feat(services): add sequential parameter to find_cheapest_schedule

When sequential: true, tasks are placed in declaration order instead of
being sorted by duration. Each task's search window starts after the
previous task ends (plus gap_minutes). If a task cannot be placed, all
subsequent tasks in the chain are also marked unscheduled.

Adds 12 tests covering ordering, chaining, gap enforcement, and
chain-breaking behavior.

Impact: Users can now schedule dependent appliances (e.g., washing
machine → dryer) in a single find_cheapest_schedule call with guaranteed
order, instead of chaining two find_cheapest_block calls.

custom_components/tibber_prices/services.yaml

@@ -973,6 +973,11 @@ find_cheapest_schedule:
           max: 120
           unit_of_measurement: min
           mode: box
+    sequential:
+      required: false
+      default: false
+      selector:
+        boolean:
     search_scope:
       required: false
       selector:

custom_components/tibber_prices/services/find_cheapest_schedule.py

@@ -92,6 +92,7 @@ FIND_CHEAPEST_SCHEDULE_SERVICE_SCHEMA = vol.Schema(
         vol.Optional("min_price_level"): vol.In([lvl.lower() for lvl in PRICE_LEVEL_ORDER]),
         vol.Optional("include_comparison_details", default=False): cv.boolean,
         vol.Optional("use_base_unit", default=False): cv.boolean,
+        vol.Optional("sequential", default=False): cv.boolean,
         vol.Optional("smooth_outliers", default=True): cv.boolean,
         vol.Optional("allow_relaxation", default=True): cv.boolean,
         vol.Optional("duration_flexibility_minutes"): vol.All(vol.Coerce(int), vol.Range(min=0, max=120)),
@@ -230,9 +231,14 @@ def _attempt_schedule(
     tasks: list[dict[str, Any]],
     gap_intervals: int,
     smooth_outliers: bool,
+    sequential: bool = False,
 ) -> tuple[list[dict[str, Any]], list[str], list[dict[str, Any]]]:
     """Attempt to schedule tasks with specific filter parameters.
 
+    When sequential=True, tasks are placed in declaration order and each task's
+    search window begins after the previous task's end + gap.  When False
+    (default), tasks are sorted longest-first for optimal greedy packing.
+
     Returns:
         (assignments, unscheduled_names, filtered_price_info)
 
@@ -247,18 +253,38 @@ def _attempt_schedule(
     if not search_data:
         return [], [t["name"] for t in tasks], filtered
 
-    # Greedy assignment: longest task first
-    tasks_sorted = sorted(tasks, key=lambda t: t["duration_intervals"], reverse=True)
+    # Task ordering: declaration order when sequential, longest-first otherwise
+    tasks_ordered = list(tasks) if sequential else sorted(tasks, key=lambda t: t["duration_intervals"], reverse=True)
+
     available = [True] * len(search_data)
     assignments: list[dict[str, Any]] = []
     unscheduled: list[str] = []
 
-    for task in tasks_sorted:
+    # In sequential mode, track the earliest allowed start index for the next task
+    sequential_min_idx = 0
+    sequential_chain_broken = False
+
+    for task in tasks_ordered:
         dur_intervals = task["duration_intervals"]
+
+        # In sequential mode, if the chain is broken (previous task failed),
+        # all remaining tasks are also unscheduled
+        if sequential and sequential_chain_broken:
+            unscheduled.append(task["name"])
+            continue
+
+        # In sequential mode, restrict search to intervals at or after the
+        # minimum start index by marking earlier slots as unavailable
+        if sequential and sequential_min_idx > 0:
+            for k in range(min(sequential_min_idx, len(search_data))):
+                available[k] = False
+
         window = _find_cheapest_window_in_pool(search_data, dur_intervals, available)
 
         if window is None:
             unscheduled.append(task["name"])
+            if sequential:
+                sequential_chain_broken = True
             continue
 
         start_idx, end_idx = window
@@ -273,6 +299,10 @@ def _attempt_schedule(
         for k in range(start_idx, gap_end):
             available[k] = False
 
