(* Guestfs Browser.
 * Copyright (C) 2010 Red Hat Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *)

open Utils

type t = {
  view : GTree.view;
  model : GTree.tree_store;
  hash : (int, hdata) Hashtbl.t;    (* hash from index_col -> hdata *)
  index_col : int GTree.column;
  mode_col : string GTree.column;
  name_col : string GTree.column;
  size_col : int64 GTree.column;
  date_col : string GTree.column;
  link_col : string GTree.column;
}

and hdata = state_t * content_t

(* The type of the hidden column used to implement on-demand loading.
 * All rows are classified as either nodes or leafs (eg. a "node" might
 * be a directory, or a top-level operating system, or anything else
 * which the user could open and look inside).
 *)
and state_t =
  | IsLeaf           (* there are no children *)
  | NodeNotStarted   (* user has not tried to open this *)
  | NodeLoading      (* user tried to open it, still loading *)
  | IsNode           (* we've loaded the children of this directory *)

(* The actual content of a row. *)
and content_t =
  | Loading                          (* special "loading ..." node *)
  | ErrorMessage of string           (* error message node *)
  | Info of string                   (* information node (eg. disk usage) *)
  | Top of Slave.source              (* top level OS or volume node *)
  | Directory of Slave.direntry      (* a directory *)
  | File of Slave.direntry           (* a file inc. special files *)

(* Store hdata into a row. *)
let store_hdata {model = model; hash = hash; index_col = index_col} row hdata =
  let index = unique () in
  Hashtbl.add hash index hdata;
  model#set ~row ~column:index_col index

(* Retrieve previously stored hdata from a row. *)
let get_hdata { model = model; hash = hash; index_col = index_col } row =
  let index = model#get ~row ~column:index_col in
  try Hashtbl.find hash index
  with Not_found -> assert false

(* Iterate over children of node, looking for matching hdata. *)
let find_child_node_by_hdata ({ model = model } as t) row hdata =
  let rec loop row =
    if hdata = get_hdata t row then
      row
    else if model#iter_next row then
      loop row
    else
      raise Not_found
  in

  if not (model#iter_has_child row) then
    raise Not_found;

  let first_child = model#iter_children (Some row) in
  loop first_child

(* Search up to the top of the tree so we know if this directory
 * comes from an OS or a volume, and the full path to here.
 *
 * The path up the tree will always look something like:
 *     Top
 *       \_ Directory
 *            \_ Directory
 *                 \_ Loading    <--- you are here
 *)
let rec get_pathname ({ model = model } as t) row =
  let hdata = get_hdata t row in
  let parent = model#iter_parent row in

  match hdata, parent with
  | (IsLeaf, (Loading|ErrorMessage _|Info _)), Some parent ->
      get_pathname t parent
  | (IsLeaf, (Loading|ErrorMessage _|Info _)), None ->
      assert false
  | (_, Directory { Slave.dent_name = name }), Some parent
  | (_, File { Slave.dent_name = name }), Some parent ->
      let src, parent_name = get_pathname t parent in
      let path =
        if parent_name = "/" then "/" ^ name
        else parent_name ^ "/" ^ name in
      src, path
  | (_, Top src), _ -> src, "/"
  | (_, Directory _), None -> assert false
  | (_, File _), None -> assert false
  | (_, Loading), _ -> assert false
  | (_, ErrorMessage _), _ -> assert false
  | (_, Info _), _ -> assert false