From c5fc7295a40b7318ebb6ecd2768c156c0d5c7623 Mon Sep 17 00:00:00 2001
From: winkidney <winkidney@gmail.com>
Date: Fri, 29 Nov 2019 00:16:28 +0800
Subject: [PATCH] Feature: LoadMore in Pins view done

---
 pinry-spa/src/components/Pins.vue         | 35 +++++++++++++++++++++++++++----
 pinry-spa/src/components/api.js           |  2 +-
 pinry-spa/src/components/utils/browser.js | 15 +++++++++++++
 pinry-spa/src/components/utils/scroll.js  | 27 ++++++++++++++++++++++++
 4 files changed, 74 insertions(+), 5 deletions(-)
 create mode 100644 pinry-spa/src/components/utils/browser.js
 create mode 100644 pinry-spa/src/components/utils/scroll.js

diff --git a/pinry-spa/src/components/Pins.vue b/pinry-spa/src/components/Pins.vue
index 24d6e62..f4757be 100644
--- a/pinry-spa/src/components/Pins.vue
+++ b/pinry-spa/src/components/Pins.vue
@@ -60,6 +60,7 @@ import API from './api';
 import pinHandler from './utils/PinHandler';
 import PinPreview from './PinPreview.vue';
 import loadingSpinner from './loadingSpinner.vue';
+import scroll from './utils/scroll';
 
 function createImageItem(pin) {
   const image = {};
@@ -101,6 +102,17 @@ export default {
     },
   },
   methods: {
+    registerScrollEvent() {
+      const self = this;
+      scroll.bindScroll2Bottom(
+        () => {
+          if (self.status.loading || !self.status.hasNext) {
+            return;
+          }
+          self.fetchMore();
+        },
+      );
+    },
     buildBlocks(results) {
       const blocks = [];
       results.forEach(
@@ -125,14 +137,23 @@ export default {
         },
       );
     },
-    fetchMore(created) {
-      let promise;
+    shouldFetchMore(created) {
       if (!created) {
         if (this.status.loading) {
-          return;
+          return false;
+        }
+        if (!this.status.hasNext) {
+          return false;
         }
       }
+      return true;
+    },
+    fetchMore(created) {
+      if (!this.shouldFetchMore(created)) {
+        return;
+      }
       this.status.loading = true;
+      let promise;
       if (this.pinFilters.tagFilter) {
         promise = API.fetchPins(this.status.offset, this.pinFilters.tagFilter);
       } else if (this.pinFilters.userFilter) {
@@ -144,7 +165,12 @@ export default {
       }
       promise.then(
         (resp) => {
-          this.blocks = this.buildBlocks(resp.data.results);
+          const { results, next } = resp.data;
+          let newBlocks = this.buildBlocks(results);
+          newBlocks = this.blocks.concat(newBlocks);
+          this.blocks = newBlocks;
+          this.status.offset = newBlocks.length;
+          this.status.hasNext = !(next === null);
           this.status.loading = false;
         },
         () => { this.status.loading = false; },
@@ -152,6 +178,7 @@ export default {
     },
   },
   created() {
+    this.registerScrollEvent();
     this.fetchMore(true);
   },
 };
diff --git a/pinry-spa/src/components/api.js b/pinry-spa/src/components/api.js
index d4dc40d..9bea45d 100644
--- a/pinry-spa/src/components/api.js
+++ b/pinry-spa/src/components/api.js
@@ -24,7 +24,7 @@ function fetchPinsForBoard(boardId) {
     (resolve, reject) => {
       axios.get(url).then(
         (resp) => {
-          resolve({ data: { results: resp.data.pins_detail } });
+          resolve({ data: { results: resp.data.pins_detail, next: null } });
         },
         error => reject(error),
       );
diff --git a/pinry-spa/src/components/utils/browser.js b/pinry-spa/src/components/utils/browser.js
new file mode 100644
index 0000000..396fced
--- /dev/null
+++ b/pinry-spa/src/components/utils/browser.js
@@ -0,0 +1,15 @@
+const utils = {
+  getDocumentHeight() {
+    const html = document.documentElement;
+    return Math.max(
+      document.body.scrollHeight, document.body.offsetHeight,
+      html.clientHeight, html.scrollHeight,
+      html.offsetHeight,
+    );
+  },
+  getWindowHeight() {
+    return window.innerHeight;
+  },
+};
+
+export default utils;
diff --git a/pinry-spa/src/components/utils/scroll.js b/pinry-spa/src/components/utils/scroll.js
new file mode 100644
index 0000000..f68a54c
--- /dev/null
+++ b/pinry-spa/src/components/utils/scroll.js
@@ -0,0 +1,27 @@
+import utils from './browser';
+
+function getDocumentScrollTop() {
+  const doc = document.documentElement;
+  return (window.pageYOffset || doc.scrollTop) - (doc.clientTop || 0);
+}
+
+function onScroll2Bottom(callback) {
+  const windowPosition = getDocumentScrollTop() + window.innerHeight;
+  const bottom = utils.getDocumentHeight() - 100;
+  if (windowPosition > bottom) {
+    callback();
+  }
+}
+
+function bindScroll2Bottom(callback) {
+  window.addEventListener(
+    'scroll',
+    () => {
+      onScroll2Bottom(callback);
+    },
+  );
+}
+
+export default {
+  bindScroll2Bottom,
+};