defmodule Prymn.Apps.Wordpress do
  use Ecto.Schema

  import Ecto.Changeset
  alias Prymn.Apps.App
  alias Prymn.Agents
  alias PrymnProto.Prymn.{ExecRequest, ExecResponse}

  @primary_key false
  embedded_schema do
    field :path, :string
    field :db_host, :string
    field :db_name, :string
    field :db_user, :string
    field :db_pass, :string
    field :admin_username, :string
    field :admin_email, :string
  end

  def changeset(app, attrs) do
    app
    |> cast(attrs, [
      :path,
      :db_host,
      :db_name,
      :db_user,
      :db_pass,
      :admin_username,
      :admin_email
    ])
    |> validate_required([
      :path,
      :db_user,
      :db_host,
      :db_user,
      :db_pass,
      :admin_email,
      :admin_username
    ])
  end

  @max_steps 6

  # TODO: We need a mechanism to drive some messages to the pubsub, maybe using Health:
  #   Health.change_task(%Health.Task{
  #     key: "create_db_user",
  #     message: "Creating db user...",
  #     curr_step: 0,
  #     max_steps: 5
  #   })
  #   |> Health.update_and_broadcast()

  def deploy(%App{type: "wordpress"} = app, agent, notify_fun) do
    # TODO: Run sanity checks
    #   e.g Database does not exist, domain does not exist, etc.
    deploy(app, agent, notify_fun, 1)
  end

  defp deploy(%App{wordpress: %__MODULE__{} = wp} = app, agent, notify_fun, 1 = step) do
    # TODO: We need a mechanism to wait for the agent to connect before proceeding,
    #       this is executed faster than the connection (which happens on deploy_app in Worker)

    Agents.exec(agent, %ExecRequest{
      user: "root",
      program: "mysql",
      args: [
        "-e",
        # TODO: Sanitize the string to protect from injection
        "create user '#{wp.db_user}'@'#{wp.db_host}' identified by '#{wp.db_pass}';"
      ]
    })
    |> then(&get_results/1)
    |> case do
      {_, _, exit_code} = data when exit_code != 0 ->
        notify_fun.(:error, data, 1 / 5 * 100)

      data ->
        notify_fun.(:progress, data, step / @max_steps * 100)
        deploy(app, agent, notify_fun, step + 1)
    end
  end

  defp deploy(%App{wordpress: %__MODULE__{} = wp} = app, agent, notify_fun, 2 = step) do
    Agents.exec(agent, %ExecRequest{
      user: "root",
      program: "mysql",
      args: [
        "-e",
        # TODO: Sanitize the string to protect from injection
        "grant all privileges on #{wp.db_name}.* to '#{wp.db_user}'@'#{wp.db_host}';"
      ]
    })
    |> then(&get_results/1)
    |> case do
      {_, _, exit_code} = data when exit_code != 0 ->
        notify_fun.(:error, data, step / @max_steps * 100)

      data ->
        notify_fun.(:progress, data, step / @max_steps * 100)
        deploy(app, agent, notify_fun, step + 1)
    end
  end

  defp deploy(%App{wordpress: %__MODULE__{} = wp} = app, agent, notify_fun, 3 = step) do
    Agents.exec(agent, %ExecRequest{
      user: "vagrant",
      program: "wp",
      args: ["core", "download", "--path=#{wp.path}"]
    })
    |> then(&get_results/1)
    |> case do
      {_, _, exit_code} = data when exit_code != 0 ->
        notify_fun.(:error, data, step / @max_steps * 100)

      data ->
        notify_fun.(:progress, data, step / @max_steps * 100)
        deploy(app, agent, notify_fun, step + 1)
    end
  end

  defp deploy(%App{wordpress: %__MODULE__{} = wp} = app, agent, notify_fun, 4 = step) do
    Agents.exec(agent, %ExecRequest{
      user: "vagrant",
      program: "wp",
      args: [
        "config",
        "create",
        "--path=#{wp.path}",
        "--dbhost=#{wp.db_host}",
        "--dbname=#{wp.db_name}",
        "--dbuser=#{wp.db_user}",
        "--dbpass=#{wp.db_pass}"
      ]
    })
    |> then(&get_results/1)
    |> case do
      {_, _, exit_code} = data when exit_code != 0 ->
        notify_fun.(:error, data, step / @max_steps * 100)

      data ->
        notify_fun.(:progress, data, step / @max_steps * 100)
        deploy(app, agent, notify_fun, step + 1)
    end
  end

  defp deploy(%App{wordpress: %__MODULE__{} = wp} = app, agent, notify_fun, 5 = step) do
    Agents.exec(agent, %ExecRequest{
      user: "vagrant",
      program: "wp",
      args: ["db", "create", "--path=#{wp.path}"]
    })
    |> then(&get_results/1)
    |> case do
      {_, _, exit_code} = data when exit_code != 0 ->
        notify_fun.(:error, data, step / @max_steps * 100)

      data ->
        notify_fun.(:progress, data, step / @max_steps * 100)
        deploy(app, agent, notify_fun, step + 1)
    end
  end

  defp deploy(%App{name: name, wordpress: %__MODULE__{} = wp}, agent, notify_fun, 6 = step) do
    Agents.exec(agent, %ExecRequest{
      user: "vagrant",
      program: "wp",
      args: [
        "core",
        "install",
        "--path=#{wp.path}",
        "--url=http://site.test",
        "--title=#{name}",
        "--admin_user=#{wp.admin_username}",
        "--admin_email=#{wp.admin_email}"
      ]
    })
    |> then(&get_results/1)
    |> case do
      {_, _, exit_code} = data when exit_code != 0 ->
        notify_fun.(:error, data, step / @max_steps * 100)

      data ->
        notify_fun.(:complete, data, step / @max_steps * 100)
    end
  end

  defp get_results(stream) do
    Enum.reduce_while(stream, {"", "", nil}, fn
      {:ok, %ExecResponse{out: {:exit_code, exit_code}}}, {stdout, stderr, _} ->
        {:halt, {stdout, stderr, exit_code}}

      {:ok, %ExecResponse{out: {:stdout, stdout}}}, {acc_stdout, stderr, exit_code} ->
        {:cont, {acc_stdout <> stdout, stderr, exit_code}}

      {:ok, %ExecResponse{out: {:stderr, stderr}}}, {stdout, acc_stderr, exit_code} ->
        {:cont, {stdout, acc_stderr <> stderr, exit_code}}
    end)
  end
end