#--
# Author:: Daniel DeLeo (<dan@opscode.com>)
# Author:: Tyler Cloke (<tyler@opscode.com>)
# Copyright:: Copyright (c) 2012 Opscode, Inc.
# License:: Apache License, Version 2.0
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
# 
#     http://www.apache.org/licenses/LICENSE-2.0
# 
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

class Chef
  module Formatters
    module ErrorInspectors
      class ResourceFailureInspector

        attr_reader :resource
        attr_reader :action
        attr_reader :exception

        def initialize(resource, action, exception)
          @resource = resource
          @action = action
          @exception = exception
        end

        def add_explanation(error_description)
          error_description.section(exception.class.name, exception.message)

          unless filtered_bt.empty?
            error_description.section("Cookbook Trace:", filtered_bt.join("\n"))
          end

          unless dynamic_resource?
            error_description.section("Resource Declaration:", recipe_snippet)
          end

          error_description.section("Compiled Resource:", "#{resource.to_text}")

          # Template errors get wrapped in an exception class that can show the relevant template code,
          # so add them to the error output.
          if exception.respond_to?(:source_listing)
            error_description.section("Template Context:", "#{exception.source_location}\n#{exception.source_listing}")
          end
        end

        def recipe_snippet
          return nil if dynamic_resource?
          @snippet ||= begin
            if file = resource.source_line[/^(([\w]:)?[^:]+):([\d]+)/,1] and line = resource.source_line[/^#{file}:([\d]+)/,1].to_i
              return nil unless ::File.exists?(file)
              lines = IO.readlines(file)

              relevant_lines = ["# In #{file}\n\n"]


              current_line = line - 1
              current_line = 0 if current_line < 0
              nesting = 0

              loop do

                # low rent parser. try to gracefully handle nested blocks in resources
                nesting += 1 if lines[current_line] =~ /[\s]+do[\s]*/
                nesting -= 1 if lines[current_line] =~ /end[\s]*$/

                relevant_lines << format_line(current_line, lines[current_line])

                break if lines[current_line + 1].nil?
                break if current_line >= (line + 50)
                break if nesting <= 0

                current_line += 1
              end
              relevant_lines << format_line(current_line + 1, lines[current_line + 1]) if lines[current_line + 1]
              relevant_lines.join("")
            end
          end
        end

        def dynamic_resource?
          !resource.source_line
        end

        def filtered_bt
          filters = Array(Chef::Config.cookbook_path).map {|p| /^#{Regexp.escape(p)}/ }
          exception.backtrace.select {|line| filters.any? {|filter| line =~ filter }}
        end

        private

        def format_line(line_nr, line)
          # Print line number as 1-indexed not zero
          line_nr_string = (line_nr + 1).to_s.rjust(3) + ": "
          line_nr_string + line
        end

      end
    end
  end
end