1 files changed, 69 insertions, 0 deletions

diff --git a/viewer/src/services/indexsearch.ts b/viewer/src/services/indexsearch.ts
new file mode 100644
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+++ b/viewer/src/services/indexsearch.ts
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+/* ldgallery - A static generator which turns a collection of tagged
+--             pictures into a searchable web gallery.
+--
+-- Copyright (C) 2019-2020  Guillaume FOUET
+--
+-- This program is free software: you can redistribute it and/or modify
+-- it under the terms of the GNU Affero General Public License as
+-- published by the Free Software Foundation, either version 3 of the
+-- License, or (at your option) any later version.
+--
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+-- GNU Affero General Public License for more details.
+--
+-- You should have received a copy of the GNU Affero General Public License
+-- along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+import { Operation } from "@/@types/Operation";
+
+export default class IndexSearch {
+
+  // Results of the search (by tags)
+  public static search(searchTags: Tag.Search[]): Gallery.Item[] {
+    const byOperation = this.extractTagsByOperation(searchTags);
+    const intersection = this.extractIntersection(byOperation);
+    const substraction = this.extractSubstraction(byOperation);
+    return this.aggregateAll(byOperation, intersection, substraction);
+  }
+
+  private static extractTagsByOperation(searchTags: Tag.Search[]): Tag.SearchByOperation {
+    let byOperation: Tag.SearchByOperation = {};
+    Object.values(Operation).forEach(
+      operation => (byOperation[operation] = searchTags.filter(tag => tag.operation === operation))
+    );
+    return byOperation;
+  }
+
+  private static extractIntersection(byOperation: Tag.SearchByOperation): Set<Gallery.Item> {
+    let intersection = new Set<Gallery.Item>();
+    if (byOperation[Operation.INTERSECTION].length > 0) {
+      byOperation[Operation.INTERSECTION]
+        .map(tag => tag.items)
+        .reduce((a, b) => a.filter(c => b.includes(c)))
+        .flatMap(items => items)
+        .forEach(item => intersection.add(item));
+    }
+    return intersection;
+  }
+
+  private static extractSubstraction(byOperation: Tag.SearchByOperation): Set<Gallery.Item> {
+    let substraction = new Set<Gallery.Item>();
+    if (byOperation[Operation.SUBSTRACTION].length > 0) {
+      byOperation[Operation.SUBSTRACTION].flatMap(tag => tag.items).forEach(item => substraction.add(item));
+    }
+    return substraction;
+  }
+
+  private static aggregateAll(
+    byOperation: Tag.SearchByOperation,
+    intersection: Set<Gallery.Item>,
+    substraction: Set<Gallery.Item>
+  ): Gallery.Item[] {
+    byOperation[Operation.ADDITION].flatMap(tag => tag.items).forEach(item => intersection.add(item));
+    substraction.forEach(item => intersection.delete(item));
+    return [...intersection];
+  }
+}