require 'json'
require 'pathname'
require 'org-ruby'
require 'ostruct'
require_relative 'file_bundle'

module Trackler
  # Track is a collection of exercises in a given language.
  class Track
    TOPICS = %w(about installation tests learning resources)
    DEFAULT_IMAGE_PATH = DocFile::DEFAULT_IMAGE_PATH

    Image = Struct.new(:path) do
      def exists?
        File.exist?(path)
      end

      def type
        File.extname(path).sub('.', '').to_sym
      end
    end

    attr_reader :id, :root, :file_bundle
    def initialize(id, root)
      @id = id
      @root = Pathname.new(root)
      @file_bundle = FileBundle.new(dir.join("global"))
    end

    def exists?
      File.exist?(dir)
    end

    def active?
      !!config["active"]
    end

    def upcoming?
      !active? && implementations.length > 0
    end

    def planned?
      !active? && implementations.length.zero?
    end

    def implementations
      @implementations ||= Implementations.new(repository, active_slugs, root, self)
    end

    def problems
      warn "DEPRECATION WARNING: A track only has implementations, call track.implementations instead"
      implementations
    end

    def checklist_issue
      config.fetch("checklist_issue", 1)
    end

    def gitter
      config["gitter"]
    end

    def icon_path
      icon.path if icon.exists?
    end

    def icon
      @icon ||= svg_icon.exists? ? svg_icon : png_icon
    end

    def language
      config['language'].to_s.strip
    end

    def repository
      config['repository'].to_s.strip
    end

    def test_pattern
      if config.key?('test_pattern')
        Regexp.new(config['test_pattern'])
      else
        /test/i
      end
    end

    def ignore_pattern
      config.fetch('ignore_pattern', 'example')
    end

    def docs(positional_image_path_which_is_deprecated = nil, image_path: nil)
      if positional_image_path_which_is_deprecated
        warn "DEPRECATION WARNING:\ntrack.docs: Positional argument is deprecated, please use keyword argument 'image_path:' instead\neg: track.docs(image_path: #{positional_image_path_which_is_deprecated.inspect})\n"
      end
      OpenStruct.new(docs_by_topic(image_path || positional_image_path_which_is_deprecated || DEFAULT_IMAGE_PATH))
    end

    def img(file_path)
      Image.new(File.join(dir, file_path))
    end

    def doc_format
      TOPICS.map { |topic|
        DocFile.find(basename: topic.upcase, track_dir: dir).extension
      }.partition(&:to_s).max_by(&:size).first
    end

    def global_zip
      @zip ||= file_bundle.zip
    end

    # Every slug mentioned in the configuration.
    def slugs
      active_slugs + foregone_slugs + deprecated_slugs
    end

    def dir
      root.join("tracks", id)
    end

    def hints
      docfile = DocFile.find(basename: 'EXERCISE_README_INSERT', track_dir: dir).render
    end

    private

    def active_slugs
      (config["exercises"] || []).map { |ex| ex["slug"] }
    end

    def foregone_slugs
      config["foregone"] || []
    end

    def deprecated_slugs
      config["deprecated"] || []
    end

    def config
      @config ||= JSON.parse(File.read(config_filename))
    end

    def config_filename
      File.join(dir, "config.json")
    end

    def docs_by_topic(image_path)
      Hash[
        TOPICS.zip(
          TOPICS.map { |topic|
            DocFile.find(basename: topic.upcase, track_dir: dir).render(image_path: image_path)
          }
        )
      ]
    end

    def svg_icon
      @svg_icon ||= Image.new(File.join(dir, "img/icon.svg"))
    end

    def png_icon
      @png_icon ||= Image.new(File.join(dir, "img/icon.png"))
    end
  end
end