%% -*- mode: Erlang; fill-column: 79; comment-column: 70; -*-
%% vi:ts=4 sw=4 et
%%%---------------------------------------------------------------------------
%%% 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 Eric Merritt
%%% @doc
%%%  Provides the ability to ask questions of the user and
%%%  get a response.
%%% @end
%%% @copyright Erlware 2006-2011
%%%---------------------------------------------------------------------------
-module(ec_talk).

%% API
-export([ask/1,
         ask/2,
         ask_default/2,
         ask_default/3,
         ask/3,
         say/1,
         say/2]).

-export_type([prompt/0,
              type/0,
              supported/0]).

%%============================================================================
%% Types
%%============================================================================
-type prompt() :: string().
-type type() :: boolean | number | string.
-type supported() ::  boolean() | number() | string().

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

%% @doc Outputs the line to the screen
-spec say(string()) -> ok.
say(Say) ->
    io:format(lists:flatten([Say, "~n"])).

-spec say(string(), [term()] | term()) -> ok.
say(Say, Args) when is_list(Args) ->
    io:format(lists:flatten([Say, "~n"]), Args);
say(Say, Args) ->
    io:format(lists:flatten([Say, "~n"]), [Args]).

%% @doc Asks the user for a response to the specified prompt.
-spec ask(prompt()) -> string().
ask(Prompt) ->
    ask_convert(Prompt, fun get_string/1, string, none).

%% @doc Asks the user for a response to the specified prompt.
-spec ask_default(prompt(), string()) -> string().
ask_default(Prompt, Default) ->
    ask_convert(Prompt, fun get_string/1, string, Default).

%% @doc Asks the user to respond to the prompt. Tries to return the
%% value in the format specified by 'Type'.
-spec ask(prompt(), type()) ->  supported().
ask(Prompt, boolean) ->
    ask_convert(Prompt, fun get_boolean/1, boolean, none);
ask(Prompt, number) ->
    ask_convert(Prompt, fun get_integer/1, number,  none);
ask(Prompt, string) ->
    ask_convert(Prompt, fun get_string/1, string, none).

%% @doc Asks the user to respond to the prompt. Tries to return the
%% value in the format specified by 'Type'.
-spec ask_default(prompt(), type(), supported()) ->  supported().
ask_default(Prompt, boolean, Default)  ->
    ask_convert(Prompt, fun get_boolean/1, boolean, Default);
ask_default(Prompt, number, Default) ->
    ask_convert(Prompt, fun get_integer/1, number, Default);
ask_default(Prompt, string, Default) ->
    ask_convert(Prompt, fun get_string/1, string, Default).

%% @doc Asks the user to respond to the number prompt with a value
%% between min and max.
-spec ask(prompt(), number(), number()) -> number().
ask(Prompt, Min, Max)
  when erlang:is_list(Prompt),
       erlang:is_number(Min),
       erlang:is_number(Max),
       Min =< Max ->
    Res = ask_convert(Prompt, fun get_integer/1, number, none),
    case (Res >= Min andalso Res =< Max) of
        true ->
            Res;
        false ->
            say("Your answer must be between ~w and ~w!", [Min, Max]),
            ask(Prompt, Min, Max)
    end.

%%============================================================================
%% Internal functions
%% ============================================================================
%% @doc Actually does the work of asking, checking result and
%% translating result into the requested format.
-spec ask_convert(prompt(), fun((any()) -> any()), type(), supported() | none) -> supported().
ask_convert(Prompt, TransFun, Type,  Default) ->
    NewPrompt =
        erlang:binary_to_list(erlang:iolist_to_binary([Prompt,
                                                       case Default of
                                                           none ->
                                                               [];
                                                           Default ->
                                                               [" (", io_lib:format("~p", [Default]) , ")"]
                                                       end, "> "])),
    Data = trim(trim(io:get_line(NewPrompt)), both, [$\n]),
    Ret = TransFun(Data),
    case Ret of
        no_data ->
            case Default of
                none ->
                    say("I didn't get that. This ~p kind of question.~n", [Type]),
                    ask_convert(Prompt, TransFun, Type, Default);
                Default ->
                    TransFun(Default)
            end;
        no_clue ->
            say("I didn't get that. This ~p kind of question.~n", [Type]),
            ask_convert(Prompt, TransFun, Type, Default);
        _ ->
            Ret
    end.

%% @doc Tries to translate the result into a boolean
-spec get_boolean(string()) -> boolean().
get_boolean([]) ->
    no_data;
get_boolean([$T | _]) ->
    true;
get_boolean([$t | _]) ->
    true;
get_boolean("ok") ->
    true;
get_boolean("OK") ->
    true;
get_boolean([$Y | _]) ->
    true;
get_boolean([$y | _]) ->
    true;
get_boolean([$f | _]) ->
    false;
get_boolean([$F | _]) ->
    false;
get_boolean([$n | _]) ->
    false;
get_boolean([$N | _]) ->
    false;
get_boolean(_) ->
    no_clue.

%% @doc Tries to translate the result into an integer
-spec get_integer(string()) -> integer().
get_integer([]) ->
    no_data;
get_integer(String) ->
    case (catch list_to_integer(String)) of
        {'Exit', _} ->
            no_clue;
        Integer ->
            Integer
    end.

%% @doc Solely returns a string give the string. This is so the same
%% translate function can be used across the board
-spec get_string(string()) -> string().
get_string([]) ->
    no_data;
get_string(String) ->
    case is_list(String) of
        true ->
            String;
        false ->
            no_clue
    end.

-ifdef(unicode_str).
trim(Str) -> string:trim(Str).
trim(Str, both, Chars) -> string:trim(Str, both, Chars).
-else.
trim(Str) -> string:strip(Str).
trim(Str, Dir, [Chars|_]) -> string:strip(Str, Dir, Chars).
-endif.

%%%====================================================================
%%% tests
%%%====================================================================
-ifdef(TEST).
-include_lib("eunit/include/eunit.hrl").

general_test_() ->
    [?_test(42 == get_integer("42")),
     ?_test(500211 == get_integer("500211")),
     ?_test(1234567890 == get_integer("1234567890")),
     ?_test(12345678901234567890 == get_integer("12345678901234567890")),
     ?_test(true == get_boolean("true")),
     ?_test(false == get_boolean("false")),
     ?_test(true == get_boolean("Ok")),
     ?_test(true == get_boolean("ok")),
     ?_test(true == get_boolean("Y")),
     ?_test(true == get_boolean("y")),
     ?_test(false == get_boolean("False")),
     ?_test(false == get_boolean("No")),
     ?_test(false == get_boolean("no"))].

-endif.