feat(main): main

api/routers/channel.py

@@ -39,11 +39,13 @@ class ChannelSourceRuleSchema(Schema):
     source_name: str
     rule_mode: str
     weight: float
+    schedule_block_label: Optional[str] = None
 
 class ChannelSourceAssignSchema(Schema):
     source_id: int
     rule_mode: str = 'allow'  # allow | prefer | avoid | block
     weight: float = 1.0
+    schedule_block_label: Optional[str] = None
 
 class AiringSchema(Schema):
     id: int
@@ -58,7 +60,21 @@ class AiringSchema(Schema):
     def from_airing(airing) -> 'AiringSchema':
         media_path = None
         if airing.media_item:
-            raw_path = airing.media_item.cached_file_path or airing.media_item.file_path
+            item = airing.media_item
+            
+            # 1. Determine if this item is from a YouTube source
+            is_youtube = False
+            if item.media_source and item.media_source.source_type in ['youtube', 'youtube_channel', 'youtube_playlist']:
+                is_youtube = True
+
+            # 2. Strict signaling: If YouTube, we MUST have it downloaded
+            if is_youtube:
+                raw_path = item.cached_file_path
+                # If cached_file_path is None, raw_path is None, and media_path remains None
+            else:
+                # Fallback for generic local files/links
+                raw_path = item.cached_file_path or item.file_path
+
             if raw_path:
                 if raw_path.startswith("http://") or raw_path.startswith("https://"):
                     media_path = raw_path
@@ -133,6 +149,7 @@ def list_channel_sources(request, channel_id: int):
             source_name=r.media_source.name,
             rule_mode=r.rule_mode,
             weight=float(r.weight),
+            schedule_block_label=r.schedule_block_label,
         )
         for r in rules
     ]
@@ -146,6 +163,7 @@ def assign_source_to_channel(request, channel_id: int, payload: ChannelSourceAss
         media_source=source,
         rule_mode=payload.rule_mode,
         weight=payload.weight,
+        schedule_block_label=payload.schedule_block_label,
     )
     return 201, ChannelSourceRuleSchema(
         id=rule.id,
@@ -153,6 +171,7 @@ def assign_source_to_channel(request, channel_id: int, payload: ChannelSourceAss
         source_name=source.name,
         rule_mode=rule.rule_mode,
         weight=float(rule.weight),
+        schedule_block_label=rule.schedule_block_label,
     )
 
 @router.delete("/{channel_id}/sources/{rule_id}", response={204: None})

api/routers/schedule.py

@@ -1,5 +1,6 @@
 from ninja import Router, Schema
 from typing import List, Optional
+from datetime import date, time
 from core.models import ScheduleTemplate, Channel, ScheduleBlock
 from django.shortcuts import get_object_or_404
 from datetime import date
@@ -27,6 +28,28 @@ class ScheduleTemplateCreateSchema(Schema):
     is_active: bool = True
     channel_id: int
 
+class ScheduleBlockSchema(Schema):
+    id: int
+    schedule_template_id: int
+    name: str
+    block_type: str
+    start_local_time: time
+    end_local_time: time
+    day_of_week_mask: int
+    spills_past_midnight: bool
+    target_content_rating: Optional[int] = None
+    default_genre_id: Optional[int] = None
+
+class ScheduleBlockCreateSchema(Schema):
+    schedule_template_id: int
+    name: str
+    block_type: str
+    start_local_time: time
+    end_local_time: time
+    day_of_week_mask: int
+    spills_past_midnight: bool = False
+    target_content_rating: Optional[int] = None
+
 @router.get("/template/", response=List[ScheduleTemplateSchema])
 def list_schedule_templates(request):
     return ScheduleTemplate.objects.all()
@@ -92,3 +115,29 @@ def generate_schedule_today(request, channel_id: int):
     generator = ScheduleGenerator(channel=channel)
     airings_created = generator.generate_for_date(date.today())
     return {"status": "success", "airings_created": airings_created}
+
+@router.get("/template/{template_id}/blocks", response=List[ScheduleBlockSchema])
+def list_schedule_blocks(request, template_id: int):
+    template = get_object_or_404(ScheduleTemplate, id=template_id)
+    return template.scheduleblock_set.all().order_by('start_local_time')
+
+@router.post("/block/", response={201: ScheduleBlockSchema})
+def create_schedule_block(request, payload: ScheduleBlockCreateSchema):
+    template = get_object_or_404(ScheduleTemplate, id=payload.schedule_template_id)
+    block = ScheduleBlock.objects.create(
+        schedule_template=template,
+        name=payload.name,
+        block_type=payload.block_type,
+        start_local_time=payload.start_local_time,
+        end_local_time=payload.end_local_time,
+        day_of_week_mask=payload.day_of_week_mask,
+        spills_past_midnight=payload.spills_past_midnight,
+        target_content_rating=payload.target_content_rating,
+    )
+    return 201, block
+
+@router.delete("/block/{block_id}", response={204: None})
+def delete_schedule_block(request, block_id: int):
+    block = get_object_or_404(ScheduleBlock, id=block_id)
+    block.delete()
+    return 204, None