+        # In sequential mode, advance the minimum start for the next task
+        if sequential:
+            sequential_min_idx = gap_end
+
         assignments.append(
             {
                 "name": task["name"],
@@ -297,6 +327,7 @@ async def handle_find_cheapest_schedule(call: ServiceCall) -> ServiceResponse:
     include_comparison_details: bool = call.data.get("include_comparison_details", False)
     smooth_outliers: bool = call.data.get("smooth_outliers", True)
     allow_relaxation: bool = call.data.get("allow_relaxation", True)
+    sequential: bool = call.data.get("sequential", False)
     duration_flexibility_minutes: int | None = call.data.get("duration_flexibility_minutes")
 
     # Validate task names are unique (before any expensive operations)
@@ -372,10 +403,11 @@ async def handle_find_cheapest_schedule(call: ServiceCall) -> ServiceResponse:
         )
 
     _LOGGER.info(
-        "%s called: %d tasks, gap=%dmin, range=%s to %s",
+        "%s called: %d tasks, gap=%dmin, sequential=%s, range=%s to %s",
         service_label,
         len(tasks),
         gap_minutes,
+        sequential,
         search_start,
         search_end,
     )
@@ -411,6 +443,7 @@ async def handle_find_cheapest_schedule(call: ServiceCall) -> ServiceResponse:
         tasks=tasks,
         gap_intervals=gap_intervals,
         smooth_outliers=smooth_outliers,
+        sequential=sequential,
     )
     all_scheduled = len(unscheduled) == 0
     level_filter_active = min_price_level is not None or max_price_level is not None
@@ -437,6 +470,7 @@ async def handle_find_cheapest_schedule(call: ServiceCall) -> ServiceResponse:
                 tasks=tasks,
                 gap_intervals=gap_intervals,
                 smooth_outliers=smooth_outliers,
+                sequential=sequential,
             )
             if len(a) > len(best_assignments):
                 best_assignments, best_unscheduled, best_filtered = a, u, f
@@ -474,6 +508,7 @@ async def handle_find_cheapest_schedule(call: ServiceCall) -> ServiceResponse:
                     tasks=reduced,
                     gap_intervals=gap_intervals,
                     smooth_outliers=smooth_outliers,
+                    sequential=sequential,
                 )
                 if len(a) > len(best_assignments):
                     best_assignments, best_unscheduled, best_filtered = a, u, f
@@ -584,6 +619,7 @@ async def handle_find_cheapest_schedule(call: ServiceCall) -> ServiceResponse:
         "must_finish_by": must_finish_by_dt.isoformat() if must_finish_by_dt else None,
         "currency": currency,
         "price_unit": price_unit,
+        "sequential": sequential,
         "all_tasks_scheduled": all_scheduled,
         "reason": reason,
         "relaxation_applied": relaxation_applied,

custom_components/tibber_prices/translations/de.json

@@ -2027,6 +2027,10 @@
           "name": "Pause zwischen Aufgaben (Minuten)",
           "description": "Mindestpause in Minuten zwischen aufeinanderfolgenden Aufgaben. Wird auf 15 Minuten aufgerundet. Standard: 0 (keine Pause)."
         },
+        "sequential": {
+          "name": "Sequenzielle Reihenfolge",
+          "description": "Aufgaben in der Reihenfolge planen, in der sie in der Aufgabenliste stehen. Jede Aufgabe startet nach dem Ende der vorherigen (plus Pause). Nutze dies für abhängige Geräte wie Waschmaschine → Trockner. Standard: deaktiviert (Aufgaben werden nach Dauer sortiert für optimale Verteilung)."
+        },
         "search_scope": {
           "name": "Suchbereich (Shortcut)",
           "description": "Kurzwahl für häufige Suchbereiche. Überschreibt alle anderen Zeitbereich-Optionen. today/tomorrow = ganzer Kalendertag, remaining_today = jetzt bis Mitternacht, next_24h/next_48h = rollierendes Fenster ab jetzt."

custom_components/tibber_prices/translations/en.json

@@ -2027,6 +2027,10 @@
           "name": "Gap Between Tasks (minutes)",
           "description": "Minimum gap in minutes between consecutive scheduled tasks. Rounded up to 15 minutes. Default: 0 (no gap)."
         },
+        "sequential": {
+          "name": "Sequential Ordering",
+          "description": "Schedule tasks in the order they appear in the task list. Each task starts after the previous one ends (plus gap). Use this for dependent appliances like washing machine → dryer. Default: disabled (tasks are sorted by duration for optimal packing)."
+        },
         "search_scope": {
           "name": "Search Scope",
           "description": "Shorthand for common search ranges. Overrides all other time range options. today / tomorrow = full calendar day, remaining_today = now until midnight, next_24h / next_48h = rolling window from now."

