#
# Copyright (c) 2009-2018 Minero Aoki, Kenshi Muto
#               2002-2008 Minero Aoki
#
# This program is free software.
# You can distribute or modify this program under the terms of
# the GNU LGPL, Lesser General Public License version 2.1.
# For details of the GNU LGPL, see the file "COPYING".
#
require 'review/configure'
require 'review/catalog'

module ReVIEW
  module Book
    class Base
      attr_accessor :config
      attr_writer :parts
      attr_writer :catalog
      attr_reader :basedir

      def self.load(dir = '.')
        new(dir)
      end

      def initialize(basedir = '.')
        @basedir = basedir
        @logger = ReVIEW.logger
        @parts = nil
        @chapter_index = nil
        @config = ReVIEW::Configure.values
        @catalog = nil
        @read_part = nil
        @warn_old_files = {} # XXX for checking CHAPS, PREDEF, POSTDEF
        @basedir_seen = {}
        update_rubyenv
      end

      def update_rubyenv
        if File.file?(File.join(@basedir, 'review-ext.rb'))
          if ENV['REVIEW_SAFE_MODE'].to_i & 2 > 0
            @logger.warn 'review-ext.rb is prohibited in safe mode. ignored.'
          else
            Kernel.load(File.expand_path(File.join(@basedir, 'review-ext.rb')))
          end
        end
      end

      def bib_file
        config['bib_file']
      end

      def reject_file
        config['reject_file']
      end

      def ext
        config['ext']
      end

      def imagedir
        File.join(@basedir, config['imagedir'])
      end

      def image_types
        config['image_types']
      end

      def image_types=(types)
        config['image_types'] = types
      end

      def contentdir
        if !config['contentdir'].present? || config['contentdir'] == '.'
          @basedir
        else
          File.join(@basedir, config['contentdir'])
        end
      end

      def page_metric
        if config['page_metric'].respond_to?(:downcase) && config['page_metric'].upcase =~ /\A[A-Z0-9_]+\Z/
          ReVIEW::Book::PageMetric.const_get(config['page_metric'].upcase)
        elsif config['page_metric'].is_a?(Array) && config['page_metric'].size == 5
          ReVIEW::Book::PageMetric.new(*config['page_metric'])
        else
          config['page_metric']
        end
      end

      def htmlversion
        if config['htmlversion'].blank?
          nil
        else
          config['htmlversion'].to_i
        end
      end

      def parts
        @parts ||= read_parts
      end

      def parts_in_file
        # TODO: should be `parts.find_all{|part| part.present? and part.file?}` ?
        parts.find_all do |part|
          part if part.present? and part.file?
        end
      end

      def part(n)
        parts.detect { |part| part.number == n }
      end

      def each_part(&block)
        parts.each(&block)
      end

      def contents
        # TODO: includes predef, appendix, postdef
        if parts.present?
          chapters + parts
        else
          chapters
        end
      end

      def chapters
        parts.map(&:chapters).flatten
      end

      def each_chapter(&block)
        chapters.each(&block)
      end

      def each_chapter_r(&block)
        chapters.reverse_each(&block)
      end

      def chapter_index
        return @chapter_index if @chapter_index

        contents = chapters
        # TODO: contents += parts.find_all { |prt| prt.id.present? }
        parts.each do |prt|
          if prt.id.present?
            contents << prt
          end
        end
        @chapter_index = ChapterIndex.new(contents)
      end

      def chapter(id)
        chapter_index[id]
      end

      def next_chapter(chapter)
        finded = false
        each_chapter do |c|
          return c if finded
          if c == chapter
            finded = true
          end
        end
        nil # not found
      end

      def prev_chapter(chapter)
        finded = false
        each_chapter_r do |c|
          return c if finded
          if c == chapter
            finded = true
          end
        end
        nil # not found
      end

      def volume
        vol = Volume.sum(chapters.map(&:volume))
        vol.page_per_kbyte = page_metric.page_per_kbyte
        vol
      end

      def load_config(filename)
        new_conf = YAML.load_file(filename)
        @config.merge!(new_conf)
      end

      def catalog
        return @catalog if @catalog.present?

