From 3de745bd33123b9203e2b160d8bbbb6772d399a1 Mon Sep 17 00:00:00 2001
From: Sameh Khamis <sameh@halfpixel.ai>
Date: Sun, 25 Oct 2026 14:08:25 -0700
Subject: [PATCH] fix(fires): reject rolled-over acquisition dates and document
 UTC times

---
 changelog.d/1395-fires-tool-acquired-time.md |  4 ++-
 docs/CURRENT-STATE.md                        |  3 ++
 src/tools/queries/hazards.js                 |  6 +++-
 src/tools/queries/hazards.test.mjs           | 29 ++++++++++++++++++++
 4 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/changelog.d/1395-fires-tool-acquired-time.md b/changelog.d/1395-fires-tool-acquired-time.md
index ea3bddd1d..17d74e481 100644
--- a/changelog.d/1395-fires-tool-acquired-time.md
+++ b/changelog.d/1395-fires-tool-acquired-time.md
@@ -1,4 +1,6 @@
 - Report a fire detection's acquisition time as a UTC timestamp in
   `get_active_fires`. The tool joined FIRMS's unpadded date and time, so a
   00:45 UTC detection read "2026-01-01 45"; it now reads
-  `2026-01-01T00:45:00.000Z` (Rudy Celekli, @rudycelekli, #1395).
+  `2026-01-01T00:45:00.000Z`. Missing or invalid dates and times remain
+  unknown rather than rolling into another calendar day
+  (Rudy Celekli, @rudycelekli, #1395).
diff --git a/docs/CURRENT-STATE.md b/docs/CURRENT-STATE.md
index b15babbb2..5332216e5 100644
--- a/docs/CURRENT-STATE.md
+++ b/docs/CURRENT-STATE.md
@@ -1984,6 +1984,9 @@ accessible name remains "Don't show this again". Control behavior is unchanged.
 ## FIRMS source status
 
 The FIRMS CSV parser rejects impossible acquisition calendar dates before the proxy filters records to the trailing 24 hours, while retaining valid UTC acquisition times.
+The `get_active_fires` tool reports acquisition times as UTC ISO timestamps,
+including zero-padded hours and minutes; missing or invalid dates and times
+remain `null`, including impossible calendar dates from a custom source.
 
 The FIRMS proxy records source success after appending its rows. If aggregation
 throws, that source reports failure without a contradictory success entry.
diff --git a/src/tools/queries/hazards.js b/src/tools/queries/hazards.js
index 194f9b8c1..2b11c639c 100644
--- a/src/tools/queries/hazards.js
+++ b/src/tools/queries/hazards.js
@@ -14,9 +14,13 @@ function acquiredMsUtc(acqDate, acqTime) {
   const hours = Number(hhmm.slice(0, 2));
   const minutes = Number(hhmm.slice(2, 4));
   if (hours > 23 || minutes > 59) return NaN;
-  return Date.parse(
+  const timestamp = Date.parse(
     `${acqDate}T${hhmm.slice(0, 2)}:${hhmm.slice(2, 4)}:00.000Z`,
   );
+  return Number.isFinite(timestamp) &&
+    new Date(timestamp).toISOString().slice(0, 10) === acqDate
+    ? timestamp
+    : NaN;
 }
 
 export const getEarthquakes = defineTool({
diff --git a/src/tools/queries/hazards.test.mjs b/src/tools/queries/hazards.test.mjs
index fe2e6ac1f..fa17158dd 100644
--- a/src/tools/queries/hazards.test.mjs
+++ b/src/tools/queries/hazards.test.mjs
@@ -15,3 +15,32 @@ test('a fire acquired at 00:45 UTC reads as 00:45, not "45"', async () => {
   ]).call('get_active_fires', { area: { bbox: [120, 23, 122, 25] } });
   assert.equal(result.data.rows[0].acquired, '2026-01-01T00:45:00.000Z');
 });
+
+test('fire acquisition timestamps reject impossible calendar dates', async () => {
+  for (const acqDate of [
+    '2026-02-29',
+    '2026-02-30',
+    '2026-04-31',
+    '1900-02-29',
+    '2026-13-01',
+    '2026-01-00',
+  ]) {
+    const result = await catalogWith([
+      { lat: 24, lon: 121, acqDate, acqTime: '45' },
+    ]).call('get_active_fires', { area: { bbox: [120, 23, 122, 25] } });
+    assert.equal(result.data.rows[0].acquired, null, acqDate);
+  }
+});
+
+test('fire acquisition timestamps preserve valid leap days and UTC times', async () => {
+  for (const [acqDate, acqTime, expected] of [
+    ['2024-02-29', '45', '2024-02-29T00:45:00.000Z'],
+    ['2000-02-29', 0, '2000-02-29T00:00:00.000Z'],
+    ['2026-04-30', '2359', '2026-04-30T23:59:00.000Z'],
+  ]) {
+    const result = await catalogWith([
+      { lat: 24, lon: 121, acqDate, acqTime },
+    ]).call('get_active_fires', { area: { bbox: [120, 23, 122, 25] } });
+    assert.equal(result.data.rows[0].acquired, expected);
+  }
+});