# typed: strict
# frozen_string_literal: true

require "sorbet-runtime"
require "bundler"
require "fileutils"
require "pathname"
require "digest"
require "time"

# This file is a script that will configure a custom bundle for the Ruby LSP. The custom bundle allows developers to use
# the Ruby LSP without including the gem in their application's Gemfile while at the same time giving us access to the
# exact locked versions of dependencies.

module RubyLsp
  class SetupBundler
    extend T::Sig

    class BundleNotLocked < StandardError; end

    FOUR_HOURS = T.let(4 * 60 * 60, Integer)

    sig { params(project_path: String, options: T.untyped).void }
    def initialize(project_path, **options)
      @project_path = project_path
      @branch = T.let(options[:branch], T.nilable(String))
      @experimental = T.let(options[:experimental], T.nilable(T::Boolean))

      # Regular bundle paths
      @gemfile = T.let(
        begin
          Bundler.default_gemfile
        rescue Bundler::GemfileNotFound
          nil
        end,
        T.nilable(Pathname),
      )
      @lockfile = T.let(@gemfile ? Bundler.default_lockfile : nil, T.nilable(Pathname))

      @gemfile_name = T.let(@gemfile&.basename&.to_s || "Gemfile", String)

      # Custom bundle paths
      @custom_dir = T.let(Pathname.new(".ruby-lsp").expand_path(Dir.pwd), Pathname)
      @custom_gemfile = T.let(@custom_dir + @gemfile_name, Pathname)
      @custom_lockfile = T.let(@custom_dir + (@lockfile&.basename || "Gemfile.lock"), Pathname)
      @lockfile_hash_path = T.let(@custom_dir + "main_lockfile_hash", Pathname)
      @last_updated_path = T.let(@custom_dir + "last_updated", Pathname)

      @dependencies = T.let(load_dependencies, T::Hash[String, T.untyped])
    end

    # Sets up the custom bundle and returns the `BUNDLE_GEMFILE`, `BUNDLE_PATH` and `BUNDLE_APP_CONFIG` that should be
    # used for running the server
    sig { returns([String, T.nilable(String), T.nilable(String)]) }
    def setup!
      raise BundleNotLocked if @gemfile&.exist? && !@lockfile&.exist?

      # Do not setup a custom bundle if both `ruby-lsp` and `debug` are already in the Gemfile
      if @dependencies["ruby-lsp"] && @dependencies["debug"]
        warn("Ruby LSP> Skipping custom bundle setup since both `ruby-lsp` and `debug` are already in #{@gemfile}")

        # If the user decided to add the `ruby-lsp` and `debug` to their Gemfile after having already run the Ruby LSP,
        # then we need to remove the `.ruby-lsp` folder, otherwise we will run `bundle install` for the top level and
        # try to execute the Ruby LSP using the custom bundle, which will fail since the gems are not installed there
        @custom_dir.rmtree if @custom_dir.exist?
        return run_bundle_install
      end

      # Automatically create and ignore the .ruby-lsp folder for users
      @custom_dir.mkpath unless @custom_dir.exist?
      ignore_file = @custom_dir + ".gitignore"
      ignore_file.write("*") unless ignore_file.exist?

      write_custom_gemfile

      unless @gemfile&.exist? && @lockfile&.exist?
        warn("Ruby LSP> Skipping lockfile copies because there's no top level bundle")
        return run_bundle_install(@custom_gemfile)
      end

      lockfile_contents = @lockfile.read
      current_lockfile_hash = Digest::SHA256.hexdigest(lockfile_contents)

      if @custom_lockfile.exist? && @lockfile_hash_path.exist? && @lockfile_hash_path.read == current_lockfile_hash
        warn("Ruby LSP> Skipping custom bundle setup since #{@custom_lockfile} already exists and is up to date")
        return run_bundle_install(@custom_gemfile)
      end

      FileUtils.cp(@lockfile.to_s, @custom_lockfile.to_s)
      @lockfile_hash_path.write(current_lockfile_hash)
      run_bundle_install(@custom_gemfile)
    end

    private

    sig { returns(T::Hash[String, T.untyped]) }
    def custom_bundle_dependencies
      @custom_bundle_dependencies ||= T.let(
        begin
          if @custom_lockfile.exist?
            ENV["BUNDLE_GEMFILE"] = @custom_gemfile.to_s
            Bundler::LockfileParser.new(@custom_lockfile.read).dependencies
          else
            {}
          end
        end,
        T.nilable(T::Hash[String, T.untyped]),
      )
    ensure
      ENV.delete("BUNDLE_GEMFILE")
    end

    sig { void }
    def write_custom_gemfile
      parts = [
        "# This custom gemfile is automatically generated by the Ruby LSP.",
        "# It should be automatically git ignored, but in any case: do not commit it to your repository.",
        "",
      ]

