# Copyright (C) 2012-2014 Zammad Foundation, http://zammad-foundation.org/

require 'mail'

module Channel::EmailBuild

=begin

  mail = Channel::EmailBuild.build(
    from: 'sender@example.com',
    to: 'recipient@example.com',
    body: 'somebody with some text',
    content_type: 'text/plain',
  )

=end

  def self.build(attr, notification = false)
    mail = Mail.new

    # set organization
    organization = Setting.get('organization')
    if organization
      mail['Organization'] = organization.to_s
    end

    # notification
    if notification
      attr['X-Loop']                   = 'yes'
      attr['Precedence']               = 'bulk'
      attr['Auto-Submitted']           = 'auto-generated'
      attr['X-Auto-Response-Suppress'] = 'All'
    end

    #attr['X-Powered-BY'] = 'Zammad - Support/Helpdesk (http://www.zammad.org/)'
    attr['X-Mailer'] = 'Zammad Mail Service (1.x)'

    # set headers
    attr.each do |key, value|
      next if key.to_s == 'attachments'
      next if key.to_s == 'body'
      next if key.to_s == 'content_type'
      mail[key.to_s] = if value && value.class != Array
                         value.to_s
                       else
                         value
                       end
    end

    # add html part
    if attr[:content_type] && attr[:content_type] == 'text/html'
      html_alternative = Mail::Part.new do
        content_type 'text/html; charset=UTF-8'

        # complete check
        html_document = Channel::EmailBuild.html_complete_check(attr[:body])

        body html_document
      end

      # generate plain part
      attr[:body] = attr[:body].html2text
    end

    # add plain text part
    text_alternative = Mail::Part.new do
      content_type 'text/plain; charset=UTF-8'
      body attr[:body]
    end

    # build email without any attachments
    if !html_alternative && ( !attr[:attachments] || attr[:attachments].empty? )
      mail.content_type 'text/plain; charset=UTF-8'
      mail.body attr[:body]
      return mail
    end

    # build email with attachments
    alternative_bodies = Mail::Part.new { content_type 'multipart/alternative' }
    alternative_bodies.add_part text_alternative

    if html_alternative
      html_container = Mail::Part.new { content_type 'multipart/related' }
      html_container.add_part html_alternative

      # place to add inline attachments related to html alternative
      if attr[:attachments]
        attr[:attachments].each do |attachment|
          next if attachment.class == Hash
          next if attachment.preferences['Content-ID'].empty?
          attachment = Mail::Part.new do
            content_type attachment.preferences['Content-Type']
            content_id "<#{attachment.preferences['Content-ID']}>"
            content_disposition attachment.preferences['Content-Disposition'] || 'inline'
            content_transfer_encoding 'binary'
            body attachment.content.force_encoding('BINARY')
          end
          html_container.add_part attachment
        end
      end
      alternative_bodies.add_part html_container
    end

    mail.add_part alternative_bodies

    # add attachments
    if attr[:attachments]
      attr[:attachments].each do |attachment|
        if attachment.class == Hash
          attachment['content-id'] = nil
          mail.attachments[ attachment[:filename] ] = attachment
        else
          next if !attachment.preferences['Content-ID'].empty?
          filename = attachment.filename
          encoded_filename = Mail::Encodings.decode_encode filename, :encode
          disposition = attachment.preferences['Content-Disposition'] || 'attachment'
          content_type = attachment.preferences['Content-Type'] || 'application/octet-stream'
          mail.attachments[attachment.filename] = {
            content_disposition: "#{disposition}; filename=\"#{encoded_filename}\"",
            content_type: "#{content_type}; filename=\"#{encoded_filename}\"",
            content: attachment.content
          }
        end
      end
    end
    mail
  end

=begin

Check if string is a complete html document. If not, add head and css styles.

  full_html_document_string = Channel::EmailBuild.html_complete_check(html_string)

=end

  def self.html_complete_check(html)

    # apply mail client fixes
    html = Channel::EmailBuild.html_mail_client_fixes(html)

    return html if html =~ /<html>/i

    css = "font-family:'Helvetica Neue', Helvetica, Arial, Geneva, sans-serif; font-size: 12px;"

    html = <<HERE
<!DOCTYPE html>
<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
    <style type="text/css">
      body {
        width: 90% !important;
        -webkit-text-size-adjust: 90%;
        -ms-text-size-adjust: 90%;
        #{css};
      }
      img {
        outline: none;
        text-decoration: none;
        -ms-interpolation-mode: bicubic;
      }
      a img {
        border: none;
      }
      table td {
        border-collapse: collapse;
      }
      table {
        border-collapse: collapse;
        mso-table-lspace: 0pt;
        mso-table-rspace: 0pt;
        border: none;
        table-layout: auto;
        display: block;
        width: 100%;
        overflow: auto;
        word-break: keep-all;
      }
      p, table, div, td {
        max-width: 600px;
      }
      table,
      pre,
      blockquote {
        margin: 0 0 16px;
      }
      td, th {
        padding: 7px 12px;
        border: 1px solid hsl(0,0%,87%);
      }
      th {
        font-weight: bold;
        text-align: center;
      }
      tbody tr:nth-child(even) {
        background: hsl(0,0%,97%);
      }
      col {
        width: auto;
      }
      p {
        margin: 0;
      }
      code {
        border: none;
        background: hsl(0,0%,97%);
        white-space: pre-wrap;
      }
      blockquote {
        padding: 8px 12px;
        border-left: 5px solid #eee;
      }
      pre {
        padding: 12px 15px;
        font-size: 13px;
        line-height: 1.45;
        background: hsl(0,0%,97%);
        white-space: pre-wrap;
        border-radius: 3px;
        border: none;
        overflow: auto;
      }
    </style>
  <head>
  <body style="#{css}">#{html}</body>
</html>
HERE

    html
  end

=begin

Add/change markup to display html in any mail client nice.

  html_string_with_fixes = Channel::EmailBuild.html_mail_client_fixes(html_string)

=end

  def self.html_mail_client_fixes(html)

    # https://github.com/martini/zammad/issues/165
    new_html = html.gsub('<blockquote type="cite">', '<blockquote type="cite" style="border-left: 2px solid blue; margin: 0 0 16px; padding: 8px 12px 8px 12px;">')
    new_html.gsub!('<p>', '<p style="margin: 0;">')
    new_html
  end

end