# Pleroma: A lightweight social networking server
# Copyright © 2017-2021 Pleroma Authors <https://pleroma.social/>
# SPDX-License-Identifier: AGPL-3.0-only

defmodule Mix.Tasks.Pleroma.Instance do
  use Mix.Task
  import Mix.Pleroma

  alias Pleroma.Config

  @shortdoc "Manages Pleroma instance"
  @moduledoc File.read!("docs/docs/administration/CLI_tasks/instance.md")

  def run(["gen" | rest]) do
    {options, [], []} =
      OptionParser.parse(
        rest,
        strict: [
          force: :boolean,
          output: :string,
          output_psql: :string,
          domain: :string,
          media_url: :string,
          instance_name: :string,
          admin_email: :string,
          notify_email: :string,
          dbhost: :string,
          dbname: :string,
          dbuser: :string,
          dbpass: :string,
          rum: :string,
          indexable: :string,
          db_configurable: :string,
          uploads_dir: :string,
          static_dir: :string,
          listen_ip: :string,
          listen_port: :string,
          strip_uploads_metadata: :string,
          read_uploads_description: :string,
          anonymize_uploads: :string
        ],
        aliases: [
          o: :output,
          f: :force
        ]
      )

    paths =
      [config_path, psql_path] = [
        Keyword.get(options, :output, "config/generated_config.exs"),
        Keyword.get(options, :output_psql, "config/setup_db.psql")
      ]

    will_overwrite = Enum.filter(paths, &File.exists?/1)
    proceed? = Enum.empty?(will_overwrite) or Keyword.get(options, :force, false)

    if proceed? do
      [domain, port | _] =
        String.split(
          get_option(
            options,
            :domain,
            "What domain will your instance use? (e.g akkoma.example.com)"
          ),
          ":"
        ) ++ [443]

      media_url =
        get_option(
          options,
          :media_url,
          "What base url will uploads use? (e.g https://media.example.com/media)\n" <>
            "  Generally this should NOT use the same domain as the instance       "
        )

      name =
        get_option(
          options,
          :instance_name,
          "What is the name of your instance? (e.g. The Corndog Emporium)",
          domain
        )

      email = get_option(options, :admin_email, "What is your admin email address?")

      notify_email =
        get_option(
          options,
          :notify_email,
          "What email address do you want to use for sending email notifications?",
          email
        )

      indexable =
        get_option(
          options,
          :indexable,
          "Do you want search engines to index your site? (y/n)",
          "y"
        ) === "y"

      db_configurable? =
        get_option(
          options,
          :db_configurable,
          "Do you want to store the configuration in the database (allows controlling it from admin-fe)? (y/n)",
          "n"
        ) === "y"

      dbhost = get_option(options, :dbhost, "What is the hostname of your database?", "localhost")

      dbname = get_option(options, :dbname, "What is the name of your database?", "akkoma")

      dbuser =
        get_option(
          options,
          :dbuser,
          "What is the user used to connect to your database?",
          "akkoma"
        )

      dbpass =
        get_option(
          options,
          :dbpass,
          "What is the password used to connect to your database?",
          :crypto.strong_rand_bytes(64) |> Base.encode64() |> binary_part(0, 64),
          "autogenerated"
        )

      rum_enabled =
        get_option(
          options,
          :rum,
          "Would you like to use RUM indices?",
          "n"
        ) === "y"

      listen_port =
        get_option(
          options,
          :listen_port,
          "What port will the app listen to (leave it if you are using the default setup with nginx)?",
          4000
        )

      listen_ip =
        get_option(
          options,
          :listen_ip,
          "What ip will the app listen to (leave it if you are using the default setup with nginx)?",
          "127.0.0.1"
        )

      uploads_dir =
        get_option(
          options,
          :uploads_dir,
          "What directory should media uploads go in (when using the local uploader)?",
          Config.get([Pleroma.Uploaders.Local, :uploads])
        )
        |> Path.expand()

      static_dir =
        get_option(
          options,
          :static_dir,
          "What directory should custom public files be read from (custom emojis, frontend bundle overrides, robots.txt, etc.)?",
          Config.get([:instance, :static_dir])
        )
        |> Path.expand()

      {strip_uploads_metadata_message, strip_uploads_metadata_default} =
        if Pleroma.Utils.command_available?("exiftool") do
          {"Do you want to strip location (GPS) data from uploaded images? This requires exiftool, it was detected as installed. (y/n)",
           "y"}
        else
          {"Do you want to strip location (GPS) data from uploaded images? This requires exiftool, it was detected as not installed, please install it if you answer yes. (y/n)",
           "n"}
        end

      strip_uploads_metadata =
        get_option(
          options,
          :strip_uploads_metadata,
          strip_uploads_metadata_message,
          strip_uploads_metadata_default
        ) === "y"

