namespace Gen7 {
    [Move effect=Assist]
    class Assist : PkmnScript {
        void ChangeAttack(MoveTurnChoice@ move, constString &inout moveName) override {
            auto user = move.User;
            auto battle = user.Battle;
            auto party = battle.FindPartyForPokemon(user).Party;
            array<const MoveData@> possibleMoves;
            for (uint64 i = 0; i < party.Length; i++){
                auto mon = party.GetAtIndex(i);
                if (mon is null){ continue; }
                if (mon is user){ continue; }
                auto moves = mon.Moves;
                for (uint64 j = 0; j < moves.Length; j++){
                    auto m = moves[j];
                    if (m is null){ continue; }
                    if (CopyableMoves::CanCopyMove(m.MoveData)){
                        possibleMoves.insertLast(m.MoveData);
                    }
                }
            } 
            if (possibleMoves.length == 0){
                // TODO: Log failure.
                return;
            }
            auto i = battle.Random.Get(possibleMoves.length);
            moveName = possibleMoves[i].Name;
        }
    }
}

#if TESTS
[Test name="Assist: Switch move to known move from party member"]
void Assist_ChangesMove(){
    auto p1 = CreateSimpleParty({"charizard", "blastoise"}, 100);
    auto p2 = CreateSimpleParty({"venusaur", "pikachu"}, 100);

    auto battle = CreateSimpleBattle(684, p1, p2);
    p1.GetAtIndex(1).LearnMove("bubble_beam");
    auto choice = CreateMoveTurnChoice("assist", p1.GetAtIndex(0), 1, 0);
    constString moveName = "assist";
    auto script = cast<Gen7::Assist>(CreateMoveScript("Assist"));
    script.ChangeAttack(choice, moveName);
    RequireEquals("bubble_beam", moveName);
}

[Test name="Assist: Doesn't switch when move can't be copied"]
void Assist_CantSwitchIntoNonCopyable(){
    auto p1 = CreateSimpleParty({"charizard", "blastoise"}, 100);
    auto p2 = CreateSimpleParty({"venusaur", "pikachu"}, 100);

    auto battle = CreateSimpleBattle(684, p1, p2);
    p1.GetAtIndex(1).LearnMove("dig");
    auto choice = CreateMoveTurnChoice("assist", p1.GetAtIndex(0), 1, 0);
    constString moveName = "assist";
    auto script = cast<Gen7::Assist>(CreateMoveScript("Assist"));
    script.ChangeAttack(choice, moveName);
    RequireEquals("assist", moveName);
}

[Test name="Assist: Doesn't switch if no move"]
void Assist_CantSwitchWhenNoOptions(){
    auto p1 = CreateSimpleParty({"charizard", "blastoise"}, 100);
    auto p2 = CreateSimpleParty({"venusaur", "pikachu"}, 100);

    auto battle = CreateSimpleBattle(684, p1, p2);
    auto choice = CreateMoveTurnChoice("assist", p1.GetAtIndex(0), 1, 0);
    constString moveName = "assist";
    auto script = cast<Gen7::Assist>(CreateMoveScript("Assist"));
    script.ChangeAttack(choice, moveName);
    RequireEquals("assist", moveName);
}

#endif