core/management/commands/run_cache_worker.py

@@ -0,0 +1,56 @@
+"""
+management command: run_cache_worker
+
+Runs continuously in the background to automatically download and cache
+upcoming programming for the next 24 hours. Intended to run as a daemon
+or Docker service.
+"""
+
+import time
+import logging
+from django.core.management.base import BaseCommand
+from core.services.cache import run_cache
+
+logger = logging.getLogger(__name__)
+
+class Command(BaseCommand):
+    help = "Run the 24-hour ahead cache worker continuously in the background."
+
+    def add_arguments(self, parser):
+        parser.add_argument(
+            "--interval",
+            type=int,
+            default=600,
+            help="Interval in seconds between cache runs (default: 600s/10m).",
+        )
+        parser.add_argument(
+            "--hours",
+            type=int,
+            default=24,
+            help="How many hours ahead to scan for upcoming airings (default: 24).",
+        )
+
+    def handle(self, *args, **options):
+        interval = options["interval"]
+        hours = options["hours"]
+
+        self.stdout.write(self.style.SUCCESS(f"Starting continuous cache worker (interval: {interval}s, ahead: {hours}h)"))
+
+        while True:
+            try:
+                self.stdout.write(f"▶  Running background cache worker (window: {hours}h)")
+                result = run_cache(hours=hours, prune_only=False)
+                
+                if result["downloaded"] > 0 or result["pruned"] > 0 or result["failed"] > 0:
+                    self.stdout.write(self.style.SUCCESS(f"   🗑  Pruned:          {result['pruned']}"))
+                    self.stdout.write(self.style.SUCCESS(f"   ↓   Downloaded:     {result['downloaded']}"))
+                    self.stdout.write(self.style.SUCCESS(f"   ✓   Already cached: {result['already_cached']}"))
+                    if result["failed"]:
+                        self.stderr.write(self.style.ERROR(f"   ✗   Failed:         {result['failed']}"))
+                
+            except Exception as e:
+                self.stderr.write(self.style.ERROR(f"Error in cache worker loop: {e}"))
+                logger.error(f"Error in cache worker loop: {e}")
+            
+            # Sleep until next interval
+            time.sleep(interval)

core/migrations/0003_channelsourcerule_schedule_block_label_and_more.py

@@ -0,0 +1,34 @@
+# Generated by Django 6.0.3 on 2026-03-08 22:07
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("core", "0002_mediaitem_cache_expires_at_and_more"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="channelsourcerule",
+            name="schedule_block_label",
+            field=models.CharField(blank=True, max_length=255, null=True),
+        ),
+        migrations.AddField(
+            model_name="scheduleblock",
+            name="target_content_rating",
+            field=models.IntegerField(
+                blank=True,
+                choices=[
+                    (1, "TV-Y / All Children"),
+                    (2, "TV-Y7 / Directed to Older Children"),
+                    (3, "TV-G / General Audience"),
+                    (4, "TV-PG / Parental Guidance Suggested"),
+                    (5, "TV-14 / Parents Strongly Cautioned"),
+                    (6, "TV-MA / Mature Audience Only"),
+                ],
+                null=True,
+            ),
+        ),
+    ]

core/models.py

@@ -255,6 +255,7 @@ class ChannelSourceRule(models.Model):
     channel = models.ForeignKey(Channel, on_delete=models.CASCADE)
     media_source = models.ForeignKey(MediaSource, on_delete=models.CASCADE, blank=True, null=True)
     media_collection = models.ForeignKey(MediaCollection, on_delete=models.CASCADE, blank=True, null=True)
+    schedule_block_label = models.CharField(max_length=255, blank=True, null=True)
     
