relx

%% -*- erlang-indent-level: 4; indent-tabs-mode: nil; fill-column: 80 -*-
%%% Copyright 2012 Erlware, LLC. All Rights Reserved.
%%%
%%% This file is provided to you under the Apache License,
%%% Version 2.0 (the "License"); you may not use this file
%%% except in compliance with the License.  You may obtain
%%% a copy of the License at
%%%
%%%   http://www.apache.org/licenses/LICENSE-2.0
%%%
%%% Unless required by applicable law or agreed to in writing,
%%% software distributed under the License is distributed on an
%%% "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
%%% KIND, either express or implied.  See the License for the
%%% specific language governing permissions and limitations
%%% under the License.
%%%---------------------------------------------------------------------------
%%% @author Eric Merritt <ericbmerritt@gmail.com>
%%% @copyright (C) 2012 Erlware, LLC.
%%%
-module(rlx_prv_release).

-behaviour(provider).

-export([init/1,
         do/1,
         format_error/1]).

-include("relx.hrl").

-define(PROVIDER, resolve_release).
-define(DEPS, [app_discover]).

%%============================================================================
%% API
%%============================================================================

-spec init(rlx_state:t()) -> {ok, rlx_state:t()}.
init(State) ->
    State1 = rlx_state:add_provider(State, providers:create([{name, ?PROVIDER},
                                                             {module, ?MODULE},
                                                             {deps, ?DEPS}])),
    {ok, State1}.

%% @doc recursively dig down into the library directories specified in the state
%% looking for OTP Applications
-spec do(rlx_state:t()) -> {ok, rlx_state:t()} | relx:error().
do(State) ->
    DepGraph = create_dep_graph(State),
    find_default_release(State, DepGraph).

-spec format_error(ErrorDetail::term()) -> iolist().
format_error(no_goals_specified) ->
    "No goals specified for this release ~n";
format_error({release_erts_error, Dir}) ->
    io_lib:format("Unable to find erts in ~s~n", [Dir]);
format_error({no_release_name, Vsn}) ->
    io_lib:format("A target release version was specified (~s) but no name", [Vsn]);
format_error({invalid_release_info, Info}) ->
    io_lib:format("Target release information is in an invalid format ~p", [Info]);
format_error({multiple_release_names, RelA, RelB}) ->
    io_lib:format("No default release name was specified and there are multiple "
                 "releases in the config: ~s, ~s",
                 [RelA, RelB]);
format_error(no_releases_in_system) ->
    "No releases have been specified in the system!";
format_error({no_releases_for, RelName}) ->
    io_lib:format("No releases exist in the system for ~s!", [RelName]);
format_error({release_not_found, {RelName, RelVsn}}) ->
    io_lib:format("No releases exist in the system for ~p:~s!", [RelName, RelVsn]);
format_error({failed_solve, Error}) ->
    io_lib:format("Failed to solve release:\n ~s",
                  [rlx_depsolver:format_error({error, Error})]);
format_error({release_error, Error}) ->
    io_lib:format("Failed to resolve release:\n ~p~n", [Error]).


%%%===================================================================
%%% Internal Functions
%%%===================================================================
-spec create_dep_graph(rlx_state:t()) -> rlx_depsolver:t().
create_dep_graph(State) ->
    Apps = rlx_state:available_apps(State),
    Graph0 = rlx_depsolver:new_graph(),
    lists:foldl(fun(App, Graph1) ->
                        AppName = rlx_app_info:name(App),
                        AppVsn = rlx_app_info:vsn(App),
                        Deps = rlx_app_info:active_deps(App) ++
                            rlx_app_info:library_deps(App),
                        rlx_depsolver:add_package_version(Graph1,
                                                          AppName,
                                                          AppVsn,
                                                          Deps)
                end, Graph0, Apps).


-spec find_default_release(rlx_state:t(), rlx_depsolver:t()) ->
                                  {ok, rlx_state:t()} | relx:error().
find_default_release(State, DepGraph) ->
    try
        case rlx_state:default_configured_release(State) of
            {undefined, undefined} ->
                resolve_default_release(State, DepGraph);
            {RelName, undefined} ->
                resolve_default_version(State, DepGraph, RelName);
            {undefined, Vsn} ->
                ?RLX_ERROR({no_release_name, Vsn});
            {RelName, RelVsn} ->
                solve_release(State, DepGraph, RelName, RelVsn);
            undefined ->
                ?RLX_ERROR(no_releases_in_system)
        end
    catch
        throw:{multiple_release_names, _, _}=Error ->
            ?RLX_ERROR(Error)
    end.

