#!/usr/bin/ruby -I../lib

require 'fusefs'
require 'livejournal/database'
require 'livejournal/entry'
require 'stringio'

class DBQuery
  def initialize
    @db = $db
  end
  def has_any?(where, *args)
    exists = @db.db.get_first_value("SELECT itemid #{where} LIMIT 1", *args)
    exists != nil
  end
  def has_year? year
    has_any?("FROM entry WHERE year=?", year)
  end
  def has_month? year, month
    has_any?("FROM entry WHERE year=? AND month=?", year, month)
  end
  def has_day? year, month, day
    has_any?("FROM entry WHERE year=? AND month=? AND day=?", year, month, day)
  end
  def has_entry? itemid
    has_any?("FROM entry WHERE itemid=?", itemid)
  end

  def get_array(sql, *args)
    array = []
    @db.db.execute("SELECT DISTINCT #{sql}", *args) do |row|
      array << row[0]
    end
    array
  end

  def years
    get_array('year FROM entry')
  end
  def months year
    get_array('month FROM entry WHERE year=?', year).map { |m| "%02d" % m }
  end
  def days year, month
    get_array('day FROM entry WHERE year=? AND month=?', year, month).map { |d| "%02d" % d }
  end

  def day_entries year, month, day
    get_array('itemid FROM entry WHERE year=? AND month=? AND day=?',
              year, month, day)
  end
end

class Dispatcher < FuseFS::FuseDir
  def initialize
    @matches = []
  end
  def register(match, target)
    @matches << [match, target]
  end

  def dispatch(sym, path, *args)
    path, rest = split_path path if path
    if path
      @matches.each do |match, target|
        if path =~ match
          return target.dispatch(sym, rest, *(args+[path]))
        end
      end
    end

    # otherwise, dispatch it to the current object
    begin
      s = self.send(sym, path, *args)
    rescue
      p $!
    end
    return s
  end
end

class DispatchDir < FuseFS::FuseDir
  def initialize dispatcher
    @dispatcher = dispatcher
  end

  def self.add_dispatch(*args)
    args.each do |sym|
      class_eval %{def #{sym}(path, *args)
        @dispatcher.dispatch(#{sym.inspect}, path, *args)
      end}
    end
  end

  add_dispatch :directory?, :file?
  add_dispatch :contents, :read_file
end

class LJFS < Dispatcher
  class Day < Dispatcher
    def contents path, year, mon, day
      entries = $dbq.day_entries year, mon, day
      entries.map do |itemid|
        "#{itemid}.txt"
      end
    end
    def directory? path, year, mon, day
      path == nil and $dbq.has_day? year, mon, day
    end
    def file? path, year, mon, day
      return false unless $dbq.has_day? year, mon, day
      return false unless path =~ /^(\d+)\.txt$/
      itemid = $1
      return false unless $dbq.has_entry? itemid
      true
    end
    def read_file path, year, mon, day
      return false unless $dbq.has_day? year, mon, day
      return false unless path =~ /^(\d+)\.txt$/
      itemid = $1
      return false unless $dbq.has_entry? itemid
      entry = $db.get_entry itemid
      out = StringIO.new
      if entry.subject
        out.puts entry.subject
        out.puts("=" * entry.subject.length)
        out.puts
      end
      out.puts entry.event
      out.rewind
      return out.read
    end
  end
  class Month < Dispatcher
    def initialize
      super
      register(/^\d{2}/, Day.new)
    end
    def directory? path, year, mon
      path == nil and $dbq.has_month? year, mon
    end
    def file? path, year, mon
      false
    end
    def contents path, year, mon
      $dbq.days year, mon
    end
  end

  class Year < Dispatcher
    def initialize
      super
      register(/^\d{2}/, Month.new)
    end
    def directory? path, year
      path == nil and $dbq.has_year? year
    end
    def file? path, year
      false
    end
    def contents path, year
      $dbq.months year
    end
  end

  def initialize
    super
    register(/^\d{4}$/, Year.new)
  end

  def directory? path
    return false
  end
  def file? path
    return path == 'username'
  end
  def read_file path
    return $db.username
  end
  def contents *args
    return ['username'] + $dbq.years
  end
end

unless ARGV.length == 2
  puts "usage: #{$0} dbfile mountpoint"
  exit 1
end
dbfile, mountpoint = ARGV

$db = LiveJournal::Database.new dbfile
$dbq = DBQuery.new  # temp hack
root = DispatchDir.new LJFS.new

FuseFS.set_root root
FuseFS.mount_under mountpoint
FuseFS.run

# vim: ts=2 sw=2 et :