     class RuleMode(models.TextChoices):
         ALLOW = 'allow', 'Allow'
@@ -347,6 +348,16 @@ class ScheduleBlock(models.Model):
     end_local_time = models.TimeField()
     day_of_week_mask = models.SmallIntegerField() # 1 to 127
     spills_past_midnight = models.BooleanField(default=False)
+    
+    class TargetRating(models.IntegerChoices):
+        TV_Y = 1, 'TV-Y / All Children'
+        TV_Y7 = 2, 'TV-Y7 / Directed to Older Children'
+        TV_G = 3, 'TV-G / General Audience'
+        TV_PG = 4, 'TV-PG / Parental Guidance Suggested'
+        TV_14 = 5, 'TV-14 / Parents Strongly Cautioned'
+        TV_MA = 6, 'TV-MA / Mature Audience Only'
+
+    target_content_rating = models.IntegerField(choices=TargetRating.choices, blank=True, null=True)
     default_genre = models.ForeignKey(Genre, on_delete=models.SET_NULL, blank=True, null=True)
     min_content_rating = models.ForeignKey(ContentRating, on_delete=models.SET_NULL, blank=True, null=True, related_name='+')
     max_content_rating = models.ForeignKey(ContentRating, on_delete=models.SET_NULL, blank=True, null=True, related_name='+')

core/services/cache.py

@@ -40,44 +40,66 @@ def run_cache(hours: int = 24, prune_only: bool = False) -> dict:
     )
 
     youtube_items: dict[int, MediaItem] = {}
-    for airing in upcoming:
-        item = airing.media_item
-        if item.media_source and item.media_source.source_type in YOUTUBE_SOURCE_TYPES:
-            youtube_items[item.pk] = item
-
     downloaded = already_cached = failed = 0
     items_status = []
+    
+    for airing in upcoming:
+        item = airing.media_item
+        
+        # Determine if we are inside the 1-hour critical safety window
+        time_until_airing = airing.starts_at - now
+        in_safety_window = time_until_airing.total_seconds() < 3600
+        
+        if item.media_source and item.media_source.source_type in YOUTUBE_SOURCE_TYPES:
+            youtube_items[item.pk] = item
+            
+            # Skip if already cached
+            if item.cached_file_path and pathlib.Path(item.cached_file_path).exists():
+                already_cached += 1
+                items_status.append({
+                    "id": item.pk,
+                    "title": item.title,
+                    "status": "cached",
+                    "path": item.cached_file_path,
+                })
+                continue
+                
+            # If in the 1-hour safety valve window, DO NOT download. Replace the airing.
+            if in_safety_window:
+                logger.warning(f"Airing {airing.id} ({item.title}) is < 1h away and not cached! Triggering emergency replacement.")
+                from core.services.scheduler import ScheduleGenerator
+                generator = ScheduleGenerator(channel=airing.channel)
+                try:
+                    generator.replace_undownloaded_airings([airing])
+                    items_status.append({
+                        "id": item.pk,
+                        "title": item.title,
+                        "status": "replaced",
+                        "error": "Not downloaded in time",
+                    })
+                except Exception as e:
+                    logger.error(f"Emergency replacement failed for airing {airing.id}: {e}")
+                continue
 
-    for item in youtube_items.values():
-        # Skip if already cached
-        if item.cached_file_path and pathlib.Path(item.cached_file_path).exists():
-            already_cached += 1
-            items_status.append({
-                "id": item.pk,
-                "title": item.title,
-                "status": "cached",
-                "path": item.cached_file_path,
-            })
-            continue
-
-        try:
-            local_path = download_for_airing(item)
-            downloaded += 1
-            items_status.append({
-                "id": item.pk,
-                "title": item.title,
-                "status": "downloaded",
-                "path": str(local_path),
-            })
-        except Exception as exc:
-            failed += 1
-            items_status.append({
-                "id": item.pk,
-                "title": item.title,
-                "status": "failed",
-                "error": str(exc),
-            })
-            logger.error("download_for_airing(%s) failed: %s", item.pk, exc)
+            # Otherwise, attempt download normally
+            try:
+                local_path = download_for_airing(item)
+                downloaded += 1
+                items_status.append({
+                    "id": item.pk,
+                    "title": item.title,
+                    "status": "downloaded",
+                    "path": str(local_path),
+                })
+            except Exception as exc:
+                failed += 1
+                items_status.append({
+                    "id": item.pk,
+                    "title": item.title,
+                    "status": "failed",
+                    "error": str(exc),
+                })
+                logger.error("download_for_airing(%s) failed: %s", item.pk, exc)
 
     logger.info(
         "run_cache(hours=%d): pruned=%d downloaded=%d cached=%d failed=%d",

core/services/scheduler.py

@@ -46,7 +46,7 @@ class ScheduleGenerator:
             return 0
 
         target_weekday_bit = 1 << target_date.weekday()
-        blocks = template.scheduleblock_set.all()
+        blocks = template.scheduleblock_set.all().order_by('start_local_time')
         airings_created = 0
 
         for block in blocks:
@@ -60,7 +60,7 @@ class ScheduleGenerator:
             if end_dt <= start_dt:
                 end_dt += timedelta(days=1)
 
