# coding: utf-8
# Generate pages from individual records in yml files
# (c) 2014-2020 Adolfo Villafiorita
# Distributed under the conditions of the MIT License

module Jekyll

  module Sanitizer
    # strip characters and whitespace to create valid filenames, also lowercase
    def sanitize_filename(name)
      if(name.is_a? Integer)
        return name.to_s
      end
      return name.tr(
  "ÀÁÂÃÄÅàáâãäåĀāĂăĄąÇçĆćĈĉĊċČčÐðĎďĐđÈÉÊËèéêëĒēĔĕĖėĘęĚěĜĝĞğĠġĢģĤĥĦħÌÍÎÏìíîïĨĩĪīĬĭĮįİıĴĵĶķĸĹĺĻļĽľĿŀŁłÑñŃńŅņŇňŉŊŋÑñÒÓÔÕÖØòóôõöøŌōŎŏŐőŔŕŖŗŘřŚśŜŝŞşŠšſŢţŤťŦŧÙÚÛÜùúûüŨũŪūŬŭŮůŰűŲųŴŵÝýÿŶŷŸŹźŻżŽž",
  "AAAAAAaaaaaaAaAaAaCcCcCcCcCcDdDdDdEEEEeeeeEeEeEeEeEeGgGgGgGgHhHhIIIIiiiiIiIiIiIiIiJjKkkLlLlLlLlLlNnNnNnNnnNnNnOOOOOOooooooOoOoOoRrRrRrSsSsSsSssTtTtTtUUUUuuuuUuUuUuUuUuUuWwYyyYyYZzZzZz"
).downcase.strip.gsub(' ', '-').gsub(/[^\w.-]/, '')
    end
  end

  # this class is used to tell Jekyll to generate a page
  class DataPage < Page
    include Sanitizer

    # - site and base are copied from other plugins: to be honest, I am not sure what they do
    #
    # - `index_files` specifies if we want to generate named folders (true) or not (false)
    # - `dir` is the default output directory
    # - `page_data_prefix` is the prefix used to output the page data
    # - `data` is the data of the record for which we are generating a page
    # - `name` is the key in `data` which determines the output filename
    # - `name_expr` is an expression for generating the output filename
    # - `title` is the key in `data` which determines the page title
    # - `title_expr` is an expression for generating the page title
    # - `template` is the name of the template for generating the page
    # - `extension` is the extension for the generated file
    def initialize(site, base, index_files, dir, page_data_prefix, data, name, name_expr, title, title_expr, template, extension, debug)
      @site = site
      @base = base

      if debug
        puts "debug (datapage-gen) Record read:"
        puts ">> #{data}"

        puts "debug (datapage-gen) Configuration variables:"
        [:index_files, :dir, :page_data_prefix, :name, :name_expr, :title, :title_expr, :template, :extension].each do |variable|
          puts ">> #{variable}: #{eval(variable.to_s)}"
        end
      end

      # @dir is the directory where we want to output the page
      # @name is the name of the page to generate
      # @name_expr is an expression for generating the name of the page
      #
      # the value of these variables changes according to whether we
      # want to generate named folders or not
      if name_expr
        record = data
        raw_filename = eval(name_expr)
        if raw_filename == nil
          puts "error (datapage-gen). name_expr '#{name_expr}' generated an empty value in record #{data}"
          return
        end
        puts "debug (datapage-gen). using name_expr: '#{raw_filename}' (sanitized) will be used as the filename" if debug
      else
        raw_filename = data[name]
        if raw_filename == nil
          puts "error (datapage-gen). empty value for field '#{name}' in record #{data}"
          return
        end
        puts "debug (datapage-gen). using name field: '#{raw_filename}' (sanitized) will be used as the filename" if debug
      end

      if title_expr
        record = data
        raw_title = eval(title_expr)
        if raw_title == nil
          puts "error (datapage-gen). title_expr '#{title_expr}' generated an empty value in record #{data}"
          return
        end
        puts "debug (datapage-gen). using title_expr: '#{raw_title}' will be used the page title" if debug
      else
        raw_title = data[title]
        if raw_title == nil
          raw_title = raw_filename # for backwards compatibility
          puts "debug (datapage-gen). empty title field: falling back to filename for the page title" if debug
        end
          puts "debug (datapage-gen). will use '#{raw_title}' as the page title" if debug
      end

