# = Trivium -- a minimalist blogging engine
#
# Copyright (C) 2008 Christian Neukirchen <purl.org/net/chneukirchen>
# Licensed under the terms of the MIT license.

require 'time'; require 'cgi'
$: << "vendor"
require 'bluecloth'; require 'rubypants'; require 'htemplate'
BlueCloth::EMPTY_ELEMENT_SUFFIX.replace(">")

Dir.mkdir("html")  rescue true

def File.write(name, content)
  File.open(name, "wb") { |out| out << content }
  puts name
end

def dep(dst, *srcs)
  yield dst  unless srcs.all? { |src|
               (File.mtime(src) < File.mtime(dst) rescue false) }
end

def parse(f)
  head, body = File.read(f).split("\n\n", 2)  rescue (return nil)
  entry = {:body => body, :id => File.basename(f, ".entry"), :file => f}
  head.scan(/(\w+): *(.*)/) { entry[$1.downcase.to_sym] = $2 }
  entry[:date] = Time.parse(entry[:date])  if entry[:date]
  entry[:updated] = entry[:updated] ? Time.parse(entry[:updated]) : entry[:date]
  entry[:title] = entry[:date].strftime("%d%b%Y").downcase  if entry[:date]
  entry
end

Entry = Hash.new { |h, k| h[k] = parse k }
ENTRIES = Dir.glob("entries/*.entry").map { |x| Entry[x] }.
                                      sort_by { |f| f[:date] }.reverse
Entry.values.each { |v| Entry[v[:id]] = v }

class SpanBlueCloth < BlueCloth
  # Don't do block transforms.
  alias apply_block_transforms apply_span_transforms

  def to_html
    super.rstrip
  end
end

class InlineMath < String
  MATH_TEX = 'http://vuxu.org/~chris/mathtex/mathtex.cgi?' +
    CGI.escape('\textstyle{}\usepackage{color}' +
               '\color{white}\rule[-0.333em]{0.01pt}{1.2em}\color{black}')
  
  def to_html
    gsub(/\$(.*?)\$/) {
      html = CGI.escapeHTML($1)
      formula = CGI.escape($1).gsub('+', '%20')
      %{<img class="inline-math" alt="#{html}" src="#{MATH_TEX}#{formula}">}
    }
  end
end

class Dots < String
  MATH_TEX = "http://vuxu.org/~chris/mathtex/mathtex.cgi?"

  def to_html
    gsub(/^\.(\w+)([^\n]*?)\n(.*?)^\.\1\.$/m) {
      name, args, body = $1, $2, $3
      case name
      when "link"
        title, desc = body.split("|", 2)
        warn "forgot link: #{title.strip}"  if args.strip.empty?
        %{<p class="link"><span><a href="#{CGI.escapeHTML(args.strip)}">#{
          title.strip}</a>#{SpanBlueCloth.new(desc.to_s).to_html}</span></p>}
      when "quote"
        if args.strip.empty?
          src = ""
        else
          src = %{<span class="source">&#x2014; #{args.strip}</span>}
        end
        text = (body + src).gsub(/^ +/) { "&#x2002;" * $&.size }.
                            gsub(/^.*$/, '> \&  ')
        %{<div class="quote">#{BlueCloth.new(text).to_html}</div>}
      when "math"
        body << "\\eqno{#{args.strip}}"  unless args.strip.empty?
        %{<div class="math"><img alt="#{CGI.escapeHTML body}" src="#{
          MATH_TEX}#{CGI.escape(body).gsub('+', '%20')}"></div>}
      when "thumb"
        '<div class="thumbs">' + body.split(/\n{2,}/).map { |para|
          alt, thumb, img = para.strip.split("\n", 3)
          %{<a class="thumb" href="#{img}"><img src="#{thumb}" alt="#{alt}"></a>}
        }.join("\n") + '</div>'
      else
        %{<div class="#{name}">#{
          BlueCloth.new(Dots.new(body).to_html).to_html}</div>}
      end
    }
  end
end

def format(e)
  [InlineMath, Dots, BlueCloth, RubyPants].inject(e[:body]) { |a,e|
    e.new(a).to_html
  }
end

def template(template, data)
  HTemplate.new(File.read(template), template).expand(data)
end

def group(entries, &block)
  r = {};  entries.each { |e| (r[block[e]] ||= []) << e };  r
end

def inner_sort(group, &block)
  group.each { |key, entries| entries.sort_by(&block) }
end

def outer_sort(group, &block)
  group.sort_by(&block)
end

def chain(group, name)
  group.each_with_index { |(key, entries), i|
    entries.each { |e|
      e[:"next_by_#{name}"] = group[i+1][0]  if group[i+1]
      e[:"prev_by_#{name}"] = group[i-1][0]  if i > 0
    }
  }
end

def deps(e)
  [e[:id], e[:next_by_date], e[:prev_by_date]].compact.map {|z| Entry[z][:file] }
end

single_by_date = group(ENTRIES) { |e| e[:id] }
single_by_date = outer_sort(single_by_date) { |k,e| e.first[:date] }
chain(single_by_date, "date")
      
single_by_date.each { |date, entries|
  entry = entries.first
  dep "html/#{entry[:id]}.html", "template/single.ht", *deps(entry) do |dst|
    File.write(dst, template("template/single.ht", entry))
  end
}

monthly = group(ENTRIES) { |e| e[:date].strftime("%Y-%m") }
inner_sort(monthly) { |e| e[:date] }
monthly = outer_sort(monthly) { |k,e| e.first[:date] }
chain(monthly, "month")

monthly.each { |month, entries|
  entry = entries.first
  dep "html/#{month}.html", "template/monthly.ht", *deps(entry) do |dst|
    File.write(dst, template("template/monthly.ht",
                             :entries => entries, :month => month))
  end
}

front = ENTRIES.first(10)
d = front.map { |e| e[:file] }
dep "html/index.html", "template/front.ht", *d do |dst|
  File.write(dst, template("template/front.ht",
                           :entries => front, :next => monthly.last))
end

feed = ENTRIES.first(20)
d = feed.map { |e| e[:file] }
dep "html/index.atom", "template/atom.ht", *d do |dst|
  File.write(dst, template("template/atom.ht",
                           :entries => feed, :time => Time.now))
end
dep "html/index.json", "template/json.ht", *d do |dst|
  File.write(dst, template("template/json.ht",
                           :entries => feed, :time => Time.now))
end

system "rsync -r data/ html"