-            # Clear existing airings in this window (idempotency)
+            # Clear existing airings whose start time is within this block's window
             Airing.objects.filter(
                 channel=self.channel,
                 starts_at__gte=start_dt,
@@ -71,8 +71,18 @@ class ScheduleGenerator:
             if not available_items:
                 continue
 
+            # Prevent overlaps: ensure we don't start before the end of the previous block's overrun
+            latest_prior_airing = Airing.objects.filter(
+                channel=self.channel,
+                starts_at__lt=start_dt
+            ).order_by('-ends_at').first()
+
+            actual_start_dt = start_dt
+            if latest_prior_airing and latest_prior_airing.ends_at > start_dt:
+                actual_start_dt = latest_prior_airing.ends_at
+
             airings_created += self._fill_block(
-                template, block, start_dt, end_dt, available_items
+                template, block, actual_start_dt, end_dt, available_items
             )
 
         return airings_created
@@ -88,14 +98,20 @@ class ScheduleGenerator:
         ).order_by('-priority')
         return qs.first()
 
-    def _get_weighted_items(self, block: ScheduleBlock) -> list:
+    def _get_weighted_items(self, block: ScheduleBlock, require_downloaded: bool = False) -> list:
         """
         Build a weighted pool of MediaItems respecting ChannelSourceRule.
 
+        If require_downloaded is True, strictly exclude items from YouTube sources
+        that have not yet been downloaded (cached_file_path is null).
+
         Returns a flat list with items duplicated according to their effective
         weight (rounded to nearest int, min 1) so random.choice() gives the
         right probability distribution without needing numpy.
         """
+        if block.block_type == ScheduleBlock.BlockType.OFF_AIR:
+            return []
+
         rules = list(
             ChannelSourceRule.objects.filter(channel=self.channel)
             .select_related('media_source')
@@ -109,6 +125,10 @@ class ScheduleGenerator:
             source_weights: dict[int, float] = {}
 
             for rule in rules:
+                # If a rule has a label, it only applies if this block's name matches
+                if rule.schedule_block_label and rule.schedule_block_label != block.name:
+                    continue
+
                 sid = rule.media_source_id
                 mode = rule.rule_mode
                 w = float(rule.weight or 1.0)
@@ -148,6 +168,14 @@ class ScheduleGenerator:
         if block.default_genre:
             base_qs = base_qs.filter(genres=block.default_genre)
 
+        # Enforce downloaded requirement for emergency replacements
+        if require_downloaded:
+            from django.db.models import Q
+            from core.services.youtube import YOUTUBE_SOURCE_TYPES
+            base_qs = base_qs.exclude(
+                Q(media_source__source_type__in=YOUTUBE_SOURCE_TYPES) & Q(cached_file_path__isnull=True)
+            )
+
         items = list(base_qs)
         if not items:
             return []
@@ -208,3 +236,51 @@ class ScheduleGenerator:
             created += 1
 
         return created
+
+    def replace_undownloaded_airings(self, airings: list[Airing]):
+        """
+        Takes a list of specific Airings that failed to download or are 
+        too close to airtime without a valid cache file. Replaces the 
+        underlying media_item with one guaranteed to be playable, and 
+        ripple-shifts all following airings on the channel by the duration diff.
+        """
+        import logging
+        logger = logging.getLogger(__name__)
+
+        for original_airing in airings:
+            # 1. Fetch available downloaded items for this block
+            safe_items = self._get_weighted_items(original_airing.schedule_block, require_downloaded=True)
+            if not safe_items:
+                logger.error(f"Cannot replace airing {original_airing.id}: No downloaded items available for block {original_airing.schedule_block.name}")
+                continue
+
+                
+            # 2. Pick a random valid fallback item
+            fallback_item = random.choice(safe_items)
+            old_duration = original_airing.ends_at - original_airing.starts_at
+            
+            # Update the original airing to reference the new item
+            original_airing.media_item = fallback_item
+            original_airing.source_reason = 'recovery'
+            
+            new_duration = timedelta(seconds=max(fallback_item.runtime_seconds or 1800, 1))
+            original_airing.ends_at = original_airing.starts_at + new_duration
+            original_airing.save(update_fields=['media_item', 'source_reason', 'ends_at'])
+            
+            logger.info(f"Replaced airing {original_airing.id} with '{fallback_item.title}' (diff: {new_duration - old_duration})")
+
+            # 3. Ripple shift downstream airings accurately
+            delta = new_duration - old_duration
+            
+            if delta.total_seconds() != 0:
+                # Find all airings strictly after this one on the same channel
+                downstream = Airing.objects.filter(
+                    channel=self.channel,
+                    starts_at__gte=original_airing.starts_at + old_duration
+                ).exclude(id=original_airing.id).order_by('starts_at')
+                
+                # Apply shift
+                for later_airing in downstream:
+                    later_airing.starts_at += delta
+                    later_airing.ends_at += delta
+                    later_airing.save(update_fields=['starts_at', 'ends_at'])

core/services/youtube.py

@@ -238,7 +238,36 @@ def download_for_airing(media_item: MediaItem) -> Path:
 
