# Copyright (c) 2008-2013 Michael Dvorkin and contributors.
#
# Fat Free CRM is freely distributable under the terms of MIT license.
# See MIT-LICENSE file or http://www.opensource.org/licenses/mit-license.php
#------------------------------------------------------------------------------
require 'fat_free_crm/mail_processor/base'

module FatFreeCRM
  module MailProcessor
    class Dropbox < Base
      KEYWORDS = %w(account campaign contact lead opportunity).freeze

      #--------------------------------------------------------------------------------------
      def initialize
        # Models are autoloaded, so the following @@assets class variable should only be set
        # when Dropbox is initialized. This needs to be done so that Rake tasks such as
        # 'assets:precompile' can run on Heroku without depending on a database.
        # See: http://devcenter.heroku.com/articles/rails31_heroku_cedar#troubleshooting
        @@assets = [Account, Contact, Lead].freeze
        @settings = Setting.email_dropbox.dup
        super
      end

      private

      # Email processing pipeline: each steps gets executed if previous one returns false.
      #--------------------------------------------------------------------------------------
      def process(_uid, email)
        with_explicit_keyword(email) do |keyword, name|
          data = { "Type" => keyword, "Name" => name }
          find_or_create_and_attach(email, data)
        end && return

        with_recipients(email) do |recipient|
          find_and_attach(email, recipient)
        end && return

        with_forwarded_recipient(email) do |recipient|
          find_and_attach(email, recipient)
        end && return

        with_recipients(email) do |recipient|
          create_and_attach(email, recipient)
        end && return

        with_forwarded_recipient(email) do |recipient|
          create_and_attach(email, recipient)
        end
      end

      # Checks the email to detect keyword on the first line.
      #--------------------------------------------------------------------------------------
      def with_explicit_keyword(email)
        first_line = plain_text_body(email).split("\n").first
        if first_line =~ %r{(#{KEYWORDS.join('|')})[^a-zA-Z0-9]+(.+)$}i
          yield Regexp.last_match[1].capitalize, Regexp.last_match[2].strip
        end
      end

      # Checks the email to detect assets on to/bcc addresses
      #--------------------------------------------------------------------------------------
      def with_recipients(email, _options = {})
        recipients = []
        recipients += email.to_addrs unless email.to.blank?
        recipients += email.cc_addrs unless email.cc.blank?

        # Ignore the dropbox email address, and any address aliases
        ignored_addresses = [@settings[:address]]
        if @settings[:address_aliases].is_a?(Array)
          ignored_addresses += @settings[:address_aliases]
        end
        recipients -= ignored_addresses

        # Process each recipient until email has been attached
        recipients.each do |recipient|
          return true if yield recipient
        end
        false
      end

      # Checks the email to detect valid email address in body (first email), detect forwarded emails
      #----------------------------------------------------------------------------------------
      def with_forwarded_recipient(email, _options = {})
        if plain_text_body(email) =~ /\b([a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,4})\b/
          yield Regexp.last_match[1]
        end
      end

      # Process pipe_separated_data or explicit keyword.
      #--------------------------------------------------------------------------------------
      def find_or_create_and_attach(email, data)
        klass = data["Type"].constantize

        if data["Email"] && klass.new.respond_to?(:email)
          conditions = [
            "(lower(email) = ? OR lower(alt_email) = ?)",
            data["Email"].downcase,
            data["Email"].downcase
          ]
        elsif klass.new.respond_to?(:first_name)
          first_name, *last_name = data["Name"].split
          conditions = if last_name.empty? # Treat single name as last name.
                         ['last_name LIKE ?', "%#{first_name}"]
                       else
                         ['first_name LIKE ? AND last_name LIKE ?', "%#{first_name}", "%#{last_name.join(' ')}"]
          end
        else
          conditions = ['name LIKE ?', "%#{data['Name']}%"]
        end

        # Find the asset from deduced conditions
        if asset = klass.where(conditions).first
          if sender_has_permissions_for?(asset)
            attach(email, asset, :strip_first_line)
          else
            log "Sender does not have permissions to attach email to #{data['Type']} #{data['Email']} <#{data['Name']}>"
          end
        else
          log "#{data['Type']} #{data['Email']} <#{data['Name']}> not found, creating new one..."
          asset = klass.create!(default_values(klass, data))
          attach(email, asset, :strip_first_line)
        end
        true
      end

