# Redmine - project management software
# Copyright (C) 2006-2015  Jean-Philippe Lang
#
# 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.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

require "digest/md5"
require "fileutils"

class Attachment < ActiveRecord::Base
  belongs_to :container, :polymorphic => true
  belongs_to :author, :class_name => "User"

  validates_presence_of :filename, :author
  validates_length_of :filename, :maximum => 255
  validates_length_of :disk_filename, :maximum => 255
  validates_length_of :description, :maximum => 255
  validate :validate_max_file_size, :validate_file_extension
  attr_protected :id

  acts_as_event :title => :filename,
                :url => Proc.new {|o| {:controller => 'attachments', :action => 'download', :id => o.id, :filename => o.filename}}

  acts_as_activity_provider :type => 'files',
                            :permission => :view_files,
                            :author_key => :author_id,
                            :scope => select("#{Attachment.table_name}.*").
                                      joins("LEFT JOIN #{Version.table_name} ON #{Attachment.table_name}.container_type='Version' AND #{Version.table_name}.id = #{Attachment.table_name}.container_id " +
                                            "LEFT JOIN #{Project.table_name} ON #{Version.table_name}.project_id = #{Project.table_name}.id OR ( #{Attachment.table_name}.container_type='Project' AND #{Attachment.table_name}.container_id = #{Project.table_name}.id )")

  acts_as_activity_provider :type => 'documents',
                            :permission => :view_documents,
                            :author_key => :author_id,
                            :scope => select("#{Attachment.table_name}.*").
                                      joins("LEFT JOIN #{Document.table_name} ON #{Attachment.table_name}.container_type='Document' AND #{Document.table_name}.id = #{Attachment.table_name}.container_id " +
                                            "LEFT JOIN #{Project.table_name} ON #{Document.table_name}.project_id = #{Project.table_name}.id")

  cattr_accessor :storage_path
  @@storage_path = Redmine::Configuration['attachments_storage_path'] || File.join(Rails.root, "files")

  cattr_accessor :thumbnails_storage_path
  @@thumbnails_storage_path = File.join(Rails.root, "tmp", "thumbnails")

  before_create :files_to_final_location
  after_commit :delete_from_disk, :on => :destroy

  # Returns an unsaved copy of the attachment
  def copy(attributes=nil)
    copy = self.class.new
    copy.attributes = self.attributes.dup.except("id", "downloads")
    copy.attributes = attributes if attributes
    copy
  end

  def validate_max_file_size
    if @temp_file && self.filesize > Setting.attachment_max_size.to_i.kilobytes
      errors.add(:base, l(:error_attachment_too_big, :max_size => Setting.attachment_max_size.to_i.kilobytes))
    end
  end

  def validate_file_extension
    if @temp_file
      extension = File.extname(filename)
      unless self.class.valid_extension?(extension)
        errors.add(:base, l(:error_attachment_extension_not_allowed, :extension => extension))
      end
    end
  end

  def file=(incoming_file)
    unless incoming_file.nil?
      @temp_file = incoming_file
      if @temp_file.size > 0
        if @temp_file.respond_to?(:original_filename)
          self.filename = @temp_file.original_filename
          self.filename.force_encoding("UTF-8")
        end
        if @temp_file.respond_to?(:content_type)
          self.content_type = @temp_file.content_type.to_s.chomp
        end
        self.filesize = @temp_file.size
      end
    end
  end

  def file
    nil
  end

  def filename=(arg)
    write_attribute :filename, sanitize_filename(arg.to_s)
    filename
  end

