# typed: strict
# frozen_string_literal: true

module OS
  module Linux
    # Helper functions for querying `ld` information.
    module Ld
      sig { returns(String) }
      def self.brewed_ld_so_diagnostics
        @brewed_ld_so_diagnostics ||= T.let({}, T.nilable(T::Hash[Pathname, String]))

        brewed_ld_so = HOMEBREW_PREFIX/"lib/ld.so"
        return "" unless brewed_ld_so.exist?

        brewed_ld_so_target = brewed_ld_so.readlink
        @brewed_ld_so_diagnostics[brewed_ld_so_target] ||= begin
          ld_so_output = Utils.popen_read(brewed_ld_so, "--list-diagnostics")
          ld_so_output if $CHILD_STATUS.success?
        end

        @brewed_ld_so_diagnostics[brewed_ld_so_target].to_s
      end

      sig { returns(String) }
      def self.sysconfdir
        fallback_sysconfdir = "/etc"

        match = brewed_ld_so_diagnostics.match(/path.sysconfdir="(.+)"/)
        return fallback_sysconfdir unless match

        match.captures.compact.first || fallback_sysconfdir
      end

      sig { returns(T::Array[String]) }
      def self.system_dirs
        dirs = []

        brewed_ld_so_diagnostics.split("\n").each do |line|
          match = line.match(/path.system_dirs\[0x.*\]="(.*)"/)
          next unless match

          dirs << match.captures.compact.first
        end

        dirs
      end

      sig { params(conf_path: T.any(Pathname, String)).returns(T::Array[String]) }
      def self.library_paths(conf_path = Pathname(sysconfdir)/"ld.so.conf")
        conf_file = Pathname(conf_path)
        return [] unless conf_file.exist?

        paths = Set.new
        directory = conf_file.realpath.dirname

        conf_file.readlines.each do |line|
          # Remove comments and leading/trailing whitespace
          line.strip!
          line.sub!(/\s*#.*$/, "")

          if line.start_with?(/\s*include\s+/)
            include_path = Pathname(line.sub(/^\s*include\s+/, "")).expand_path
            wildcard = include_path.absolute? ? include_path : directory/include_path

            Dir.glob(wildcard.to_s).each do |include_file|
              paths += library_paths(include_file)
            end
          elsif line.empty?
            next
          else
            paths << line
          end
        end

        paths.to_a
      end
    end
  end
end