require 'erb'
require 'openapi3_parser'
require 'uri'
require 'pry'
require 'govuk_tech_docs/api_reference/api_reference_renderer'

module GovukTechDocs
  module ApiReference
    class Extension < Middleman::Extension
      expose_to_application api: :api

      def initialize(app, options_hash = {}, &block)
        super

        @app = app
        @config = @app.config[:tech_docs]

        # If no api path then just return.
        if @config['api_path'].to_s.empty?
          @api_parser = false
          return
        end

        # Is the api_path a url or path?
        if uri?(@config['api_path'])
          @api_parser = true
          @document = Openapi3Parser.load_url(@config['api_path'])
        elsif File.exist?(@config['api_path'])
          # Load api file and set existence flag.
          @api_parser = true
          @document = Openapi3Parser.load_file(@config['api_path'])
        else
          @api_parser = false
          raise 'Unable to load api path from tech-docs.yml'
        end
        @render = Renderer.new(@app, @document)
      end

      def uri?(string)
        uri = URI.parse(string)
        %w(http https).include?(uri.scheme)
      rescue URI::BadURIError
        false
      rescue URI::InvalidURIError
        false
      end

      def api(text)
        if @api_parser == true

          keywords = {
            'api&gt;' => 'default',
            'api_schema&gt;' => 'schema'
          }

          regexp = keywords.map { |k, _| Regexp.escape(k) }.join('|')

          md = text.match(/^<p>(#{regexp})/)
          if md
            key = md.captures[0]
            type = keywords[key]

            text.gsub!(/#{Regexp.escape(key)}\s+?/, '')

            # Strip paragraph tags from text
            text = text.gsub(/<\/?[^>]*>/, '')
            text = text.strip

            if text == 'api&gt;'
              @render.api_full(api_info, api_servers)
            elsif type == 'default'
              output = @render.path(text)
              # Render any schemas referenced in the above path
              output += @render.schemas_from_path(text)
              output
            else
              @render.schema(text)
            end

          else
            return text
          end
        else
          text
        end
      end

    private

      def api_info
        @document.info
      end

      def api_servers
        @document.servers
      end
    end
  end
end

::Middleman::Extensions.register(:api_reference, GovukTechDocs::ApiReference::Extension)