require 'json'
require 'ostruct'
require 'fileutils'

module Chest
  CONFIG_BASE_DIR = File.expand_path('.config/chest', '~')
  CONFIG_PATH = File.join(CONFIG_BASE_DIR, 'config.json')

  class FileMissingError < StandardError; end

  class Config < OpenStruct
    attr_reader :file_path

    def initialize(file_path = CONFIG_PATH)
      super({})
      @file_path = file_path
      load!
    end

    def load!
      if File.exist? @file_path
        File.open(@file_path, 'r') do |f|
          marshal_load(symbolize_keys(JSON(f.read)))
        end
      end
    rescue Errno::ENOENT, IOError
      raise FileMissingError, @file_path
    end

    def method_missing(name, *args)
      super(name, *args)
    end

    def update!(attributes = {})
      attributes_with!(attributes)
    end

    def attributes_with!(attributes = {})
      attributes.each do |key, value|
        send(key.to_s + '=', value) if respond_to?(key.to_s + '=')
      end
    end

    def save
      FileUtils.mkpath(File.dirname(@file_path))
      File.open(@file_path, 'w') { |f| f.puts to_json }
    end

    def to_hash
      table.to_h
    end

    def to_json
      JSON.pretty_generate(to_hash)
    end

    private

    def symbolize_keys(hash)
      hash.inject({}) { |res, (k, v)| res[k.to_sym] = v; res }
    end
  end
end