#!/usr/bin/env ruby
# encoding: utf-8
#
#--
# Copyright protects this work.
# See LICENSE file for details.
#++

module Aurb
  class Aur
    # Search the AUR for given +packages+.
    # Returns an array of results.
    #
    #   search(['aurb']) # => [{:ID => ..., :Name => 'aurb', ...}, {...}]
    def search(packages)
      packages.map do |package|
        list_search_results(package)
      end.flatten.delete_if(&:blank?)
    end

    # Download +packages+ from the AUR.
    # Returns an array of downloadable package urls.
    #
    #   download(['aurb']) # => ['http://.../aurb.tar.gz']
    def download(packages)
      packages.map do |package|
        Aurb.aur_download_path URI.escape(package.to_s)
      end.select do |package|
        downloadable?(package)
      end.delete_if(&:blank?)
    end

    # Returns a +list+ of names of packages that have an upgrade
    # available to them, which could then in turn be passed on to
    # the +download+ method.
    #
    #   # With Aurb on the AUR as version [0, 8, 2, 1]
    #   upgrade(['aurb 0.0.0.0', 'aurb 0.9.9.9']) # => [:aurb]
    def upgrade(list)
      list.inject([]) do |ary, line|
        name, version = line.split
        next if in_community?(name)
        ary << name.to_sym if upgradable?(name, version)
        ary
      end
    end

    protected

    # See if +package+ is available in the community repository.
    def in_community?(package)
      Dir["/var/lib/pacman/sync/community/#{package}-*"].any?
    end

    # Check if +package+ is available for download.
    def downloadable?(package)
      open package rescue false
    end

    # Compare version of local +package+ with the one on the AUR.
    def upgradable?(package, version)
      parse_json(Aurb.aur_path(:info, package.to_s)) do |json|
        return false if json.type =~ /error/

        remote_package = json.results

        local_version  = VersionNumber.new(version)
        remote_version = VersionNumber.new(remote_package.Version)

        local_version < remote_version
      end
    end

    # Returns an array containing a hash of search results
    # for a given +package+.
    def list_search_results(package)
      json = parse_json(Aurb.aur_path(:search, URI.escape(package.to_s)))
      return [] if json.type =~ /error/

      ids = json.results.map(&:ID)
      ids.inject([]) do |ary, id|
        parse_json(Aurb.aur_path(:info, id)) do |json|
          next if json.type =~ /error/
          result = json.results.symbolize_keys
          ary << result unless in_community?(result.Name)
        end
        ary
      end
    end

    private

    # Shortcut to the +Yajl+ JSON parser.
    def parse_json(json)
      json = Yajl::Parser.new.parse(open(json).read)

      if block_given?
        yield json
      else
        json
      end
    end
  end
end