     # Persist the cache location on the model
     media_item.cached_file_path = str(downloaded_path)
-    media_item.save(update_fields=["cached_file_path"])
+    
+    # Extract exact runtime from the cached file using ffprobe-static via Node.js
+    import subprocess
+    import json
+    
+    exact_duration = None
+    try:
+        # Resolve ffprobe path from the npm package
+        node_cmd = ["node", "-e", "console.log(require('ffprobe-static').path)"]
+        result = subprocess.run(node_cmd, capture_output=True, text=True, check=True)
+        ffprobe_cmd = result.stdout.strip()
+        
+        probe_cmd = [
+            ffprobe_cmd,
+            "-v", "error",
+            "-show_entries", "format=duration",
+            "-of", "default=noprint_wrappers=1:nokey=1",
+            str(downloaded_path)
+        ]
+        probe_result = subprocess.run(probe_cmd, capture_output=True, text=True, check=True)
+        exact_duration = float(probe_result.stdout.strip())
+    except Exception as e:
+        logger.warning(f"Failed to extract exact runtime for {video_id} using ffprobe: {e}")
+        
+    if exact_duration:
+        # Round up to nearest integer to be safe on bounds
+        import math
+        media_item.runtime_seconds = int(math.ceil(exact_duration))
+        
+    media_item.save(update_fields=["cached_file_path", "runtime_seconds"])
 
-    logger.info("downloaded %s -> %s", video_id, downloaded_path)
+    logger.info("downloaded %s -> %s (exact runtime: %s)", video_id, downloaded_path, exact_duration)
     return downloaded_path

frontend/src/api.js

@@ -34,6 +34,13 @@ export const deleteTemplate = async (id) => { await apiClient.delete(`/schedule/
 export const generateScheduleToday = async (channelId) =>
   (await apiClient.post(`/schedule/generate-today/${channelId}`)).data;
 
+export const fetchTemplateBlocks = async (templateId) =>
+  (await apiClient.get(`/schedule/template/${templateId}/blocks`)).data;
+export const createTemplateBlock = async (payload) =>
+  (await apiClient.post('/schedule/block/', payload)).data;
+export const deleteTemplateBlock = async (blockId) => 
+  (await apiClient.delete(`/schedule/block/${blockId}`)).data;
+
 // Legacy – used by guide
 export const fetchScheduleGenerations = async (channelId) =>
   (await apiClient.post(`/schedule/generate/${channelId}`)).data;

frontend/src/components/ChannelTuner.jsx

@@ -142,6 +142,24 @@ export default function ChannelTuner({ onOpenGuide }) {
             muted={!isCurrent}
             loop
             playsInline
+            onLoadedMetadata={(e) => {
+              const video = e.target;
+              if (currentAiring && currentAiring.starts_at) {
+                const startTime = new Date(currentAiring.starts_at).getTime();
+                const nowTime = Date.now();
+                
+                if (nowTime > startTime) {
+                  const offsetSeconds = (nowTime - startTime) / 1000;
+                  // If the video is shorter than the offset (e.g. repeating a short clip), 
+                  // modulo the offset by duration to emulate a continuous loop.
+                  if (video.duration && video.duration > 0) {
+                    video.currentTime = offsetSeconds % video.duration;
+                  } else {
+                    video.currentTime = offsetSeconds;
+                  }
+                }
+              }
+            }}
             onError={(e) => {
               if (e.target.src !== chan.fallbackFile) {
                 console.warn(`Video failed to load: ${e.target.src}, falling back.`);

frontend/src/components/Settings.jsx

@@ -4,6 +4,7 @@ import {
   fetchChannels, createChannel, deleteChannel, updateChannel,
   fetchChannelSources, assignSourceToChannel, removeSourceFromChannel,
   fetchTemplates, createTemplate, deleteTemplate, generateScheduleToday,
+  fetchTemplateBlocks, createTemplateBlock, deleteTemplateBlock,
   fetchSources, createSource, syncSource, deleteSource,
   fetchLibraries,
   fetchDownloadStatus, triggerCacheUpcoming, downloadItem,
@@ -156,7 +157,7 @@ function ChannelsTab() {
   const [channelSources, setChannelSources] = useState({});  // { channelId: [rules] }
   const [showForm, setShowForm] = useState(false);
   const [form, setForm] = useState({ name: '', slug: '', channel_number: '', description: '', library_id: '', owner_user_id: '' });
-  const [assignForm, setAssignForm] = useState({ source_id: '', rule_mode: 'allow', weight: 1.0 });
+  const [assignForm, setAssignForm] = useState({ source_id: '', rule_mode: 'allow', weight: 1.0, schedule_block_label: '' });
   const [syncingId, setSyncingId] = useState(null);
   const [feedback, setFeedback, ok, err] = useFeedback();
 
