! 2022 nomennescio
USING: accessors combinators io.encodings.utf8 io.files kernel math math.parser prettyprint sequences splitting ;
IN: aoc2022

TUPLE: file size name ;
TUPLE: dir name parent entries ;
UNION: entry file dir ;

GENERIC: size ( entry -- size )

M: file size size>> ;
M: dir size entries>> [ size ] map-sum ;

GENERIC: sizes<=n ( n seq entry -- n seq' )

M: file sizes<=n drop ;
M: dir sizes<=n [ entries>> [ sizes<=n ] each ] [ size ] bi dup reach <= [ suffix ] [ drop ] if ;

GENERIC: sizes>=n ( n seq entry -- n seq' )

M: file sizes>=n drop ;
M: dir sizes>=n [ entries>> [ sizes>=n ] each ] [ size ] bi dup reach >= [ suffix ] [ drop ] if ;

: prefix? ( string prefix -- ? ) subseq-index 0 = ;
: cd ( cwd dir -- cwd' ) swap entries>> [ name>> over = ] find 2nip ;
: add-entry ( cwd entry -- cwd' ) over entries>> push ;
: add-dir ( cwd name -- cwd' ) over V{ } clone dir boa add-entry ;
: add-file ( cwd size name -- cwd' ) file boa add-entry ;
: parse-line ( root cwd line -- root' cwd' )
  {
    { [ dup "$ ls" = ] [ drop ] }
    { [ dup "$ cd /" = ] [ drop ] }
    { [ dup "$ cd .." = ] [ drop parent>> ] }
    { [ dup "$ cd " prefix? ] [ 5 tail cd ] }
    { [ dup "dir " prefix? ] [ 4 tail add-dir ] }
    [ " " split1 [ dec> ] dip add-file ]
  } cond ;
: parse-file ( path encoding -- root ) file-lines [ "/" f V{ } clone dir boa dup ] dip [ parse-line ] each drop ;
: part1 ( root -- size )  [ 100000 { } clone ] dip sizes<=n sum nip ;
: part2 ( root -- size ) [ 30000000 70000000 ] dip [ size - - { } clone ] keep sizes>=n infimum nip ;
: day7 ( -- ) "input-7.txt" utf8 parse-file [ part1 . ] [ part2 . ] bi ;

MAIN: day7