[PR] Adding drag n drop and index-based reordering

.formatter.exs

@@ -4,7 +4,7 @@
   plugins: [Phoenix.LiveView.HTMLFormatter],
   inputs: [
     "*.{heex,ex,exs}",
-    "{config,lib,test}/**/*.{heex,ex,exs}",
+    "{config,lib}/**/*.{heex,ex,exs}",
     "priv/*/seeds.exs"
   ],
   line_length: 80

BUILDIT.md

@@ -118,9 +118,11 @@ With that in place, let's get building!
   - [15.2 Changing how the timer datetime is displayed](#152-changing-how-the-timer-datetime-is-displayed)
   - [15.3 Persisting the adjusted timezone](#153-persisting-the-adjusted-timezone)
   - [15.4 Adding test](#154-adding-test)
-- [16. Run the _Finished_ MVP App!](#16-run-the-finished-mvp-app)
-  - [16.1 Run the Tests](#161-run-the-tests)
-  - [16.2 Run The App](#162-run-the-app)
+- [16. `Lists`](#16-lists)
+- [17. Reordering `items` Using Drag \& Drop](#17-reordering-items-using-drag--drop)
+- [18. Run the _Finished_ MVP App!](#18-run-the-finished-mvp-app)
+  - [18.1 Run the Tests](#181-run-the-tests)
+  - [18.2 Run The App](#182-run-the-app)
 - [Thanks!](#thanks)
 
 
@@ -3593,7 +3595,13 @@ We are showing each timer whenever an `item` is being edited.
                   required="required"
                   name="timer_start"
                   id={"#{changeset.data.id}_start"}
-                  value={changeset.data.start}
+                  value={
+                    NaiveDateTime.add(
+                      changeset.data.start,
+                      @hours_offset_fromUTC,
+                      :hour
+                    )
+                  }
                 />
               </div>
               <div class="flex flex-row items-center">
@@ -3602,7 +3610,17 @@ We are showing each timer whenever an `item` is being edited.
                   type="text"
                   name="timer_stop"
                   id={"#{changeset.data.id}_stop"}
-                  value={changeset.data.stop}
+                  value={
+                    if is_nil(changeset.data.stop) do
+                      changeset.data.stop
+                    else
+                      NaiveDateTime.add(
+                        changeset.data.stop,
+                        @hours_offset_fromUTC,
+                        :hour
+                      )
+                    end
+                  }
                 />
               </div>
               <input
@@ -4861,7 +4879,7 @@ which is a PostgreSQL GUI.
 If you don't have this installed, 
 [we highly recommend you doing so](https://github.com/dwyl/learn-postgresql/issues/43#issuecomment-469000357).
 
-<img width="1824" alt="dbeaver" src="https://user-images.githubusercontent.com/17494745/211629270-996e6c4a-8322-49b4-9ef6-7be2335ccfb7.png">
+<img width="1824" alt="papertrail_versions" src="https://user-images.githubusercontent.com/17494745/211629270-996e6c4a-8322-49b4-9ef6-7be2335ccfb7.png">
 
 As you can see, update/insert events are being tracked,
 with the corresponding `person_id` (in `originator_id`),
@@ -5785,11 +5803,56 @@ we expect the persisted value to be
 one hour *less* than what the person inputted. 
 
 
-# 16. Run the _Finished_ MVP App!
+# 16. `Lists`
+
+In preparation for the next set of features in the `MVP`,
+we added `lists`
+which are simply a collection of `items`.
+
+Please see: 
+[book/mvp/lists](https://dwyl.github.io/book/mvp/16-lists.html)
+
+We didn't add a lot of code for `lists`
+there is currently no way for the `person` 
+to create a `new list` 
+or "move" `items` between `lists`.
+
+If you want to help with defining the interface,
+please comment on the issue:
+[dwyl/mvp#365](https://github.com/dwyl/mvp/issues/365)
+
+
+
+# 17. Reordering `items` Using Drag & Drop
+
+At present `people` using the `App`
+can only add new `items` to a stack
+where the newest is on top; no ordering.
+
+`people` that tested the `MVP`
+noted that the ability to **reorder `items`**
+was an **_essential_ feature**:
+[dwyl/mvp#145](https://github.com/dwyl/mvp/issues/145)
+
+So in this step we are going to 
+add the ability to organize `items`.
+We will implement reordering using 
+**drag and drop**!
+And by using `Phoenix LiveView`,
+**other people** will also be able 
+to **see the changes in real time**!
+
+For _all_ the detail implementing this feature,
+please see: 
+[book/mvp/reordering](https://dwyl.github.io/book/mvp/18-reordering.html)
+
+
+
+# 18. Run the _Finished_ MVP App!
 
 With all the code saved, let's run the tests one more time.
 
