%% -*- erlang-indent-level: 4;indent-tabs-mode: nil -*-
%% ex: ts=4 sw=4 et
%%
%% This file is part of Triq - Trifork QuickCheck
%%
%% Copyright (c) 2010-2013 by Trifork
%% Copyright 2013-2018 Triq authors
%%
%% Licensed 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.

-module(triq_fsm).

-export([commands/1,
         commands/2,
         run_commands/2,
         run_commands/3,
         state_names/1]).
-import(triq_expr,
        [eval/2]).


%% FSM API

commands(Module) when is_atom(Module) ->
    triq_statem_fsm:commands(Module).

commands(Module, {InitialName, State}) when is_atom(Module) ->
    triq_statem_fsm:commands(Module, {InitialName, State}).

run_commands(Module, Commands) ->
    run_commands(Module, Commands, []).

run_commands(Module,Commands,Env) ->
    do_run_command(Commands,
                   Env,
                   Module,
                   [],
                   triq_fsm_stub:initial_state(Module)).

do_run_command(Commands, Env, Module, History, State) ->
    case Commands of
        [] ->
            {History, eval(Env,State), ok};

        [{init,S}|Rest] ->
            do_run_command(Rest, Env, Module, History, S);

        [{set, {var,V}=Var, {call,M,F,A}=SymCall}|Rest] ->
            M2=eval(Env,M),
            F2=eval(Env,F),
            A2=eval(Env,A),

            %% Same as eval(Env, SymCall), but we need to log in History.
            Res = apply(M2,F2,A2),

            SubstCall = {call, M2,F2,A2},
            {Name, _} = State,
            History2 = [{{Name,SubstCall},Res}|History],

            case triq_fsm_stub:postcondition(Module,State,SubstCall,Res) of
                true ->
                    Env2 = [{V,Res}|proplists:delete(V,Env)],
                    State2 = triq_fsm_stub:next_state(Module,State,Var,SymCall),
                    do_run_command(Rest, Env2, Module, History2, State2);

                Other ->
                    {History, eval(Env,State), {postcondition, Other}}
            end
    end.

state_names(H) ->
    [N || {{N,_},_} <- H].