require 'erb'
require 'tmpdir'
require 'zip/zip'

module Documentalist
  # Merge an ODF document with an arbitrary hash of data
  def self.odf_merge(template, options = {})
    ODFMerge.merge_template(template, options)
  end

  # This module provides open document merge functionality
  module ODFMerge
    include Documentalist::Dependencies

    def self.merge_string(string, options = {})
      locals = options[:locals]

      if locals and locals.is_a? Hash
        locals.each do |k,v|
          instance_variable_set("@#{k.to_s}".to_sym, v)
        end
      end

      ERB.new(string).result(binding)
    end

    def self.get_contents(odt_file)
      contents = String.new
      Zip::ZipFile.open(odt_file) { |zip| contents = zip.read("content.xml") }
      contents.gsub("&lt;%", "<%").gsub("%&gt;", "%>")
    end

    def self.merge_template(template, options = {})
      # Get template contents
      tmp_contents= Tempfile.new("officer-contents")
      tmp_contents.write(merge_string(get_contents(template), :locals => options[:locals]))
      tmp_contents.close

      # Copy the template so we can merge the data into the copy
      tmp_merged_template = File.join(Dir.tmpdir, "merged-template-#{rand(10**9)}#{File.extname(template)}")
      FileUtils.cp(template, tmp_merged_template)

      # Stuff the merged contents.xml into the OpenDocument zip
      Zip::ZipFile.open(tmp_merged_template) do |zip|
        zip.replace("content.xml", tmp_contents.path)
        zip.commit
      end

      # Remove the merged contents.xml
      tmp_contents.unlink

      # Manages the converted file depending on the context
      if options[:to]
        if File.extname(options[:to]) == File.extname(template)
          FileUtils.mv(tmp_merged_template, options[:to])
        else
          Documentalist.convert(tmp_merged_template, :to => options[:to])
          FileUtils.rm(tmp_merged_template)
        end
      else
        FileUtils.rm(template)
        FileUtils.mv(tmp_merged_template, template)
      end
    end
  end
end