#include <string.h>

#include "database.h"
#include "sql.h"
#include "user.h"

char *db_get_all_users() {
  pthread_mutex_lock(&db_mutex);
  if (!db) {
    fprintf(stderr, "Database not initialized\n");
    pthread_mutex_unlock(&db_mutex);
    return nullptr;
  }
  sqlite3_stmt *stmt;
  int rc;

  rc = sqlite3_prepare_v2(db, SELECT_ALL_USERS_SQL, -1, &stmt, nullptr);
  if (rc != SQLITE_OK) {
    fprintf(stderr, "Cannot prepare statement: %s\n", sqlite3_errmsg(db));
    pthread_mutex_unlock(&db_mutex);
    return nullptr;
  }

  char *result = malloc(1024);
  if (!result) {
    sqlite3_finalize(stmt);
    pthread_mutex_unlock(&db_mutex);
    return nullptr;
  }

  strcpy(result, "[");
  size_t result_size = strlen(result);
  size_t result_capacity = 1024;

  int first_record = 1;

  while ((rc = sqlite3_step(stmt)) == SQLITE_ROW) {
    int id = sqlite3_column_int(stmt, 0);
    const unsigned char *username = sqlite3_column_text(stmt, 1);
    const unsigned char *email = sqlite3_column_text(stmt, 2);
    const unsigned char *group = sqlite3_column_text(stmt, 4);
    int is_superuser = sqlite3_column_int(stmt, 5);

    char *escaped_username = json_escape((const char *)username);
    char *escaped_email = json_escape((const char *)email);
    char *escaped_group = json_escape((const char *)group);
    if (!escaped_username || !escaped_email || !escaped_group) {
      free(escaped_username);
      free(escaped_email);
      free(escaped_group);
      sqlite3_finalize(stmt);
      return NULL;
    }

    char record[512];
    if (sqlite3_column_type(stmt, 2) == SQLITE_NULL) {
      snprintf(record, sizeof(record),
               "%s{\"id\":%d,\"username\":\"%s\",\"email\":\"%s\",\"group\":"
               "\"%s\",\"is_superuser\":%s}",
               first_record ? "" : ",", id, escaped_username, escaped_email,
               escaped_group, is_superuser ? "true" : "false");
    } else {
      snprintf(record, sizeof(record),
               "%s{\"id\":%d,\"username\":\"%s\",\"email\":\"%s\",\"group\":"
               "\"%s\",\"is_superuser\":%s}",
               first_record ? "" : ",", id, escaped_username, escaped_email,
               escaped_group, is_superuser ? "true" : "false");
    }

    free(escaped_username);
    free(escaped_email);
    free(escaped_group);

    size_t record_len = strlen(record);
    if (result_size + record_len + 10 > result_capacity) {
      result_capacity *= 2;
      char *new_result = realloc(result, result_capacity);
      if (!new_result) {
        free(result);
        sqlite3_finalize(stmt);
        return nullptr;
      }
      result = new_result;
    }
    strcat(result, record);
    result_size += record_len;
    first_record = 0;
  }

  if (rc != SQLITE_DONE) {
    fprintf(stderr, "Error reading data: %s\n", sqlite3_errmsg(db));
    free(result);
    sqlite3_finalize(stmt);
    return NULL;
  }
  strcat(result, "]");
  sqlite3_finalize(stmt);
  pthread_mutex_unlock(&db_mutex);
  return result;
}