# typed: false
# frozen_string_literal: true

# `brew uses foo bar` returns formulae that use both foo and bar
# If you want the union, run the command twice and concatenate the results.
# The intersection is harder to achieve with shell tools.

require "formula"
require "cli/parser"
require "cask/caskroom"
require "dependencies_helpers"

module Homebrew
  extend T::Sig

  extend DependenciesHelpers

  module_function

  sig { returns(CLI::Parser) }
  def uses_args
    Homebrew::CLI::Parser.new do
      description <<~EOS
        Show formulae and casks that specify <formula> as a dependency; that is, show dependents
        of <formula>. When given multiple formula arguments, show the intersection
        of formulae that use <formula>. By default, `uses` shows all formulae and casks that
        specify <formula> as a required or recommended dependency for their stable builds.
      EOS
      switch "--recursive",
             description: "Resolve more than one level of dependencies."
      switch "--installed",
             description: "Only list formulae and casks that are currently installed."
      switch "--all",
             description: "List all formulae and casks whether installed or not.",
             hidden:      true
      switch "--include-build",
             description: "Include all formulae that specify <formula> as `:build` type dependency."
      switch "--include-test",
             description: "Include all formulae that specify <formula> as `:test` type dependency."
      switch "--include-optional",
             description: "Include all formulae that specify <formula> as `:optional` type dependency."
      switch "--skip-recommended",
             description: "Skip all formulae that specify <formula> as `:recommended` type dependency."
      switch "--formula", "--formulae",
             description: "Include only formulae."
      switch "--cask", "--casks",
             description: "Include only casks."

      conflicts "--formula", "--cask"
      conflicts "--installed", "--all"

      named_args :formula, min: 1
    end
  end

  def uses
    args = uses_args.parse

    Formulary.enable_factory_cache!

    used_formulae_missing = false
    used_formulae = begin
      args.named.to_formulae
    rescue FormulaUnavailableError => e
      opoo e
      used_formulae_missing = true
      # If the formula doesn't exist: fake the needed formula object name.
      args.named.map { |name| OpenStruct.new name: name, full_name: name }
    end

    use_runtime_dependents = args.installed? &&
                             !used_formulae_missing &&
                             !args.include_build? &&
                             !args.include_test? &&
                             !args.include_optional? &&
                             !args.skip_recommended?

    uses = intersection_of_dependents(use_runtime_dependents, used_formulae, args: args)

    return if uses.empty?

    puts Formatter.columns(uses.map(&:full_name).sort)
    odie "Missing formulae should not have dependents!" if used_formulae_missing
  end

  def intersection_of_dependents(use_runtime_dependents, used_formulae, args:)
    recursive = args.recursive?
    show_formulae_and_casks = !args.formula? && !args.cask?
    includes, ignores = args_includes_ignores(args)

    # TODO: 3.6.0: odeprecate not specifying args.all?, require args.installed?

    deps = []
    if use_runtime_dependents
      if show_formulae_and_casks || args.formula?
        deps += used_formulae.map(&:runtime_installed_formula_dependents)
                             .reduce(&:&)
                             .select(&:any_version_installed?)
      end
      if show_formulae_and_casks || args.cask?
        deps += select_used_dependents(
          dependents(Cask::Caskroom.casks),
          used_formulae, recursive, includes, ignores
        )
      end

      deps
    else
      if show_formulae_and_casks || args.formula?
        deps += args.installed? ? Formula.installed : Formula.all
      end
      if show_formulae_and_casks || args.cask?
        deps += args.installed? ? Cask::Caskroom.casks : Cask::Cask.all
      end

      select_used_dependents(dependents(deps), used_formulae, recursive, includes, ignores)
    end
  end

  def select_used_dependents(dependents, used_formulae, recursive, includes, ignores)
    dependents.select do |d|
      deps = if recursive
        recursive_includes(Dependency, d, includes, ignores)
      else
        reject_ignores(d.deps, ignores, includes)
      end

      used_formulae.all? do |ff|
        deps.any? do |dep|
          match = begin
            dep.to_formula.full_name == ff.full_name if dep.name.include?("/")
          rescue
            nil
          end
          next match unless match.nil?

          dep.name == ff.name
        end
      rescue FormulaUnavailableError
        # Silently ignore this case as we don't care about things used in
        # taps that aren't currently tapped.
        next
      end
    end
  end
end