require 'open-uri'

DEFAULT_WHITELIST_URL = "https://raw.githubusercontent.com/mercadolibre/mobile-dependencies_whitelist/master/ios-whitelist.json"
ERROR_MESSAGE = "Please check your dependencies"

class AllowedDependency
  attr_accessor :name
  attr_accessor :version
  def initialize(name, version)
    @name = name
    @version = version
 end
end

module Pod
  class Command
    class Whitelist < Command
      self.summary = "Validate Podspec's dependencies against a whitelist of pods."
      self.description = <<-DESC
        Validate Podspec's dependencies against a whitelist of pods.
      DESC

      self.arguments = [ CLAide::Argument.new('config', false),
                         CLAide::Argument.new('podspec', false),
                         CLAide::Argument.new('fail-on-error', false) ]

      def self.options
        [ ['--config=CONFIG', 'Config file or URL for the blacklist'],
          ['--podspec=PODSPEC', 'Podspec file to be lint'],
          ['--fail-on-error', 'Raise an exception in case of error']
        ].concat(super)
      end

      def initialize(argv)
        @whitelist_url = argv ? argv.option('config', DEFAULT_WHITELIST_URL) : DEFAULT_WHITELIST_URL
        @pospec_path = argv ? argv.option('podspec') : nil
        @fail_on_error = argv ? argv.flag?('fail-on-error') : false
        @failure = false
        super
      end

      def validate!
        help! "A whitelist file or URL is needed." unless @whitelist_url
      end

      def run
        whitelist = get_whitelist
        specifications = get_podspec_specifications

        if specifications.empty?
            UI.puts "No Podspec found".yellow
            return
        end

        specifications.map do |specification|
          validate_dependencies(JSON.parse(specification.to_json), whitelist)
        end

        show_error_message
      end

      def show_error_message
        return unless @failure
        if @fail_on_error
          raise Informative.new(ERROR_MESSAGE)
        else
          UI.puts ERROR_MESSAGE.red
        end
      end

      # Checks the dependencies the project contains are in the whitelist
      def validate_dependencies(podspec, whitelist, parentName = nil)
        pod_name = parentName ? "#{parentName}/#{podspec['name']}" : podspec['name']
        UI.puts "Verifying dependencies in #{pod_name}"

        dependencies = podspec["dependencies"] ? podspec["dependencies"] : []
        not_allowed = []

        dependencies.each do |name, versions|
          # Skip subspec dependency
          next if parentName && name.start_with?("#{parentName}/")

          allowedDependency = whitelist.select { |item|
             name == item.name && (versions.empty? || !item.version || versions.grep(/#{item.version}/).any?)
          }

          if allowedDependency.empty?
            not_allowed.push("#{name} (#{versions.join(", ")})")
            next
          end
        end

        if not_allowed.any?
          UI.puts " Error: Found dependencies not allowed:".red
          not_allowed.each {|dependency| UI.puts "  - #{dependency}".red}
          @failure = true
        else
          UI.puts " OK".green
        end

        # Validate subspecs dependencies
        if podspec["subspecs"]
          podspec["subspecs"].each do |subspec|
            validate_dependencies(subspec, whitelist, pod_name)
          end
        end
      end

      def get_whitelist
        begin
          open(@whitelist_url) { |io|
            buffer = io.read
            parse_whitelist(buffer)
          }
        rescue OpenURI::HTTPError => e
          status = e.io.status.join(' ')
          raise "Failed to fetch whitelist from '#{@whitelist_url}'.\n Error: #{status}"
        end
      end

      def parse_whitelist(raw_whitelist)
        json = JSON.parse(raw_whitelist)
        return json["whitelist"].map { |dependencyJson|
          AllowedDependency.new(dependencyJson["name"], dependencyJson["version"])
        }
      end

      def get_podspec_specifications
        if @pospec_path
          return [Pod::Specification.from_file(@pospec_path)]
        end

        # Search .podspec in current directory
        podspecs = Dir.glob("./*.podspec")

        if podspecs.count == 0
          # Search .podspec in parent directory.
          # Some projects has Podfile into a subdirectory ("Example"), and run "pod install" from there.
          podspecs = Dir.glob("../*.podspec")
        end

        return podspecs.map { |path|  Pod::Specification.from_file(path) }
      end
    end
  end
end