  # Copies the temporary file to its final location
  # and computes its MD5 hash
  def files_to_final_location
    if @temp_file && (@temp_file.size > 0)
      self.disk_directory = target_directory
      self.disk_filename = Attachment.disk_filename(filename, disk_directory)
      logger.info("Saving attachment '#{self.diskfile}' (#{@temp_file.size} bytes)") if logger
      path = File.dirname(diskfile)
      unless File.directory?(path)
        FileUtils.mkdir_p(path)
      end
      md5 = Digest::MD5.new
      File.open(diskfile, "wb") do |f|
        if @temp_file.respond_to?(:read)
          buffer = ""
          while (buffer = @temp_file.read(8192))
            f.write(buffer)
            md5.update(buffer)
          end
        else
          f.write(@temp_file)
          md5.update(@temp_file)
        end
      end
      self.digest = md5.hexdigest
    end
    @temp_file = nil

    if content_type.blank? && filename.present?
      self.content_type = Redmine::MimeType.of(filename)
    end
    # Don't save the content type if it's longer than the authorized length
    if self.content_type && self.content_type.length > 255
      self.content_type = nil
    end
  end

  # Deletes the file from the file system if it's not referenced by other attachments
  def delete_from_disk
    if Attachment.where("disk_filename = ? AND id <> ?", disk_filename, id).empty?
      delete_from_disk!
    end
  end

  # Returns file's location on disk
  def diskfile
    File.join(self.class.storage_path, disk_directory.to_s, disk_filename.to_s)
  end

  def title
    title = filename.to_s
    if description.present?
      title << " (#{description})"
    end
    title
  end

  def increment_download
    increment!(:downloads)
  end

  def project
    container.try(:project)
  end

  def visible?(user=User.current)
    if container_id
      container && container.attachments_visible?(user)
    else
      author == user
    end
  end

  def editable?(user=User.current)
    if container_id
      container && container.attachments_editable?(user)
    else
      author == user
    end
  end

  def deletable?(user=User.current)
    if container_id
      container && container.attachments_deletable?(user)
    else
      author == user
    end
  end

  def image?
    !!(self.filename =~ /\.(bmp|gif|jpg|jpe|jpeg|png)$/i)
  end

  def thumbnailable?
    image?
  end

  # Returns the full path the attachment thumbnail, or nil
  # if the thumbnail cannot be generated.
  def thumbnail(options={})
    if thumbnailable? && readable?
      size = options[:size].to_i
      if size > 0
        # Limit the number of thumbnails per image
        size = (size / 50) * 50
        # Maximum thumbnail size
        size = 800 if size > 800
      else
        size = Setting.thumbnails_size.to_i
      end
      size = 100 unless size > 0
      target = File.join(self.class.thumbnails_storage_path, "#{id}_#{digest}_#{size}.thumb")

      begin
        Redmine::Thumbnail.generate(self.diskfile, target, size)
      rescue => e
        logger.error "An error occured while generating thumbnail for #{disk_filename} to #{target}\nException was: #{e.message}" if logger
        return nil
      end
    end
  end

  # Deletes all thumbnails
  def self.clear_thumbnails
    Dir.glob(File.join(thumbnails_storage_path, "*.thumb")).each do |file|
      File.delete file
    end
  end

  def is_text?
    Redmine::MimeType.is_type?('text', filename)
  end

  def is_diff?
    self.filename =~ /\.(patch|diff)$/i
  end

  # Returns true if the file is readable
  def readable?
    File.readable?(diskfile)
  end

  # Returns the attachment token
  def token
    "#{id}.#{digest}"
  end

  # Finds an attachment that matches the given token and that has no container
  def self.find_by_token(token)
    if token.to_s =~ /^(\d+)\.([0-9a-f]+)$/
      attachment_id, attachment_digest = $1, $2
      attachment = Attachment.where(:id => attachment_id, :digest => attachment_digest).first
      if attachment && attachment.container.nil?
        attachment
      end
    end
  end

  # Bulk attaches a set of files to an object
  #
  # Returns a Hash of the results:
  # :files => array of the attached files
  # :unsaved => array of the files that could not be attached
  def self.attach_files(obj, attachments)
    result = obj.save_attachments(attachments, User.current)
    obj.attach_saved_attachments
    result
  end

