From 763341eacffb82116a86f3ad9a2eb40689d0cf25 Mon Sep 17 00:00:00 2001
From: flammermann <github@flammermann.de>
Date: Tue, 2 Jan 2024 22:38:50 +0000
Subject: [PATCH] Support date properties in facet search - move parseDateField

---
 umap/static/umap/js/umap.controls.js |  2 +-
 umap/static/umap/js/umap.core.js     | 60 ++++++++++++++++++++++++++++
 umap/static/umap/js/umap.features.js | 12 +-----
 3 files changed, 62 insertions(+), 12 deletions(-)

diff --git a/umap/static/umap/js/umap.controls.js b/umap/static/umap/js/umap.controls.js
index 77e7d0f8..fc0bced2 100644
--- a/umap/static/umap/js/umap.controls.js
+++ b/umap/static/umap/js/umap.controls.js
@@ -695,7 +695,7 @@ const ControlsMixin = {
         keys.forEach((key) => {
           let value = feature.properties[key]
           if (facetKeys[key]["type"] === "date") {
-            value = feature.parseDateField(value)
+            value = L.Util.parseDateField(value)
             if (!!value && (!facetCriteria[key]["min"] || facetCriteria[key]["min"] > value)) {
               facetCriteria[key]["min"] = value
             }
diff --git a/umap/static/umap/js/umap.core.js b/umap/static/umap/js/umap.core.js
index 4981086b..47468070 100644
--- a/umap/static/umap/js/umap.core.js
+++ b/umap/static/umap/js/umap.core.js
@@ -67,6 +67,66 @@ L.Util.setNullableBooleanFromQueryString = function (options, name) {
   }
 }
 
+// the Date() constructor can handle various inputs to create a date
+// - value: epoch (unix timestamp) in milliseconds
+// - dateString: ISO 8601 formatted (YYYY-MM-DDTHH:mm:ss.sssZ)
+// - dateObject: JS date object
+// - multiple parameters for different date fields (year, month, ...)
+//
+// a mix of those options shall be supported without the user having
+// to specify the exact format, since umap is based on json the type
+// of the feature property value can only be
+// - string, number or boolean
+// - object or array
+// - null
+//
+// therefore, the following inputs shall be covered
+// - epoch (unix timestamp) in milliseconds as number
+// - epoch (unix timestamp) in seconds as number
+// - epoch (unix timestamp) in milliseconds as string
+// - epoch (unix timestamp) in seconds as string
+// - date in ISO 8601 format as string
+//
+// this function tries to guess the format of the feature property value
+// and adjust it a little before passing it to Date() constructor
+//
+L.Util.parseDateField = function (value) {
+  if (value != null && parseFloat(value).toString() === value.toString()) {
+    // if the string representation of the feature property value is
+    // the same with and without being parsed as a float, the value is
+    // a number (either of type number or string)
+    //
+    // numbers are assumed to be epochs (unix timestamps) but so far
+    // it is unclear whether it is in seconds, milliseconds or nanoseconds
+    //
+    // without user input it can never be determined with certainty, but
+    // by making some assumptions and sacrificing some small date ranges,
+    // it is possible to work around that
+    //
+    value = parseFloat(value);
+    if (Math.abs(value) < 10000000000) {
+      // if the absolute value of that number is smaller than 10000000000,
+      // it is assumed to be in seconds and must be multiplied by 1000
+      //
+      value = value * 1000;
+    } else if (Math.abs(value) > 10000000000000) {
+      // if the absolute value of that number is bigger than 10000000000000,
+      // it is assumed to be in nanoseconds and must be divided by 1000
+      //
+      value = value / 1000;
+    }
+    // in all other cases the number is assumed to be in milliseconds
+  }
+  // in all other cases the value is passed to the Date() constructor
+  // without modification and the constructor will try to make something out of it
+  //
+  // this can either result in something proper (e.g. string containing dateString),
+  // something wrong (e.g. boolean) or an invalid date (e.g. object, array, null,
+  // string not containing dateString)
+  //
+  return new Date(value);
+}
+
 L.DomUtil.add = (tagName, className, container, content) => {
   const el = L.DomUtil.create(tagName, className, container)
   if (content) {
diff --git a/umap/static/umap/js/umap.features.js b/umap/static/umap/js/umap.features.js
index 297da47b..d3c14dab 100644
--- a/umap/static/umap/js/umap.features.js
+++ b/umap/static/umap/js/umap.features.js
@@ -492,16 +492,6 @@ U.FeatureMixin = {
     return false
   },
 
-  parseDateField: function (value) {
-    if (parseFloat(value).toString() === value.toString()) {
-      value = parseFloat(value);
-      if (value < 10000000000) {
-        value = value * 1000;
-      }
-    }
-    return new Date(value);
-  },
-
   matchFacets: function () {
     const facets = this.map.facets
     for (const [property, criteria] of Object.entries(facets)) {
@@ -510,7 +500,7 @@ U.FeatureMixin = {
       if (type === "date") {
         const min = new Date(criteria["min"])
         const max = new Date(criteria["max"])
-        value = this.parseDateField(value)
+        value = L.Util.parseDateField(value)
         if (!!min && (!value || min > value)) return false
         if (!!max && (!value || max < value)) return false
       } else {