require 'erb'

module Aws
  module Api
    module Docs
      class Builder

        DOC_SRC = File.expand_path('../../../../../../doc-src/', __FILE__)

        def self.document(svc_module)
          new(svc_module).document
        end

        def initialize(svc_module)
          @svc_module = svc_module
          @svc_name = svc_module.name.split('::').last
          @client_class = svc_module.const_get(:Client)
          @api = @client_class.api
          @full_name = @api.metadata['serviceFullName']
          @uid = @api.metadata['uid']
          @error_names = @api.operations.map {|_,o| o.errors.map(&:shape).map(&:name) }
          @error_names = @error_names.flatten.uniq.sort
          @namespace = YARD::Registry['Aws']
        end

        def document
          document_service
          document_types
          document_client
          document_errors
        end

        private

        def document_service
          yard_mod = YARD::CodeObjects::ModuleObject.new(@namespace, @svc_name)
          yard_mod.docstring = service_docstring
          yard_mod.docstring.add_tag(YARD::Tags::Tag.new(:service, @svc_name))
          @namespace = yard_mod
        end

        def service_docstring
          path = "#{DOC_SRC}/services/#{@svc_name}/service.md"
          path = "#{DOC_SRC}/services/default/service.md" unless File.exist?(path)
          template = read(path)
          svc_name = @svc_name
          api = @api
          full_name = @full_name
          ERB.new(template).result(binding)
        end

        def document_errors
          yard_mod = YARD::CodeObjects::ModuleObject.new(@namespace, 'Errors')
          yard_mod.docstring = errors_docstring

          base_error = YARD::CodeObjects::ClassObject.new(yard_mod, 'ServiceError')
          base_error.docstring = "Base class for all Aws::#{@svc_name} errors."
          base_error.superclass = YARD::Registry['Aws::Errors::ServiceError']

          @error_names.each do |error_name|
            error_klass = YARD::CodeObjects::ClassObject.new(yard_mod, error_name)
            error_klass.superclass = base_error
          end
        end

        def errors_docstring
          path = "#{DOC_SRC}/services/#{@svc_name}/errors.md"
          path = "#{DOC_SRC}/services/default/errors.md" unless File.exist?(path)
          template = read(path)
          svc_name = @svc_name
          api = @api
          full_name = @full_name
          known_errors = @error_names
          ERB.new(template).result(binding)
        end

        def document_client
          yard_class = YARD::CodeObjects::ClassObject.new(@namespace, 'Client')
          yard_class.superclass = YARD::Registry['Seahorse::Client::Base']
          yard_class.docstring = client_docstring
          document_client_constructor(yard_class)
          document_client_operations(yard_class)
          document_client_waiters(yard_class)
        end

        def document_types
          namespace = YARD::CodeObjects::ModuleObject.new(@namespace, 'Types')
          documenter = ClientTypeDocumenter.new(namespace)
          @api.metadata['shapes'].each_structure do |shape|
            documenter.document(@api, shape)
          end
        end

        def client_docstring
          path = "#{DOC_SRC}/services/#{@svc_name}/client.md"
          path = "#{DOC_SRC}/services/default/client.md" unless File.exist?(path)
          render(path)
        end

        def render(path)
          svc_name = @svc_name
          api = @api
          full_name = @full_name
          ERB.new(read(path)).result(binding)
        end

        def document_client_constructor(namespace)
          constructor = YARD::CodeObjects::MethodObject.new(namespace, :initialize)
          constructor.group = 'Constructor'
          constructor.scope = :instance
          constructor.parameters << ['options', '{}']
          constructor.docstring = client_constructor_docstring
        end

        def client_constructor_docstring
          <<-DOCS.strip
Constructs an API client.
#{client_constructor_options}
@return [#{@client_class.name}] Returns an API client.
          DOCS
        end

        def client_constructor_options
          options = {}
          @client_class.plugins.each do |plugin|
            if p = YARD::Registry[plugin.name]
              p.tags.each do |tag|
                if tag.tag_name == 'seahorse_client_option'
                  option_name = tag.text.match(/.+(:\w+)/)[1]
                  option_text = "@option options " + tag.text.split("\n").join("\n  ")
                  options[option_name] = option_text +
                    "  See {#{plugin.name}} for more details."
                end
              end
            end
          end
          options.sort_by { |k,v| k }.map(&:last).join("\n")
        end

        def document_client_operations(namespace)
          @api.operations.each do |method_name, operation|
            document_client_operation(namespace, method_name, operation)
          end
        end

        def document_client_operation(namespace, method_name, operation)
          documenter = OperationDocumenter.new(@svc_name, namespace, @uid)
          documenter.document(method_name, operation)
        end

        def document_client_waiters(yard_class)
          m = YARD::CodeObjects::MethodObject.new(yard_class, :wait_until)
          m.scope = :instance
          m.parameters << ['waiter_name', nil]
          m.parameters << ['params', '{}']
          m.docstring = YARD::Registry['Aws::ClientWaiters#wait_until'].docstring

          waiters = @client_class.waiters.waiter_names.sort.inject('') do |w,name|
            waiter = @client_class.waiters.waiter(name)
            operation = waiter.poller.operation_name
            w << "<tr><td><tt>:#{name}</tt></td><td>{##{operation}}</td><td>#{waiter.delay}</td><td>#{waiter.max_attempts}</td></tr>"
          end
          docstring = <<-DOCSTRING
Returns the list of supported waiters. The following table lists the supported
waiters and the client method they call:
<table>
<thead>
<tr><th>Waiter Name</th><th>Client Method</th><th>Default Delay:</th><th>Default Max Attempts:</th></tr>
</thead>
<tbody>
#{waiters}
</tbody>
</table>
@return [Array<Symbol>] the list of supported waiters.
          DOCSTRING
          m = YARD::CodeObjects::MethodObject.new(yard_class, :waiter_names)
          m.scope = :instance
          m.docstring = docstring
        end

        class Tabulator

          def initialize
            @tabs = []
            @tab_contents = []
          end

          def tab(method_name, tab_name, &block)
            tab_class = tab_name.downcase.gsub(/[^a-z]+/i, '-')
            tab_id = "#{method_name.to_s.gsub(/_/, '-')}-#{tab_class}"
            class_names = ['tab-contents', tab_class]
            @tabs << [tab_id, tab_name]
            @tab_contents << "<div class=\"#{class_names.join(' ')}\" id=\"#{tab_id}\">"
            @tab_contents << yield
            @tab_contents << '</div>'
          end

          def to_html
            lines = []
            lines << '<div class="tab-box">'
            lines << '<ul class="tabs">'
            @tabs.each do |tab_id, tab_name|
              lines << "<li data-tab-id=\"#{tab_id}\">#{tab_name}</li>"
            end
            lines << '</ul>'
            lines.concat(@tab_contents)
            lines << '</div>'
            lines.join
          end
          alias inspect to_html
          alias to_str to_html
          alias to_s to_html

        end

        def read(path)
          File.open(path, 'r', encoding: 'UTF-8') { |f| f.read }
        end

      end
    end
  end
end