custom_components/tibber_prices/translations/nb.json

@@ -2027,6 +2027,10 @@
           "name": "Pause mellom oppgaver (minutter)",
           "description": "Minimum pause i minutter mellom paafoeglende planlagte oppgaver. Avrundes opp til 15 minutter. Standard: 0 (ingen pause)."
         },
+        "sequential": {
+          "name": "Sekvensiell rekkefølge",
+          "description": "Planlegg oppgaver i rekkefølgen de står i oppgavelisten. Hver oppgave starter etter at den forrige er ferdig (pluss pause). Bruk dette for avhengige apparater som vaskemaskin → tørketrommel. Standard: deaktivert (oppgaver sorteres etter varighet for optimal fordeling)."
+        },
         "search_scope": {
           "name": "Soekeomfang (snarvei)",
           "description": "Snarvei for vanlige soekeomraader. Overstyrer alle andre tidsalternativer. today/tomorrow = hele kalenderdagen, remaining_today = naa til midnatt, next_24h/next_48h = rullende vindu fra naa."

custom_components/tibber_prices/translations/nl.json

@@ -2027,6 +2027,10 @@
           "name": "Tussenpose tussen taken (minuten)",
           "description": "Minimale tussenpose in minuten tussen opeenvolgende ingeplande taken. Afgerond omhoog tot 15 minuten. Standaard: 0 (geen tussenpose)."
         },
+        "sequential": {
+          "name": "Sequentiële volgorde",
+          "description": "Plan taken in de volgorde waarin ze in de takenlijst staan. Elke taak start na het einde van de vorige (plus tussenpose). Gebruik dit voor afhankelijke apparaten zoals wasmachine → droger. Standaard: uitgeschakeld (taken worden gesorteerd op duur voor optimale verdeling)."
+        },
         "search_scope": {
           "name": "Zoekbereik (snelkoppeling)",
           "description": "Snelkoppeling voor veelgebruikte zoekbereiken. Overschrijft alle andere tijdopties. today/tomorrow = volledige kalenderdag, remaining_today = nu tot middernacht, next_24h/next_48h = rolling venster vanaf nu."

custom_components/tibber_prices/translations/sv.json

@@ -2027,6 +2027,10 @@
           "name": "Paus mellan uppgifter (minuter)",
           "description": "Minsta paus i minuter mellan paa varandra foeoljande schemalagda uppgifter. Avrundas uppaat till 15 minuter. Standard: 0 (ingen paus)."
         },
+        "sequential": {
+          "name": "Sekventiell ordning",
+          "description": "Schemalägg uppgifter i den ordning de står i uppgiftslistan. Varje uppgift startar efter att den föregående är klar (plus paus). Använd detta för beroende apparater som tvättmaskin → torktumlare. Standard: inaktiverad (uppgifter sorteras efter varaktighet för optimal fördelning)."
+        },
         "search_scope": {
           "name": "Soekumfaang (genvaeg)",
           "description": "Genvaeg foer vanliga soekomraaden. Aasidosaetter alla andra tidsalternativ. today/tomorrow = hela kalenderdagen, remaining_today = nu till midnatt, next_24h/next_48h = rullande foenster fraen nu."

