with Ada.Text_IO; use Ada.Text_IO;
with Ada.Containers.Vectors;

procedure Day_3 is

    type Mul is
        record
            X : Integer;
            Y : Integer;
        end record;

    type Muls is array (Natural range <>) of Mul;

    package mul_vec is new Ada.Containers.Vectors(
        Index_Type => Natural, Element_Type => Mul);

    procedure Find_Muls( S : String; Vec : in out mul_vec.Vector ) is

        type State_Machine is (
            Start,
            Bracket_Open,
            First_Num,
            Second_Num
        );

        State : State_Machine := Start;
        Index : Natural := S'First;
        Num_Start : Natural;
        FNum_Length, SNum_Length : Natural := 0;
        First, Second : Integer;

    begin

        State_Loop:
        while Index <= S'Last loop
            case State is
                when Start =>
                    if Index + 2 > S'Last then
                        exit State_Loop;
                    end if;
                    if S(Index .. Index + 2) = "mul" then
                        State := Bracket_Open;
                        FNum_Length := 0;
                        SNum_Length := 0;
                        Index := @ + 2;
                    end if;
                    Index := @ + 1;
                when Bracket_Open =>
                    if S(Index) = '(' then
                        State := First_Num;
                        Num_Start := Index + 1;
                    else
                        State := Start;
                    end if;
                    Index := @ + 1;
                when First_Num =>
                    case S(Index) is
                        when ',' =>
                            First := Integer'Value(S(Num_Start .. Index - 1));
                            State := Second_Num;
                            Num_Start := Index + 1;
                            Index := @ + 1;
                        when '0' .. '9' =>
                            FNum_Length := @ + 1;
                            Index := @ + 1;
                        when others =>
                            State := Start;
                    end case;

                    if FNum_Length > 3 then
                        State := Start;
                    end if;
                when Second_Num =>
                    case S(Index) is
                        when ')' =>
                            Second := Integer'Value(S(Num_Start .. Index - 1));
                            State := Start;
                            Num_Start := Index + 1;
                            Vec.Append(
                                Mul'(X => First, Y => Second)
                            );
                            Index := @ + 1;
                        when '0' .. '9' =>
                            SNum_Length := @ + 1;
                            Index := @ + 1;
                        when others =>
                            State := Start;
                    end case;

                    if SNum_Length > 3 then
                        State := Start;
                    end if;
            end case;
        end loop State_Loop;

    end Find_Muls;

    procedure Find_Muls_Cond( S : String; Vec : in out mul_vec.Vector; Enabled : in out Boolean ) is

        type State_Machine is (
            Start,
            Bracket_Open,
            First_Num,
            Second_Num
        );

        State : State_Machine := Start;
        Index : Natural := S'First;
        Num_Start : Natural;
        FNum_Length, SNum_Length : Natural := 0;
        First, Second : Integer;

    begin
        State_Loop:
        while Index <= S'Last loop
            if Index + 7 < S'Last then
                if S(Index .. Index + 3) = "do()" then
                    Put_Line(S(Index .. Index + 3));
                    Index := @ + 4;
                    Enabled := True;
                elsif S(Index .. Index + 6) = "don't()" then
                    Put_Line(S(Index .. Index + 6));
                    Enabled := False;
                    State := Start;
                    Index := @ + 7;
                end if;
            end if;

            case State is
                when Start =>
                    if Index + 2 > S'Last then
                        exit State_Loop;
                    end if;
                    if S(Index .. Index + 2) = "mul" then
                        State := Bracket_Open;
                        FNum_Length := 0;
                        SNum_Length := 0;
                        Index := @ + 2;
                    end if;
                    Index := @ + 1;
                when Bracket_Open =>
                    if S(Index) = '(' then
                        State := First_Num;
                        Num_Start := Index + 1;
                    else
                        State := Start;
                    end if;
                    Index := @ + 1;
                when First_Num =>
                    case S(Index) is
                        when ',' =>
                            First := Integer'Value(S(Num_Start .. Index - 1));
                            State := Second_Num;
                            Num_Start := Index + 1;
                            Index := @ + 1;
                        when '0' .. '9' =>
                            FNum_Length := @ + 1;
                            Index := @ + 1;
                        when others =>
                            State := Start;
                    end case;

                    if FNum_Length > 3 then
                        State := Start;
                    end if;
                when Second_Num =>
                    case S(Index) is
                        when ')' =>
                            Second := Integer'Value(S(Num_Start .. Index - 1));
                            State := Start;
                            Num_Start := Index + 1;
                            if Enabled then
                                Put_Line("mul(" & First'Image & "," & Second'Image & ")");
                                Vec.Append(
                                    Mul'(X => First, Y => Second)
                                );
                            else
                                Put_Line("Disabled");
                            end if;
                            Index := @ + 1;
                        when '0' .. '9' =>
                            SNum_Length := @ + 1;
                            Index := @ + 1;
                        when others =>
                            State := Start;
                    end case;

                    if SNum_Length > 3 then
                        State := Start;
                    end if;
            end case;
        end loop State_Loop;
    end Find_Muls_Cond;

    function Read_File( File_Name : String; cond : Boolean ) return Muls is
        File : File_Type;
        Vec : mul_vec.Vector;
        Enabled : Boolean := True;
    begin
        Open(File, In_File, File_Name);

        while not End_Of_File(File) loop
            if cond then
                Find_Muls_cond(Get_Line(File), Vec, Enabled);
            else
                Find_Muls(Get_Line(File), Vec);
            end if;
        end loop;

        Close(File);

        return M : Muls( 0 .. Integer(Vec.Length) - 1) do
            for I in 0 .. Integer(Vec.Length) - 1 loop
                M(I) := Vec(I);
            end loop;
        end return;

    end Read_File;

    function Day_1_1( M : Muls ) return Integer is
        Sum : Integer := 0;
    begin
        For Mult of M loop
            Sum := @ + Mult.X * Mult.Y;
        end loop;

        return Sum;
    end Day_1_1;

    File_Name : String := "input_day_3.txt";

begin

    Put_Line(Day_1_1(Read_File(File_Name, False))'Image);
    Put_Line(Day_1_1(Read_File(File_Name, True))'Image);

end Day_3;