      filename = sanitize_filename(raw_filename).to_s

      @dir = dir + (index_files ? "/" + filename + "/" : "")
      @name = (index_files ? "index" : filename)
      
      if extension
        @name += "." + extension.to_s
      end

      self.process(@name)

      if @site.layouts[template].path.end_with? 'html'
        @path = @site.layouts[template].path.dup
      else
        @path = File.join(@site.layouts[template].path, @site.layouts[template].name)
      end

      base_path = @site.layouts[template].path
      base_path.slice! @site.layouts[template].name
      self.read_yaml(base_path, @site.layouts[template].name)

      self.data['title'] = raw_title

      # add all the information defined in _data for the current record to the
      # current page (so that we can access it with liquid tags)
      if page_data_prefix
        self.data[page_data_prefix] = data
      else
        if data.key?('name')
          data['_name'] = data['name']
        end
        self.data.merge!(data)
      end

    end
  end

  class JekyllDatapageGenerator < Generator
    safe true

    # the function =generate= loops over the =_config.yml/page_gen=
    # specification, determining what sets of pages have to be generated,
    # reading the data for each set and invoking the =DataPage=
    # constructor for each record found in the data

    def generate(site)
      # page_gen-dirs is a global option which determines whether we want to
      # generate index pages (name/index.html) or HTML files (name.html) for
      # all sets
      index_files = site.config['page_gen-dirs'] == true

      # data contains the specification of all the datasets for which we want
      # to generate individual pages (look at the README file for its documentation)
      data = site.config['page_gen']
      if data
        data.each do |data_spec|
          index_files_for_this_data = data_spec['index_files'] != nil ? data_spec['index_files'] : index_files
          template         = data_spec['template'] || data_spec['data']
          name             = data_spec['name']
          name_expr        = data_spec['name_expr']
          title            = data_spec['title']
          title_expr       = data_spec['title_expr']
          dir              = data_spec['dir'] || data_spec['data']
          page_data_prefix = data_spec['page_data_prefix']
          debug            = data_spec['debug']

          unless data_spec.key? 'extension'
            data_spec['extension'] = 'html'
          end
          
          if not site.layouts.key? template
            puts "error (datapage-gen). could not find template #{template}. Skipping dataset #{name}."
          else
            # records is the list of records for which we want to generate
            # individual pages
            records = nil

            data_spec['data'].split('.').each do |level|
              if records.nil?
                records = site.data[level]
              else
                records = records[level]
              end
            end
            if (records.kind_of?(Hash))
              records = records.values
            end

            # apply filtering conditions:
            # - filter requires the name of a boolean field
            # - filter_condition evals a ruby expression which can use =record= as argument
            records = records.select { |record| record[data_spec['filter']] } if data_spec['filter']
            records = records.select { |record| eval(data_spec['filter_condition']) } if data_spec['filter_condition']

            # we now have the list of all records for which we want to generate individual pages
            # iterate and call the constructor
            records.each do |record|
              site.pages << DataPage.new(site, site.source, index_files_for_this_data, dir, page_data_prefix, record, name, name_expr, title, title_expr, template, data_spec['extension'], debug)
            end
          end
        end
      end
    end
  end

  module DataPageLinkGenerator
    include Sanitizer

    # use it like this: {{input | datapage_url: dir}}
    # to generate a link to a data_page.
    #
    # the filter is smart enough to generate different link styles
    # according to the data_page-dirs directive ...
    #
    # ... however, the filter is not smart enough to support different
    # extensions for filenames.
    #
    # Thus, if you use the `extension` feature of this plugin, you
    # need to generate the links by hand
    def datapage_url(input, dir)
      extension = @context.registers[:site].config['page_gen-dirs'] ? '/' : '.html'
      "#{dir}/#{sanitize_filename(input)}#{extension}"
    end
  end

end

Liquid::Template.register_filter(Jekyll::DataPageLinkGenerator)
