lit_w = lookup_word_internal("lit");
                if (lit_w == NULL) {
                    printf("Fatal: lit word not found\n");
                    return;
                }
                if (compile_idx + 2 > COMPILE_BUF_SIZE) {
                    printf("Compile buffer full\n");
                    return;
                }
                compile_buf[compile_idx++] = (Cell){.word = lit_w};
                compile_buf[compile_idx++] = (Cell){.num = (int32_t)v};
            }
        } else {
            printf("Unknown word: '%s'\n", token);
        }
    }
}

void outer_interpreter(void) {
    while (1) {
        printf("ok ");
        fflush(stdout);
        if (fgets(input_buf, INPUT_BUF_SIZE, stdin) == NULL) {
            break; // EOF
        }
        input_ptr = input_buf;
        char* tok;
        while ((tok = next_token()) != NULL) {
            process_token(tok);
        }
    }
    printf("\n");
}