#!/usr/bin/env escript
%% -*- mode: erlang;erlang-indent-level: 4;indent-tabs-mode: nil -*-
%% ex: ft=erlang ts=4 sw=4 et

main(_Args) ->
    %% Fetch and build deps required to build rebar3
    BaseDeps = [{providers, []}
               ,{getopt, []}
               ,{erlware_commons, ["ec_dictionary.erl", "ec_vsn.erl"]}],
    Deps = get_deps(),
    [fetch_and_compile(Dep, Deps) || Dep <- BaseDeps],

    %% Build rebar3 modules with compile:file
    bootstrap_rebar3(),

    %% Build rebar.app from rebar.app.src
    {ok, App} = rebar_app_info:new(rebar, "3.0.0", filename:absname("_build/default/lib/rebar/")),
    rebar_otp_app:compile(rebar_state:new(), App),

    %% Because we are compiling files that are loaded already we want to silence
    %% not_purged errors in rebar_erlc_compiler:opts_changed/1
    error_logger:tty(false),

    setup_env(),
    os:putenv("REBAR_PROFILE", "bootstrap"),
    {ok, State} = rebar3:run(["compile"]),
    reset_env(),
    os:putenv("REBAR_PROFILE", ""),
    %% Build erlydtl files (a hook on compile in the default profile) and escript file
    DepsPaths = rebar_state:code_paths(State, all_deps),
    code:add_pathsa(DepsPaths),

    rebar3:run(["clean", "-a"]),
    rebar3:run(["escriptize"]),

    %% Done with compile, can turn back on error logger
    error_logger:tty(true),

    %% Finally, update executable perms for our script on *nix,
    %%  or write out script files on win32.
    ec_file:copy("_build/default/bin/rebar3", "./rebar3"),
    case os:type() of
        {unix,_} ->
            [] = os:cmd("chmod u+x rebar3"),
            ok;
        {win32,_} ->
            write_windows_scripts(),
            ok;
        _ ->
            ok
    end.

fetch_and_compile({Name, ErlFirstFiles}, Deps) ->
    {Name, _, Repo} = lists:keyfind(Name, 1, Deps),
    ok = fetch(Repo, Name),
    compile(Name, ErlFirstFiles).

fetch({git, Url, Source}, App) ->
    Dir = filename:join([filename:absname("_build/default/lib/"), App]),
    case filelib:is_dir(Dir) of
        true ->
            true = code:add_path(filename:join(Dir, "ebin")),
            ok;
        false ->
            fetch_source(Dir, Url, Source),
            ok
    end.

fetch_source(Dir, Url, {ref, Ref}) ->
    ok = filelib:ensure_dir(Dir),
    os:cmd(io_lib:format("git clone ~s ~s", [Url, Dir])),
    {ok, Cwd} = file:get_cwd(),
    file:set_cwd(Dir),
    os:cmd(io_lib:format("git checkout -q ~s", [Ref])),
    file:set_cwd(Cwd);
fetch_source(Dir, Url, {_, Branch}) ->
    ok = filelib:ensure_dir(Dir),
    os:cmd(io_lib:format("git clone ~s ~s -b ~s --single-branch",
                         [Url, Dir, Branch])).

compile(App, FirstFiles) ->
    Dir = filename:join(filename:absname("_build/default/lib/"), App),
    filelib:ensure_dir(filename:join([Dir, "ebin", "dummy.beam"])),
    code:add_path(filename:join(Dir, "ebin")),
    FirstFilesPaths = [filename:join([Dir, "src", Module]) || Module <- FirstFiles],
    Sources = FirstFilesPaths ++ filelib:wildcard(filename:join([Dir, "src", "*.erl"])),
    [compile:file(X, [{i, filename:join(Dir, "include")}
                     ,{outdir,  filename:join(Dir, "ebin")}
                     ,return]) || X <- Sources].

bootstrap_rebar3() ->
    filelib:ensure_dir("_build/default/lib/rebar/ebin/dummy.beam"),
    file:make_symlink(filename:absname("src"), filename:absname("_build/default/lib/rebar/src")),
    Sources = filelib:wildcard("src/*.erl"),
    [compile:file(X, [{outdir, "_build/default/lib/rebar/ebin/"}]) || X <- Sources],
    code:add_path(filename:absname("_build/default/lib/rebar/ebin")).

setup_env() ->
    %% We don't need or want erlydtl or relx providers loaded yet
    application:load(rebar),
    {ok, Providers} = application:get_env(rebar, providers),
    Providers1 = Providers -- [rebar_prv_erlydtl_compiler,
                               rebar_prv_release,
                               rebar_prv_tar],
    application:set_env(rebar, providers, Providers1).

reset_env() ->
    %% Reset the env so we get all providers and can build erlydtl files
    application:unset_env(rebar, providers),
    application:unload(rebar),
    application:load(rebar).

write_windows_scripts() ->
    CmdScript=
        "@echo off\r\n"
        "setlocal\r\n"
        "set rebarscript=%~f0\r\n"
        "escript.exe \"%rebarscript:.cmd=%\" %*\r\n",
    ok = file:write_file("rebar3.cmd", CmdScript).

get_deps() ->
    case file:consult("rebar.lock") of
        {ok, [Deps]} ->
            [{binary_to_atom(Name, utf8), "", Source} || {Name, Source, _Level} <- Deps];
        _ ->
            {ok, Config} = file:consult("rebar.config"),
            proplists:get_value(deps, Config)
    end.