fix(web,core): rebase remote promote-all onto series master delta

packages/core/src/util/event/shift-series-schedule-by-occurrence-edit.test.ts

@@ -0,0 +1,110 @@
+import {
+  DateOnlySchema,
+  DateTimeSchema,
+  TimeZoneSchema,
+} from "@core/types/domain-primitives";
+import { type EventSchedule } from "@core/types/event.contracts";
+import { shiftSeriesScheduleByOccurrenceEdit } from "@core/util/event/shift-series-schedule-by-occurrence-edit";
+import { describe, expect, it } from "bun:test";
+
+const timed = (start: string, end: string): EventSchedule => ({
+  kind: "timed",
+  start: DateTimeSchema.parse(start),
+  end: DateTimeSchema.parse(end),
+  timeZone: TimeZoneSchema.parse("UTC"),
+});
+
+const allDay = (start: string, end: string): EventSchedule => ({
+  kind: "allDay",
+  start: DateOnlySchema.parse(start),
+  end: DateOnlySchema.parse(end),
+});
+
+describe("shiftSeriesScheduleByOccurrenceEdit", () => {
+  it("shifts a timed series master by a middle occurrence's day delta", () => {
+    const base = timed("2026-05-04T09:00:00.000Z", "2026-05-04T10:00:00.000Z");
+    const edited = timed(
+      "2026-05-07T09:00:00.000Z",
+      "2026-05-07T10:00:00.000Z",
+    );
+
+    expect(
+      shiftSeriesScheduleByOccurrenceEdit(
+        base,
+        "2026-05-06T09:00:00.000Z",
+        edited,
+      ),
+    ).toEqual(timed("2026-05-05T09:00:00+00:00", "2026-05-05T10:00:00+00:00"));
+  });
+
+  it("propagates a timed duration change onto the master", () => {
+    const base = timed("2026-05-04T09:00:00.000Z", "2026-05-04T10:00:00.000Z");
+    const edited = timed(
+      "2026-05-06T09:00:00.000Z",
+      "2026-05-06T11:00:00.000Z",
+    );
+
+    expect(
+      shiftSeriesScheduleByOccurrenceEdit(
+        base,
+        "2026-05-06T09:00:00.000Z",
+        edited,
+      ),
+    ).toEqual(timed("2026-05-04T09:00:00+00:00", "2026-05-04T11:00:00+00:00"));
+  });
+
+  it("returns the timed base unchanged for a zero delta", () => {
+    const base = timed("2026-05-04T09:00:00.000Z", "2026-05-04T10:00:00.000Z");
+    const edited = timed(
+      "2026-05-06T09:00:00.000Z",
+      "2026-05-06T10:00:00.000Z",
+    );
+
+    expect(
+      shiftSeriesScheduleByOccurrenceEdit(
+        base,
+        "2026-05-06T09:00:00.000Z",
+        edited,
+      ),
+    ).toBe(base);
+  });
+
+  it("shifts an all-day series master by a middle occurrence's day delta", () => {
+    const base = allDay("2026-05-04", "2026-05-05");
+    const edited = allDay("2026-05-07", "2026-05-08");
+
+    expect(
+      shiftSeriesScheduleByOccurrenceEdit(
+        base,
+        "2026-05-06T00:00:00.000Z",
+        edited,
+      ),
+    ).toEqual(allDay("2026-05-05", "2026-05-06"));
+  });
+
+  it("returns the all-day base unchanged for a zero delta", () => {
+    const base = allDay("2026-05-04", "2026-05-05");
+    const edited = allDay("2026-05-06", "2026-05-07");
+
+    expect(
+      shiftSeriesScheduleByOccurrenceEdit(
+        base,
+        "2026-05-06T00:00:00.000Z",
+        edited,
+      ),
+    ).toBe(base);
+  });
+
+  it("returns edited unchanged on a timed ↔ allDay kind flip", () => {
+    const base = timed("2026-05-04T09:00:00.000Z", "2026-05-04T10:00:00.000Z");
+    const edited = allDay("2026-05-07", "2026-05-08");
+
+    expect(
+      shiftSeriesScheduleByOccurrenceEdit(
+        base,
+        "2026-05-06T09:00:00.000Z",
+        edited,
+      ),
+    ).toBe(edited);
+  });
+});

packages/core/src/util/event/shift-series-schedule-by-occurrence-edit.ts

@@ -0,0 +1,73 @@
+import { DateOnlySchema, DateTimeSchema } from "@core/types/domain-primitives";
+import { type EventSchedule } from "@core/types/event.contracts";
+import dayjs from "@core/util/date/dayjs";
+
+/**
+ * Apply an occurrence edit's schedule delta onto the series base.
+ *
+ * Clients send the occurrence's absolute schedule on replace. Treating that
+ * absolute value as the series DTSTART would shift the whole series by the
+ * occurrence's offset from the master. Infer the pre-edit occurrence end from
+ * the master's duration so a duration change on the occurrence still
+ * propagates.
+ *
+ * Kind flips (timed ↔ allDay) return `edited` unchanged — there is no
+ * unambiguous delta onto a differently-shaped master schedule.
+ */
+export function shiftSeriesScheduleByOccurrenceEdit(
+  base: EventSchedule,
+  occurrenceStart: string,
+  edited: EventSchedule,
+): EventSchedule {
+  if (base.kind !== edited.kind) {
+    return edited;
+  }
+
+  if (base.kind === "timed" && edited.kind === "timed") {
+    const originalStart = dayjs(occurrenceStart);
+    const originalEnd = originalStart.add(
+      dayjs(base.end).diff(base.start),
+      "millisecond",
+    );
+    const startDelta = dayjs(edited.start).diff(originalStart);
+    const endDelta = dayjs(edited.end).diff(originalEnd);
+    if (
+      startDelta === 0 &&
+      endDelta === 0 &&
+      base.timeZone === edited.timeZone
+    ) {
+      return base;
+    }
+    return {
+      kind: "timed",
+      start: DateTimeSchema.parse(
+        dayjs(base.start).add(startDelta, "millisecond").format(),
+      ),
+      end: DateTimeSchema.parse(
+        dayjs(base.end).add(endDelta, "millisecond").format(),
+      ),
+      timeZone: edited.timeZone,
+    };
+  }
+
+  // allDay: occurrence ids embed midnight-Z; schedules use YYYY-MM-DD.
+  const originalStart = dayjs(occurrenceStart).utc().format("YYYY-MM-DD");
+  const baseDurationDays = dayjs(base.end).diff(base.start, "day");
+  const originalEnd = dayjs(originalStart)
+    .add(baseDurationDays, "day")
+    .format("YYYY-MM-DD");
+  const startDeltaDays = dayjs(edited.start).diff(dayjs(originalStart), "day");
+  const endDeltaDays = dayjs(edited.end).diff(dayjs(originalEnd), "day");
+  if (startDeltaDays === 0 && endDeltaDays === 0) {
+    return base;
+  }
+  return {
+    kind: "allDay",
+    start: DateOnlySchema.parse(
+      dayjs(base.start).add(startDeltaDays, "day").format("YYYY-MM-DD"),
+    ),
+    end: DateOnlySchema.parse(
+      dayjs(base.end).add(endDeltaDays, "day").format("YYYY-MM-DD"),
+    ),
+  };
+}