USING: arrays combinators continuations grouping hash-sets
io.encodings.utf8 io.files kernel math math.parser math.vectors
multiline namespaces peg.ebnf prettyprint ranges sequences sets
;
IN: aoc.14

: input ( -- lines ) "~/factor/aoc/14/test.in" utf8 file-lines ;
EBNF: parse [=[
  num   = [0-9]+ => [[ dec> ]]
  coord = num ","~ num
  cave  = (coord " -> "*~)+ => [[ 2 clump ]]
]=]
SYMBOL: floor
: I ( -- hashset ) input [ parse ] map concat [ concat [ second ] map supremum 2 + floor namespaces:set ] keep
    [ first2 [ [a..b] ] 2map first2 cartesian-product concat ] map concat >hash-set ;

DEFER: dfs
: search-neighbours ( hashset coord -- hashset )
    [ { [ { 0 1 } v+ ] [ { -1 1 } v+ ] [ { 1 1 } v+ ] } cleave 3array [ dfs ] each ] keep over adjoin ;
SYMBOL: fn
: dfs ( hashset coord -- hashset )
    fn get call( -- )
    2dup [ swap in? ] [ nip second floor get = ] 2bi or [ drop ] [ search-neighbours ] if ;
: (part) ( quot -- n ) fn namespaces:set I [ dup clone { 500 0 } dfs ] [ ] recover [ cardinality ] bi@ swap - ;
: part1 ( -- n ) [ [ second floor get = [ throw ] when ] keep ] (part) ;
: part2 ( -- n ) [                                            ] (part) ;

: solve ( -- ) part1 . part2 . ;