[WIP] tags & categories for pages

lib/models/page.js

@@ -8,6 +8,7 @@ const { full_url_for } = require('hexo-util');
 
 module.exports = ctx => {
   const Page = new Schema({
+    id: String,
     title: {type: String, default: ''},
     date: {
       type: Moment,
@@ -41,3 +42,141 @@ module.exports = ctx => {
 
   return Page;
 };
+
+  Page.virtual('tags').get(function() {
+    const PageTag = ctx.model('PageTag');
+    const Tag = ctx.model('Tag');
+
+    const ids = PageTag.find({page_id: this._id}, {lean: true}).map(item => item.tag_id);
+
+    return Tag.find({_id: {$in: ids}});
+  });
+
+  Page.method('setTags', function(tags) {
+    tags = removeEmptyTag(tags);
+
+    const PageTag = ctx.model('PageTag');
+    const Tag = ctx.model('Tag');
+    const id = this._id;
+    const existed = PageTag.find({page_id: id}, {lean: true}).map(pickID);
+
+    return Promise.map(tags, tag => {
+      // Find the tag by name
+      const data = Tag.findOne({name: tag}, {lean: true});
+      if (data) return data;
+
+      // Insert the tag if not exist
+      return Tag.insert({name: tag}).catch(err => {
+        // Try to find the tag again. Throw the error if not found
+        const data = Tag.findOne({name: tag}, {lean: true});
+
+        if (data) return data;
+        throw err;
+      });
+    }).map(tag => {
+      // Find the reference
+      const ref = PageTag.findOne({page_id: id, tag_id: tag._id}, {lean: true});
+      if (ref) return ref;
+
+      // Insert the reference if not exist
+      return PageTag.insert({
+        page_id: id,
+        tag_id: tag._id
+      });
+    }).then(tags => {
+      // Remove old tags
+      const deleted = existed.filter(item => !tags.map(pickID).includes(item));
+      return deleted;
+    }).map(tag => PageTag.removeById(tag));
+  });
+
+  Page.virtual('categories').get(function() {
+    const PageCategory = ctx.model('PageCategory');
+    const Category = ctx.model('Category');
+
+    const ids = PageCategory.find({page_id: this._id}, {lean: true}).map(item => item.category_id);
+
+    return Category.find({_id: {$in: ids}});
+  });
+
+  Page.method('setCategories', function(cats) {
+    // Remove empty categories, preserving hierarchies
+    cats = cats.filter(cat => {
+      return Array.isArray(cat) || (cat != null && cat !== '');
+    }).map(cat => {
+      return Array.isArray(cat) ? removeEmptyTag(cat) : `${cat}`;
+    });
+
+    const PageCategory = ctx.model('PageCategory');
+    const Category = ctx.model('Category');
+    const id = this._id;
+    const allIds = [];
+    const existed = PageCategory.find({page_id: id}, {lean: true}).map(pickID);
+    const hasHierarchy = cats.filter(Array.isArray).length > 0;
+
+    // Add a hierarchy of categories
+    const addHierarchy = catHierarchy => {
+      const parentIds = [];
+      if (!Array.isArray(catHierarchy)) catHierarchy = [catHierarchy];
+      // Don't use "Promise.map". It doesn't run in series.
+      // MUST USE "Promise.each".
+      return Promise.each(catHierarchy, (cat, i) => {
+        // Find the category by name
+        const data = Category.findOne({
+          name: cat,
+          parent: i ? parentIds[i - 1] : {$exists: false}
+        }, {lean: true});
+
+        if (data) {
+          allIds.push(data._id);
+          parentIds.push(data._id);
+          return data;
+        }
+
+        // Insert the category if not exist
+        const obj = {name: cat};
+        if (i) obj.parent = parentIds[i - 1];
+
+        return Category.insert(obj).catch(err => {
+          // Try to find the category again. Throw the error if not found
+          const data = Category.findOne({
+            name: cat,
+            parent: i ? parentIds[i - 1] : {$exists: false}
+          }, {lean: true});
+
+          if (data) return data;
+          throw err;
+        }).then(data => {
+          allIds.push(data._id);
+          parentIds.push(data._id);
+          return data;
+        });
+      });
+    };
+
+    return (hasHierarchy ? Promise.each(cats, addHierarchy) : Promise.resolve(addHierarchy(cats))
+    ).then(() => allIds).map(catId => {
+      // Find the reference
+      const ref = PageCategory.findOne({page_id: id, category_id: catId}, {lean: true});
+      if (ref) return ref;
+
+      // Insert the reference if not exist
+      return PageCategory.insert({
+        page_id: id,
+        category_id: catId
+      });
+    }).then(pageCats => // Remove old categories
+      existed.filter(item => !pageCats.map(pickID).includes(item))).map(cat => PageCategory.removeById(cat));
+  });
+
+  // Remove PageTag references
+  Page.pre('remove', data => {
+    const PageTag = ctx.model('PageTag');
+    return PageTag.remove({page_id: data._id});
+  });
+
+  // Remove PageCategory references
+  Page.pre('remove', data => {
+    const PageCategory = ctx.model('PageCategory');
+    return PageCategory.remove({page_id: data._id});
+  });