# == Schema Information
#
# Table name: profile_photos
#
#  id      :integer          not null, primary key
#  data    :binary           not null
#  user_id :integer
#  draft   :boolean          default(FALSE), not null
#

# models/profile_photo.rb:
# Image of user that goes on their profile.
#
# Copyright (c) 2009 UK Citizens Online Democracy. All rights reserved.
# Email: hello@mysociety.org; WWW: http://www.mysociety.org/

class ProfilePhoto < ActiveRecord::Base
    # deliberately don't strip_attributes, so keeps raw photo properly

    WIDTH = 96
    HEIGHT = 96
    MAX_DRAFT = 500 # keep even pre-cropped images reasonably small

    belongs_to :user

    validate :data_and_draft_checks

    attr_accessor :x, :y, :w, :h
    attr_accessor :image

    after_initialize :convert_data_to_image

    # make image valid format and size
    def convert_image
        return if data.nil?
        return if image.nil?

        # convert to PNG if it isn't, and to right size
        altered = false
        if image.format != 'PNG'
            self.image.format = 'PNG'
            altered = true
        end

        # draft images are before the user has cropped them
        if !draft && (image.columns != WIDTH || image.rows != HEIGHT)
            # do any exact cropping (taken from Jcrop interface)
            if w && h
                image.crop!(x.to_i, y.to_i, w.to_i, h.to_i)
            end
            # do any further cropping
            image.resize_to_fill!(WIDTH, HEIGHT)
            altered = true
        end

        if draft && (image.columns > MAX_DRAFT || image.rows > MAX_DRAFT)
            image.resize_to_fit!(MAX_DRAFT, MAX_DRAFT)
            altered = true
        end

        if altered
            write_attribute(:data, image.to_blob)
        end
    end

    private

    def data_and_draft_checks
        if data.nil?
            errors.add(:data, _("Please choose a file containing your photo."))
            return
        end

        if image.nil?
            errors.add(:data, _("Couldn't understand the image file that you uploaded. PNG, JPEG, GIF and many other common image file formats are supported."))
            return
        end

        if image.format != 'PNG'
            errors.add(:data, _("Failed to convert image to a PNG"))
        end

        if !draft && (image.columns != WIDTH || image.rows != HEIGHT)
            errors.add(:data, _("Failed to convert image to the correct size: at {{cols}}x{{rows}}, need {{width}}x{{height}}",
                                :cols => image.columns,
                                :rows => image.rows,
                                :width => WIDTH,
                                :height => HEIGHT))
        end

        if draft && user_id
            raise "Internal error, draft pictures must not have a user"
        end

        if !draft && !user_id
            raise "Internal error, real pictures must have a user"
        end
    end

    # Convert binary data blob into ImageMagick image when assigned
    def convert_data_to_image
        if data.nil?
            self.image = nil
            return
        end

        image_list = Magick::ImageList.new

        begin
            image_list.from_blob(data)
        rescue Magick::ImageMagickError
            self.image = nil
            return
        end

        # TODO: perhaps take largest image or somesuch if there were multiple
        # in the file?
        self.image = image_list[0]
        convert_image
    end
end