      {read_uploads_description_message, read_uploads_description_default} =
        if Pleroma.Utils.command_available?("exiftool") do
          {"Do you want to read data from uploaded files so clients can use it to prefill fields like image description? This requires exiftool, it was detected as installed. (y/n)",
           "y"}
        else
          {"Do you want to read data from uploaded files so clients can use it to prefill fields like image description? This requires exiftool, it was detected as not installed, please install it if you answer yes. (y/n)",
           "n"}
        end

      read_uploads_description =
        get_option(
          options,
          :read_uploads_description,
          read_uploads_description_message,
          read_uploads_description_default
        ) === "y"

      anonymize_uploads =
        get_option(
          options,
          :anonymize_uploads,
          "Do you want to anonymize the filenames of uploads? (y/n)",
          "n"
        ) === "y"

      Config.put([:instance, :static_dir], static_dir)

      secret = :crypto.strong_rand_bytes(64) |> Base.encode64() |> binary_part(0, 64)
      jwt_secret = :crypto.strong_rand_bytes(64) |> Base.encode64() |> binary_part(0, 64)
      signing_salt = :crypto.strong_rand_bytes(8) |> Base.encode64() |> binary_part(0, 8)
      lv_signing_salt = :crypto.strong_rand_bytes(8) |> Base.encode64() |> binary_part(0, 8)
      {web_push_public_key, web_push_private_key} = :crypto.generate_key(:ecdh, :prime256v1)
      template_dir = Application.app_dir(:pleroma, "priv") <> "/templates"

      result_config =
        EEx.eval_file(
          template_dir <> "/sample_config.eex",
          domain: domain,
          media_url: media_url,
          port: port,
          email: email,
          notify_email: notify_email,
          name: name,
          dbhost: dbhost,
          dbname: dbname,
          dbuser: dbuser,
          dbpass: dbpass,
          secret: secret,
          jwt_secret: jwt_secret,
          signing_salt: signing_salt,
          lv_signing_salt: lv_signing_salt,
          web_push_public_key: Base.url_encode64(web_push_public_key, padding: false),
          web_push_private_key: Base.url_encode64(web_push_private_key, padding: false),
          db_configurable?: db_configurable?,
          static_dir: static_dir,
          uploads_dir: uploads_dir,
          rum_enabled: rum_enabled,
          listen_ip: listen_ip,
          listen_port: listen_port,
          upload_filters:
            upload_filters(%{
              strip_metadata: strip_uploads_metadata,
              read_description: read_uploads_description,
              anonymize: anonymize_uploads
            })
        )

      result_psql =
        EEx.eval_file(
          template_dir <> "/sample_psql.eex",
          dbname: dbname,
          dbuser: dbuser,
          dbpass: dbpass,
          rum_enabled: rum_enabled
        )

      config_dir = Path.dirname(config_path)
      psql_dir = Path.dirname(psql_path)

      # Note: Distros requiring group read (0o750) on those directories should
      # pre-create the directories.
      to_create =
        [config_dir, psql_dir, static_dir, uploads_dir]
        |> Enum.reject(&File.exists?/1)

      for dir <- to_create do
        File.mkdir_p!(dir)
        File.chmod!(dir, 0o700)
      end

      shell_info("Writing config to #{config_path}.")

      # Sadly no fchmod(2) equivalent in Elixir…
      File.touch!(config_path)
      File.chmod!(config_path, 0o640)
      File.write(config_path, result_config)
      shell_info("Writing the postgres script to #{psql_path}.")
      File.write(psql_path, result_psql)

      write_robots_txt(static_dir, indexable, template_dir)

      shell_info(
        "\n All files successfully written! Refer to the installation instructions for your platform for next steps."
      )

      if db_configurable? do
        shell_info(
          " Please transfer your config to the database after running database migrations. Refer to \"Transfering the config to/from the database\" section of the docs for more information."
        )
      end
    else
      shell_error(
        "The task would have overwritten the following files:\n" <>
          Enum.map_join(will_overwrite, &"- #{&1}\n") <> "Rerun with `--force` to overwrite them."
      )
    end
  end

  defp write_robots_txt(static_dir, indexable, template_dir) do
    robots_txt =
      EEx.eval_file(
        template_dir <> "/robots_txt.eex",
        indexable: indexable
      )

    robots_txt_path = Path.join(static_dir, "robots.txt")

    if File.exists?(robots_txt_path) do
      File.cp!(robots_txt_path, "#{robots_txt_path}.bak")
      shell_info("Backing up existing robots.txt to #{robots_txt_path}.bak")
    end

    File.write(robots_txt_path, robots_txt)
    shell_info("Writing #{robots_txt_path}.")
  end

  defp upload_filters(filters) when is_map(filters) do
    enabled_filters =
      if filters.strip_metadata do
        [Pleroma.Upload.Filter.Exiftool.StripMetadata]
      else
        []
      end

    enabled_filters =
      if filters.read_description do
        enabled_filters ++ [Pleroma.Upload.Filter.Exiftool.ReadDescription]
      else
        enabled_filters
      end

    enabled_filters =
      if filters.anonymize do
        enabled_filters ++ [Pleroma.Upload.Filter.AnonymizeFilename]
      else
        enabled_filters
      end

    enabled_filters
  end
end