program day2
    implicit none
    integer, parameter :: max_games = 100
    integer, parameter :: max_subgames = 100
    integer, parameter :: max_cdraws = 3
    integer, parameter :: max_chars = 10000
    integer, parameter :: max_red = 12
    integer, parameter :: max_green = 13
    integer, parameter :: max_blue = 14
    integer :: game, subgame, cdraw
    integer :: game_red, game_green, game_blue
    integer :: ca_1, ca_2
    integer :: cb_1, cb_2
    integer :: n_arguments
    character(max_chars) :: GameLine
    integer :: tLLen
    character(200) :: fname
    logical :: f_col, game_poss
    integer :: cubes
    integer :: sum_games, game_power, sum_power
    n_arguments = command_argument_count()
    if (n_arguments .eq. 1) then
        call get_command_argument(1, fname)
        print *, "File: ", fname
    else
        print *, "Wrong number of arguments: ", n_arguments
        stop
    end if
    open(10, file=fname)
    sum_games = 0
    sum_power = 0
    do game=1,max_games
        read(10, "(a)") GameLine
        tLLen = len_trim(GameLine)
        if (tLLen .eq. 0) then
            continue
        end if
        f_col = .false.
        ca_2 = index(GameLine, ':')
        if ((ca_2 .eq. 0) .or. (ca_2 .ge. tLLen)) then
            continue
        end if
        game_poss = .true.
        game_red = 0
        game_green = 0
        game_blue = 0
        do subgame=1,max_subgames
            ca_1 = ca_2
            if (ca_1 .ge. tLLen) then
                exit
            end if
            ca_2 = index(GameLine((ca_1 + 1):tLLen), ';')
            if (ca_2 .eq. 0) then
                ca_2 = tLLen
            else
                ca_2 = ca_1 + ca_2
            end if

            cb_2 = ca_1
            do cdraw=1,max_cdraws
                cb_1 = cb_2
                if (cb_1 .eq. ca_2) then
                    exit
                end if
                cb_2 = index(GameLine(cb_1 + 1:ca_2), ',')
                if (cb_2 .eq. 0) then
                    cb_2 = ca_2
                else
                    cb_2 = cb_1 + cb_2
                end if
                read(GameLine((cb_1 + 1):cb_2), *) cubes
                if (index(GameLine((cb_1 + 1):cb_2), "red") .ne. 0) then
                    if (cubes .gt. max_red) then
                        game_poss = .false.
                    end if
                    if (cubes .gt. game_red) then
                        game_red = cubes
                    end if
                else if (index(GameLine((cb_1 + 1):cb_2), "green") .ne. 0) then
                    if (cubes .gt. max_green) then
                        game_poss = .false.
                    end if
                    if (cubes .gt. game_green) then
                        game_green = cubes
                    end if
                else
                    if (cubes .gt. max_blue) then
                        game_poss = .false.
                    end if
                    if (cubes .gt. game_blue) then
                        game_blue = cubes
                    end if
                end if
            end do
        end do
        game_power = game_red * game_green * game_blue
        sum_power = sum_power + game_power
        if (game_poss) then
            print *, "Possible game! ", game, " Power = ", game_power
            sum_games = sum_games + game
        else
            print *, "Not possible. Power = ", game_power
        end if
    end do
    print *, "Sum of possible games: ", sum_games
    print *, "Sum of game powers: ", sum_power
    close(10)
end program day2