      #----------------------------------------------------------------------------------------
      def find_and_attach(email, recipient)
        attached = false
        @@assets.each do |klass|
          asset = klass.where(["(lower(email) = ?)", recipient.downcase]).first

          # Leads and Contacts have an alt_email: try it if lookup by primary email has failed.
          if !asset && klass.column_names.include?("alt_email")
            asset = klass.where(["(lower(alt_email) = ?)", recipient.downcase]).first
          end

          if asset && sender_has_permissions_for?(asset)
            attach(email, asset)
            attached = true
          end
        end
        attached
      end

      #----------------------------------------------------------------------------------------
      def create_and_attach(email, recipient)
        contact = Contact.create!(default_values_for_contact(email, recipient))
        attach(email, contact)
      end

      #----------------------------------------------------------------------------------------
      def attach(email, asset, strip_first_line = false)
        # If 'sent_to' email cannot be found, default to Dropbox email address
        to = email.to.blank? ? @settings[:address] : email.to.join(", ")
        cc = email.cc.blank? ? nil : email.cc.join(", ")

        email_body = if strip_first_line
                       plain_text_body(email).split("\n")[1..-1].join("\n").strip
                     else
                       plain_text_body(email)
        end

        Email.create(
          imap_message_id: email.message_id,
          user:            @sender,
          mediator:        asset,
          sent_from:       email.from.first,
          sent_to:         to,
          cc:              cc,
          subject:         email.subject,
          body:            email_body,
          received_at:     email.date,
          sent_at:         email.date
        )
        asset.touch

        if asset.is_a?(Lead) && asset.status == "new"
          asset.update_attribute(:status, "contacted")
        end

        if @settings[:attach_to_account] && asset.respond_to?(:account) && asset.account
          Email.create(
            imap_message_id: email.message_id,
            user:            @sender,
            mediator:        asset.account,
            sent_from:       email.from.first,
            sent_to:         to,
            cc:              cc,
            subject:         email.subject,
            body:            email_body,
            received_at:     email.date,
            sent_at:         email.date
          )
          asset.account.touch
        end
      end

      #----------------------------------------------------------------------------------------
      def default_values(klass, data)
        data = data.dup
        keyword = data.delete("Type").capitalize

        defaults = {
          user:   @sender,
          access: default_access
        }

        case keyword
        when "Account", "Campaign", "Opportunity"
          defaults[:status] = "planned" if keyword == "Campaign"      # TODO: I18n
          defaults[:stage] = Opportunity.default_stage if keyword == "Opportunity" # TODO: I18n

        when "Contact", "Lead"
          first_name, *last_name = data.delete("Name").split(' ')
          defaults[:first_name] = first_name
          defaults[:last_name] = (last_name.any? ? last_name.join(" ") : "(unknown)")
          defaults[:status] = "contacted" if keyword == "Lead"        # TODO: I18n
        end

        data.each do |key, value|
          key = key.downcase
          defaults[key.to_sym] = value if klass.new.respond_to?(key + '=')
        end

        defaults
      end

      #----------------------------------------------------------------------------------------
      def default_values_for_contact(_email, recipient)
        recipient_local, recipient_domain = recipient.split('@')

        defaults = {
          user:       @sender,
          first_name: recipient_local.capitalize,
          last_name:  "(unknown)",
          email:      recipient,
          access:     default_access
        }

        # Search for domain name in Accounts.
        account = Account.where('(lower(email) like ? OR lower(website) like ?)', "%#{recipient_domain.downcase}", "%#{recipient_domain.downcase}%").first
        if account
          log "asociating new contact #{recipient} with the account #{account.name}"
          defaults[:account] = account
        else
          log "creating new account #{recipient_domain.capitalize} for the contact #{recipient}"
          defaults[:account] = Account.create!(
            user:   @sender,
            email:  recipient,
            name:   recipient_domain.capitalize,
            access: default_access
          )
        end
        defaults
      end

      # If default access is 'Shared' then change it to 'Private' because we don't know how
      # to choose anyone to share it with here.
      #--------------------------------------------------------------------------------------
      def default_access
        Setting.default_access == "Shared" ? 'Private' : Setting.default_access
      end

      # Notify users with the results of the operations
      #--------------------------------------------------------------------------------------
      def notify(email, mediator_links)
        DropboxMailer.create_dropbox_notification(
          @sender, @settings[:address], email, mediator_links
        ).deliver_now
      end
    end
  end
end