@@ -210,9 +211,10 @@ function ChannelsTab() {
         source_id: parseInt(assignForm.source_id),
         rule_mode: assignForm.rule_mode,
         weight: parseFloat(assignForm.weight),
+        schedule_block_label: assignForm.schedule_block_label || null,
       });
       setChannelSources(cs => ({ ...cs, [channelId]: [...(cs[channelId] || []), rule] }));
-      setAssignForm({ source_id: '', rule_mode: 'allow', weight: 1.0 });
+      setAssignForm({ source_id: '', rule_mode: 'allow', weight: 1.0, schedule_block_label: '' });
       ok('Source assigned to channel.');
     } catch { err('Failed to assign source.'); }
   };
@@ -367,6 +369,13 @@ function ChannelsTab() {
                         style={{ width: 60 }}
                         title="Weight (higher = more airings)"
                       />
+                      <input
+                        placeholder="Target Block Label (Optional)"
+                        value={assignForm.schedule_block_label}
+                        onChange={e => setAssignForm(f => ({ ...f, schedule_block_label: e.target.value }))}
+                        style={{ flex: 1 }}
+                        title="If set, this source will ONLY play during blocks with this exact name"
+                      />
                       <button className="btn-sync sm" onClick={() => handleAssign(ch.id)}>+ Add Rule</button>
                     </div>
 
@@ -690,12 +699,35 @@ function SchedulingTab() {
   const [form, setForm] = useState({ name: '', channel_id: '', timezone_name: 'America/New_York', priority: 10 });
   const [feedback, setFeedback, ok, err] = useFeedback();
 
+  // Block Editor State
+  const [expandedTmplId, setExpandedTmplId] = useState(null);
+  const [templateBlocks, setTemplateBlocks] = useState({}); // { tmplId: [blocks] }
+  const [blockForm, setBlockForm] = useState({
+    name: 'A Block',
+    block_type: 'PROGRAM',
+    start_local_time: '08:00',
+    end_local_time: '12:00',
+    day_of_week_mask: 127,
+    target_content_rating: ''
+  });
+
   useEffect(() => {
     Promise.all([fetchTemplates(), fetchChannels()])
       .then(([t, c]) => { setTemplates(t); setChannels(c); })
       .catch(() => err('Failed to load schedule data'));
   }, []);
 
+  const toggleExpand = async (tmpl) => {
+    const next = expandedTmplId === tmpl.id ? null : tmpl.id;
+    setExpandedTmplId(next);
+    if (next && !templateBlocks[next]) {
+      try {
+        const blocks = await fetchTemplateBlocks(tmpl.id);
+        setTemplateBlocks(tb => ({ ...tb, [tmpl.id]: blocks }));
+      } catch { err('Failed to load blocks'); }
+    }
+  };
+
   const handleCreate = async (e) => {
     e.preventDefault();
     try {
@@ -780,25 +812,105 @@ function SchedulingTab() {
 
