# plemp.rb - The Plemp! application, create your own on-line pile of junk!
# 
# Plemp! is Copyright © 2010 Paul van Tilburg <paul@luon.net>
# 
# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free Software
# Foundation; either version 2 of the License, or (at your option) any later 
# version.

require "active_record"
require "camping"
require "coderay"
require "fileutils"
require "json"
require "markaby"
require "mime/types"
require "pathname"

Camping.goes :Plemp

# We want (somewhat) indent HTML to be produced.
Markaby::Builder.set(:indent, 2)

# Global variables.
unless defined? BASE_DIR
  BASE_DIR = Pathname.new(__FILE__).dirname
  PUBLIC_DIR = BASE_DIR + "public"
  UPLOAD_DIR = BASE_DIR + "upload"

  Program = "Plemp!"
  Version = "0.1"
end

# = The Plemp module
module Plemp

  # Calls methods at application creation/setup time.
  def self.create
    Plemp::Models.create_schema
  end

end

# = The Plemp models
module Plemp::Models

  # = The draggable model class
  # 
  # This class represents an draggable object attached to an uploaded
  # file.
  class Draggable < Base
  end

  # = The basic fields class
  #
  # Class that connects model classes to database tables.
  class BasicFields < V 1.0
    def self.up
      create_table Draggable.table_name do |d|
        d.string :file
        d.integer :left, :top, :z_index
        # This gives us created_at and updated_at.
        d.timestamps
      end
    end
    
    def self.down
      drop_table Draggable.table_name
    end
  end

end # module Plemp::Models

# = The Plemp controllers
module Plemp::Controllers

  # = The index controller
  #
  # Main controller that shows the canvas with the draggable objects.
  #
  # path:: /
  # view:: Views#main
  class Index
    # Retrieves all draggables and renders the main view.
    def get
      @draggables = Draggable.all
      render :main
    end
  end

  # = The current controller
  #
  # Controller accessed through AJAX requests by the main page for getting
  # the current (global) state (position) of the draggables.
  #
  # path:: /current
  # view:: N/A
  class Current
    # Retrieves all draggables with there top/left position and returns
    # an Hash in JSON format.
    def get
      out = Hash.new
      Draggable.all.each { |d| out[d.file] = [d.left, d.top] }
      $stderr.puts("Current status requested: #{out.to_json}")
      out.to_json
    end
  end

  # = The draggable controller
  #
  # Controller that provides direct access to the HTML generating code
  # for draggable objects.
  #
  # path:: /draggable/<id>
  # view:: views#Draggable
  class DraggableX
    # Retrieves the draggable with the given _id_ from the database and
    # returns the HTML.
    def get(id)
      @drag = Draggable.find_by_file(id)
      if @drag.nil?
       @status = "404"
       return "Error 404: Unknown draggable ID: #{id}"
      end
      # Call draggable from the views, but do not wrap the layout.
      mab(false) { draggable }
    end
  end

  # = The position save controller
  #
  # Controller used through AJAX request by the main page for committing
  # position changes of the draggables to the database, i.e. the global
  # state.
  #
  # path:: /savepos/<id>/<top>/<left>
  # view:: N/A
  class SaveposXXX
    # Retrieves the draggable _file_ from the database and updates its
    # _top_ and _left_ position.
    def post(file, top, left)
      [top, left].each { |pos| pos.gsub!(/px$/, '') }
      $stderr.puts("Got: file id: #{file} -> top: #{top}, left: #{left}")
      drag = Draggable.find_by_file(file)
      drag.top = top
      drag.left = left
      drag.save
      ""
    end
  end

  # = The static controller
  #
  # Controller to serve static data from either the public or upload
  # subdirectory using X-Sendfile.
  #
  # path:: /static/(public,upload)/<file>
  # view:: N/A (X-Sendfile)
  class StaticXX
    # Determines the MIME type of the file referenced by _path_ and sets
    # the suitable headers and X-Sendfile header.  The _type_ can be either
    # _public_ if the file came with Plemp!, or _upload_ if the file was
    # once uploaded to Plemp!.
    def get(type, path)
      mime_type = MIME::Types.type_for(path).first 
      @headers['Content-Type'] = mime_type.nil? ? "text/plain" : mime_type.to_s
      unless path.include? ".." or not ["public", "upload"].include? type
        @headers['X-Sendfile'] = (BASE_DIR + type + path).to_s
      else
        @status = "403"
        "Error 403: Invalid path: #{path}"
      end
    end
  end 

