Free drag & drop with fixed positions, empty cells and kept pages (0.2.31)

Tiles get an absolute grid slot instead of a packed order: a tile lands exactly
where it is dropped, dropping on another tile swaps the two, everything else
stays put, and empty cells and empty pages persist. The mockup previews the
result while dragging, a new page waits below the last one, "Pagina toevoegen"
keeps an empty page, empty cells accept the next tile from the picker, and the
mouse no longer selects text while dragging.

Storage and protocol stay version 1: `tiles[].slot` (0-47) and `pages` (1-8)
are additive, the layout message carries `slots` and `pages`. Firmware 0.2.26
places tiles on those slots (`place()` next to `pack()`); older firmware packs
in order as before and the editor says so.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

screen_manager/app/core.py

@@ -16,7 +16,7 @@ WEEKDAYS = ['ma', 'di', 'wo', 'do', 'vr', 'za', 'zo']
 REPO = 'https://github.com/MaxGramser/homeassistant_espscreen'
 REFS = {'cyd': 'main', 'guition': 'main'}
 # Firmware shipped with this app release; screens below it get an update offer.
-FIRMWARE_VERSION = '0.2.25'
+FIRMWARE_VERSION = '0.2.26'
 ATTRS = frozenset('brightness percentage current_position current_temperature temperature current_humidity min_temp max_temp target_temp_step supported_color_modes hvac_modes hvac_action hs_color color_temp_kelvin min_color_temp_kelvin max_color_temp_kelvin fan_speed_list unit_of_measurement battery_level fan_speed volume_level is_volume_muted media_title options min max step temperature_unit supported_features device_class next_rising next_setting finishes_at duration remaining humidity wind_speed wind_speed_unit apparent_temperature fan_modes swing_modes fan_mode swing_mode'.split())
 # Attributes whose boolean value the screen needs; every other bool stays behind.
 BOOL_ATTRS = frozenset(['is_volume_muted'])
@@ -42,6 +42,36 @@ DISPLAYS = {'weather': ('standard', 'watch', 'forecast'), 'sensor': ('standard',
 # Displays that only work on a double-width card.
 WIDE_ONLY = ('forecast', 'sunpath')
 
+# Grid positions: two columns, three rows per page, at most eight pages. A tile's
+# `slot` is its absolute cell (page * 6 + row * 2 + column); a wide tile starts in
+# the left column and also covers the cell to its right. Empty cells are allowed.
+SLOTS_PER_PAGE = 6
+MAX_PAGES = 8
+MAX_SLOTS = MAX_PAGES * SLOTS_PER_PAGE
+
+def is_wide(tile):
+    return tile.get('options', {}).get('size') == 'wide'
+
+def footprint(slot, wide):
+    return (slot, slot + 1) if wide else (slot,)
+
+def pack_slots(tiles):
+    """In-order packing, the rule before explicit positions and what firmware without
+    `slots` still does: fill left to right, a wide card starts a new row."""
+    position, slots = 0, []
+    for tile in tiles:
+        wide = is_wide(tile)
+        if wide and position % 2:
+            position += 1
+        slots.append(position)
+        position += 2 if wide else 1
+    return slots
+
+def has_gaps(tiles):
+    """True when the stored positions differ from the in-order packing, so firmware
+    before 0.2.26 (which ignores `slots`) would show another arrangement."""
+    return [t.get('slot') for t in tiles] != pack_slots(tiles)
+
 # Direct controls on the right half of a double-width card (firmware 0.2.19+), like
 # Home Assistant's own entity rows. The first choice is what a wide card shows
 # when the tile has no explicit choice; 'none' keeps the plain card.
@@ -182,7 +212,30 @@ def validate_layout(data):
                     raise ValueError('Deze entiteit ondersteunt die directe bediening niet.')
             item['options'] = dict(options)
         clean.append(item)
+    # Positions: every tile or none (an older editor sends none and keeps its order).
+    given = [tile.get('slot') for tile in tiles]
+    if any(slot is not None for slot in given):
+        occupied = set()
+        for item, slot in zip(clean, given):
+            if type(slot) is not int or not 0 <= slot < MAX_SLOTS:
+                raise ValueError('Ongeldige tegelpositie; vernieuw de beheerpagina.')
+            if is_wide(item) and slot % 2:
+                raise ValueError('Een dubbelbrede tegel begint in de linkerkolom.')
+            for cell in footprint(slot, is_wide(item)):
+                if cell in occupied:
+                    raise ValueError('Twee tegels staan op dezelfde plek.')
+                occupied.add(cell)
+            item['slot'] = slot
+        clean.sort(key=lambda item: item['slot'])
+    else:
+        for item, slot in zip(clean, pack_slots(clean)):
+            item['slot'] = slot
     result = {'title': title.strip(), 'tiles': clean}
+    # Pages kept on purpose, empty ones included; the screen shows at least what the tiles need.
+    if 'pages' in data:
+        if type(data['pages']) is not int or not 1 <= data['pages'] <= MAX_PAGES:
+            raise ValueError(f'Een scherm heeft 1 tot {MAX_PAGES} pagina\'s.')
+        result['pages'] = data['pages']
     if 'settings' in data:
         result['settings'] = validate_settings(data['settings'])
     return result