program day5
    implicit none
    integer, parameter :: i_kind = selected_int_kind(20)
    integer, parameter :: max_chars = 300
    integer, parameter :: max_iter = 20
    character(200) :: fname
    character(max_chars) :: fline
    integer :: n_arguments
    integer :: istat
    integer(kind=i_kind), allocatable :: seedvals(:)
    integer(kind=i_kind), allocatable :: dat_source(:), dat_dest(:)
    integer(kind=i_kind) :: ldat(1:3)
    logical, allocatable :: dat_point_found(:)
    integer :: pos_col, num_seeds, num_chars, i, sec
    integer(kind=i_kind) :: s_min, d_min, r_len, source_val
    integer(kind=i_kind) :: min_val
    integer :: min_index

    print *, "Number of bits: ", i_kind * 8
    n_arguments = command_argument_count()
    if (n_arguments .eq. 1) then
        call get_command_argument(1, fname)
        print *, "File: ", trim(fname)
        print *
    else
        print *, "Wrong number of arguments: ", n_arguments
        stop
    end if

    open(10, file=fname)
    read(10, "(A)", iostat = istat) fline
    pos_col = scan(fline, ":")
    num_seeds = 0
    num_chars = len_trim(fline)
    do i=pos_col + 1,num_chars
        if (fline(i:i) .eq. ' ') then
            num_seeds = num_seeds + 1
        end if
    end do
    print *, "Number of seeds: ", num_seeds
    allocate(seedvals(1:num_seeds))
    allocate(dat_source(1:num_seeds))
    allocate(dat_dest(1:num_seeds))
    allocate(dat_point_found(1:num_seeds))

    read(fline((pos_col + 1):(num_chars)), *) seedvals

    read(10, "(A)", iostat = istat) fline
    dat_dest = seedvals
    do sec=1, max_iter
        dat_source = dat_dest
        dat_dest = 0
        dat_point_found = .false.
        read(10, "(A)", iostat = istat) fline
        if (is_iostat_end(istat)) then
            exit
        end if
        do
            read(10, "(A)", iostat = istat) fline
            num_chars = len_trim(fline)
            if (is_iostat_end(istat) .or. (num_chars .eq. 0)) then
                exit
            end if
            read(fline, *) ldat
            s_min = ldat(2)
            d_min = ldat(1)
            r_len = ldat(3)
            do i=1,num_seeds
                source_val = dat_source(i)
                if ((source_val .ge. s_min) .and. (source_val .lt. (s_min + r_len))) then
                    dat_point_found(i) = .true.
                    dat_dest(i) = source_val - s_min + d_min
                    !write(*, 20) ldat(1), ldat(2), ldat(3), source_val, dat_dest(i)
                end if
            end do
        end do
        do i=1,num_seeds
            if (.not. dat_point_found(i)) then
                dat_dest(i) = dat_source(i)
                !write(*, 21) i, dat_dest(i), dat_dest(i)
            end if
        end do
        !print *
        if (is_iostat_end(istat)) then
            exit
        end if
    end do
    close(10)

    min_val = huge(min_val)
    min_index = -1
    do i=1,num_seeds
        if (dat_dest(i) .lt. min_val) then
            min_index = 1
            min_val = dat_dest(i)
        end if
    end do
    print "(a, i11)", "Minimum location number: ", min_val


    deallocate(seedvals)
    deallocate(dat_source)
    deallocate(dat_dest)
    deallocate(dat_point_found)

!20  format(i4, i4, i4, ': ', i4, ' -> ', i4)
!21  format(i4, ': ', i4, ' -> ', i4)

end program day5