-## 16.1 Run the Tests
+## 18.1 Run the Tests
 
 In your terminal window, run: 
 
@@ -5802,23 +5865,37 @@ mix c
 You should see output similar to the following:
 
 ```sh
-Finished in 0.7 seconds (0.1s async, 0.5s sync)
-85 tests, 0 failures
+Finished in 1.5 seconds (1.4s async, 0.1s sync)
+117 tests, 0 failures
 
+Randomized with seed 947856
 ----------------
 COV    FILE                                        LINES RELEVANT   MISSED
-100.0% lib/app/item.ex                               245       34        0
-100.0% lib/app/timer.ex                               97       16        0
-100.0% lib/app_web/controllers/auth_controller.       35        9        0
-100.0% lib/app_web/live/app_live.ex                  186       57        0
-[TOTAL]  100.0%
+100.0% lib/api/item.ex                               218       56        0
+100.0% lib/api/tag.ex                                101       24        0
+100.0% lib/api/timer.ex                              152       40        0
+100.0% lib/app/color.ex                               90        1        0
+100.0% lib/app/item.ex                               415       62        0
+100.0% lib/app/item_tag.ex                            12        1        0
+100.0% lib/app/tag.ex                                108       18        0
+100.0% lib/app/timer.ex                              452       84        0
+100.0% lib/app_web/controllers/auth_controller.       26        4        0
+100.0% lib/app_web/controllers/init_controller.       41        6        0
+100.0% lib/app_web/controllers/tag_controller.e       77       25        0
+100.0% lib/app_web/live/app_live.ex                  476      132        0
+100.0% lib/app_web/live/stats_live.ex                 77       21        0
+100.0% lib/app_web/router.ex                          49        9        0
+100.0% lib/app_web/views/error_view.ex                59       12        0
+  0.0% lib/app_web/views/profile_view.ex               3        0        0
+  0.0% lib/app_web/views/tag_view.ex                   3        0        0
+[TOTAL] 100.0%
 ----------------
 ```
 
 All tests pass and we have **`100%` Test Coverage**.
 This reminds us just how few _relevant_ lines of code there are in the MVP!
 
-## 16.2 Run The App
+## 18.2 Run The App
 
 In your second terminal tab/window, run:
 

assets/css/app.css

@@ -85,3 +85,17 @@ input[type=radio].has-error:not(.phx-no-feedback) {
 }
 
 [x-cloak] { display: none !important; }
+
+
+/* For the drag and drop feature */
+.cursor-grab {
+  cursor: grab;
+}
+
+.cursor-grabbing {
+  cursor: grabbing; 
+}
+
+.bg-teal-300 {
+  background-color: #5eead4;
+}

assets/js/app.js

@@ -5,8 +5,103 @@ import {Socket} from "phoenix"
 import {LiveSocket} from "phoenix_live_view"
 import topbar from "../vendor/topbar"
 
+// Show progress bar on live navigation and form submits
+topbar.config({barColors: {0: "#29d"}, shadowColor: "rgba(0, 0, 0, .3)"})
+window.addEventListener("phx:page-loading-start", info => topbar.show())
+window.addEventListener("phx:page-loading-stop", info => topbar.hide())
+
+// Drag and drop highlight handlers
+window.addEventListener("phx:highlight", (e) => {
+  document.querySelectorAll("[data-highlight]").forEach(el => {
+    if(el.id == e.detail.id) {
+        liveSocket.execJS(el, el.getAttribute("data-highlight"))
+    }
+  })
+})
+
+// Item id of the destination in the DOM
+let itemId_to;
 