tests/services/test_sequential_scheduling.py

@@ -0,0 +1,355 @@
+"""Tests for sequential scheduling feature in find_cheapest_schedule."""
+
+from __future__ import annotations
+
+from datetime import UTC, datetime, timedelta
+from typing import Any, cast
+
+from custom_components.tibber_prices.services.find_cheapest_schedule import (
+    FIND_CHEAPEST_SCHEDULE_SERVICE_SCHEMA,
+    _attempt_schedule,
+)
+
+
+def _make_intervals(
+    prices: list[float],
+    start: datetime | None = None,
+    *,
+    level: str = "NORMAL",
+) -> list[dict[str, Any]]:
+    """Create contiguous quarter-hour intervals for tests."""
+    base = start or datetime(2026, 1, 1, 0, 0, tzinfo=UTC)
+    return [
+        {
+            "startsAt": (base + timedelta(minutes=15 * i)).isoformat(),
+            "total": price,
+            "level": level,
+        }
+        for i, price in enumerate(prices)
+    ]
+
+
+def _make_tasks(*specs: tuple[str, int]) -> list[dict[str, Any]]:
+    """Create task dicts from (name, duration_intervals) tuples."""
+    return [
+        {
+            "name": name,
+            "duration_minutes_requested": dur * 15,
+            "duration_minutes": dur * 15,
+            "duration_intervals": dur,
+            "power_profile": None,
+        }
+        for name, dur in specs
+    ]
+
+
+class TestSequentialSchema:
+    """Schema accepts sequential parameter."""
+
+    def test_schema_accepts_sequential_true(self) -> None:
+        """Schema should accept sequential: true."""
+        result = cast(
+            "dict[str, Any]",
+            FIND_CHEAPEST_SCHEDULE_SERVICE_SCHEMA(
+                {
+                    "tasks": [{"name": "dishwasher", "duration": timedelta(hours=1)}],
+                    "sequential": True,
+                }
+            ),
+        )
+        assert result["sequential"] is True
+
+    def test_schema_defaults_sequential_false(self) -> None:
+        """Sequential should default to false when omitted."""
+        result = cast(
+            "dict[str, Any]",
+            FIND_CHEAPEST_SCHEDULE_SERVICE_SCHEMA(
+                {
+                    "tasks": [{"name": "dishwasher", "duration": timedelta(hours=1)}],
+                }
+            ),
+        )
+        assert result["sequential"] is False
+
+
+class TestSequentialOrdering:
+    """Sequential mode preserves declaration order and chains search windows."""
+
+    def test_non_sequential_sorts_by_duration(self) -> None:
+        """Default (non-sequential) mode sorts tasks longest-first."""
+        # 16 intervals = 4 hours of data
+        # Prices: first 8 cheap, last 8 expensive
+        prices = [5.0] * 8 + [20.0] * 8
+        pool = _make_intervals(prices)
+
+        # Task A is short (2 intervals), Task B is long (4 intervals)
+        tasks = _make_tasks(("short_a", 2), ("long_b", 4))
+
+        assignments, unscheduled, _ = _attempt_schedule(
+            pool,
+            max_price_level=None,
+            min_price_level=None,
+            tasks=tasks,
+            gap_intervals=0,
+            smooth_outliers=False,
+            sequential=False,
+        )
+
+        assert not unscheduled
+        assert len(assignments) == 2
+        # Greedy longest-first: long_b gets placed first (cheapest window)
+        # Assignments are returned in placement order (longest first)
+        assert assignments[0]["name"] == "long_b"
+        assert assignments[1]["name"] == "short_a"
+
+    def test_sequential_preserves_declaration_order(self) -> None:
+        """Sequential mode places tasks in the order they appear."""
+        # 16 intervals, all same price
+        prices = [10.0] * 16
+        pool = _make_intervals(prices)
+
+        # Declare short task first, long task second
+        tasks = _make_tasks(("short_a", 2), ("long_b", 4))
+
+        assignments, unscheduled, _ = _attempt_schedule(
+            pool,
+            max_price_level=None,
+            min_price_level=None,
+            tasks=tasks,
+            gap_intervals=0,
+            smooth_outliers=False,
+            sequential=True,
+        )
+
+        assert not unscheduled
+        assert len(assignments) == 2
+        # Sequential: short_a placed first, long_b after
+        assert assignments[0]["name"] == "short_a"
+        assert assignments[1]["name"] == "long_b"