       <div className="settings-row-list">
         {templates.length === 0 && <EmptyState text="No schedule templates yet. Create one above." />}
-        {templates.map(t => (
-          <div key={t.id} className="settings-row">
-            <div className="row-avatar" style={{ fontSize: '1.2rem' }}>📄</div>
-            <div className="row-info">
-              <strong>{t.name}</strong>
-              <span className="row-sub">{channelName(t.channel_id)} · {t.timezone_name}</span>
-              <span className="row-badges">
-                <span className="badge badge-type">Priority {t.priority}</span>
-                {t.is_active
-                  ? <span className="badge badge-ok">Active</span>
-                  : <span className="badge badge-muted">Inactive</span>
-                }
-              </span>
+        {templates.map(t => {
+          const isExpanded = expandedTmplId === t.id;
+          const blocks = templateBlocks[t.id] || [];
+          return (
+            <div key={t.id} className={`settings-row-expandable ${isExpanded ? 'expanded' : ''}`}>
+              <div className="settings-row" onClick={() => toggleExpand(t)}>
+                <div className="row-avatar" style={{ fontSize: '1.2rem' }}>📄</div>
+                <div className="row-info">
+                  <strong>{t.name}</strong>
+                  <span className="row-sub">{channelName(t.channel_id)} · {t.timezone_name}</span>
+                  <span className="row-badges">
+                    <span className="badge badge-type">Priority {t.priority}</span>
+                    {t.is_active
+                      ? <span className="badge badge-ok">Active</span>
+                      : <span className="badge badge-muted">Inactive</span>
+                    }
+                  </span>
+                </div>
+                <div className="row-actions" onClick={e => e.stopPropagation()}>
+                  <IconBtn icon="🗑" kind="danger" onClick={() => handleDelete(t)} />
+                  <span className="expand-chevron">{isExpanded ? '▲' : '▼'}</span>
+                </div>
+              </div>
+              
+              {isExpanded && (
+                <div className="channel-expand-panel block-editor" style={{ background: 'rgba(0,0,0,0.1)', borderTop: 'none', padding: '1rem', borderBottomLeftRadius: '6px', borderBottomRightRadius: '6px' }}>
+                  <h4 style={{ margin: '0 0 1rem 0', opacity: 0.9 }}>Schedule Blocks</h4>
+                  
+                  {blocks.length === 0 && (
+                    <div style={{ fontSize: '0.9rem', opacity: 0.7, marginBottom: '1rem' }}>
+                      No blocks defined. By default, PYTV acts as if there is a single 24/7 block. If you define blocks here, you must completely cover the 24 hours of a day to avoid dead air.
+                    </div>
+                  )}
+
+                  <div style={{ display: 'flex', flexDirection: 'column', gap: '0.5rem', marginBottom: '1.5rem' }}>
+                    {blocks.map(b => (
+                      <div key={b.id} style={{ display: 'flex', gap: '0.5rem', background: '#353b48', padding: '0.5rem', borderRadius: '4px', alignItems: 'center', fontSize: '0.9rem' }}>
+                        <strong style={{ minWidth: 100 }}>{b.name}</strong>
+                        <span style={{ fontFamily: 'monospace', opacity: 0.8 }}>{b.start_local_time.slice(0,5)} - {b.end_local_time.slice(0,5)}</span>
+                        <span className={`badge ${b.block_type === 'OFF_AIR' ? 'badge-warn' : 'badge-ok'}`}>{b.block_type}</span>
+                        {b.target_content_rating && <span className="badge badge-type">Rating Tier: {b.target_content_rating}</span>}
+                        <div style={{ flex: 1 }} />
+                        <IconBtn icon="✕" kind="danger" onClick={async () => {
+                          try {
+                            await deleteTemplateBlock(b.id);
+                            setTemplateBlocks(tb => ({ ...tb, [t.id]: tb[t.id].filter(x => x.id !== b.id) }));
+                            ok('Block deleted.');
+                          } catch { err('Failed to delete block.'); }
+                        }} />
+                      </div>
+                    ))}
+                  </div>
+
+                  <form className="assign-form" style={{ background: '#2f3640' }} onSubmit={async (e) => {
+                    e.preventDefault();
+                    if (!blockForm.name || !blockForm.start_local_time || !blockForm.end_local_time) { err('Fill req fields'); return; }
+                    try {
+                      const nb = await createTemplateBlock({
+                        schedule_template_id: t.id,
+                        name: blockForm.name,
+                        block_type: blockForm.block_type,
+                        start_local_time: blockForm.start_local_time,
+                        end_local_time: blockForm.end_local_time,
+                        day_of_week_mask: parseInt(blockForm.day_of_week_mask),
+                        target_content_rating: blockForm.target_content_rating ? parseInt(blockForm.target_content_rating) : null,
+                      });
+                      setTemplateBlocks(tb => ({ ...tb, [t.id]: [...(tb[t.id] || []), nb] }));
+                      ok('Block created.');
+                    } catch { err('Failed to create block'); }
+                  }}>
+                    <div style={{ display: 'flex', gap: '0.5rem', alignItems: 'center' }}>
+                      <input placeholder="Block Name (e.g. Morning News)" required style={{ flex: 1 }} value={blockForm.name} onChange={e => setBlockForm(f => ({...f, name: e.target.value}))} />
+                      <select value={blockForm.block_type} onChange={e => setBlockForm(f => ({...f, block_type: e.target.value}))}>
+                        <option value="PROGRAM">Programming</option>
+                        <option value="OFF_AIR">Off Air / Dead Time</option>
+                      </select>
+                      <input type="time" required value={blockForm.start_local_time} onChange={e => setBlockForm(f => ({...f, start_local_time: e.target.value}))} />
+                      <span style={{ opacity: 0.5 }}>to</span>
+                      <input type="time" required value={blockForm.end_local_time} onChange={e => setBlockForm(f => ({...f, end_local_time: e.target.value}))} />
+                    </div>
+                    <div style={{ display: 'flex', gap: '0.5rem', alignItems: 'center', marginTop: '0.5rem' }}>
+                      <select value={blockForm.target_content_rating} onChange={e => setBlockForm(f => ({...f, target_content_rating: e.target.value}))}>
+                        <option value="">Any content rating</option>
+                        <option value="1">TV-Y</option>
+                        <option value="2">TV-Y7</option>
+                        <option value="3">TV-G</option>
+                        <option value="4">TV-PG</option>
+                        <option value="5">TV-14</option>
+                        <option value="6">TV-MA</option>
+                      </select>
+                      <button type="submit" className="btn-sync sm">+ Add Block</button>
+                    </div>
+                  </form>
+
+                </div>
+              )}
             </div>
-            <div className="row-actions">
-              <IconBtn icon="🗑" kind="danger" onClick={() => handleDelete(t)} />
-            </div>
-          </div>
-        ))}
+          );
+        })}
       </div>
     </div>
   );

