#! /usr/bin/env ruby
# -*- coding: UTF-8 -*-

require 'redcarpet'

module ImANerdRules

    class CustomRender < Redcarpet::Render::HTML
        def header(text, header_level)
            text =~ /([\d+\.?]+)/
            "<h#{header_level} id=\"hdr#{$1}\">#{text}</h#{header_level}>"
        end
        def image link, title, alt_text
            "<a data-fancybox='gallery' data-caption='#{title}' href='#{link}'><img src='#{link.gsub(/.png/,'_th.png')}'></a>"
        end
    end

    class Node
        include Enumerable
        @@glossary = {}
        # @@line_num = 0
        attr_reader :name, :parent, :content
        def self.glossary
            @@glossary
        end
        def initialize name, lvl, parent
            @name = name
            @lvl = lvl
            @parent = parent
            @children = nil
        end
        def add name
            @children ||= []
            @children << Node.new( name, @lvl + 1, self)
            @children[-1]
        end
        def lvl o=nil, r=''
            if not (o.nil? or @children.nil?)
                r = (@children.index(o) + 1).to_s + '.'*(r.length > 0 ? 1 : 0) + r
            end
            return r if @parent.nil?
            @parent.lvl(self, r)    # tail recursive
        end
        def each &block
            yield self
            @children.each { |n| n.each &block } unless @children.nil?
        end
        def to_s r=''
            r += "\n#{lvl}" + ' ' * (10-lvl.length) + ' ' + @name
            return r if @children.nil?
            @children.inject(r) { |r,c| c.to_s(r) }
        end
        def set_meta name, value
            instance_variable_set("@#{name}", value)
            if not self.class.method_defined? name.to_sym
                self.class.define_method(name.to_sym) { instance_variable_get "@#{name}" }
            end
        end
        def load dirname
            out = false
            meta = false
            @content = ''
            File.read(File.join(dirname, @name+'.md')).each_line { |l|
                if l =~ /^---\s*/
                    meta = !meta
                    out = true if not meta
                    next
                end
                if meta
                    if l =~ /(\w+)\s*:\s*(.+)/
                        set_meta $1, $2
                    end
                end
                Node.glossary.each { |k,v|
                    r = /#{k}/
                    if l =~ r
                        # @@line_num += 1
                        # l.gsub! r, "<span id='ref#{@@line_num}'> [#{k}](#glos#{v[0]}) </span>"
                        l.gsub! r, "[#{k}](#glos#{v[0]})"
                        r = v[-1]
                        if r.empty? or r[-1] != self
                            r <<  self
                        end
                    end
                }
                @content += l if out
            }
            # FIXME
            # @content += "[toc](#ptoc)"
        end
        def href
            "#hdr#{lvl}"
        end
        def title_md
            "#{'#' * (@lvl+1)}  #{lvl} #{title}"
        end
        def anchor
            "<div id='#{@lvl == 0 ? 'ptoc' : 'p'+lvl}'>"
        end
        def toc
            return '' if @lvl == 0
            "#{'  ' * @lvl} #{'*' * (@lvl > 0 ? 1 : 0)} #{lvl} [#{@title}](#{href})\n"
        end
    end

    class Doc < Node
        def initialize dirname
            @dirname = dirname
            super nil, 0, nil
            @silent = false
        end
        def error line, line_num, why
            puts "#{line_num} : >#{line}< : #{why}"
            exit 1
        end
        def say what
            puts what unless @silent
        end
        def read_toc filename
            level = 0
            node = self
            last = nil
            File.foreach(File.join @dirname, filename).with_index do |line, line_num|
                line.chomp!
                if line =~ /^\s*(-*)\s*(\w+)$/
                    l = $1.length
                    entry = $2
                else
                    error line, line_num, "line not matching"
                end
                if l > (level + 1)
                    error line, line_num, "too deep in one step (from #{level} to #{l})"
                elsif l == (level + 1)
                    level = l
                    node = last
                elsif l < level
                    while level > l
                        node = node.parent
                        level -= 1
                    end
                end
                last = node.add entry
            end
        end
        def read_glossary filename
            g=1
            File.foreach(File.join @dirname, filename).with_index do |line, line_num|
                line.chomp!
                if line =~ /^\s*(.+)\s:\s(.+)\s:\s(.+)\s*$/
                    Node.glossary[$1] = [g, $2, $3, []]
                    g += 1
                else
                    error line, line_num, "line not matching"
                end
            end
        end
        def print_toc
            each { |n| puts "#{n.lvl}#{' ' * (10-n.lvl.length)} #{n.name}" }
        end
        def load dirname
        end
        def load_content header
            @header = header
            each { |n| n.load @dirname }
        end
        def content
            inject('') { |a,n| a+= n.toc }
        end
        def glossary
            c='<h2>Glossary</h2><dl>'
            Node.glossary.keys.sort.each { |k|
                v = Node.glossary[k]
                n = select { |n| n.name == v[2]}
                error "--", 0, "glossary '#{k} does not link to a known chapter" if n.size != 1
                n = n[0]
                c += "<dt id='glos#{v[0]}'>#{k}</dt><dd>#{v[1]}</br>\n"
                c += "<a href='#{n.href}'>#{n.name}</a>\n"
                o = v[-1].select{|e| e!=n }.collect{ |e| "<a href='#{e.href}'>#{e.name}</a>" }.join(',')
                c += ' + ' + o unless o.empty?
                c += "</dd></br>"
            }
            c + '</dl>'
        end
        def gen_html outf, html_header, html_footer
            md = Redcarpet::Markdown.new(CustomRender, {})
            File.open(outf,'w') { |f|
                f.write File.read(html_header)
                f.write md.render(File.read(File.join @dirname, @header))
                each { |n|
                    f.write md.render(n.title_md) + "\n#{n.anchor}\n"
                    f.write md.render(n.content) + "\n</div>\n"
                }
                f.write glossary
                f.write File.read(html_footer)
            }
            say "#{outf} generated"
        end
    end
end

if __FILE__ == $0

    doc = ImANerdRules::Doc.new './TankOnTank'
    doc.read_toc '_toc'
    doc.read_glossary '_glossary'
    doc.load_content 'header.md'
    doc.gen_html 'TankOnTank.html', 'header', 'footer'

    exit 0
end

# EOF