        catalogfile_path = filename_join(@basedir, config['catalogfile'])
        if File.file? catalogfile_path
          @catalog = File.open(catalogfile_path, 'r:BOM|utf-8') { |f| Catalog.new(f) }
        end
        if @catalog
          @catalog.validate!(@config, basedir)
        end
        @catalog
      end

      def read_chaps
        if catalog
          catalog.chaps
        else
          read_file(config['chapter_file'])
        end
      end

      def read_predef
        if catalog
          catalog.predef
        else
          read_file(config['predef_file'])
        end
      end

      def read_appendix
        if catalog
          catalog.appendix
        else
          read_file(config['postdef_file']) # for backward compatibility
        end
      end

      def read_postdef
        if catalog
          catalog.postdef
        else
          ''
        end
      end

      def read_part
        return @read_part if @read_part

        if catalog
          @read_part = catalog.parts
        else
          @read_part = File.read(File.join(@basedir, config['part_file']))
        end
      end

      def part_exist?
        if catalog
          catalog.parts.present?
        else
          File.exist?(File.join(@basedir, config['part_file']))
        end
      end

      def read_bib
        File.read(File.join(@basedir, bib_file))
      end

      def bib_exist?
        File.exist?(File.join(@basedir, bib_file))
      end

      def prefaces
        if catalog
          return mkpart_from_namelist(catalog.predef.split("\n"))
        end

        begin
          predef_file = filename_join(@basedir, config['predef_file'])
          if File.file?(predef_file)
            mkpart_from_namelistfile(predef_file)
          end
        rescue FileNotFound => err
          raise FileNotFound, "preface #{err.message}"
        end
      end

      def appendix
        if catalog
          names = catalog.appendix.split("\n")
          chaps = names.each_with_index.map { |n, idx| mkchap_ifexist(n, idx) }.compact
          return mkpart(chaps)
        end

        begin
          postdef_file = filename_join(@basedir, config['postdef_file'])
          if File.file?(postdef_file)
            mkpart_from_namelistfile(postdef_file)
          end
        rescue FileNotFound => err
          raise FileNotFound, "postscript #{err.message}"
        end
      end

      def postscripts
        if catalog
          mkpart_from_namelist(catalog.postdef.split("\n"))
        end
      end

      private

      def read_parts
        list = parse_chapters
        # NOTE: keep this = style to work this logic.
        if pre = prefaces
          list.unshift pre
        end
        if app = appendix
          list.push app
        end
        if post = postscripts
          list.push post
        end
        list
      end

      # return Array of Part, not Chapter
      #
      def parse_chapters
        part = 0
        num = 0

        if catalog
          return catalog.parts_with_chaps.map do |entry|
            if entry.is_a?(Hash)
              chaps = entry.values.first.map do |chap|
                chap = Chapter.new(self, num += 1, chap, File.join(contentdir, chap))
                chap
              end
              Part.new(self, part += 1, chaps, read_part.split("\n")[part - 1])
            else
              chap = Chapter.new(self, num += 1, entry, File.join(contentdir, entry))
              if chap.number
                num = chap.number
              else
                num -= 1
              end
              Part.new(self, nil, [chap])
            end
          end
        end

        chap = read_chaps.
               strip.lines.map(&:strip).join("\n").split(/\n{2,}/).
               map do |part_chunk|
          chaps = part_chunk.split.map { |chapid| Chapter.new(self, num += 1, chapid, File.join(contentdir, chapid)) }
          if part_exist? && read_part.split("\n").size > part
            Part.new(self, part += 1, chaps, read_part.split("\n")[part - 1])
          else
            Part.new(self, nil, chaps)
          end
        end
        chap
      end

      def mkpart_from_namelistfile(path)
        chaps = []
        File.read(path, mode: 'r:BOM|utf-8').split.each_with_index do |name, idx|
          if path =~ /PREDEF/
            chaps << mkchap(name)
          else
            chaps << mkchap(name, idx + 1)
          end
        end
        mkpart(chaps)
      end

      def mkpart_from_namelist(names)
        mkpart(names.map { |n| mkchap_ifexist(n) }.compact)
      end

      def mkpart(chaps)
        chaps.empty? ? nil : Part.new(self, nil, chaps)
      end

      def mkchap(name, number = nil)
        name += ext if File.extname(name).empty?
        path = File.join(contentdir, name)
        raise FileNotFound, "file not exist: #{path}" unless File.file?(path)
        Chapter.new(self, number, name, path)
      end

      def mkchap_ifexist(name, idx = nil)
        name += ext if File.extname(name).empty?
        path = File.join(contentdir, name)
        if File.file?(path)
          idx += 1 if idx
          Chapter.new(self, idx, name, path)
        end
      end

      def read_file(filename)
        unless @warn_old_files[filename]
          @warn_old_files[filename] = true
          if caller.none? { |item| item =~ %r{/review/test/test_} }
            @logger.warn "!!! #{filename} is obsoleted. please use catalog.yml."
          end
        end
        res = ''
        File.open(filename_join(@basedir, filename), 'r:BOM|utf-8') do |f|
          f.each_line do |line|
            next if /\A#/ =~ line
            line.gsub!(/#.*\Z/, '')
            res << line
          end
        end
        res
      rescue Errno::ENOENT
        Dir.glob("#{@basedir}/*#{ext}").sort.join("\n")
      rescue Errno::EISDIR
        ''
      end

      def filename_join(*args)
        File.join(args.reject(&:nil?))
      end
    end
  end
end