#include <sol/types.hpp>
#include <sstream>
#include <vector>

#include "session.h"
#include "db/database_manager.h"
#include "i_network_bridge.h"
#include "lua_api.h"
#include "lua_processor.h"
#include "machine.h"
#include "vfs.h"
#include "util.h"

vfs_node* find_node_by_id(vfs_node* root, long long id) {
  if(root->id == id) {
    return root;
  }
  for(auto const& [name, child] : root->children) {
    vfs_node* found = find_node_by_id(child, id);
    if(found) {
      return found;
    }
  }
  return nullptr;
}

Session::Session(Machine* home_machine,
                 DatabaseManager* db_manager,
                 MachineManager* machine_manager,
                 INetworkBridge* network_bridge) :
    _machine_manager(machine_manager),
    _db_manager(db_manager),
    _network_bridge(network_bridge),
    _home_machine(home_machine),
    _session_machine(home_machine) {

  if(home_machine) _current_dir = home_machine->vfs_root;
}

Session::~Session(void) {
}

vfs_node* Session::get_current_dir(void) {
  return _current_dir;
}

Machine* Session::get_home_machine(void)     { return _home_machine; }
Machine* Session::get_session_machine(void)  { return _session_machine; }

DatabaseManager* Session::get_db_manager(void) {
  return _db_manager;
}

MachineManager* Session::get_machine_manager(void) {
  return _machine_manager;
}

INetworkBridge* Session::get_network_bridge(void) {
  return _network_bridge;
}

void Session::set_current_dir(vfs_node* node) {
  _current_dir = node;
}

void Session::set_session_machine(Machine* machine) {
  _session_machine = machine;
  if(_session_machine) {
    _current_dir = _session_machine->vfs_root;
  }
}

uint32_t Session::get_current_uid(void) {
  return _home_machine->owner_id;
}

uint32_t Session::get_current_gid(void) {
  return _home_machine->owner_id;
}

std::string Session::process_command(const std::string& command) {
  /*
   * Creating the Lua processor on-demand to ensure it exists on the same
   * thread that will execute the script.
   */
  LuaProcessor lua(*this);

  /* Trim trailing whitespace. */
  std::string cmd = command;
  size_t end = cmd.find_last_not_of(" \t\n\r");
  cmd = (end == std::string::npos) ? "" : cmd.substr(0, end+1);

  /* === Generic script executer. === */
  /* Parse the command and it's arguments. */
  std::stringstream ss(cmd);
  std::string command_name;
  ss >> command_name;

  std::vector<std::string> args;
  std::string arg;
  while(ss >> arg) {
    args.push_back(arg);
  }

  vfs_node* command_node = nullptr;
  if(command_name.find('/') != std::string::npos) {
    /* Path provided, find node directly. */
    command_node = find_node_by_path(_session_machine->vfs_root, command_name);
  } else {
    /* No path, search current dir then /bin. */
    vfs_node* current_dir = get_current_dir();
    if(current_dir->children.count(command_name)) {
      command_node = current_dir->children.at(command_name);
    } else {
      vfs_node* bin_dir = find_node_by_path(_session_machine->vfs_root, "/bin");
      if(bin_dir && bin_dir->children.count(command_name)) {
        command_node = bin_dir->children.at(command_name);
      }
    }
  }

  if(command_node) {
    if(command_node->type == EXEC_NODE) {
      if(!has_permission(command_node, *this, EXEC_PERM)) {
        return "Cannot execute '" + command_name + "': Permission denied.";
      }
      bool is_remote = (_session_machine != _home_machine);
      std::string deobfuscated_content = util::xor_string(command_node->content);
      sol::object result = lua.execute(deobfuscated_content, *this, args, is_remote);
      return result.is<std::string>() ? result.as<std::string>()
                                      : "[Script returned non-string value]";
    } else if(command_node->type == DIR_NODE) {
      return "Cannot execute '" + command_name + "' It is a directory.";
    } else {
      return "Cannot execute '" + command_name + "': Not an executable file.";
    }
  }
  return "Unknown command: " + command_name;
}

std::string Session::write_file(const std::string& path, const std::string& content) {
  return api::write_file(*this, path, content);
}

std::string Session::read_file(const std::string& path) {
  vfs_node* root = get_session_machine()->vfs_root;
  vfs_node* node = nullptr;

  if(path[0] == '/') {
    node = find_node_by_path(root, path);
  } else {
    /* Relative path. */
    vfs_node* current_dir = get_current_dir();
    if(current_dir->children.count(path)) {
      node = current_dir->children.at(path);
    }
  }

  if(node && (node->type == FILE_NODE || node->type == EXEC_NODE)) {
    return node->content;
  }
  return "Error: file not found.";
}

std::string Session::get_username(void) {
  if(!_home_machine || !_home_machine->vfs_root) {
    return "unknown";
  }

  vfs_node* passwd_node = find_node_by_path(_home_machine->vfs_root, "/etc/passwd");
  if(!passwd_node || passwd_node->type != FILE_NODE) {
    return "unknown";
  }

  std::stringstream ss(passwd_node->content);
  std::string line;
  uint32_t player_id = _home_machine->owner_id;

  while(std::getline(ss, line)) {
    std::vector<std::string> parts;
    std::stringstream line_ss(line);
    std::string part;
    while(std::getline(line_ss, part, ':')) {
      parts.push_back(part);
    }

    if(parts.size() >= 3) {
      if(std::to_string(player_id) == parts[2]) {
        return parts[0]; /* Username. */
      }
    }
  }
  return "unknown";
}