require "addressable/uri"

module Jekyll
  module Commands
    class Doctor < Command
      class << self
        def init_with_program(prog)
          prog.command(:doctor) do |c|
            c.syntax "doctor"
            c.description "Search site and print specific deprecation warnings"
            c.alias(:hyde)

            c.option "config", "--config CONFIG_FILE[,CONFIG_FILE2,...]", Array,
                            "Custom configuration file"

            c.action do |_, options|
              Jekyll::Commands::Doctor.process(options)
            end
          end
        end

        def process(options)
          site = Jekyll::Site.new(configuration_from_options(options))
          site.reset
          site.read
          site.generate

          if healthy?(site)
            Jekyll.logger.info "Your test results", "are in. Everything looks fine."
          else
            abort
          end
        end

        def healthy?(site)
          [
            fsnotify_buggy?(site),
            !deprecated_relative_permalinks(site),
            !conflicting_urls(site),
            !urls_only_differ_by_case(site),
            proper_site_url?(site),
          ].all?
        end

        def deprecated_relative_permalinks(site)
          if site.config["relative_permalinks"]
            Jekyll::Deprecator.deprecation_message "Your site still uses relative" \
                                " permalinks, which was removed in" \
                                " Jekyll v3.0.0."
            return true
          end
        end

        def conflicting_urls(site)
          conflicting_urls = false
          urls = {}
          urls = collect_urls(urls, site.pages, site.dest)
          urls = collect_urls(urls, site.posts.docs, site.dest)
          urls.each do |url, paths|
            next unless paths.size > 1
            conflicting_urls = true
            Jekyll.logger.warn "Conflict:", "The URL '#{url}' is the destination" \
              " for the following pages: #{paths.join(", ")}"
          end
          conflicting_urls
        end

        def fsnotify_buggy?(_site)
          return true unless Utils::Platforms.osx?
          if Dir.pwd != `pwd`.strip
            Jekyll.logger.error "  " + <<-STR.strip.gsub(%r!\n\s+!, "\n  ")
              We have detected that there might be trouble using fsevent on your
              operating system, you can read https://github.com/thibaudgg/rb-fsevent/wiki/no-fsevents-fired-(OSX-bug)
              for possible work arounds or you can work around it immediately
              with `--force-polling`.
            STR

            false
          end

          true
        end

        def urls_only_differ_by_case(site)
          urls_only_differ_by_case = false
          urls = case_insensitive_urls(site.pages + site.docs_to_write, site.dest)
          urls.each do |_case_insensitive_url, real_urls|
            next unless real_urls.uniq.size > 1
            urls_only_differ_by_case = true
            Jekyll.logger.warn "Warning:", "The following URLs only differ" \
              " by case. On a case-insensitive file system one of the URLs" \
              " will be overwritten by the other: #{real_urls.join(", ")}"
          end
          urls_only_differ_by_case
        end

        def proper_site_url?(site)
          url = site.config["url"]
          [
            url_exists?(url),
            url_valid?(url),
            url_absolute(url),
          ].all?
        end

        private
        def collect_urls(urls, things, destination)
          things.each do |thing|
            dest = thing.destination(destination)
            if urls[dest]
              urls[dest] << thing.path
            else
              urls[dest] = [thing.path]
            end
          end
          urls
        end

        def case_insensitive_urls(things, destination)
          things.each_with_object({}) do |thing, memo|
            dest = thing.destination(destination)
            (memo[dest.downcase] ||= []) << dest
          end
        end

        def url_exists?(url)
          return true unless url.nil? || url.empty?
          Jekyll.logger.warn "Warning:", "You didn't set an URL in the config file, "\
              "you may encounter problems with some plugins."
          false
        end

        def url_valid?(url)
          Addressable::URI.parse(url)
          true
        rescue
          Jekyll.logger.warn "Warning:", "The site URL does not seem to be valid, "\
              "check the value of `url` in your config file."
          false
        end

        def url_absolute(url)
          return true if Addressable::URI.parse(url).absolute?
          Jekyll.logger.warn "Warning:", "Your site URL does not seem to be absolute, "\
              "check the value of `url` in your config file."
          false
        end
      end
    end
  end
end
