module Nanoc
  class Site

    DEFAULT_CONFIG = {
      :output_dir   => 'output',
      :eruby_engine => 'erb',
      :data_source  => 'filesystem'
    }

    attr_reader :config
    attr_reader :compiler, :data_source
    attr_reader :code, :pages, :page_defaults, :layouts, :templates

    # Creating a Site object

    def self.from_cwd
      File.file?('config.yaml') ? new : nil
    end

    def initialize
      # Load configuration
      @config = DEFAULT_CONFIG.merge((YAML.load_file('config.yaml') || {}).clean)

      # Create data source
      @data_source_class = PluginManager.data_source_named(@config[:data_source])
      error "Unrecognised data source: #{@config[:data_source]}" if @data_source_class.nil?
      @data_source = @data_source_class.new(self)

      # Create compiler
      @compiler     = Compiler.new(self)
      @autocompiler = AutoCompiler.new(self)

      # Set not loaded
      @data_loaded = false
    end

    def load_data(force=false)
      return if @data_loaded and !force

      # Load data
      @data_source.loading do
        @code           = @data_source.code
        @pages          = @data_source.pages.map { |p| Page.new(p, self) }
        @page_defaults  = @data_source.page_defaults
        @layouts        = @data_source.layouts
        @templates      = @data_source.templates
      end

      # Setup child-parent links
      @pages.each do |page|
        # Get parent
        parent_path = page.path.sub(/[^\/]+\/$/, '')
        parent = @pages.find { |p| p.path == parent_path }
        next if parent.nil? or page.path == '/'

        # Link
        page.parent = parent
        parent.children << page
      end

      # Set loaded
      @data_loaded = true
    end

    # Creating a new site on disk

    def self.create(sitename)
      # Check whether site exists
      error "A site named '#{sitename}' already exists." if File.exist?(sitename)

      FileUtils.mkdir_p sitename
      in_dir([sitename]) do
        # Create output
        FileManager.create_dir 'output'

        # Create config
        FileManager.create_file 'config.yaml' do
          "output_dir:  \"output\"\n" +
          "data_source: \"filesystem\"\n"
        end

        # Create rakefile
        FileManager.create_file 'Rakefile' do
          "Dir['tasks/**/*.rake'].sort.each { |rakefile| load rakefile }\n" +
          "\n" +
          "task :default do\n" +
          "  puts 'This is an example rake task.'\n" +
          "end\n"
        end

        # Create tasks
        FileManager.create_file 'tasks/default.rake' do
          "task :example do\n" +
          "  puts 'This is an example rake task in tasks/default.rake.'\n" +
          "end\n"
        end

        # Setup site
        Site.from_cwd.setup
      end
    end

    # Compiling

    def compile
      @compiler.run
    end

    def autocompile(port)
      @autocompiler.start(port)
    end

    # Creating

    def setup
      @data_source.loading { @data_source.setup }
    end

    def create_page(name, template_name='default')
      load_data

      template = @templates.find { |t| t[:name] == template_name }
      error "A template named '#{template_name}' was not found; aborting." if template.nil?

      @data_source.loading { @data_source.create_page(name, template) }
    end

    def create_template(name)
      load_data

      @data_source.loading {@data_source.create_template(name) }
    end

    def create_layout(name)
      load_data

      @data_source.loading { @data_source.create_layout(name) }
    end

  end
end