1 files changed, 74 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) 2019-2022  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 { Item } from '@/@types/gallery';
+import { Operation } from '@/@types/operation';
+import { TagSearch, TagSearchByOperation } from '@/@types/tag';
+
+function _extractTagsByOperation(searchTags: TagSearch[]): TagSearchByOperation {
+  const byOperation: TagSearchByOperation = {};
+  Object.values(Operation).forEach(
+    operation => (byOperation[operation] = searchTags.filter(tag => tag.operation === operation)),
+  );
+  return byOperation;
+}
+
+function _extractIntersection(byOperation: TagSearchByOperation): Set<Item> {
+  const intersection = new Set<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;
+}
+
+function _extractSubstraction(byOperation: TagSearchByOperation): Set<Item> {
+  const substraction = new Set<Item>();
+  if (byOperation[Operation.SUBSTRACTION].length > 0) {
+    byOperation[Operation.SUBSTRACTION].flatMap(tag => tag.items).forEach(item => substraction.add(item));
+  }
+  return substraction;
+}
+
+function _aggregateAll(
+  byOperation: TagSearchByOperation,
+  intersection: Set<Item>,
+  substraction: Set<Item>,
+): Item[] {
+  byOperation[Operation.ADDITION].flatMap(tag => tag.items).forEach(item => intersection.add(item));
+  substraction.forEach(item => intersection.delete(item));
+  return [...intersection];
+}
+
+// ---
+
+export const useIndexSearch = () => {
+  // Results of the search (by tags)
+  function indexSearch(searchTags: TagSearch[]): Item[] {
+    const byOperation = _extractTagsByOperation(searchTags);
+    const intersection = _extractIntersection(byOperation);
+    const substraction = _extractSubstraction(byOperation);
+    return _aggregateAll(byOperation, intersection, substraction);
+  }
+
+  return indexSearch;
+};