# Metadata-only ABI triage so the full build avoids downloading every source.
# Mirrors bincraft::abi_classify rules 1-2; "ambiguous" packages still need a
# source grep via bincraft::needs_per_minor_recompile().

classify_from_metadata <- function(needs_compilation, linking_to, risky_deps) {
  nc <- if (length(needs_compilation) == 0L || is.na(needs_compilation)) {
    ""
  } else {
    tolower(trimws(needs_compilation))
  }
  if (!identical(nc, "yes")) {
    return("not-sensitive")
  }
  lt <- if (length(linking_to) == 0L || is.na(linking_to)) "" else linking_to
  linked <- trimws(unlist(strsplit(lt, "[,\n]")))
  linked <- sub("\\s*\\(.*\\)$", "", linked) # strip "(>= x)" constraints
  linked <- linked[nzchar(linked)]
  if (any(linked %in% risky_deps)) {
    return("sensitive")
  }
  "ambiguous"
}

parse_build_args <- function(args) {
  sensitive_only <- "--sensitive-only" %in% args
  pos <- args[!startsWith(args, "--")]
  list(
    sensitive_only = sensitive_only,
    split_into = as.integer(pos[1L]),
    split_index = as.integer(pos[2L]),
    ncpus = as.integer(pos[3L])
  )
}

# Bound the {pkgcache} metadata dir, which otherwise grows without limit: the
# "patched" repo mints a new content hash on every PACKAGES change, so each build
# writes a fresh ~70 MB _metadata/pkgs-<hash>.rds (+ patched-<hash>/) that is
# never reused. Keep the `keep` newest entries by mtime; only remove entries
# older than `min_age_secs`, so a concurrent split-job's in-flight files are
# never deleted (each build uses a unique hash, so aged entries are
# unreferenced). Stable repo dirs (CRAN-*, BioC*, INLA-*) and pkg/ downloads are
# not matched and thus preserved. Returns the number of entries removed.
trim_pkgcache_metadata <- function(cache_dir = Sys.getenv("R_PKG_CACHE_DIR"),
                                   keep = 20L,
                                   min_age_secs = 600) {
  meta <- file.path(cache_dir, "R", "pkgcache", "_metadata")
  if (!nzchar(cache_dir) || !dir.exists(meta)) {
    return(0L)
  }
  entries <- c(
    Sys.glob(file.path(meta, "patched-*")),
    Sys.glob(file.path(meta, "pkgs-*.rds"))
  )
  if (length(entries) == 0L) {
    return(0L)
  }
  info <- file.info(entries)
  order_new_first <- order(info$mtime, decreasing = TRUE)
  ranked <- entries[order_new_first]
  ranked_mtime <- info$mtime[order_new_first]
  if (length(ranked) <= keep) {
    return(0L)
  }
  candidates <- ranked[(keep + 1L):length(ranked)]
  candidate_age <- as.numeric(Sys.time()) - as.numeric(ranked_mtime[(keep + 1L):length(ranked)])
  removable <- candidates[candidate_age >= min_age_secs]
  if (length(removable) == 0L) {
    return(0L)
  }
  unlink(removable, recursive = TRUE, force = TRUE)
  length(removable)
}