USING: assocs assocs.extras grouping.extras io.encodings.ascii
io.files kernel literals math math.parser multiline namespaces
peg peg.ebnf prettyprint sequences sorting strings ;
IN: aoc2022.day07

CONSTANT: total-space 70,000,000
CONSTANT: update-size 30,000,000

CONSTANT: input $[
    "vocab:aoc2022/day07/input.txt" ascii file-lines
]

SYMBOLS: files cwd ;
H{ } clone files set-global
V{ } clone cwd set-global

EBNF: construct-files [=[
  cdin = "$ cd "~ .+ => [[ cwd swap '[ _ >string suffix! ] change ignore ]]
  cdout = "$ cd .." => [[ cwd [ dup pop* ] change ignore ]]
  cd = cdout | cdin
  ls = "$ ls"~
  dir = "dir "~ (.+)~
  num = [0-9]+ => [[ dec> ]]
  file = num:n " "~ (.+)~ => [[ cwd get head-clump [ concat ] map [ n swap files get at+ ] each ignore ]]
  output = file | cd | ls | dir
]=]

: part1 ( -- )
    input [ construct-files drop ] each files get
    [ 100,000 <= ] filter-values sum-values . ;

: unused-space ( -- n ) total-space "/" files get at - ;
: target-deletion ( -- n ) update-size unused-space - ;

: part2 ( -- )
    files get values natural-sort
    target-deletion '[ _ >= ] find nip . ;

: day07 ( -- ) part1 part2 ;

MAIN: day07