MongoDB Schema and Index Design

Create MongoDB schema design for:

Application Type: {{APPLICATION_TYPE}}
Collections Needed: {{COLLECTIONS}}
Query Patterns: {{QUERY_PATTERNS}}
Data Volume: {{EXPECTED_VOLUME}}

Generate complete MongoDB setup:

1. **Collection Schemas:**
   - Document structure
   - Field types
   - Required fields
   - Default values
   - Embedded vs referenced documents

2. **JSON Schema Validation:**
   - Validation rules
   - Custom validators
   - Error messages

3. **Index Strategy:**
   - Single field indexes
   - Compound indexes
   - Text indexes
   - Geospatial indexes
   - TTL indexes
   - Partial indexes
   - Index intersection analysis

4. **Mongoose Models (if applicable):**
   - Schema definitions
   - Virtual fields
   - Instance methods
   - Static methods
   - Middleware/hooks
   - Plugins

5. **Aggregation Pipelines:**
   - Common query pipelines
   - Reporting aggregations
   - Lookup/join patterns
   - Performance optimization

6. **Migration Scripts:**
   - Schema versioning
   - Data transformation
   - Index creation
   - Rollback procedures

7. **Seed Data:**
   - Test data generation
   - Faker.js integration
   - Bulk insert scripts

8. **Performance Considerations:**
   - Sharding key selection
   - Read/write concerns
   - Connection pooling
   - Query optimization

Include explain plan analysis for critical queries.