      # If there's a top level Gemfile, we want to evaluate from the custom bundle. We get the source from the top level
      # Gemfile, so if there isn't one we need to add a default source
      if @gemfile&.exist?
        parts << "eval_gemfile(File.expand_path(\"../#{@gemfile_name}\", __dir__))"
      else
        parts.unshift('source "https://rubygems.org"')
      end

      unless @dependencies["ruby-lsp"]
        ruby_lsp_entry = +'gem "ruby-lsp", require: false, group: :development'
        ruby_lsp_entry << ", github: \"Shopify/ruby-lsp\", branch: \"#{@branch}\"" if @branch
        parts << ruby_lsp_entry
      end

      unless @dependencies["debug"]
        parts << 'gem "debug", require: false, group: :development, platforms: :mri'
      end

      content = parts.join("\n")
      @custom_gemfile.write(content) unless @custom_gemfile.exist? && @custom_gemfile.read == content
    end

    sig { returns(T::Hash[String, T.untyped]) }
    def load_dependencies
      return {} unless @lockfile&.exist?

      # We need to parse the Gemfile.lock manually here. If we try to do `bundler/setup` to use something more
      # convenient, we may end up with issues when the globally installed `ruby-lsp` version mismatches the one included
      # in the `Gemfile`
      dependencies = Bundler::LockfileParser.new(@lockfile.read).dependencies

      # When working on a gem, the `ruby-lsp` might be listed as a dependency in the gemspec. We need to make sure we
      # check those as well or else we may get version mismatch errors. Notice that bundler allows more than one
      # gemspec, so we need to make sure we go through all of them
      Dir.glob("{,*}.gemspec").each do |path|
        dependencies.merge!(Bundler.load_gemspec(path).dependencies.to_h { |dep| [dep.name, dep] })
      end

      dependencies
    end

    sig { params(bundle_gemfile: T.nilable(Pathname)).returns([String, T.nilable(String), T.nilable(String)]) }
    def run_bundle_install(bundle_gemfile = @gemfile)
      # If the user has a custom bundle path configured, we need to ensure that we will use the absolute and not
      # relative version of it when running `bundle install`. This is necessary to avoid installing the gems under the
      # `.ruby-lsp` folder, which is not the user's intention. For example, if the path is configured as `vendor`, we
      # want to install it in the top level `vendor` and not `.ruby-lsp/vendor`
      path = Bundler.settings["path"]
      expanded_path = File.expand_path(path, Dir.pwd) if path

      # Use the absolute `BUNDLE_PATH` to prevent accidentally creating unwanted folders under `.ruby-lsp`
      env = {}
      env["BUNDLE_GEMFILE"] = bundle_gemfile.to_s
      env["BUNDLE_PATH"] = expanded_path if expanded_path

      local_config_path = File.join(Dir.pwd, ".bundle")
      env["BUNDLE_APP_CONFIG"] = local_config_path if Dir.exist?(local_config_path)

      # If both `ruby-lsp` and `debug` are already in the Gemfile, then we shouldn't try to upgrade them or else we'll
      # produce undesired source control changes. If the custom bundle was just created and either `ruby-lsp` or `debug`
      # weren't a part of the Gemfile, then we need to run `bundle install` for the first time to generate the
      # Gemfile.lock with them included or else Bundler will complain that they're missing. We can only update if the
      # custom `.ruby-lsp/Gemfile.lock` already exists and includes both gems

      # When not updating, we run `(bundle check || bundle install)`
      # When updating, we run `((bundle check && bundle update ruby-lsp debug) || bundle install)`
      command = +"(bundle check"

      if should_bundle_update?
        # If ruby-lsp or debug are not in the Gemfile, try to update them to the latest version
        command.prepend("(")
        command << " && bundle update "
        command << "ruby-lsp " unless @dependencies["ruby-lsp"]
        command << "debug " unless @dependencies["debug"]
        command << "--pre" if @experimental
        command.delete_suffix!(" ")
        command << ")"

        @last_updated_path.write(Time.now.iso8601)
      end

      command << " || bundle install) "

      # Redirect stdout to stderr to prevent going into an infinite loop. The extension might confuse stdout output with
      # responses
      command << "1>&2"

      # Add bundle update
      warn("Ruby LSP> Running bundle install for the custom bundle. This may take a while...")
      warn("Ruby LSP> Command: #{command}")
      system(env, command)
      [bundle_gemfile.to_s, expanded_path, env["BUNDLE_APP_CONFIG"]]
    end

    sig { returns(T::Boolean) }
    def should_bundle_update?
      # If both `ruby-lsp` and `debug` are in the Gemfile, then we shouldn't try to upgrade them or else it will produce
      # version control changes
      return false if @dependencies["ruby-lsp"] && @dependencies["debug"]

      # If the custom lockfile doesn't include either the `ruby-lsp` or `debug`, we need to run bundle install before
      # updating
      return false if custom_bundle_dependencies["ruby-lsp"].nil? || custom_bundle_dependencies["debug"].nil?

      # If the last updated file doesn't exist or was updated more than 4 hours ago, we should update
      !@last_updated_path.exist? || Time.parse(@last_updated_path.read) < (Time.now - FOUR_HOURS)
    end
  end
end