%%%-------------------------------------------------------------------
%%% @author Jose Luis Gordo Romero <jgordor@gmail.com>
%%% @doc Chicago Boss rebar plugin
%%%  Manage compilation/configuration/scripts stuff the rebar way
%%% @end
%%%-------------------------------------------------------------------
-module(boss_plugin).

-export([boss/2,
		 pre_compile/2,
		 pre_eunit/2]).

-define(BOSS_PLUGIN_CLIENT_VERSION, 1).
-define(BOSS_CONFIG_FILE, "boss.config").
-define(BOSS_TEST_CONFIG_FILE, "boss.test.config").

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

%%--------------------------------------------------------------------
%% @doc boss command
%% @spec boss(_Config, _AppFile) -> ok | {error, Reason}
%%       Boss enabled rebar commands, usage:
%%       ./rebar boss c=command
%% @end
%%--------------------------------------------------------------------
boss(RebarConf, AppFile) ->
	case is_base_dir(RebarConf) of
		true -> 
            Command = rebar_config:get_global(RebarConf, c, "help"),
   			{ok, BossConf} = init(RebarConf, AppFile, Command),
			case boss_rebar:run(?BOSS_PLUGIN_CLIENT_VERSION, Command, RebarConf, BossConf, AppFile) of
				{error, command_not_found} ->
					io:format("ERROR: boss command not found.~n",[]), 
					boss_rebar:help(),
					halt(1);
				{error, Reason} -> 
					io:format("ERROR: executing ~s task: ~s~n", [Command, Reason]), 
					halt(1);
				ok -> ok
			end;
		false -> ok
	end.

%%--------------------------------------------------------------------
%% @doc initializes the rebar boss connector plugin
%% @spec init(Config, AppFile) -> {ok, BossConf} | {error, Reason}
%%       Set's the ebin cb_apps and loads the connector 
%% @end
%%--------------------------------------------------------------------
init(_RebarConf, AppFile, Command) ->
    %% Compile and load the boss_rebar code, this can't be compiled
	%% as a normal boss lib without the rebar source dep
	%% The load of ./rebar boss:
	%% - Rebar itself searchs in rebar.config for {plugin_dir, ["priv/rebar"]}.
	%% - Rebar itself compile this plugin and adds it to the execution chain
	%% - This plugin compiles and loads the boss_rebar code in ["cb/priv/rebar"],
	%%   so we can extend/bugfix/tweak the framework without the need of manually
	%%   recopy code to user apps
    {BossConf, BossConfFile} = boss_config(Command,rebar_config:get_global(_RebarConf, config, ?BOSS_CONFIG_FILE)),
	BossPath = case boss_config_value(boss, path, BossConf) of
				   {error, _} ->
					   io:format("FATAL: Failed to read boss=>path config in ~p.~n", [BossConfFile]),
					   halt(1);
				   Val -> Val
			   end,
	RebarErls = rebar_utils:find_files(filename:join([BossPath, "priv", "rebar"]), ".*\\.erl\$"),
	
	rebar_log:log(debug, "Auto-loading boss rebar modules ~p~n", [RebarErls]),
	
	lists:map(fun(F) ->
					  case compile:file(F, [binary]) of
						  error ->
							  io:format("FATAL: Failed compilation of ~s module~n", [F]),
							  halt(1);
						  {ok, M, Bin} ->
							  {module, _} = code:load_binary(M, F, Bin),
							  rebar_log:log(debug, "Loaded ~s~n", [M])
					  end
			  end, RebarErls),

	%% add all cb_apps defined in config file to code path
	%% including the deps ebin dirs
	[code:add_path(CodePath) || CodePath <- boss_rebar:all_ebin_dirs(BossConf, AppFile)],
    
    %% Load the config in the environment
    boss_rebar:init_conf(BossConf),
	
	{ok, BossConf}.
	
%%--------------------------------------------------------------------
%% @doc pre_compile hook
%% @spec pre_compile(_Config, AppFile) -> ok | {error, Reason}
%%       Pre compile hook, compile the boss way
%%       Compatibility hook, the normal ./rebar compile command works,
%%         but only calls the ./rebar boss c=compile and halts (default
%%         rebar task never hits)
%% @end
%%--------------------------------------------------------------------
pre_compile(RebarConf, AppFile) ->
	case is_base_dir(RebarConf) of
		true -> 
			{ok, BossConf} = init(RebarConf, AppFile, "compile"),
			boss_rebar:run(?BOSS_PLUGIN_CLIENT_VERSION, compile, RebarConf, BossConf, AppFile),
			halt(0);
		false -> ok
	end.

%%--------------------------------------------------------------------
%% @doc pre_eunit hook
%% @spec pre_eunit(RebarConf, AppFile) -> ok | {error, Reason}
%%       Pre eunit hook, .eunit compilation the boss way
%%       Compatibility hook, the normal ./rebar eunit command works,
%%         but only calls the ./rebar boss c=test_eunit and halts
%%         (default rebar task never hits)
%% @end
%%--------------------------------------------------------------------
pre_eunit(RebarConf, AppFile) ->
	case is_base_dir(RebarConf) of
		true -> 
			{ok, BossConf} = init(RebarConf, AppFile, "test_eunit"),
			boss_rebar:run(?BOSS_PLUGIN_CLIENT_VERSION, test_eunit, RebarConf, BossConf, AppFile),
			halt(0);
		false -> ok
	end.

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

%% Checks if the current dir (rebar execution) is the base_dir
%% Used to prevent run boss tasks in deps directory
is_base_dir(RebarConf) ->
    filename:absname(rebar_utils:get_cwd()) =:= rebar_config:get_xconf(RebarConf, base_dir, undefined).

%% Gets the boss.config central configuration file
boss_config(Command,Config) ->
    BossConfFile = case lists:prefix("test_", Command) of
        false ->
            Config;
        true ->
            case file:read_file_info(?BOSS_TEST_CONFIG_FILE) of
                {ok, _} -> ?BOSS_TEST_CONFIG_FILE;
                _ -> Config
            end
    end,
    case file:consult(BossConfFile) of
        {error,enoent} ->
            io:format("FATAL: Config file ~p not found.~n", [BossConfFile]),
            halt(1);
        {ok, [BossConfig]} ->
            {BossConfig, BossConfFile}
    end.

%%--------------------------------------------------------------------
%% @doc Get Boss config value app, key
%% @spec boss_config_value(App, Key) -> Value | {error, Reason}
%%       Searchs in boss config for a given App and Key
%% @end
%%--------------------------------------------------------------------
boss_config_value(App, Key, BossConfig) ->
	case lists:keyfind(App, 1, BossConfig) of
		false -> 
			{error, boss_config_app_not_found};
		{App, AppConfig} -> 
			case lists:keyfind(Key, 1, AppConfig) of
				false -> 
					{error, boss_config_app_setting_not_found};
				{Key, KeyConfig} ->
					KeyConfig
			end
	end.