+
+    def test_sequential_chains_search_windows(self) -> None:
+        """Each sequential task starts after the previous task's end."""
+        # 12 intervals: first 4 are cheap, next 4 medium, last 4 expensive
+        prices = [5.0] * 4 + [10.0] * 4 + [20.0] * 4
+        pool = _make_intervals(prices)
+
+        # Two tasks of 3 intervals each
+        tasks = _make_tasks(("task_a", 3), ("task_b", 3))
+
+        assignments, unscheduled, _ = _attempt_schedule(
+            pool,
+            max_price_level=None,
+            min_price_level=None,
+            tasks=tasks,
+            gap_intervals=0,
+            smooth_outliers=False,
+            sequential=True,
+        )
+
+        assert not unscheduled
+        assert len(assignments) == 2
+
+        # Task A should get the cheapest window (intervals 0-2)
+        a_end_last = datetime.fromisoformat(assignments[0]["intervals"][-1]["startsAt"])
+
+        # Task B must start at or after task A's end
+        b_start = datetime.fromisoformat(assignments[1]["intervals"][0]["startsAt"])
+        assert b_start >= a_end_last + timedelta(minutes=15)
+
+    def test_sequential_respects_gap(self) -> None:
+        """Sequential mode enforces gap between tasks."""
+        # 16 intervals of uniform price
+        prices = [10.0] * 16
+        pool = _make_intervals(prices)
+
+        # 2 tasks of 3 intervals each, with 2-interval (30 min) gap
+        tasks = _make_tasks(("washer", 3), ("dryer", 3))
+
+        assignments, unscheduled, _ = _attempt_schedule(
+            pool,
+            max_price_level=None,
+            min_price_level=None,
+            tasks=tasks,
+            gap_intervals=2,
+            smooth_outliers=False,
+            sequential=True,
+        )
+
+        assert not unscheduled
+        assert len(assignments) == 2
+
+        washer_end = datetime.fromisoformat(assignments[0]["intervals"][-1]["startsAt"]) + timedelta(minutes=15)
+        dryer_start = datetime.fromisoformat(assignments[1]["intervals"][0]["startsAt"])
+
+        # Gap should be at least 30 minutes (2 intervals × 15 min)
+        gap = dryer_start - washer_end
+        assert gap >= timedelta(minutes=30)
+
+    def test_sequential_chain_breaks_on_failure(self) -> None:
+        """If a sequential task can't be placed, all later tasks are unscheduled."""
+        # Only 6 intervals — not enough for 3 tasks of 3 intervals each
+        prices = [10.0] * 6
+        pool = _make_intervals(prices)
+
+        tasks = _make_tasks(("task_a", 3), ("task_b", 3), ("task_c", 3))
+
+        assignments, unscheduled, _ = _attempt_schedule(
+            pool,
+            max_price_level=None,
+            min_price_level=None,
+            tasks=tasks,
+            gap_intervals=0,
+            smooth_outliers=False,
+            sequential=True,
+        )
+
+        # Task A and B fit (6 intervals total), task C doesn't
+        assert len(assignments) == 2
+        assert assignments[0]["name"] == "task_a"
+        assert assignments[1]["name"] == "task_b"
+        assert unscheduled == ["task_c"]
+
+    def test_sequential_all_fail_after_first_failure(self) -> None:
+        """If the first task fails in sequential mode, all are unscheduled."""
+        # 2 intervals — not enough for any 3-interval task
+        prices = [10.0] * 2
+        pool = _make_intervals(prices)
+
+        tasks = _make_tasks(("task_a", 3), ("task_b", 2))
+
+        assignments, unscheduled, _ = _attempt_schedule(
+            pool,
+            max_price_level=None,
+            min_price_level=None,
+            tasks=tasks,
+            gap_intervals=0,
+            smooth_outliers=False,
+            sequential=True,
+        )
+
+        # Task A can't fit (needs 3, only 2 available)
+        # Task B should also be unscheduled because the chain is broken
+        assert len(assignments) == 0
+        assert unscheduled == ["task_a", "task_b"]
+
+    def test_sequential_optimizes_within_window(self) -> None:
+        """Sequential still finds cheapest window within each task's available range."""
+        # 12 intervals: pattern cheap-expensive-cheap-expensive...
+        # First 6 for task A, second 6 for task B
+        # Within each half, there's a cheaper sub-window
