require "path"
require "file_utils"
require "socket"

require "./module"
require "./config"
require "../common/network"

module DocMachine::Build
  class Run
    Log = DocMachine::Build::Log.for("run")

    def initialize(@config : DocMachine::Build::Config)
      data = "#{@config.data_dir}:#{@config.port}"
      @basehash = Digest::SHA256.hexdigest(data)[0..6]
      @docker_name = "docmachine-#{@basehash}"
      @docker_image = "glenux/docmachine:latest"
      @docker_opts = [] of String
      @process = nil
    end

    # cleanup environment
    # create directories
    # setup permissions
    def prepare()
      Log.info { "basedir      = #{@config.data_dir}" }
      Log.info { "docker_image = #{@docker_image}" }
      Log.info { "action       = #{@config.action}" }

      self._pull_image()
      self._avoid_duplicates() unless @config.enable_multiple
    end

    private def _avoid_duplicates
      Log.info { "Multiple Instances: stopping duplicate containers (for #{@docker_name})" }
      docker_cid = %x{docker ps -f "name=#{@docker_name}" -q}.strip

      Log.info { "Multiple Instances: docker_name: #{@docker_name}" }
      Log.info { "Multiple Instances: docker_cid: #{docker_cid || "-"}" }

      if !docker_cid.empty?
        Process.run("docker", ["kill", @docker_name])
        Process.run("docker", ["rm", @docker_name])
      end
    end

    def _pull_image
      # FIXME: add option to force update
      data_cache_dir = if ENV["XDG_CACHE_HOME"]? 
                         Path[ENV["XDG_CACHE_HOME"], "docmachine"]
                       else Path[ENV["HOME"], ".cache", "docmachine"]
                       end

      ## Build cache if it doesnt exist
      data_cache_file = data_cache_dir  / "image.tar"
      Log.info { "Checking cache #{data_cache_file}..." }
      if ! File.exists? data_cache_file.to_s
        Log.info { "Downloading #{@docker_image} image..." }
        Process.run("docker", ["pull", @docker_image], output: STDOUT)
        Log.info { "Building cache for image (#{data_cache_dir})" }
        FileUtils.mkdir_p(data_cache_dir)
        status = Process.run(
          "docker", 
          ["image", "save", @docker_image, "-o", data_cache_file.to_s], 
          output: STDOUT
        )
        if status.success? 
          Log.info { "done" }
        else
          Log.error { "Unable to save cache image" }
          exit 1
        end

      else 
        Log.info { "Cache already exist. Skipping." }
      end

      if @config.enable_cache
        Log.info { "Loading #{@docker_image} image from cache..." }
        docker_image_loaded = false
        status = Process.run(
          "docker", 
          ["image", "load", "-i", data_cache_file.to_s], 
          output: STDOUT
        )
        if status.success? 
          Log.info { "done" }
        else
          Log.error { "Unable to load cache image" }
          exit 1
        end
      else
        Log.info { "Loading #{@docker_image} image from local registry..." }
        # FIXME: check that local image exists
      end
    end

    def start()
      uid = %x{id -u}.strip
      gid = %x{id -g}.strip
      Log.info { "uid: #{uid}" }
      Log.info { "cid: #{gid}" }

      docker_opts = [] of String
      docker_opts << "run"
      docker_opts << "-i"
      # add tty support
      docker_opts << "-t" if @config.enable_tty
      # add container name
      docker_opts.concat ["--name", @docker_name]
      docker_opts << "--rm"
      docker_opts << "--shm-size=1gb"
      docker_opts.concat ["-e", "EXT_UID=#{uid}"]
      docker_opts.concat ["-e", "EXT_GID=#{gid}"]
      docker_opts.concat ["-v", "#{@config.data_dir}/docs:/app/docs"]
      docker_opts.concat ["-v", "#{@config.data_dir}/slides:/app/slides"]
      docker_opts.concat ["-v", "#{@config.data_dir}/images:/app/images"]
      docker_opts.concat ["-v", "#{@config.data_dir}/_build:/app/_build"]

      ## Detect Marp SCSS
      if File.exists?("#{@config.data_dir}/.marp/theme.scss")
        docker_opt_marp_theme = ["-v", "#{@config.data_dir}/.marp:/app/.marp"]
        docker_opts.concat docker_opt_marp_theme
        Log.info { "Theme: detected Marp files. Adding option to command line (#{docker_opt_marp_theme})" }
      else
        Log.info { "Theme: no theme detected. Using default files" }
        end

      ## Detect Mkdocs configuration - old format (full)
      if File.exists?("#{@config.data_dir}/mkdocs.yml")
        Log.info { "Docs: detected mkdocs.yml file. Please rename to mkdocs-patch.yml" }
        exit 1
      end

      ## Detect Mkdocs configuration - new format (patch)
      if File.exists?("#{@config.data_dir}/mkdocs-patch.yml")
        docker_opt_mkdocs_config = ["-v", "#{@config.data_dir}/mkdocs-patch.yml:/app/mkdocs-patch.yml"]
        docker_opts.concat docker_opt_mkdocs_config
        Log.info { "Docs: detected mkdocs-patch.yml file. Adding option to command line (#{docker_opt_mkdocs_config})" }
      else
        Log.info { "Docs: no mkdocs-patch.yml detected. Using default files" }
        end

      ## Detect docs
      if Dir.exists?("#{@config.data_dir}/docs")
        Log.info { "Docs: detected docs directory." }
        mkdocs_port = Network.find_port(@config.port)
        docker_opt_mkdocs_port = ["-p", "#{mkdocs_port}:5100"]
        docker_opts.concat docker_opt_mkdocs_port
        Log.notice { "Using port #{mkdocs_port} for docs" }
        Log.info { "Docs: Adding option to command line (#{docker_opt_mkdocs_port})" }
      else
        Log.info { "Docs: no docs detected." }
      end

      ## Detect slides
      if Dir.exists?("#{@config.data_dir}/slides")
        Log.info { "Slides: detected slides directory." }
        marp_port = Network.find_port(@config.port+100)
        docker_opt_marp_port = ["-p", "#{marp_port}:5200"]
        docker_opts.concat docker_opt_marp_port 
        Log.info { "Slides: Adding option to command line (#{docker_opt_marp_port})" }
        Log.notice { "Slides: Using port #{marp_port} for slides" }
      else
        Log.info { "Slides: no slides directory detected." }
        end

      docker_opts << @docker_image
      docker_opts << @config.action

      Log.info { docker_opts.inspect.colorize(:yellow) }
      @process = Process.new("docker", docker_opts, output: STDOUT, error: STDERR)
    end

    def wait()
      process = @process
      return if process.nil?

      Signal::INT.trap do
        Log.warn { "Received CTRL-C" }
        process.signal(Signal::KILL)
        Process.run("docker", ["kill", @docker_name])
      end
      process.wait
    end

    def stop()
    end

    def docker_opts()
    end
  end
end