tests/test_channel_signaling.py

@@ -0,0 +1,103 @@
+import pytest
+import os
+from datetime import timedelta
+from django.utils import timezone
+from core.models import Channel, MediaSource, MediaItem, Airing
+from api.routers.channel import channel_now_playing
+from django.conf import settings
+
+@pytest.mark.django_db
+def test_channel_signaling_now_playing():
+    """
+    Test what file should be playing on a channel, and whether the API 
+    response correctly signals an existing local file or fallback.
+    """
+    channel = Channel.objects.first()
+    if not channel:
+        pytest.skip("No channels found in test database to test signaling")
+
+    # Clear current airings to set up a controlled test
+    Airing.objects.filter(channel=channel).delete()
+
+    source = MediaSource.objects.first()
+    
+    # 1. Test a fully downloaded video
+    good_item = MediaItem.objects.create(
+        title="Valid Cached Video",
+        media_source=source,
+        cached_file_path=os.path.join(settings.MEDIA_ROOT, "test_valid.mp4"),
+        runtime_seconds=600,
+        is_active=True
+    )
+    
+    # Create a dummy file to simulate it existing
+    os.makedirs(settings.MEDIA_ROOT, exist_ok=True)
+    with open(good_item.cached_file_path, 'w') as f:
+        f.write("dummy video data")
+
+    now = timezone.now()
+    
+    airing = Airing.objects.create(
+        channel=channel,
+        media_item=good_item,
+        starts_at=now - timedelta(minutes=5),
+        ends_at=now + timedelta(minutes=5),
+        slot_kind="program"
+    )
+
+    # Call the API function
+    response = channel_now_playing(None, channel.id)
+    
+    # Assertions
+    assert response is not None, "API should return an airing"
+    assert response.media_item_title == "Valid Cached Video"
+    assert response.media_item_path is not None, "A valid path must be returned"
+    
+    # Check if the returned path maps to a real file
+    if not response.media_item_path.startswith("http"):
+        # The API returns a URL path like /media/..., we need to strip /media to get rel_path
+        rel_path = response.media_item_path.replace(settings.MEDIA_URL, "")
+        fs_path = os.path.join(settings.MEDIA_ROOT, rel_path)
+        assert os.path.exists(fs_path), f"Signaled file {fs_path} does not actually exist!"
+
+    # Cleanup
+    if os.path.exists(good_item.cached_file_path):
+        os.remove(good_item.cached_file_path)
+
+@pytest.mark.django_db
+def test_channel_signaling_youtube_raw_url():
+    """
+    Test what happens if the video is NOT downloaded and only has a raw YouTube URL.
+    This demonstrates the bug where the frontend fails to play it.
+    """
+    channel = Channel.objects.first()
+    if not channel:
+        pytest.skip("No channels found")
+
+    Airing.objects.filter(channel=channel).delete()
+    source = MediaSource.objects.filter(source_type__icontains='youtube').first()
+    if not source:
+        pytest.skip("No youtube source found")
+
+    raw_item = MediaItem.objects.create(
+        title="Uncached YouTube URL",
+        media_source=source,
+        file_path="https://www.youtube.com/watch?v=dQw4w9WgXcQ",
+        cached_file_path=None,
+        runtime_seconds=600,
+        is_active=True
+    )
+
+    now = timezone.now()
+    Airing.objects.create(
+        channel=channel,
+        media_item=raw_item,
+        starts_at=now - timedelta(minutes=5),
+        ends_at=now + timedelta(minutes=5),
+        slot_kind="program"
+    )
+
+    response = channel_now_playing(None, channel.id)
+    assert response is not None
+    assert response.media_item_path == "https://www.youtube.com/watch?v=dQw4w9WgXcQ"
+    print(f"\\nWARNING: Backend signaled {response.media_item_path} which HTML5 <video> CANNOT play directly.")