+        prices = [20.0, 5.0, 5.0, 20.0, 20.0, 20.0, 20.0, 20.0, 5.0, 5.0, 20.0, 20.0]
+        pool = _make_intervals(prices)
+
+        tasks = _make_tasks(("task_a", 2), ("task_b", 2))
+
+        assignments, unscheduled, _ = _attempt_schedule(
+            pool,
+            max_price_level=None,
+            min_price_level=None,
+            tasks=tasks,
+            gap_intervals=0,
+            smooth_outliers=False,
+            sequential=True,
+        )
+
+        assert not unscheduled
+        assert len(assignments) == 2
+
+        # Task A should pick the cheapest 2-interval window: indices 1-2 (price 5.0 each)
+        a_prices = [iv["total"] for iv in assignments[0]["intervals"]]
+        assert a_prices == [5.0, 5.0]
+
+        # Task B searches from index 2 onward, cheapest is indices 8-9 (price 5.0 each)
+        b_prices = [iv["total"] for iv in assignments[1]["intervals"]]
+        assert b_prices == [5.0, 5.0]
+
+    def test_sequential_single_task_same_as_non_sequential(self) -> None:
+        """With a single task, sequential and non-sequential produce the same result."""
+        prices = [20.0, 5.0, 5.0, 20.0, 10.0, 10.0]
+        pool = _make_intervals(prices)
+        tasks = _make_tasks(("only_task", 2))
+
+        a_seq, u_seq, _ = _attempt_schedule(
+            pool,
+            max_price_level=None,
+            min_price_level=None,
+            tasks=tasks,
+            gap_intervals=0,
+            smooth_outliers=False,
+            sequential=True,
+        )
+        a_non, u_non, _ = _attempt_schedule(
+            pool,
+            max_price_level=None,
+            min_price_level=None,
+            tasks=tasks,
+            gap_intervals=0,
+            smooth_outliers=False,
+            sequential=False,
+        )
+
+        assert not u_seq
+        assert not u_non
+        assert len(a_seq) == len(a_non) == 1
+        assert a_seq[0]["intervals"] == a_non[0]["intervals"]
+
+
+class TestSequentialThreeTasks:
+    """Sequential scheduling with three tasks (washer → dryer → fold reminder)."""
+
+    def test_three_tasks_chained(self) -> None:
+        """Three sequential tasks are placed in order with no overlap."""
+        # 24 intervals (6 hours) with varying prices
+        prices = [15.0, 10.0, 5.0, 5.0, 10.0, 15.0, 20.0, 25.0] * 3
+        pool = _make_intervals(prices)
+
+        tasks = _make_tasks(("washer", 4), ("dryer", 3), ("fold", 1))
+
+        assignments, unscheduled, _ = _attempt_schedule(
+            pool,
+            max_price_level=None,
+            min_price_level=None,
+            tasks=tasks,
+            gap_intervals=0,
+            smooth_outliers=False,
+            sequential=True,
+        )
+
+        assert not unscheduled
+        assert len(assignments) == 3
+        assert assignments[0]["name"] == "washer"
+        assert assignments[1]["name"] == "dryer"
+        assert assignments[2]["name"] == "fold"
+
+        # Verify no overlap: each task starts after previous ends
+        for i in range(1, len(assignments)):
+            prev_end = datetime.fromisoformat(assignments[i - 1]["intervals"][-1]["startsAt"]) + timedelta(minutes=15)
+            curr_start = datetime.fromisoformat(assignments[i]["intervals"][0]["startsAt"])
+            assert curr_start >= prev_end
+
+    def test_three_tasks_with_gap(self) -> None:
+        """Three sequential tasks respect gap between each pair."""
+        prices = [10.0] * 24
+        pool = _make_intervals(prices)
+
+        tasks = _make_tasks(("washer", 4), ("dryer", 3), ("fold", 1))
+
+        assignments, unscheduled, _ = _attempt_schedule(
+            pool,
+            max_price_level=None,
+            min_price_level=None,
+            tasks=tasks,
+            gap_intervals=1,  # 15 min gap
+            smooth_outliers=False,
+            sequential=True,
+        )
+
+        assert not unscheduled
+        assert len(assignments) == 3
+
+        # Verify gaps between each pair
+        for i in range(1, len(assignments)):
+            prev_end = datetime.fromisoformat(assignments[i - 1]["intervals"][-1]["startsAt"]) + timedelta(minutes=15)
+            curr_start = datetime.fromisoformat(assignments[i]["intervals"][0]["startsAt"])
+            gap = curr_start - prev_end
+            assert gap >= timedelta(minutes=15)