# typed: strict
# frozen_string_literal: true

require "abstract_command"
require "formula"
require "cask/caskroom"
require "dependencies_helpers"

module Homebrew
  module Cmd
    # `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.
    class Uses < AbstractCommand
      include DependenciesHelpers

      class UnavailableFormula < T::Struct
        const :name, String
        const :full_name, String
      end

      cmd_args 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.

          *Note:* `--missing` and `--skip-recommended` have precedence over `--include-*`.
        EOS
        switch "--recursive",
               description: "Resolve more than one level of dependencies."
        switch "--installed",
               description: "Only list formulae and casks that are currently installed."
        switch "--missing",
               description: "Only list formulae and casks that are not currently installed."
        switch "--eval-all",
               description: "Evaluate all available formulae and casks, whether installed or not, to show " \
                            "their dependents.",
               env:         :eval_all
        switch "--include-implicit",
               description: "Include formulae that have <formula> as an implicit dependency for " \
                            "downloading and unpacking source files."
        switch "--include-build",
               description: "Include formulae that specify <formula> as a `:build` dependency."
        switch "--include-test",
               description: "Include formulae that specify <formula> as a `:test` dependency."
        switch "--include-optional",
               description: "Include formulae that specify <formula> as an `:optional` dependency."
        switch "--skip-recommended",
               description: "Skip all formulae that specify <formula> as a `:recommended` dependency."
        switch "--formula", "--formulae",
               description: "Include only formulae."
        switch "--cask", "--casks",
               description: "Include only casks."

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

        named_args :formula, min: 1
      end

      sig { override.void }
      def run
        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| UnavailableFormula.new name:, full_name: name }
        end

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

        uses = intersection_of_dependents(use_runtime_dependents, used_formulae)

        return if uses.empty?

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

      private

      sig {
        params(use_runtime_dependents: T::Boolean, used_formulae: T::Array[T.any(Formula, UnavailableFormula)])
          .returns(T::Array[T.any(Formula, CaskDependent)])
      }
      def intersection_of_dependents(use_runtime_dependents, used_formulae)
        recursive = args.recursive?
        show_formulae_and_casks = !args.formula? && !args.cask?
        includes, ignores = args_includes_ignores(args)

        deps = []
        if use_runtime_dependents
          # We can only get here if `used_formulae_missing` is false, thus there are no UnavailableFormula.
          used_formulae = T.cast(used_formulae, T::Array[Formula])
          if show_formulae_and_casks || args.formula?
            deps += T.must(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
          eval_all = args.eval_all?

          if !args.installed? && !eval_all
            raise UsageError, "`brew uses` needs `--installed` or `--eval-all` passed or `$HOMEBREW_EVAL_ALL` set!"
          end

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

          if args.missing?
            deps.reject! do |dep|
              case dep
              when Formula
                dep.any_version_installed?
              when Cask::Cask
                dep.installed?
              end
            end
            ignores.delete(:satisfied?)
          end

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

      sig {
        params(
          dependents:    T::Array[T.any(Formula, CaskDependent)],
          used_formulae: T::Array[T.any(Formula, UnavailableFormula)],
          recursive:     T::Boolean,
          includes:      T::Array[Symbol],
          ignores:       T::Array[Symbol],
        ).returns(T::Array[T.any(Formula, CaskDependent)])
      }
      def select_used_dependents(dependents, used_formulae, recursive, includes, ignores)
        dependents.select do |d|
          deps = if recursive
            recursive_dep_includes(d, includes, ignores)
          else
            select_includes(d.deps, ignores, includes)
          end

          used_formulae.all? do |ff|
            deps.any? do |dep|
              match = case dep
              when Dependency
                dep.to_formula.full_name == ff.full_name if dep.name.include?("/")
              when Requirement
                nil
              else
                T.absurd(dep)
              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
  end
end
