require "option_parser"
require "yaml"

module Guff
  class Config
    DEFAULTS = {
      "host":         "localhost",
      "port":         "8989",
      "data":         "./data",
      "public":       "./public",
      "environment":  "development",
      "stuff":        "/usr/local/share/guff/stuff",
    }

    DIRS = %w{
      data
      public
    }

    def initialize(app, args)
      @data = defaults
      parse_args(app, args)
    end

    def [](key : String) : String
      @data[key]
    end

    def []=(key : String, val : String | Nil) : String
      @data[key] = val
    end

    private def defaults : Hash(String, String)
      DEFAULTS.merge(DEFAULTS.keys.reduce({} of String => String) do |r, key|
        env_key = "GUFF_" + key.upcase
        r[key] = ENV[env_key] if ENV.has_key?(env_key)
        r
      end)
    end

    private def parse_args(app, args)
      OptionParser.parse(args) do |p|
        p.on(
          "--config PATH",
          "Read config from YAML file."
        ) do |path|
          YAML.parse(File.read(path)).each do |k, v|
            self[k.as_s] = v.as_s
          end
        end

        p.on(
          "-h HOST",
          "--host HOST",
          "Host (defaults to \"%s\")." % [
            DEFAULTS["host"]
          ]
        ) do |host|
          self["host"] = host
        end

        p.on(
          "-p PORT",
          "--port PORT",
          "Port (defaults to %s)." % [
            DEFAULTS["port"]
          ]
        ) do |port|
          self["port"] = port
        end

        p.on(
          "-d PATH",
          "--data-dir PATH",
          "Path to data directory (defaults to \"%s\")." % [
            DEFAULTS["data"],
          ]
        ) do |path|
          self["data"] = path
        end

        p.on(
          "--public-dir PATH",
          "Path to public directory (defaults to \"%s\")." % [
            DEFAULTS["public"],
          ]
        ) do |path|
          self["public"] = path
        end

        p.on(
          "--stuff-dir PATH",
          "Path to Guff static files directory (defaults to \"%s\")." % [
            DEFAULTS["stuff"],
          ]
        ) do |path|
          self["stuff"] = path
        end

        p.on(
          "-e ENV",
          "--environment ENV",
          "Environment (defaults to \"%s\")." % [
            DEFAULTS["environment"],
          ]
        ) do |path|
          self["public"] = path
        end


        p.on(
          "--help",
          "Print usage"
        ) do
          puts p.to_s
          exit 0
        end
      end

      # expand output directory paths and create them
      %w{data public}.each do |key|
        # expand path (unless it is absolute)
        self[key] = File.expand_path(File.join(
          File.dirname(app),
          self[key]
        )) unless self[key][0] == '/'

        # puts "DEBUG: %s: %s" % [key, self[key]]
        Dir.mkdir(self[key], 0o770) unless Dir.exists?(self[key])
      end
    end
  end
end