1	import Base
2	import ../../../effs/io.bend as X
3	import ../../../plan/type.bend as P
4	import ./type.bend as Br
5	import ./ops.bend as BrO
6	
7	# Homebrew as it is, and what applying the declared entries would change. Only brew bundle's read-only
8	# commands run: dump writes its temporary Brewfile, check and cleanup (without --force) only report.
9	
10	def declared_file() -> String:
11	  "/tmp/v-declared.Brewfile"
12	
13	def observed_file() -> String:
14	  "/tmp/v-observed.Brewfile"
15	
16	# brew bundle exits 1 when something is missing or would be removed, and says what: Base's Process.run
17	# keeps the output of a failing program.
18	def bundle(args: List<String>) -> IO(Result<&1, &1, U32 & String, U32 & (String & String)>):
19	  Process.run("brew", "bundle" <> args, "", 67108864, 600000)
20	
21	# ---- installs: `brew bundle check --verbose` says "→ Formula x needs to be installed." per entry ----
22	def text_before(cs: List<&2, Char>, +pat: String) -> String:
23	  match cs:
24	    case []:
25	      ""
26	    case +c <> +rest:
27	      Bool.pick(String, String.starts_with(String.from_list(c <> rest), pat), "", String.from_list([c]) ++ text_before(rest, pat))
28	
29	def missing(ls: List<&2, String>) -> List<&2, P.Step>:
30	  match ls:
31	    case []:
32	      []
33	    case l <> rest:
34	      +t = String.trim(l)
35	      List.append(&2, P.Step,
36	        Bool.pick(List<&2, P.Step>, String.starts_with(t, "→ "),
37	          [P.Change{"homebrew", "(absent)", text_before(String.to_list(String.drop(t, 2n)), " needs to be ")}], []),
38	        missing(rest))
39	
40	def some_or(+xs: List<&2, P.Step>, +f: String) -> List<&2, P.Step>:
41	  Bool.pick(List<&2, P.Step>, List.is_empty(&2, P.Step, xs),
42	    [P.Change{"homebrew", "declared entries missing", "see brew bundle check --verbose --file " ++ f}], xs)
43	
44	def installs(r: Result<&1, &1, U32 & String, U32 & (String & String)>, +f: String) -> List<&2, P.Step>:
45	  match r:
46	    case Done{(status, (_, err))}:
47	      Bool.pick(List<&2, P.Step>, U32.is_eq(status, 0), [], some_or(missing(String.lines(err)), f))
48	    case Fail{_}:
49	      [P.Blocked{"homebrew", "brew bundle check could not run"}]
50	
51	# ---- removals: `brew bundle cleanup` lists them under "Would uninstall casks:", "Would untap:" and so on ----
52	def label_of(+heading: String) -> String:
53	  Bool.pick(String, String.eq(heading, "casks"), "Cask",
54	    Bool.pick(String, String.eq(heading, "formulae"), "Formula", heading))
55	
56	# The label of the section a line starts, the current one for an entry, or "" outside any section.
57	def section(+l: String, +label: String) -> String:
58	  Bool.pick(String, String.starts_with(l, "Would uninstall ") && String.ends_with(l, ":"),
59	    label_of(String.take(String.drop(l, 16n), Nat.sub(String.length(l), 17n))),
60	    Bool.pick(String, String.eq(l, "Would untap:"), "Tap",
61	      Bool.pick(String, String.is_empty(l) || String.starts_with(l, "Would ") || String.starts_with(l, "Run ") || String.starts_with(l, "==>"), "", label)))
62	
63	def removals(ls: List<&2, String>, +label: String) -> List<&2, P.Step>:
64	  match ls:
65	    case []:
66	      []
67	    case l <> rest:
68	      +t = String.trim(l)
69	      +next = section(t, label)
70	      List.append(&2, P.Step,
71	        Bool.pick(List<&2, P.Step>, Bool.not(String.is_empty(label)) && String.eq(next, label) && Bool.not(String.is_empty(t)),
72	          [P.Change{"homebrew", label ++ " " ++ t, "(absent)"}], []),
73	        removals(rest, next))
74	
75	def removed(r: Result<&1, &1, U32 & String, U32 & (String & String)>) -> List<&2, P.Step>:
76	  match r:
77	    case Done{(_, (out, _))}:
78	      removals(String.lines(out), "")
79	    case Fail{_}:
80	      [P.Blocked{"homebrew", "brew bundle cleanup could not run"}]
81	
82	# What applying the declared entries would install and remove.
83	def changes(brews: List<&2, Br.Brew>) -> IO(List<&2, P.Step>):
84	  do IO<List<&2, P.Step>>:
85	    X.write(declared_file(), BrO.brewfile(brews))
86	    c : Result<&1, &1, U32 & String, U32 & (String & String)> <- bundle(["check", "--no-upgrade", "--verbose", "--file", declared_file()])
87	    r : Result<&1, &1, U32 & String, U32 & (String & String)> <- bundle(["cleanup", "--file", declared_file()])
88	    return List.append(&2, P.Step, installs(c, declared_file()), removed(r))
89	
90	# The Mac's Homebrew entries, as `brew bundle dump` writes them.
91	def observed() -> IO(List<&2, Br.Brew>):
92	  do IO<List<&2, Br.Brew>>:
93	    ok : Bool <- X.succeeds("brew", ["bundle", "dump", "--force", "--file=" ++ observed_file()])
94	    text : String <- X.read(observed_file())
95	    return Bool.pick(List<&2, Br.Brew>, ok, BrO.of_brewfile(text), [])