From 9e40938a2931e46522bee745e64b69e42d0d4671 Mon Sep 17 00:00:00 2001
From: Calixte Denizet <calixte.denizet@gmail.com>
Date: Thu, 22 Sep 2022 13:25:52 +0200
Subject: [PATCH] [JS] Try to guess what the date is when it doesn't follow the
 given format (issue #15490)

We use the format to guess in which order we can find month, day, ... we get the numbers
in the date and consider them as month, day, ...
---
 src/scripting_api/aform.js  | 90 ++++++++++++++++++++++++++++++++++++-
 test/unit/scripting_spec.js | 13 +++++-
 2 files changed, 100 insertions(+), 3 deletions(-)

diff --git a/src/scripting_api/aform.js b/src/scripting_api/aform.js
index 7045cd990..95048ea6b 100644
--- a/src/scripting_api/aform.js
+++ b/src/scripting_api/aform.js
@@ -38,6 +38,7 @@ class AForm {
       "m/d/yy HH:MM",
     ];
     this._timeFormats = ["HH:MM", "h:MM tt", "HH:MM:ss", "h:MM:ss tt"];
+    this._dateActionsCache = new Map();
 
     // The e-mail address regex below originates from:
     // https://html.spec.whatwg.org/multipage/input.html#valid-e-mail-address
@@ -52,6 +53,93 @@ class AForm {
     return event.target ? `[ ${event.target.name} ]` : "";
   }
 
+  _tryToGuessDate(cFormat, cDate) {
+    // We use the format to know the order of day, month, year, ...
+
+    let actions = this._dateActionsCache.get(cFormat);
+    if (!actions) {
+      actions = [];
+      this._dateActionsCache.set(cFormat, actions);
+      cFormat.replace(
+        /(d+)|(m+)|(y+)|(H+)|(M+)|(s+)/g,
+        function (match, d, m, y, H, M, s) {
+          if (d) {
+            actions.push((n, date) => {
+              if (n >= 1 && n <= 31) {
+                date.setDate(n);
+                return true;
+              }
+              return false;
+            });
+          } else if (m) {
+            actions.push((n, date) => {
+              if (n >= 1 && n <= 12) {
+                date.setMonth(n - 1);
+                return true;
+              }
+              return false;
+            });
+          } else if (y) {
+            actions.push((n, date) => {
+              if (n < 50) {
+                n += 2000;
+              } else if (n < 100) {
+                n += 1900;
+              }
+              date.setYear(n);
+              return true;
+            });
+          } else if (H) {
+            actions.push((n, date) => {
+              if (n >= 0 && n <= 23) {
+                date.setHours(n);
+                return true;
+              }
+              return false;
+            });
+          } else if (M) {
+            actions.push((n, date) => {
+              if (n >= 0 && n <= 59) {
+                date.setMinutes(n);
+                return true;
+              }
+              return false;
+            });
+          } else if (s) {
+            actions.push((n, date) => {
+              if (n >= 0 && n <= 59) {
+                date.setSeconds(n);
+                return true;
+              }
+              return false;
+            });
+          }
+          return "";
+        }
+      );
+    }
+
+    const number = /\d+/g;
+    let i = 0;
+    let array;
+    const date = new Date();
+    while ((array = number.exec(cDate)) !== null) {
+      if (i < actions.length) {
+        if (!actions[i++](parseInt(array[0]), date)) {
+          return null;
+        }
+      } else {
+        break;
+      }
+    }
+
+    if (i === 0) {
+      return null;
+    }
+
+    return date;
+  }
+
   _parseDate(cFormat, cDate) {
     let date = null;
     try {
@@ -60,7 +148,7 @@ class AForm {
     if (!date) {
       date = Date.parse(cDate);
       if (isNaN(date)) {
-        date = null;
+        date = this._tryToGuessDate(cFormat, cDate);
       } else {
         date = new Date(date);
       }
diff --git a/test/unit/scripting_spec.js b/test/unit/scripting_spec.js
index a6a5debec..c852021c1 100644
--- a/test/unit/scripting_spec.js
+++ b/test/unit/scripting_spec.js
@@ -608,14 +608,23 @@ describe("Scripting", function () {
       it("should parse a date with a format", async () => {
         const check = async (date, format, expected) => {
           const value = await myeval(
-            `AFParseDateEx("${date}", "${format}").toISOString()`
+            `AFParseDateEx("${date}", "${format}").toISOString().replace(/T.*$/, "")`
+          );
+          expect(value).toEqual(
+            new Date(expected).toISOString().replace(/T.*$/, "")
           );
-          expect(value).toEqual(new Date(expected).toISOString());
         };
 
         await check("05", "dd", "2000/01/05");
         await check("12", "mm", "2000/12/01");
         await check("2022", "yyyy", "2022/01/01");
+        await check("a1$9bbbb21", "dd/mm/yyyy", "2021/09/01");
+
+        // The following test isn't working as expected because
+        // the quickjs date parser has been replaced by the browser one
+        // and the date "1.9.2021" is valid in Chrome but not in Firefox.
+        // The supported date format is not specified...
+        // await check("1.9.2021", "dd/mm/yyyy", "2021/09/01");
       });
     });