  # Updates the filename and description of a set of attachments
  # with the given hash of attributes. Returns true if all
  # attachments were updated.
  #
  # Example:
  #   Attachment.update_attachments(attachments, {
  #     4 => {:filename => 'foo'},
  #     7 => {:filename => 'bar', :description => 'file description'}
  #   })
  #
  def self.update_attachments(attachments, params)
    params = params.transform_keys {|key| key.to_i}

    saved = true
    transaction do
      attachments.each do |attachment|
        if p = params[attachment.id]
          attachment.filename = p[:filename] if p.key?(:filename)
          attachment.description = p[:description] if p.key?(:description)
          saved &&= attachment.save
        end
      end
      unless saved
        raise ActiveRecord::Rollback
      end
    end
    saved
  end

  def self.latest_attach(attachments, filename)
    attachments.sort_by(&:created_on).reverse.detect do |att|
      filename.casecmp(att.filename) == 0
    end
  end

  def self.prune(age=1.day)
    Attachment.where("created_on < ? AND (container_type IS NULL OR container_type = '')", Time.now - age).destroy_all
  end

  # Moves an existing attachment to its target directory
  def move_to_target_directory!
    return unless !new_record? & readable?

    src = diskfile
    self.disk_directory = target_directory
    dest = diskfile

    return if src == dest

    if !FileUtils.mkdir_p(File.dirname(dest))
      logger.error "Could not create directory #{File.dirname(dest)}" if logger
      return
    end

    if !FileUtils.mv(src, dest)
      logger.error "Could not move attachment from #{src} to #{dest}" if logger
      return
    end

    update_column :disk_directory, disk_directory
  end

  # Moves existing attachments that are stored at the root of the files
  # directory (ie. created before Redmine 2.3) to their target subdirectories
  def self.move_from_root_to_target_directory
    Attachment.where("disk_directory IS NULL OR disk_directory = ''").find_each do |attachment|
      attachment.move_to_target_directory!
    end
  end

  # Returns true if the extension is allowed, otherwise false
  def self.valid_extension?(extension)
    extension = extension.downcase.sub(/\A\.+/, '')

    denied, allowed = [:attachment_extensions_denied, :attachment_extensions_allowed].map do |setting|
      Setting.send(setting).to_s.split(",").map {|s| s.strip.downcase.sub(/\A\.+/, '')}.reject(&:blank?)
    end
    if denied.present? && denied.include?(extension)
      return false
    end
    unless allowed.blank? || allowed.include?(extension)
      return false
    end
    true
  end

  private

  # Physically deletes the file from the file system
  def delete_from_disk!
    if disk_filename.present? && File.exist?(diskfile)
      File.delete(diskfile)
    end
  end

  def sanitize_filename(value)
    # get only the filename, not the whole path
    just_filename = value.gsub(/\A.*(\\|\/)/m, '')

    # Finally, replace invalid characters with underscore
    just_filename.gsub(/[\/\?\%\*\:\|\"\'<>\n\r]+/, '_')
  end

  # Returns the subdirectory in which the attachment will be saved
  def target_directory
    time = created_on || DateTime.now
    time.strftime("%Y/%m")
  end

  # Returns an ASCII or hashed filename that do not
  # exists yet in the given subdirectory
  def self.disk_filename(filename, directory=nil)
    timestamp = DateTime.now.strftime("%y%m%d%H%M%S")
    ascii = ''
    if filename =~ %r{^[a-zA-Z0-9_\.\-]*$}
      ascii = filename
    else
      ascii = Digest::MD5.hexdigest(filename)
      # keep the extension if any
      ascii << $1 if filename =~ %r{(\.[a-zA-Z0-9]+)$}
    end
    while File.exist?(File.join(storage_path, directory.to_s, "#{timestamp}_#{ascii}"))
      timestamp.succ!
    end
    "#{timestamp}_#{ascii}"
  end
end