# frozen_string_literal: true

require 'curb'
require 'json'
require 'nokogiri'
require 'date'
require 'basiccache'

##
# Rugged is used if available to look up the user's Github username

begin
  require 'rugged'
  USE_RUGGED = true
rescue LoadError
  USE_RUGGED = false
end

##
# Definitions of user objects for GithubStats
module GithubStats
  ##
  # Helper method for creating new user objects

  def self.new(*args)
    self::User.new(*args)
  end

  ##
  # Default host for grabbing data

  DEFAULT_HOST = (ENV['GITHUB_URL'] || 'https://github.com').freeze

  ##
  # Default URL for grabbing data

  DEFAULT_URL = "#{DEFAULT_HOST}/users/%s/contributions".freeze

  ##
  # User object
  class User
    include MethodCacher

    attr_reader :name, :url, :last_updated

    ##
    # Creates a new user object

    def initialize(params = {})
      params = { name: params } unless params.is_a? Hash
      @name = params[:name] || guess_user
      @url = (params[:url] || DEFAULT_URL) % @name
      @last_updated = nil
      enable_caching %i[streak longest_streak streaks]
    end

    ##
    # Print human-readable string about object

    def to_s
      "Contributions from #{@name}"
    end
    alias inspect to_s

    ##
    # Set a custom streaks value that takes into account GitHub,
    # which makes available streak data for longer than a year

    def streak
      return [] if streaks.empty?
      streaks.last.last.date >= Date.today - 1 ? streaks.last : []
    end

    def streaks
      naive = data.streaks
      return naive if naive.last.nil? || naive.last.size < 365
      [real_streak]
    end

    ##
    # Set a custom longest_streak to account for the overriden streak

    def longest_streak
      return data.longest_streak if data.longest_streak.size < 365
      streak
    end

    ##
    # Lazy loader for data

    def data(reload = false)
      load_data if reload == true || @last_updated.nil?
      @data
    end

    ##
    # Adjust respond_to? to properly respond with patched method_missing

    def respond_to_missing?(method, include_private = false)
      load_data if @last_updated.nil?
      super || @data.respond_to?(method, include_private)
    end

    private

    ##
    # Guesses the user's name based on system environment

    def guess_user(names = [])
      names << Rugged::Config.global['github.user'] if USE_RUGGED
      names << ENV['USER']
      names.find { |name| name } || (raise 'Failed to guess username')
    end

    ##
    # Creates a new Data object from downloaded data

    def load_data
      @data = GithubStats::Data.new download
      @last_updated = Time.now
    end

    ##
    # Set a custom longest_streak that takes into account GitHub's
    # historical records

    def real_streak_rewind(partial_streak)
      new_data = download(partial_streak.first.date - 1)
      old_data = partial_streak.map(&:to_a)
      new_stats = GithubStats::Data.new(new_data + old_data)
      partial_streak = new_stats.streaks.last
      return partial_streak if partial_streak.first.date != new_stats.start_date
      real_streak_rewind partial_streak
    end

    def real_streak
      @real_streak ||= real_streak_rewind(data.streaks.last)
    end

    ##
    # Downloads new data from Github

    def download(to_date = nil)
      url = to_date ? @url + "?to=#{to_date.strftime('%Y-%m-%d')}" : @url
      res = Curl::Easy.perform(url)
      code = res.response_code
      raise("Failed loading data from GitHub: #{url} #{code}") if code != 200
      html = Nokogiri::HTML(res.body_str)
      html.css('.day').map do |x|
        x.attributes.values_at('data-date', 'data-count').map(&:value)
      end
    end

    def method_missing(sym, *args, &block)
      load_data if @last_updated.nil?
      return super unless @data.respond_to? sym
      define_singleton_method(sym) { |*a, &b| @data.send(sym, *a, &b) }
      send(sym, *args, &block)
    end
  end
end

require 'githubstats/version'
require 'githubstats/data'