  # = The upload controller
  #
  # Controller to handle uploads from the main site.  This can either
  # be a file or some pasted text.  After upload the controler redirects
  # to the main page which includes the just uploaded file.
  #
  # path:: /upload
  # redirect:: Index
  class Upload
    # Creates a text file from input text or otherise from the supplied
    # uploaded temp file.  The file name is base on the current timestamp
    # plus the appropriate extension.  Also creates an Draggable object in
    # the database.
    def post
      # TODO: store the MIME type in the database!
      # TODO: in case of text + filename, commit both.
      if @input.text.empty?
        # Text input has priority over file uploads.
        orig_ext = File.extname(@input.file[:filename]).downcase
        file_base = Time.now.strftime("%Y%m%d%H%M%S#{orig_ext}")
        contents = @input.file[:tempfile].read
      else
        file_base = Time.now.strftime("%Y%m%d%H%M%S.txt")
        contents = @input.text.chomp + "\n"
      end
      new_file = UPLOAD_DIR + file_base
      new_file.open("w") do |f|
        f.write(contents)
      end
      Draggable.create(:file => file_base, 
                       :left => 350, :top => 200, :z_index => 0)
      redirect Index
    end
  end

end # module Plemp::Controllers

# The Plemp views
module Plemp::Views

  # The main layout used by Controllers::*#render.  Loads the appropriate
  # style and JavaScript files.
  def layout
    xhtml_strict do
      head do
        title "Plemp!"
        link :rel => "stylesheet", :type => "text/css",
             :media => "screen", :href => R(StaticXX, "public", "plemp.css")
        ['prototype', 'scriptaculous', 'dragreg'].each do |js|
          script :src => R(StaticXX, "public", "#{js}.js"), 
                 :type => "text/javascript"
        end
        script :type => "text/javascript" do
          "init_plemp();"
        end 
      end
      # TODO: move this to init_plemp()?
      body(:onLoad => "return setup_draggables();") do
        self << yield
      end
    end
  end

  # The main view. Shows the header, the (hidden) add_dialog and the
  # cavnas with the draggable objects.
  def main
    div.header! do
      h1 do
        div.title! { span Program; span.subtitle! "v#{Version}" }
        div.add!(:onClick => "show_add_dialog(); return false;") { "+" }
      end
    end
    add_dialog
    draggables
  end

  # The add dialog. A hidden dialog only shown when the Plus button/key
  # is used.  Uses Controllers::Upload to upload a file or pasted text.
  def add_dialog
    div.add_dialog!(:style => "display:none;") do 
      div.background {}
      form :action => R(Upload), :method => "post", :id => "add_form",
           :enctype => "multipart/form-data" do
        h2 "Plemp it!"
        p "Scribble something below:"
        textarea :name => "text", :id => "text", :cols => 60, :rows => 12
        p do
          span "… or upload a file:"
          input :name => "file", :id => "file", :type => "file"
        end
        div.right do
          input :type => "button", :value => "Cancel", 
                :onClick => "hide_add_dialog(); return false;"
          input :type => "submit", :value => "Upload!"
        end
      end
    end 
  end

  # The canvas with draggables repsenting the objects in the database.
  def draggables
    div.draggables! do
      @draggables.each { |d| @drag = d; draggable }
    end
  end # def draggables

  # Creates a draggable HTML (block) element including the actually
  # contents of the associated file for Draggbale object _d_.
  def draggable
    file = UPLOAD_DIR + @drag.file
    unless file.exist?
      # The associated file of this Draggable object is gone, remove
      # the object from the database too.
      @drag.destroy
      return ""
    end
    # Determine the MIME type.
    file_type = `file --brief --mime-type #{file}`.chomp
    mime_type = MIME::Types[file_type].first
    if mime_type.nil?
      mime_type = MIME::Type.new(file_type)
    end
    # Create an HTML element based on the type of the Draggable object.
    default_style = "left:#{@drag.left}px;top:#{@drag.top}px;z-index:0;display:none"
    case mime_type.media_type
      when "image"
        img.draggable :id => @drag.file, :style => default_style, 
                      :src => R(StaticXX, "upload", file.basename),
                      :alt => file.basename
      when "video"
        # HTML5 is not supported by Markaby!
        self << \
        "    <video class=\"draggable\" id=\"#{@drag.file}\" " +
          "style=\"#{default_style}\" " +
          "src=\"#{R(StaticXX, "upload", @drag.file)}\" " + 
          "controls=\"true\">" + "</video>\n"
      when "audio"
        # HTML5 is not supported by Markaby!
        self <<
        "    <audio class=\"draggable\" id=\"#{@drag.file}\" " +
          "style=\"#{default_style};height=80px;\" " +
          "src=\"#{R(StaticXX, "upload", @drag.file)}\" " + 
          "controls=\"true\">" + "</audio>\n"
      when "text"
        div.draggable :id => @drag.file, :style => default_style do
          CodeRay.scan_file(file).div(:tab_width => 2, 
                                      :line_numbers => :inline)
        end
      else
        span.draggable :id => @drag.file, :style => default_style do
          em "#{@drag.file}: Unsupported file type!"
        end
    end # case
  end # def draggable

end # module Plemp::Views