#include <common/fzl_colors.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <vm/fzl_vm.h>

typedef struct
{
  char *filepath;
  bool help;
  bool debug;
  bool allow_infinite;
  uint64_t max_iter;
} run_args_t;

void print_hint()
{
  printf("Usage: fz [flags] <file path>\n");
  printf("Flags:\n");
  printf("\t-h\t--help\t\t\tprint usage information\n");
  printf("\t-d\t--debug\t\t\tdisplay program opcodes\n");
  printf("\t\t--allow-infinite\tallow infinite loops\n");
  printf("\t\t--max-iter N\t\trestrict loops to maximum N iterations\n");
}

// Parse passed arguments and build args setup structure
run_args_t *parse_args(int argc, char **argv)
{
  if (argc < 2)
  {
    print_hint();
    return NULL;
  }

  run_args_t *args     = malloc(sizeof(run_args_t));
  args->filepath       = NULL;
  args->help           = false;
  args->debug          = false;
  args->allow_infinite = false;
  args->max_iter       = 100000;

  for (int i = 0; i < argc; i++)
  {
    if (argv[i][0] != '-')
      continue;

    if (strcmp(argv[i], "-h") == 0 || strcmp(argv[i], "--help") == 0)
    {
      args->help = true;
      return args;
    }
    else if (strcmp(argv[i], "-d") == 0 || strcmp(argv[i], "--debug") == 0)
      args->debug = true;
    else if (strcmp(argv[i], "--allow-infinite") == 0)
      args->allow_infinite = true;
    else if (strcmp(argv[i], "--max-iter") == 0)
    {
      char *n = argv[++i];
      if (!n || argc <= i || !(n[0] >= '0' && n[0] <= '9'))
      {
        printf("%sError%s: --max-iter options requires number after it\n",
               FZL_CERROR, FZL_CRST);
        free(args);
        return NULL;
      }

      uint64_t iters = strtol(n, NULL, 10);
      if (iters < 1)
      {
        printf("%sError%s: '--max-iter 0' is not allowed\n", FZL_CERROR,
               FZL_CRST);
        free(args);
        return NULL;
      }

      args->max_iter = iters;
    }
    else
    {
      printf("%sError%s: unknown flag '%s'.\n", FZL_CERROR, FZL_CRST, argv[i]);
      printf("Use 'fz --help' to read the usage\n");
      free(args);
      return NULL;
    }
  }

  if (argv[argc - 1][0] == '-')
  {
    printf("%sError%s: last argument MUST be a file path\n", FZL_CERROR,
           FZL_CRST);
    printf("Use 'fz --help' for help\n");
    free(args);
    return NULL;
  }

  args->filepath = argv[argc - 1];

  return args;
}

int main(int argc, char **argv)
{
  run_args_t *args = parse_args(argc, argv);
  if (!args)
    return -1;
  else if (args->help)
  {
    print_hint();
    free(args);
    return 0;
  }

  fzl_vm_t *vm = fzl_mkvm(args->filepath);
  if (!vm)
  {
    printf("%sError%s: %s\n", FZL_CERROR, FZL_CRST, fzl_vm_geterror());
    free(args);
    return -1;
  }

  if (args->debug)
    fzl_vm_print_ops(vm);
  else
  {
    int result = fzl_vm_run(vm, args->allow_infinite, args->max_iter);
    if (result != 0)
    {
      char *err = fzl_vm_geterror();
      if (err && err[0])
        printf("%sError%s: %s\n", FZL_CERROR, FZL_CRST, err);

      free(args);
      fzl_freevm(vm);
      return -1;
    }
  }

  free(args);
  fzl_freevm(vm);

  return 0;
}