"""Dashboard API & view – visualization panel for the school meal planner."""
import json
from collections import Counter

from django.http import JsonResponse
from django.shortcuts import render
from django.db.models import Avg, Count, Max, Min, Sum

from .models import Dish


def _dashboard_stats():
    """Return aggregate statistics for the dashboard."""
    total = Dish.objects.count()
    active = Dish.objects.filter(is_active=True).count()
    inactive = total - active

    # Count by type
    type_counts = dict(
        Dish.objects.values_list('dish_type').annotate(c=Count('id')).values_list('dish_type', 'c')
    )

    # Count by cuisine
    cuisine_counts = dict(
        Dish.objects.values_list('cuisine').annotate(c=Count('id')).values_list('cuisine', 'c')
    )

    # Nutrition averages (active dishes only, meat + veg only for meaningful stats)
    nutrition = Dish.objects.filter(is_active=True, dish_type__in=('meat', 'veg')).aggregate(
        avg_protein=Avg('protein'),
        avg_fat=Avg('fat'),
        avg_calorie=Avg('calorie'),
        max_calorie=Max('calorie'),
        min_calorie=Min('calorie'),
    )

    # Per-type nutrition averages
    type_nutrition = {}
    for dt in ('meat', 'veg', 'soup', 'staple'):
        agg = Dish.objects.filter(is_active=True, dish_type=dt).aggregate(
            avg_protein=Avg('protein'),
            avg_fat=Avg('fat'),
            avg_calorie=Avg('calorie'),
            count=Count('id'),
        )
        type_nutrition[dt] = agg

    # Recent 10 dishes
    recent = list(
        Dish.objects.order_by('-created_at')[:10].values(
            'id', 'name', 'dish_type', 'cuisine', 'protein', 'fat', 'calorie', 'is_active', 'created_at',
        )
    )
    for r in recent:
        r['created_at'] = r['created_at'].strftime('%Y-%m-%d %H:%M') if r['created_at'] else ''

    return {
        'total': total,
        'active': active,
        'inactive': inactive,
        'type_counts': type_counts,
        'cuisine_counts': cuisine_counts,
        'nutrition': {
            'avg_protein': round(float(nutrition['avg_protein'] or 0), 1),
            'avg_fat': round(float(nutrition['avg_fat'] or 0), 1),
            'avg_calorie': round(float(nutrition['avg_calorie'] or 0)),
            'max_calorie': int(nutrition['max_calorie'] or 0),
            'min_calorie': int(nutrition['min_calorie'] or 0),
        },
        'type_nutrition': {
            k: {
                'avg_protein': round(float(v['avg_protein'] or 0), 1),
                'avg_fat': round(float(v['avg_fat'] or 0), 1),
                'avg_calorie': round(float(v['avg_calorie'] or 0)),
                'count': v['count'],
            }
            for k, v in type_nutrition.items()
        },
        'recent': recent,
    }


def dashboard_api(request):
    """GET /api/dashboard/  -> JSON stats for the dashboard."""
    return JsonResponse(_dashboard_stats())


def dashboard_view(request):
    """GET /dashboard/  -> serve the dashboard HTML page."""
    return render(request, 'dashboard.html')