 let Hooks = {}
+Hooks.Items = {
+  mounted() {
+    const hook = this
+
+    this.el.addEventListener("highlight", e => {
+      hook.pushEventTo("#items", "highlight", {id: e.detail.id})
+      // console.log('highlight', e.detail.id)
+    })
+
+    this.el.addEventListener("remove-highlight", e => {
+      hook.pushEventTo("#items", "removeHighlight", {id: e.detail.id})
+      // console.log('remove-highlight', e.detail.id)
+    })
+
+    this.el.addEventListener("dragoverItem", e => {
+      // console.log("dragoverItem", e.detail)
+      const currentItemId = e.detail.currentItem.id
+      const selectedItemId = e.detail.selectedItemId
+      if( currentItemId != selectedItemId) {
+        hook.pushEventTo("#items", "dragoverItem", {currentItemId: currentItemId, selectedItemId: selectedItemId})
+        itemId_to = e.detail.currentItem.dataset.id
+      }
+    })
+
+    this.el.addEventListener("update-indexes", e => {
+      const item_id = e.detail.fromItemId 
+      const list_ids = get_list_item_cids()
+      console.log("update-indexes", e.detail, "list: ", list_ids)
+      // Check if both "from" and "to" are defined
+      if(item_id && itemId_to && item_id != itemId_to) {
+        hook.pushEventTo("#items", "update_list_seq", 
+          {seq: list_ids})
+      }
+
+      itemId_to = null;
+    })
+  }
+}
+
+/**
+ * `get_list_item_ids/0` retrieves the full `list` of visible `items` form the DOM
+ * and returns a String containing the IDs as a space-separated list e.g: "1 2 3 42 71 93"
+ * This is used to determine the `position` of the `item` that has been moved.
+ */
+function get_list_item_cids() {
+  console.log("invoke get_list_item_ids")
+  const lis = document.querySelectorAll("label[phx-value-cid]");
+  return Object.values(lis).map(li => {
+    return li.attributes["phx-value-cid"].nodeValue
+  }).join(",")
+}
+
+window.addEventListener("phx:remove-highlight", (e) => {
+  document.querySelectorAll("[data-highlight]").forEach(el => {
+    if(el.id == e.detail.id) {
+        liveSocket.execJS(el, el.getAttribute("data-remove-highlight"))
+    }
+  })
+})
+
+window.addEventListener("phx:dragover-item", (e) => {
+  console.log("phx:dragover-item", e.detail)
+  const selectedItem = document.querySelector(`#${e.detail.selected_item_id}`)
+  const currentItem = document.querySelector(`#${e.detail.current_item_id}`)
+
+  const items = document.querySelector('#items')
+  const listItems = [...document.querySelectorAll('.item')]
+
+  if(listItems.indexOf(selectedItem) < listItems.indexOf(currentItem)){
+    items.insertBefore(selectedItem, currentItem.nextSibling)
+  }
+
+  if(listItems.indexOf(selectedItem) > listItems.indexOf(currentItem)){
+    items.insertBefore(selectedItem, currentItem)
+  }
+})
+
+// liveSocket related setup:
+
 let csrfToken = document.querySelector("meta[name='csrf-token']").getAttribute("content")
 
 let liveSocket = new LiveSocket("/live", Socket, {
@@ -24,12 +119,6 @@ let liveSocket = new LiveSocket("/live", Socket, {
   }
 })
 
-
-// Show progress bar on live navigation and form submits
-topbar.config({barColors: {0: "#29d"}, shadowColor: "rgba(0, 0, 0, .3)"})
-window.addEventListener("phx:page-loading-start", info => topbar.show())
-window.addEventListener("phx:page-loading-stop", info => topbar.hide())
-
 // connect if there are any LiveViews on the page
 liveSocket.connect()
 

config/config.exs

@@ -1,7 +1,9 @@
 import Config
 
 config :app,
-  ecto_repos: [App.Repo]
+  ecto_repos: [App.Repo],
+  # rickaard.se/blog/how-to-only-run-some-code-in-production-with-phoenix-and-elixir
+  env: config_env()
 
 # Configures the endpoint
 config :app, AppWeb.Endpoint,
@@ -50,6 +52,9 @@ import_config "#{config_env()}.exs"
 # https://hexdocs.pm/joken/introduction.html#usage
 config :joken, default_signer: System.get_env("SECRET_KEY_BASE")
 
-#
+# https://github.com/dwyl/auth_plug
 config :auth_plug,
   api_key: System.get_env("AUTH_API_KEY")
+
+# https://github.com/dwyl/cid#how
+config :excid, base: :base58

config/dev.exs

@@ -75,3 +75,8 @@ config :phoenix, :stacktrace_depth, 20
 
 # Initialize plugs at runtime for faster development compilation
 config :phoenix, :plug_init_mode, :runtime
+
+# github.com/dwyl/elixir-pre-commit
+config :pre_commit,
+  commands: ["format", "c"],
+  verbose: true

config/test.exs

@@ -19,6 +19,7 @@ config :app, AppWeb.Endpoint,
   http: [ip: {127, 0, 0, 1}, port: 4002],
   secret_key_base:
     "aEkLhne04vW3X5PM63O85Ie57c+KoT1z5bl0TdtBE1veN8BbER7MpOgZ6FgD7dWu",
+  # github.com/dwyl/mvp/issues/359
   server: false
 
 # Print only warnings and errors during test

lib/app/cid.ex

@@ -0,0 +1,25 @@
+defmodule App.Cid do
+  @moduledoc """
+  Helper functions for adding `cid` to records transparently in a changeset pipeline.
+  """
+
+  @doc """
+  `put_cid/1` as its' name suggests puts the `cid` for the record into the `changeset`.
+  This is done transparently so nobody needs to _think_ about cids.
+  """
+  def put_cid(changeset) do
+    # don't add a cid to a changeset that already has one
+    if Map.has_key?(changeset.changes, :cid) do
+      changeset
+    else
+      # Only add cid to changeset that has :name i.e. list.name or :text i.e. item.text
+      if Map.has_key?(changeset.changes, :name) ||
+           Map.has_key?(changeset.changes, :text) do
+        cid = Cid.cid(changeset.changes)
+        %{changeset | changes: Map.put(changeset.changes, :cid, cid)}
+      else
+        changeset
+      end
+    end
+  end
+end