require 'csv'
require 'tempfile'

require 'action_view'
require 'action_view/helpers'

namespace :import do

    include ActionView::Helpers::DateHelper

    desc 'Import public bodies from CSV provided on standard input'
    task :import_csv => :environment do
        dryrun = ENV['DRYRUN'] != '0'
        if dryrun
            STDERR.puts "Only a dry run; public bodies will not be created"
        end

        tmp_csv = Tempfile.new 'alaveteli'
        tmp_csv.write STDIN.read

        number_of_rows = 0

        STDERR.puts "Preliminary check for ambiguous names or slugs..."

        # Check that the name and slugified version of the name are
        # unique:
        url_part_count = Hash.new { 0 }
        name_count = Hash.new { 0 }
        reader = CSV.open tmp_csv.path, 'r'
        header_line = reader.shift
        headers = header_line.collect { |h| h.gsub /^#/, ''}

        reader.each do |row_array|
            row = Hash[headers.zip row_array]
            name = row['name']
            url_part = MySociety::Format::simplify_url_part name, "body"
            name_count[name] += 1
            url_part_count[url_part] += 1
            number_of_rows += 1
        end

        non_unique_error = false

        [[name_count, 'name'],
         [url_part_count, 'url_part']].each do |counter, field|
            counter.sort.map do |name, count|
                if count > 1
                    non_unique_error = true
                    STDERR.puts "The #{field} #{name} was found #{count} times."
                end
            end
        end

        next if non_unique_error

        STDERR.puts "Now importing the public bodies..."

        start = Time.now.to_f

        # Now it's (probably) safe to try to import:
        errors, notes = PublicBody.import_csv(tmp_csv.path,
                                              tag='',
                                              tag_behaviour='replace',
                                              dryrun,
                                              editor="#{ENV['USER']} (Unix user)",
                                              I18n.available_locales) do |row_number, fields|
            now = Time.now.to_f
            percent_complete = (100 * row_number.to_f / number_of_rows).to_i
            expected_end = number_of_rows * (now - start) / row_number.to_f + start
            time_left = distance_of_time_in_words now, expected_end
            STDERR.print "#{row_number} out of #{number_of_rows} "
            STDERR.print "(#{percent_complete}% complete) "
            STDERR.puts "#{time_left} remaining"
        end

        if errors.length > 0
            STDERR.puts "Import failed, with the following errors:"
            errors.each do |error|
                STDERR.puts "  #{error}"
            end
        else
            STDERR.puts "Done."
        end

    end
end