require "json"
require 'fileutils'
require 'yaml'

module Jekyll
  class AirtableFetcher < Jekyll::Generator
    safe true
    priority :lowest      

    def generate(site)
      return false if site.config['AIRTABLE_API_KEY'].nil? || site.config['AIRTABLE_API_KEY'] == ''
      return false if site.config['SYNC_WITH_AIRTABLE'] == 'false'

      Airtable.configure do |config|
        config.api_key = site.config['AIRTABLE_API_KEY']
      end

      client = Airtable.client(base_uid: site.config['AIRTABLE_BASE_UID'])

      site.config['AIRTABLE_TABLE_NAMES'].each do |table_name|
        records = client.list_records(table_name: table_name)
        next if records.size == 0

        converted_table_name = to_snake(table_name)
        directory_name       = "collections/_" + converted_table_name

        Dir.mkdir(directory_name) unless File.exists?(directory_name)

        records.each do |record|
          fields    = record['fields']
          # We use the first field as the primary key
          # Then find the value of the primary key to be stored as the slug, which
          # will be used as file name and the path to the record in the url.
          # However, if the record has field called 'slug', it will be used instead
          pkey      = fields.keys.first
          slug      = fields['slug'].nil? ? fields[pkey] : fields['slug']
          uid       = record['id']

          out_file  = File.new("#{directory_name}/#{slug}.md", "w")
          out_file.puts(front_matter_mark)
          out_file.puts("uid: #{uid}")

          fields.each do |key, value|
            snake_key = to_snake(key)

            if value.class.name == 'Array'
              out_file.puts("#{snake_key}:")
              write_array_values(out_file, value)
            else
              value = stringify_value_if_necessary(value)
              out_file.puts("#{snake_key}: #{value}")
            end
          end

          out_file.puts(front_matter_mark)
          
          out_file.close               
        end
      end
    end

    private

    def front_matter_mark
      '---'
    end

    def to_snake(string)
      string.split(' ').map(&:downcase).join('_')
    end

    def write_array_values(file, array)
      array.each do |element|
        #   - { name: 'Low', color: '#306d8c' }
        value = stringify_value_if_necessary(element)
        file.puts("   - #{value}")
      end
    end

    def stringify_value_if_necessary(value)
      return "'#{value}'" if value.include?(':')
      value
    end
  end
end