%% -*- erlang-indent-level: 4;indent-tabs-mode: nil -*-
%% ex: ts=4 sw=4 et
%% -------------------------------------------------------------------
%%
%% rebar: Erlang Build Tools
%%
%% Copyright (c) 2009 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.
%% -------------------------------------------------------------------
-module(rebar_base_compiler).

-include("rebar.hrl").

-export([run/4, run/7, run/8]).


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

run(Config, FirstFiles, RestFiles, CompileFn) ->
    %% Compile the first files in sequence
    compile_each(FirstFiles, Config, CompileFn),

    %% Spin up workers for the rest of the files
    case RestFiles of
        [] ->
            ok;
        _ ->
            Self = self(),
            F = fun() -> compile_worker(Self, Config, CompileFn) end,
            Jobs = rebar_config:get_jobs(),
            ?DEBUG("Starting ~B compile worker(s)~n", [Jobs]),
            Pids = [spawn_monitor(F) || _I <- lists:seq(1,Jobs)],
            compile_queue(Pids, RestFiles)
    end.

run(Config, FirstFiles, SourceDir, SourceExt, TargetDir, TargetExt,
    Compile3Fn) ->
    run(Config, FirstFiles, SourceDir, SourceExt, TargetDir, TargetExt,
        Compile3Fn, [check_last_mod]).

run(Config, FirstFiles, SourceDir, SourceExt, TargetDir, TargetExt,
    Compile3Fn, Opts) ->
    %% Convert simple extension to proper regex
    SourceExtRe = ".*\\" ++ SourceExt ++ [$$],

    %% Find all possible source files
    FoundFiles = rebar_utils:find_files(SourceDir, SourceExtRe),

    %% Remove first files from found files
    RestFiles = [Source || Source <- FoundFiles,
                           not lists:member(Source, FirstFiles)],

    %% Check opts for flag indicating that compile should check lastmod
    CheckLastMod = proplists:get_bool(check_last_mod, Opts),

    run(Config, FirstFiles, RestFiles,
        fun(S, C) ->
                Target = target_file(S, SourceDir, SourceExt,
                                     TargetDir, TargetExt),
                simple_compile_wrapper(S, Target, Compile3Fn, C, CheckLastMod)
        end).


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

simple_compile_wrapper(Source, Target, Compile3Fn, Config, false) ->
    Compile3Fn(Source, Target, Config);
simple_compile_wrapper(Source, Target, Compile3Fn, Config, true) ->
    case filelib:last_modified(Target) < filelib:last_modified(Source) of
        true ->
            Compile3Fn(Source, Target, Config);
        false ->
            skipped
    end.

target_file(SourceFile, SourceDir, SourceExt, TargetDir, TargetExt) ->
    %% Remove all leading components of the source dir from the file -- we want
    %% to maintain the deeper structure (if any) of the source file path
    BaseFile = remove_common_path(SourceFile, SourceDir),
    filename:join([TargetDir, filename:dirname(BaseFile),
                   filename:basename(BaseFile, SourceExt) ++ TargetExt]).


remove_common_path(Fname, Path) ->
    remove_common_path1(filename:split(Fname), filename:split(Path)).

remove_common_path1([Part | RestFilename], [Part | RestPath]) ->
    remove_common_path1(RestFilename, RestPath);
remove_common_path1(FilenameParts, _) ->
    filename:join(FilenameParts).


compile(Source, Config, CompileFn) ->
    case CompileFn(Source, Config) of
        ok ->
            ok;
        skipped ->
            skipped
    end.


compile_each([], _Config, _CompileFn) ->
    ok;
compile_each([Source | Rest], Config, CompileFn) ->
    case compile(Source, Config, CompileFn) of
        ok ->
            ?CONSOLE("Compiled ~s\n", [Source]);
        skipped ->
            ?INFO("Skipped ~s\n", [Source])
    end,
    compile_each(Rest, Config, CompileFn).



compile_queue([], []) ->
    ok;
compile_queue(Pids, Targets) ->
    receive
        {next, Worker} ->
            case Targets of
                [] ->
                    Worker ! empty,
                    compile_queue(Pids, Targets);
                [Source | Rest] ->
                    Worker ! {compile, Source},
                    compile_queue(Pids, Rest)
            end;

        {fail, Error} ->
            ?DEBUG("Worker compilation failed: ~p\n", [Error]),
            ?FAIL;

        {compiled, Source} ->
            ?CONSOLE("Compiled ~s\n", [Source]),
            compile_queue(Pids, Targets);

        {skipped, Source} ->
            ?INFO("Skipped ~s\n", [Source]),
            compile_queue(Pids, Targets);

        {'DOWN', Mref, _, Pid, normal} ->
            ?DEBUG("Worker exited cleanly\n", []),
            Pids2 = lists:delete({Pid, Mref}, Pids),
            compile_queue(Pids2, Targets);

        {'DOWN', _Mref, _, _Pid, Info} ->
            ?DEBUG("Worker failed: ~p\n", [Info]),
            ?FAIL
    end.

compile_worker(QueuePid, Config, CompileFn) ->
    QueuePid ! {next, self()},
    receive
        {compile, Source} ->
            case catch(compile(Source, Config, CompileFn)) of
                ok ->
                    QueuePid ! {compiled, Source},
                    compile_worker(QueuePid, Config, CompileFn);
                skipped ->
                    QueuePid ! {skipped, Source},
                    compile_worker(QueuePid, Config, CompileFn);
                Error ->
                    QueuePid ! {fail, [{error, Error},
                                       {source, Source}]},
                    ok
            end;

        empty ->
            ok
    end.