%% -*- erlang-indent-level: 4;indent-tabs-mode: nil -*-
%% ex: ts=4 sw=4 et
%% -------------------------------------------------------------------
%%
%% rebar: Erlang Build Tools
%%
%% Copyright (c) 2010 Dave Smith (dizzyd@dizzyd.com)
%%
%% Permission is hereby granted, free of charge, to any person obtaining a copy
%% of this software and associated documentation files (the "Software"), to deal
%% in the Software without restriction, including without limitation the rights
%% to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
%% copies of the Software, and to permit persons to whom the Software is
%% furnished to do so, subject to the following conditions:
%%
%% The above copyright notice and this permission notice shall be included in
%% all copies or substantial portions of the Software.
%%
%% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
%% IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
%% FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
%% AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
%% LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
%% OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
%% THE SOFTWARE.
%% -------------------------------------------------------------------
%% @author Dave Smith <dizzyd@dizzyd.com>
%% @doc rebar_edoc supports the following command:
%% <ul>
%%   <li>doc (essentially erl -noshell -run edoc_run application
%% "'$(&lt;app_name&gt;)'"
%% '"."' '[&lt;options&gt;]')</li>
%% </ul>
%% EDoc options can be given in the <code>edoc_opts</code> option in
%% <code>rebar.config</code>.
%% @copyright 2010 Dave Smith
%% -------------------------------------------------------------------
-module(rebar_edoc).

-export([doc/2]).

-include("rebar.hrl").

%% ===================================================================
%% Public API
%% ===================================================================

doc(Config, File) ->
    %% Save code path
    CodePath = setup_code_path(),

    %% Get the edoc_opts and app file info
    EDocOpts = rebar_config:get(Config, edoc_opts, []),
    {ok, Config1, AppName, _AppData} =
        rebar_app_utils:load_app_file(Config, File),

    %% Determine the age of the summary file
    EDocInfoName = filename:join(proplists:get_value(dir, EDocOpts, "doc"),
                                 "edoc-info"),
    EDocInfoLastMod = filelib:last_modified(EDocInfoName),

    %% For each source directory, look for a more recent file than
    %% SumaryLastMod; in that case, we go ahead and do a full regen
    NeedsRegen = newer_file_exists(proplists:get_value(source_path,
                                                       EDocOpts, ["src"]),
                                   EDocInfoLastMod),

    case NeedsRegen of
        true ->
            ?INFO("Regenerating edocs for ~p\n", [AppName]),
            ok = edoc:application(AppName, ".", EDocOpts);
        false ->
            ?INFO("Skipping regeneration of edocs for ~p\n", [AppName]),
            ok
    end,

    %% Restore code path
    true = code:set_path(CodePath),
    {ok, Config1}.

%% ===================================================================
%% Internal functions
%% ===================================================================

setup_code_path() ->
    %% Setup code path prior to calling edoc so that edown, asciiedoc,
    %% and the like can work properly when generating their own
    %% documentation.
    CodePath = code:get_path(),
    true = code:add_patha(rebar_utils:ebin_dir()),
    CodePath.

newer_file_exists(Paths, LastMod) ->
    CheckFile = fun(Filename, _) ->
                        FLast = filelib:last_modified(Filename),
                        case FLast > LastMod of
                            true ->
                                ?DEBUG("~p is more recent than edoc-info: "
                                       "~120p > ~120p\n",
                                       [Filename, FLast, LastMod]),
                                throw(newer_file_exists);
                            false ->
                                false
                        end
                end,
    try
        lists:foldl(fun(P, _) ->
                            filelib:fold_files(P, ".*.erl", true,
                                               CheckFile, false)
                    end, undefined, Paths),
        false
    catch
        throw:newer_file_exists ->
            true
    end.