import pytest
from django.utils import timezone
from datetime import timedelta
from core.models import MediaSource, MediaItem, Channel, ScheduleBlock, ChannelSourceRule, Airing, AppUser, Library
from api.routers.channel import AiringSchema
from django.test import Client

@pytest.fixture
def test_channel(db):
    user = AppUser.objects.create(username="playback_tester")
    library = Library.objects.create(name="Test Library", owner_user=user)
    channel = Channel.objects.create(name="Test Channel", channel_number=10, owner_user=user, library=library)
    source = MediaSource.objects.create(library=library, name="Test Source", source_type="solid_color")
    ChannelSourceRule.objects.create(channel=channel, media_source=source, rule_mode='allow', weight=1.0)
    
    # Create media item
    item = MediaItem.objects.create(
        media_source=source,
        title="Color Loop",
        item_kind="solid_color",
        runtime_seconds=600  # 10 minutes length
    )
    
    return channel, item

import uuid

@pytest.mark.django_db
def test_playback_offset_calculation(test_channel):
    channel, item = test_channel
    now = timezone.now()
    
    # Airing started exactly 3 minutes ago
    starts_at = now - timedelta(minutes=3)
    ends_at = starts_at + timedelta(minutes=30)
    
    airing = Airing.objects.create(
        channel=channel,
        media_item=item,
        starts_at=starts_at,
        ends_at=ends_at,
        slot_kind='content',
        generation_batch_uuid=uuid.uuid4()
    )
    
    schema = AiringSchema.from_airing(airing)
    
    # Airing started 3 minutes (180 seconds) ago.
    # The item runtime is 600s, so offset is simply 180s.
    assert schema.exact_playback_offset_seconds == pytest.approx(180.0, rel=1e-2)

@pytest.mark.django_db
def test_playback_offset_modulo(test_channel):
    channel, item = test_channel
    now = timezone.now()
    
    # Airing started exactly 14 minutes ago
    starts_at = now - timedelta(minutes=14)
    ends_at = starts_at + timedelta(minutes=30)
    
    airing = Airing.objects.create(
        channel=channel,
        media_item=item,
        starts_at=starts_at,
        ends_at=ends_at,
        slot_kind='content',
        generation_batch_uuid=uuid.uuid4()
    )
    
    schema = AiringSchema.from_airing(airing)
    
    # 14 minutes = 840 seconds. 
    # Video is 600 seconds. 
    # 840 % 600 = 240 seconds offset into the second loop.
    assert schema.exact_playback_offset_seconds == pytest.approx(240.0, rel=1e-2)

@pytest.mark.django_db
def test_channel_now_api_returns_offset(test_channel, client: Client):
    channel, item = test_channel
    now = timezone.now()
    
    starts_at = now - timedelta(seconds=45)
    ends_at = starts_at + timedelta(minutes=10)
    
    Airing.objects.create(
        channel=channel,
        media_item=item,
        starts_at=starts_at,
        ends_at=ends_at,
        slot_kind='content',
        generation_batch_uuid=uuid.uuid4()
    )
    
    response = client.get(f"/api/channel/{channel.id}/now")
    assert response.status_code == 200
    data = response.json()
    assert "exact_playback_offset_seconds" in data
    assert data["exact_playback_offset_seconds"] == pytest.approx(45.0, rel=1e-1)