defmodule PhoenixIntegration do

  @moduledoc """
  Lightweight server-side integration test functions for Phoenix. Works within the existing
  Phoenix.ConnTest framework and emphasizes both speed and readability.

  ## Configuration

  You need to tell phoenix_integration what Endpoint to use for the request calls to work.
  To do this, add the following to your `config/test.exs` file

      config :phoenix_integration,
        endpoint: MyApp.Endpoint

  Where MyApp is the name of your app.


  ## Overview

  phoenix_integration provides two assertion and six request functions to be used
  alongside the existing `get`, `post`, `put`, `patch`, and `delete` utilities
  inside of a Phoenix.ConnTest test suite.

  The goal is to chain together a string of requests and assertions that thouroughly
  exercise your application in as lightweight and readable manner as possible.

  Each function accepts a conn and some other data, and returns a conn intended to be
  passed into the next function via a pipe.

  ### Examples
      test "Basic page flow", %{conn: conn} do
        # get the root index page
        get( conn, page_path(conn, :index) )
        # click/follow through the various about pages
        |> follow_link( "About Us" )
        |> follow_link( "Contact" )
        |> follow_link( "Privacy" )
        |> follow_link( "Terms of Service" )
        |> follow_link( "Home" )
        |> assert_response( status: 200, path: page_path(conn, :index) )
      end

      test "Create new user", %{conn: conn} do
        # get the root index page
        get( conn, page_path(conn, :index) )
        # click/follow through the various about pages
        |> follow_link( "Sign Up" )
        |> follow_form( %{ user: %{
              name: "New User",
              email: "user@example.com",
              password: "test.password",
              confirm_password: "test.password"
            }} )
        |> assert_response(
            status: 200,
            path: page_path(conn, :index),
            html: "New User" )
      end

  ### Simulate multiple users
  Since all user state is held in the conn that is being passed around (just like when
  a user is hitting your application in a browser), you can simulate multiple users
  simply by tracking separate conns for them.

  In the example below, I'm assuming an application-specific `test_sign_in` function, which
  itself uses the `follow_*` functions to sign a given user in.

  Notice how `user_conn` is tracked and reused. This keeps the state the user builds
  up as the various links are followed, just like it would be when a proper browser is used.

  ### Example
      test "admin grants a user permissions", %{conn: conn, user: user, admin: admin} do
        # sign in the user and admin
        user_conn = test_sign_in( conn, user )
        admin_conn = test_sign_in( conn, admin )

        # user can't see a restricted page
        user_conn = get( user_conn, page_path(conn, :index) )
        |> follow_link( "Restricted" )
        |> assert_response( status: 200, path: session_path(conn, :new) )
        |> refute_response( body: "Restricted Content" )

        # admin grants the user permission
        get( admin_conn, page_path(conn, :index) )
        |> follow_link( "Admin Dashboard" )
        |> follow_form( %{ user: %{
              permissoin: "ok_to_do_thing"
            }} )
        |> assert_response(
            status: 200,
            path: admin_path(conn, :index),
            html: "Permission Granted" )

        # the user should now be able to see the restricted page
        get( user_conn, page_path(conn, :index) )
        |> follow_link( "Restricted" )
        |> assert_response(
            status: 200,
            path: restricted_path(conn, :index),
            html: "Restricted Content"
          )
      end

  ### Tip

  You can intermix `IO.inspect` calls in the pipe chain to help with debugging. This
  will print the current state of the conn into the console.

      test "Basic page flow", %{conn: conn} do
        # get the root index page
        get( conn, page_path(conn, :index) )
        |> follow_link( "About Us" )
        |> IO.inspect
        |> follow_link( "Home" )
        |> assert_response( status: 200, path: page_path(conn, :index) )
      end

  I like to use `assert_response` pretty heavily to make sure the content I expect
  is really there and to make sure I am traveling to the right locations.

        test "Basic page flow", %{conn: conn} do
          get(conn, page_path(conn, :index) )
          |> assert_response(
              status: 200,
              path: page_path(conn, :index),
              html: "Test App"
            )
          |> follow_link( "About" )
          |> assert_response(
              status: 200,
              path: about_path(conn, :index),
              html: "About Test App"
            )
          |> follow_link( "Contact" )
          |> assert_response(
              status: 200,
              path: about_path(conn, :contact),
              html: "Contact"
            )
          |> follow_link( "Home" )
          |> assert_response(
              status: 200,
              path: page_path(conn, :index),
              html: "Test App"
            )
        end


  ### What phoenix_integration is NOT

  phoenix_integration is not a client-side acceptence test suite. It does not use
  a real browser and does not exercise javascript code that lives there. It's focus
  is on fast, readable, server-side integration.

  Try using a tool like [`Hound`](https://hex.pm/packages/hound) for full-stack
  integration tests.
  """

  defmacro __using__(_opts) do
    quote do
      import PhoenixIntegration.Assertions
      import PhoenixIntegration.Requests
    end # quote
  end # defmacro


end