resolve_default_release(State0, DepGraph) ->
    %% Here we will just get the highest versioned release and run that.
    case lists:sort(fun release_sort/2,
                    ec_dictionary:to_list(rlx_state:configured_releases(State0))) of
        [{{RelName, RelVsn}, _} | _] ->
            State1 = rlx_state:default_configured_release(State0, RelName, RelVsn),
            solve_release(State1, DepGraph, RelName, RelVsn);
        [] ->
            ?RLX_ERROR(no_releases_in_system)
    end.

resolve_default_version(State0, DepGraph, RelName) ->
    %% Here we will just get the lastest version and run that.
    AllReleases = ec_dictionary:to_list(rlx_state:configured_releases(State0)),
    SpecificReleases = [Rel || Rel={{PossibleRelName, _}, _} <- AllReleases,
                               PossibleRelName =:= RelName],
    case lists:sort(fun release_sort/2, SpecificReleases) of
        [{{RelName, RelVsn}, _} | _] ->
            State1 = rlx_state:default_configured_release(State0, RelName, RelVsn),
            solve_release(State1, DepGraph, RelName, RelVsn);
        [] ->
            ?RLX_ERROR({no_releases_for, RelName})
    end.

-spec release_sort({{rlx_release:name(),rlx_release:vsn()}, term()},
                   {{rlx_release:name(),rlx_release:vsn()}, term()}) ->
                          boolean().
release_sort({{RelName, RelVsnA}, _},
             {{RelName, RelVsnB}, _}) ->
    ec_semver:lte(RelVsnB, RelVsnA);
release_sort({{RelA, _}, _}, {{RelB, _}, _}) ->
    %% The release names are different. When the releases are named differently
    %% we can not just take the lastest version. You *must* provide a default
    %% release name at least. So we throw an error here that the top can catch
    %% and return
    erlang:throw({multiple_release_names, RelA, RelB}).

solve_release(State0, DepGraph, RelName, RelVsn) ->
    ec_cmd_log:debug(rlx_state:log(State0),
                     "Solving Release ~p-~s~n",
                     [RelName, RelVsn]),
    try
        Release =
            case get_realized_release(State0, RelName, RelVsn) of
                undefined ->
                    rlx_state:get_configured_release(State0, RelName, RelVsn);
                {ok, Release0} ->
                    rlx_release:relfile(rlx_state:get_configured_release(State0, RelName, RelVsn), rlx_release:relfile(Release0))
            end,

        %% get per release config values and override the State with them
        Config = rlx_release:config(Release),
        {ok, State1} = lists:foldl(fun rlx_config:load_terms/2, {ok, State0}, Config),
        Goals = rlx_release:goals(Release),
        case Goals of
            [] ->
                ?RLX_ERROR(no_goals_specified);
            _ ->
                case rlx_depsolver:solve(DepGraph, Goals) of
                    {ok, Pkgs} ->
                        set_resolved(State1, Release, Pkgs);
                    {error, Error} ->
                        ?RLX_ERROR({failed_solve, Error})
                end
        end
    catch
        throw:not_found ->
            ?RLX_ERROR({release_not_found, {RelName, RelVsn}})
    end.

set_resolved(State, Release0, Pkgs) ->
    case rlx_release:realize(Release0, Pkgs, rlx_state:available_apps(State)) of
        {ok, Release1} ->
            ec_cmd_log:info(rlx_state:log(State),
                            "Resolved ~p-~s~n",
                            [rlx_release:name(Release1),
                             rlx_release:vsn(Release1)]),
            ec_cmd_log:debug(rlx_state:log(State),
                             fun() ->
                                     rlx_release:format(0, Release1)
                             end),
            case rlx_state:get(State, include_erts, undefined) of
                IncludeErts when is_atom(IncludeErts) ->
                    {ok, rlx_state:add_realized_release(State, Release1)};
                ErtsDir ->
                    try
                        [Erts | _] = filelib:wildcard(filename:join(ErtsDir, "erts-*")),
                        [_, ErtsVsn] = rlx_string:lexemes(filename:basename(Erts), "-"),
                        {ok, rlx_state:add_realized_release(State, rlx_release:erts(Release1, ErtsVsn))}
                    catch
                        _:_ ->
                            ?RLX_ERROR({release_erts_error, ErtsDir})
                    end
            end
    end.

get_realized_release(State, RelName, RelVsn) ->
    try
        Release = rlx_state:get_realized_release(State, RelName, RelVsn),
        {ok, Release}
    catch
        throw:not_found ->
            undefined
    end.

%%%===================================================================
%%% Test Functions
%%%===================================================================