Tasks Models - Task Management & Delivery Scheduling

# From models.py:4-29

class Task(models.Model):
    PRIORITY_CHOICES = [('low', 'Low'), ('medium', 'Medium'), ('high', 'High')]
    TASK_STATUS_CHOICES = [('pending', 'Pending'), ('in_progress', 'In Progress'), ('completed', 'Completed')]

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    task_id = models.CharField(max_length=100, unique=True)
    sanity_id = models.CharField(max_length=255, unique=True, null=True, blank=True)
    title = models.CharField(max_length=255)
    description = models.TextField(blank=True)
    assigned_to = models.ForeignKey('users.User', on_delete=models.SET_NULL, null=True, blank=True)
    store = models.ForeignKey('stores.Store', on_delete=models.PROTECT)
    priority = models.CharField(max_length=20, choices=PRIORITY_CHOICES)
    status = models.CharField(max_length=20, choices=TASK_STATUS_CHOICES, default='pending')
    due_date = models.DateField(null=True, blank=True)
    completed_by = models.ForeignKey(
        'users.User',
        related_name='completed_tasks',
        on_delete=models.SET_NULL,
        null=True,
        blank=True
    )
    completed_at = models.DateTimeField(null=True, blank=True)
    created_at = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return self.title

pending (new task)
    │
    ├─ Employee accepts task
    │
    ▼
in_progress (being worked on)
    │
    ├─ Employee completes task
    │
    ▼
completed (finished)
    │
    └─ completed_at timestamp set
    └─ completed_by employee recorded

# From models.py:31-43

class DeliverySchedule(models.Model):
    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    delivery_id = models.CharField(max_length=100, unique=True)
    vendor_name = models.CharField(max_length=255, help_text='Vendor or supplier name for this delivery')
    vendor_reference = models.CharField(max_length=100, blank=True, help_text='External vendor reference or ID')
    store = models.ForeignKey('stores.Store', on_delete=models.PROTECT)
    scheduled_date = models.DateField()
    scheduled_time = models.TimeField()
    status = models.CharField(max_length=50, default='scheduled')
    actual_arrival = models.DateTimeField(null=True, blank=True)

    def __str__(self):
        return f'Delivery {self.delivery_id} from {self.vendor_name}'

scheduled (new delivery scheduled)
    │
    ├─ Vendor dispatches
    │
    ▼
in_transit (on the way)
    │
    ├─ Arrives at store
    │
    ▼
arrived (delivery received)
    │
    └─ actual_arrival timestamp set

CREATE TABLE tasks_task (
    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
    task_id VARCHAR(100) UNIQUE NOT NULL,
    sanity_id VARCHAR(255) UNIQUE NULL,
    title VARCHAR(255) NOT NULL,
    description TEXT,
    assigned_to_id UUID NULL REFERENCES users_user(id) ON DELETE SET NULL,
    store_id UUID NOT NULL REFERENCES stores_store(id) ON DELETE PROTECT,
    priority VARCHAR(20) NOT NULL CHECK (priority IN ('low', 'medium', 'high')),
    status VARCHAR(20) NOT NULL DEFAULT 'pending' CHECK (status IN ('pending', 'in_progress', 'completed')),
    due_date DATE NULL,
    completed_by_id UUID NULL REFERENCES users_user(id) ON DELETE SET NULL,
    completed_at TIMESTAMP NULL,
    created_at TIMESTAMP NOT NULL DEFAULT NOW()
);

-- Indexes
CREATE INDEX idx_tasks_task_status ON tasks_task(status);
CREATE INDEX idx_tasks_task_assigned_to ON tasks_task(assigned_to_id);
CREATE INDEX idx_tasks_task_store ON tasks_task(store_id);
CREATE INDEX idx_tasks_task_due_date ON tasks_task(due_date);

CREATE TABLE tasks_deliveryschedule (
    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
    delivery_id VARCHAR(100) UNIQUE NOT NULL,
    vendor_name VARCHAR(255) NOT NULL,
    vendor_reference VARCHAR(100),
    store_id UUID NOT NULL REFERENCES stores_store(id) ON DELETE PROTECT,
    scheduled_date DATE NOT NULL,
    scheduled_time TIME NOT NULL,
    status VARCHAR(50) NOT NULL DEFAULT 'scheduled',
    actual_arrival TIMESTAMP NULL
);

-- Indexes
CREATE INDEX idx_delivery_schedule_store ON tasks_deliveryschedule(store_id);
CREATE INDEX idx_delivery_schedule_date ON tasks_deliveryschedule(scheduled_date);
CREATE INDEX idx_delivery_schedule_status ON tasks_deliveryschedule(status);

# Webhook from Sanity creates task with sanity_id
task = Task.objects.create(
    task_id='task_12345',
    sanity_id='task_a1b2c3d4',  # From Sanity document
    title='Restock dairy section',
    store=store,
    priority='high',
    status='pending'
)

# Django-created task (no sanity_id initially)
task = Task.objects.create(
    task_id='task_67890',
    title='Emergency cleanup',
    store=store,
    priority='high',
    status='pending'
    # sanity_id will be set during outbound sync
)

# 1. Assign task to employee
task.assigned_to = employee
task.status = 'in_progress'
task.save(update_fields=['assigned_to', 'status'])

# 2. Employee works on task (status remains 'in_progress')

# 3. Complete task
from django.utils import timezone
task.status = 'completed'
task.completed_by = employee  # May differ from assigned_to
task.completed_at = timezone.now()
task.save(update_fields=['status', 'completed_by', 'completed_at'])

from datetime import date

# In service or view logic
task = Task.objects.get(task_id='task_12345')

is_overdue = (
    task.due_date and
    task.due_date < date.today() and
    task.status != 'completed'
)

# Used in TaskService.get_task_with_details()
task_details = {
    'is_overdue': is_overdue,
    # ... other fields
}

# Query tasks for specific store
store_tasks = Task.objects.filter(store=store)

# Cannot reassign task to different store (PROTECT constraint)
task.store = other_store  # Requires creating new task instead

# Good: Single query with JOINs
task = Task.objects.select_related(
    'assigned_to', 'completed_by', 'store'
).get(task_id=task_id)

# Bad: N+1 queries
task = Task.objects.get(task_id=task_id)
assigned_name = task.assigned_to.name  # Extra query
store_name = task.store.name  # Extra query

Sanity Webhook → InboundWebhookView → TaskAdapter
    │
    ├─ Creates/updates Task with sanity_id
    ├─ Resolves store reference
    ├─ Sets priority and status
    │
    ▼
Task persisted in Django

Task saved → post_save signal → sync_task_to_sanity()
    │
    ├─ Generates sanity_id if missing
    ├─ Formats payload for Sanity
    ├─ Sends to Sanity API
    │
    ▼
Sanity document created/updated

# View delegates to service
from .services import TaskService

task_details = TaskService.get_task_with_details(task_id)
# Returns enhanced data with related objects, computed fields

# GET /api/tasks/{task_id}/
# Uses TaskService for enhanced response
response = TaskViewSet.retrieve(request, task_id='task_12345')
# Returns full task details with is_overdue, related names, etc.