# typed: strict
# frozen_string_literal: true

require "abstract_command"
require "fileutils"
require "formula"

module Homebrew
  module DevCmd
    class GenerateFormulaApi < AbstractCommand
      FORMULA_JSON_TEMPLATE = <<~EOS
        ---
        layout: formula_json
        ---
        {{ content }}
      EOS

      cmd_args do
        description <<~EOS
          Generate `homebrew/core` API data files for <#{HOMEBREW_API_WWW}>.
          The generated files are written to the current directory.
        EOS

        switch "-n", "--dry-run", description: "Generate API data without writing it to files."

        named_args :none
      end

      sig { override.void }
      def run
        tap = CoreTap.instance
        raise TapUnavailableError, tap.name unless tap.installed?

        unless args.dry_run?
          directories = ["_data/formula", "api/formula", "formula", "api/internal"]
          FileUtils.rm_rf directories + ["_data/formula_canonical.json"]
          FileUtils.mkdir_p directories
        end

        Homebrew.with_no_api_env do
          tap_migrations_json = JSON.dump(tap.tap_migrations)
          File.write("api/formula_tap_migrations.json", tap_migrations_json) unless args.dry_run?

          Formulary.enable_factory_cache!
          Formula.generating_hash!

          all_formulae = {}
          latest_macos = MacOSVersion.new((HOMEBREW_MACOS_NEWEST_UNSUPPORTED.to_i - 1).to_s).to_sym
          Homebrew::SimulateSystem.with(os: latest_macos, arch: :arm) do
            tap.formula_names.each do |name|
              formula = Formulary.factory(name)
              name = formula.name
              all_formulae[name] = formula.to_hash_with_variations
              json = JSON.pretty_generate(all_formulae[name])
              html_template_name = html_template(name)

              unless args.dry_run?
                File.write("_data/formula/#{name.tr("+", "_")}.json", "#{json}\n")
                File.write("api/formula/#{name}.json", FORMULA_JSON_TEMPLATE)
                File.write("formula/#{name}.html", html_template_name)
              end
            rescue
              onoe "Error while generating data for formula '#{name}'."
              raise
            end
          end

          canonical_json = JSON.pretty_generate(tap.formula_renames.merge(tap.alias_table))
          File.write("_data/formula_canonical.json", "#{canonical_json}\n") unless args.dry_run?

          OnSystem::VALID_OS_ARCH_TAGS.each do |bottle_tag|
            variation_formulae = all_formulae.to_h do |name, formula|
              formula = Homebrew::API.merge_variations(formula, bottle_tag:)

              version = Version.new(formula.dig("versions", "stable"))
              pkg_version = PkgVersion.new(version, formula["revision"])
              rebuild = formula.dig("bottle", "stable", "rebuild") || 0
              sha256 = newest_bottle_sha256(formula, bottle_tag)

              [name, [pkg_version.to_s, rebuild, sha256]]
            end

            unless args.dry_run?
              File.write("api/internal/formula.#{bottle_tag}.json", JSON.generate(variation_formulae))
            end
          end
        end
      end

      sig {
        params(formula_json: T::Hash[String, T.untyped], bottle_tag: Utils::Bottles::Tag).returns(T.nilable(String))
      }
      def newest_bottle_sha256(formula_json, bottle_tag)
        available_tags = formula_json.dig("bottle", "stable", "files")&.keys&.map(&:to_sym)
        return unless available_tags

        return formula_json.dig("bottle", "stable", "files", :all, "sha256") if available_tags.include? :all

        if available_tags.include? bottle_tag.to_sym
          return formula_json.dig("bottle", "stable", "files", bottle_tag.to_sym, "sha256")
        end

        return unless bottle_tag.macos?

        # If the actual tag is not available, find the newest tag with matching arch that's older than the actual tag
        newest_viable_macos_tag = available_tags.filter_map do |tag_sym|
          tag = Utils::Bottles::Tag.from_symbol(tag_sym)
          next unless tag.macos?
          next if tag.arch != bottle_tag.arch
          next if tag.to_macos_version > bottle_tag.to_macos_version

          tag
        end.max_by(&:to_macos_version)
        return unless newest_viable_macos_tag

        formula_json.dig("bottle", "stable", "files", newest_viable_macos_tag.to_sym, "sha256")
      end

      private

      sig { params(title: String).returns(String) }
      def html_template(title)
        <<~EOS
          ---
          title: '#{title}'
          layout: formula
          redirect_from: /formula-linux/#{title}
          ---
          {{ content }}
        EOS
      end
    end
  end
end