course_files

#!/usr/bin/env ruby

require 'yaml'
require 'dry-struct'
require 'dry-types'
require 'active_support'
require 'active_support/core_ext/string'
require 'fileutils'

module Types
  include Dry.Types()
end

class Chapter < Dry::Struct
  attribute :name, Types::String
  attribute :sections, Types::Array.of(Types::String)
end

class Course < Dry::Struct
  attribute :category, Types::String
  attribute :name, Types::String
  attribute :chapters, Types::Array.of(Chapter)
end

def chapter_directory(course, chapter_num, chapter)
  File.join(course.category.parameterize.underscore, course.name.parameterize.underscore, format('%02d', chapter_num + 1) + "_" + chapter.name.parameterize.underscore)
end

def section_file(chapter_directory, section_num, section)
  File.join(chapter_directory, format('%02d', section_num + 1) + "_" + section.parameterize.underscore) + ".md"
end

def write_course_toc(file, course)
  file.puts "  - #{course.category}:"
  file.puts "    - #{course.name}:"
  course.chapters.each_with_index do |chapter, chapter_num|
    file.puts "      - #{chapter.name}:"
    chapter_directory = chapter_directory(course, chapter_num, chapter)
    chapter.sections.each_with_index do |section, section_num|
      section_file = section_file(chapter_directory, section_num, section)
      file.puts "        - #{section}: #{section_file}"
    end
  end
end

def write_course_files(course)
  course.chapters.each_with_index do |chapter, chapter_num|
    chapter_directory = chapter_directory(course, chapter_num, chapter)
    chapter.sections.each_with_index do |section, section_num|
      section_file = File.join('docs', section_file(chapter_directory, section_num, section))
      FileUtils.mkdir_p(File.dirname(section_file))
      File.write(section_file, "# #{section}\n")
    end
  end
end

def usage(error_message = nil)
  STDERR.puts "ERROR: #{error_message}" if error_message
  puts "USAGE: $0 FILE toc|files"
  exit error_message ? 1 : 0
end

usage if ARGV == 0
usage("Missing one or more arguments") if ARGV.size != 2

course_file = ARGV[0]
command = ARGV[1]

usage("File does not exist: '${course_file}'") unless File.exist?(course_file)
usage("Invalid command: '${command}'") unless %w[toc files].include?(command)

yaml_data = YAML.load_file('course.yml', symbolize_names: true)
course = Course.new(yaml_data)

if ARGV[0] == "toc"
  write_course_toc(STDOUT, course)
elsif ARGV[0] == "files"
  write_course_files(course)
end