#include <unistd.h>
#include <sys/random.h>
#include <sys/wait.h>
#include <assert.h>
#include <string.h>

#include "lib.h"

struct tmp_repo tmp_repo_init() {
  unsigned char rng_bytes[64];
  assert(getrandom(rng_bytes, sizeof(rng_bytes), 0) == sizeof(rng_bytes));

  char repo_path[70] = "/tmp/";
  for (int i = 0; i < 64; i++) {
    repo_path[5 + i] = (char)('a' + rng_bytes[i] % 26);
  }
  repo_path[69] = '\0';

  git_libgit2_init();

  git_repository *repo = NULL;
  assert(git_repository_init(&repo, repo_path, 0) == 0);
  struct tmp_repo output;
  memcpy(output.path, repo_path, 70);
  output.repo = repo;
  return output;
}

void tmp_repo_deinit(struct tmp_repo repo) {
  pid_t pid;
  if ((pid = fork()) == 0) {
    char *argv[] = {"/usr/bin/rm", "-rf", repo.path, NULL};
    execv(argv[0], argv);
  }
  assert(waitpid(pid, NULL, 0) != -1);
}

int check_for_backupignore() {
  FILE *file = fopen(".backupignore", "r");
  if (file == NULL) {
    fprintf(stderr, "Missing .backupignore file in the current directory\n");
    return 1;
  } else fclose(file);
  return 0;
}

void copy_over_backupignore(struct tmp_repo repo) {
  char cp_destination[81];
  snprintf(cp_destination, 81, "%s/.gitignore", repo.path);

  pid_t pid;
  if ((pid = fork()) == 0) {
    char *argv[] = {"/usr/bin/cp", ".backupignore", cp_destination, NULL};
    execv(argv[0], argv);
  }
  assert(waitpid(pid, NULL, 0) != -1);
}

int is_ignored(struct tmp_repo repo, char *path) {
  if (is_git_metadata_dir(path)) return 0;
  int ignored;
  assert(git_ignore_path_is_ignored(&ignored, repo.repo, path) >= 0);
  return ignored;
}

int is_git_metadata_dir(char *path) {
  int n = strnlen(path, PATH_MAX);
  for (int i = 0; i < n - 6; i++) {
    if (strncmp(path + i, "/.git/", 6) == 0) return 1;
  }
  return 0;
}