#include "vm_types.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

// Safe file reading
static uint8_t* read_file(const char* filename, size_t* size) {
    FILE* file = fopen(filename, "rb");
    if (!file) {
        fprintf(stderr, "Cannot open file: %s\n", filename);
        return NULL;
    }

    fseek(file, 0, SEEK_END);
    long file_size = ftell(file);
    fseek(file, 0, SEEK_SET);

    if (file_size <= 0 || file_size > 10 * 1024 * 1024) { // 10MB limit
        fclose(file);
        fprintf(stderr, "Invalid file size\n");
        return NULL;
    }

    uint8_t* buffer = malloc(file_size);
    if (!buffer) {
        fclose(file);
        fprintf(stderr, "Memory allocation failed\n");
        return NULL;
    }

    if (fread(buffer, 1, file_size, file) != (size_t)file_size) {
        fclose(file);
        free(buffer);
        fprintf(stderr, "File read error\n");
        return NULL;
    }

    fclose(file);
    *size = file_size;
    return buffer;
}

int main(int argc, char* argv[]) {
    if (argc != 2) {
        printf("Usage: %s <file.popclass>\n", argv[0]);
        return 1;
    }

    size_t file_size;
    uint8_t* bytecode = read_file(argv[1], &file_size);
    if (!bytecode) {
        return 1;
    }

    vm_t* vm = vm_create(bytecode, file_size);
    if (!vm) {
        fprintf(stderr, "Failed to create VM\n");
        free(bytecode);
        return 1;
    }

    if (!vm_validate_bytecode(vm)) {
        fprintf(stderr, "Invalid bytecode file\n");
        vm_destroy(vm);
        free(bytecode);
        return 1;
    }

    printf("Executing program...\n");
    vm_execute(vm);
    printf("Program finished\n");

    vm_destroy(vm);
    free(bytecode);
    return 0;
}