"""
Optimized projection fields for different use cases to reduce data transfer and improve performance.
"""
from datetime import datetime

CURRENT_DATE = datetime.now()

# Minimal fields for list views and search results
MINIMAL_FIELDS = {
    "_id": 0,
    "merchant_id": 1,
    "business_name": 1,
    "average_rating": "$average_rating.value",
    "city": 1,
    "merchant_category": 1,
    "profile_picture": {"$arrayElemAt": ["$display_picture", 0]},
}

# Essential fields for card views
CARD_FIELDS = {
    "_id": 0,
    "merchant_id": 1,
    "business_name": 1,
    "business_url": 1,
    "description": 1,
    "profile_picture": {"$arrayElemAt": ["$display_picture", 0]},
    "average_rating": "$average_rating.value",
    "city": 1,
    "merchant_category": 1,
    "merchant_subcategory": 1,
    # Include entire address object (formatted_address fallback handled in pipeline)
    "address": 1,
    "promotions": 1,
}

# Optimized years_in_business calculation using $dateDiff (MongoDB 5.0+)
YEARS_IN_BUSINESS_OPTIMIZED = {
    "$let": {
        "vars": {
            "years": {"$dateDiff": {"startDate": "$available_from", "endDate": "$$NOW", "unit": "year"}},
            "months": {"$dateDiff": {"startDate": "$available_from", "endDate": "$$NOW", "unit": "month"}},
            "days": {"$dateDiff": {"startDate": "$available_from", "endDate": "$$NOW", "unit": "day"}}
        },
        "in": {
            "$switch": {
                "branches": [
                    {
                        "case": {"$gte": ["$$years", 1]},
                        "then": {"$concat": [{"$toString": "$$years"}, " years in business"]}
                    },
                    {
                        "case": {"$gte": ["$$months", 1]},
                        "then": {"$concat": [{"$toString": "$$months"}, " months in business"]}
                    }
                ],
                "default": {"$concat": [{"$toString": "$$days"}, " days in business"]}
            }
        }
    }
}

# Optimized common fields with improved years_in_business calculation
COMMON_FIELDS_OPTIMIZED = {
    "_id": 0,
    "merchant_id": 1,
    "business_name": 1,
    "business_url": 1,
    "description": 1,
    "display_picture": 1,
    "profile_picture": {"$arrayElemAt": ["$display_picture", 0]},
    "average_rating": 1,
    "city": 1,
    "country": 1,
    "merchant_category": 1,
    "merchant_subcategory": 1,
    "address": 1,
    "business_hour": 1,
    "promotions": 1,
    "trending": 1,
    "amenities": 1,
    "cancellation_policy": 1,
    "share_description": 1,
    "years_in_business": YEARS_IN_BUSINESS_OPTIMIZED
}

# Fields for detailed merchant view
DETAILED_FIELDS = {
    "_id": 0,
    "merchant_id": 1,
    "business_name": 1,
    "business_url": 1,
    "description": 1,
    "display_picture": 1,
    "profile_picture": {"$arrayElemAt": ["$display_picture", 0]},
    "average_rating": 1,
    "city": 1,
    "country": 1,
    "merchant_category": 1,
    "merchant_subcategory": 1,
    "address": 1,
    "business_hour": 1,
    "promotions": 1,
    "trending": 1,
    "amenities": 1,
    "cancellation_policy": 1,
    "share_description": 1,
    "payment_modes": 1,
    "contact_info": 1,
    "social_media": 1,
    "years_in_business": YEARS_IN_BUSINESS_OPTIMIZED
}

# Fields for recommended merchants (lightweight)
RECOMMENDED_FIELDS_OPTIMIZED = {
    "_id": 0,
    "merchant_id": 1,
    "address.formatted_address": 1,
    "location_id": 1,
    "business_name": 1,
    "business_url": 1,
    "description": 1,
    "business_hour.weekdays": 1,  # Only weekdays for quick availability check
    "promotions": 1,
    "cancellation_policy": 1,
    "amenities": 1,
    "profile_picture": {"$arrayElemAt": ["$display_picture", 0]},
    "average_rating": "$average_rating.value",
    "share_description": 1,
    "city": 1,
    "country": 1,
    "merchant_subcategory": 1,
    "merchant_category": 1,
    "payment_modes": 1
}

# Fields for search results with geospatial data
SEARCH_FIELDS_WITH_GEO = {
    "_id": 0,
    "merchant_id": 1,
    "business_name": 1,
    "business_url": 1,
    "description": 1,
    "profile_picture": {"$arrayElemAt": ["$display_picture", 0]},
    "average_rating": 1,
    "city": 1,
    "merchant_category": 1,
    "merchant_subcategory": 1,
    "address": 1,
    "promotions": 1,
    "distance": {
        "$round": [
            {
                "$multiply": [
                    {
                        "$acos": {
                            "$add": [
                                {
                                    "$multiply": [
                                        {"$sin": {"$degreesToRadians": {"$arrayElemAt": ["$address.location.coordinates", 1]}}},
                                        {"$sin": {"$degreesToRadians": "$$userLat"}}
                                    ]
                                },
                                {
                                    "$multiply": [
                                        {"$cos": {"$degreesToRadians": {"$arrayElemAt": ["$address.location.coordinates", 1]}}},
                                        {"$cos": {"$degreesToRadians": "$$userLat"}},
                                        {"$cos": {"$degreesToRadians": {"$subtract": [{"$arrayElemAt": ["$address.location.coordinates", 0]}, "$$userLng"]}}}
                                    ]
                                }
                            ]
                        }
                    },
                    6371000  # Earth's radius in meters
                ]
            },
            0
        ]
    }
}

# Fields for catalogue and associate data (minimal for performance)
CATALOGUE_MINIMAL_FIELDS = {
    "_id": 0,
    "merchant_id": 1,
    "business_name": 1,
    "location_id": 1,
    "catalogue": {
        "$map": {
            "input": {"$objectToArray": "$catalogue"},
            "as": "cat",
            "in": {
                "category": "$$cat.k",
                "services": {
                    "$map": {
                        "input": "$$cat.v",
                        "as": "service",
                        "in": {
                            "service_id": "$$service.service_id",
                            "service_name": "$$service.service_name",
                            "price": {"$round": ["$$service.price", 2]},
                            "currency": "$$service.currency",
                            "duration": "$$service.duration",
                        }
                    }
                }
            }
        }
    }
}

ASSOCIATE_MINIMAL_FIELDS = {
    "_id": 0,
    "merchant_id": 1,
    "business_name": 1,
    "location_id": 1,
    "associates": {
        "$map": {
            "input": "$associate",
            "as": "s",
            "in": {
                "associate_id": "$$s.associate_id",
                "name": "$$s.name",
                "role": "$$s.role",
                "rating": "$$s.rating",
            }
        }
    }
}

# Performance monitoring fields
PERFORMANCE_FIELDS = {
    "_id": 0,
    "merchant_id": 1,
    "stats.total_bookings": 1,
    "stats.response_time": 1,
    "average_rating.total_reviews": 1,
    "go_live_from": 1,
    "last_updated": 1
}