source: music/views.py

from django.shortcuts import render
import os
import django
from django.db import connection
from django.shortcuts import redirect

os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'MuiscOrganizationSystem.settings')
django.setup()

from music.models import *


# Create your views here.

def home_page(request):
    return render(request, 'home.html')

def redirect_to_home(request, exception):
    return redirect('home_page')

## LIST OF ALL ##
def album_list(request):
    heading = request.GET.get('model', 'All Albums')
    data = Album.objects.values_list('title', flat=True)
    return render(request, 'list.html', {'data': data, 'heading': heading})


def track_list(request):
    heading = request.GET.get('model', 'All Tracks')
    data = Track.objects.values_list('name', flat=True)
    return render(request, 'list.html', {'data': data, 'heading': heading})


def artist_list(request):
    heading = request.GET.get('model', 'All Artists')
    data = Artist.objects.values_list('name', flat=True)

    return render(request, 'list.html', {'data': data, 'heading': heading})


## VIEWS ##
def tracks_count_per_genre(request):
    with connection.cursor() as cursor:
        cursor.execute("SELECT * FROM track_count_per_genre;")
        rows = cursor.fetchall()

    data = [{'genre': row[0], 'count': row[1]} for row in rows]

    return render(request, 'track_count_per_genre.html', {'data': data})


def avg_track_duration(request):
    with connection.cursor() as cursor:
        cursor.execute("SELECT * FROM avg_track_duration_per_artist;")
        rows = cursor.fetchall()

    data = [{'artist': row[0], 'avg': row[1]} for row in rows]

    return render(request, 'avg_track_duration.html', {'data': data})


def rank_list_most_active_customers(request):
    with connection.cursor() as cursor:
        cursor.execute("SELECT * FROM rank_list_most_active_customers_view;")
        rows = cursor.fetchall()

    data = [{'name': row[0], 'total_orders': row[1], 'total_money_spent': row[2]} for row in rows]

    return render(request, 'rank_list_most_active_customers.html', {'data': data})


def avg_price_per_artist(request):
    with connection.cursor() as cursor:
        cursor.execute("SELECT * FROM avg_price_per_artist;")
        rows = cursor.fetchall()

    data = [{'name': row[0], 'avg_price_per_track': row[1]} for row in rows]

    return render(request, 'avg_price_per_artist.html', {'data': data})


def rank_list_artists(request):
    with connection.cursor() as cursor:
        cursor.execute("SELECT * FROM rank_list_artists;")
        rows = cursor.fetchall()

    data = [{'name': row[0], 'num_invoices': row[1], 'money_earned': row[2]} for row in rows]

    return render(request, 'rank_list_artists.html', {'data': data})


def media_type_percentage(request):
    with connection.cursor() as cursor:
        cursor.execute("SELECT * FROM media_type_percentage;")
        rows = cursor.fetchall()

    data = [{'name': row[0], 'num_of_tracks': row[1], 'percentage': row[2]} for row in rows]

    return render(request, 'media_type_percentage.html', {'data': data})


def most_listened_genre_per_customer(request):
    with connection.cursor() as cursor:
        cursor.execute("SELECT * FROM most_listened_genre_per_customer;")
        rows = cursor.fetchall()

    data = [{'first_name': row[0], 'last_name': row[1], 'most_listened_genre': row[2]} for row in rows]

    return render(request, 'most_listened_genre_per_customer.html', {'data': data})


## QUERRIES ##

def genres_per_customer(request):
    customers = Customer.objects.all()
    selected_customer_id = request.GET.get('customer_id')
    data = []
    customer = None

    if selected_customer_id:
        customer = Customer.objects.filter(customer_id=selected_customer_id).first()
        query = """
            SELECT c.first_name as first_name, c.last_name as last_name, g.name as genre, COUNT(tr.track_id) as track_count
            FROM customer c
            LEFT JOIN invoice i ON c.customer_id = i.customer_id
            LEFT JOIN invoice_line il ON i.invoice_id = il.invoice_id
            LEFT JOIN track tr ON il.track_id = tr.track_id
            LEFT JOIN genre g ON tr.genre_id = g.genre_id
            WHERE c.customer_id = %s
            GROUP BY c.customer_id, c.first_name, c.last_name, g.genre_id, g.name
            ORDER BY c.first_name
        """

        with connection.cursor() as cursor:
            cursor.execute(query, [selected_customer_id])
            rows = cursor.fetchall()
            data = [{'first_name': row[0], 'last_name': row[1], 'genre': row[2], 'track_count': row[3]} for row in rows]

    return render(request, 'genres_per_customer.html', {
        'customers': customers,
        'data': data,
        'customer': customer,
        'selected_customer_id': selected_customer_id,
    })

def most_popular_artist_per_customer_per_genre(request):
    customers = Customer.objects.all()
    selected_customer_id = request.GET.get('customer_id')
    data = []
    customer = []
    if selected_customer_id:
        query = """WITH PlayCounts AS (
                SELECT
                    g.genre_id,
                    g.name AS genre_name,
                    ar.name AS artist_name,
                    COUNT(*) AS play_count
                FROM customer c
                JOIN invoice i ON c.customer_id = i.customer_id
                JOIN invoice_line il ON i.invoice_id = il.invoice_id
                JOIN track tr ON il.track_id = tr.track_id
                JOIN genre g ON tr.genre_id = g.genre_id
                JOIN album a ON tr.album_id = a.album_id
                JOIN artist ar ON a.artist_id = ar.artist_id
                WHERE c.customer_id = %s
                GROUP BY g.genre_id, g.name, ar.name
            ),
            MaxPlayCounts AS (
                SELECT genre_id, MAX(play_count) AS max_count
                FROM PlayCounts
                GROUP BY genre_id
            )
            SELECT pc.genre_name, pc.artist_name, pc.play_count
            FROM PlayCounts pc
            JOIN MaxPlayCounts mpc ON pc.genre_id = mpc.genre_id AND pc.play_count = mpc.max_count;
        """
        customer = Customer.objects.filter(customer_id=selected_customer_id).first()

        with connection.cursor() as cursor:
            cursor.execute(query, [selected_customer_id])
            rows = cursor.fetchall()
            data = [{'genre': row[0], 'arist': row[1]} for row in rows]

    return render(request, 'most_popular_artist_per_customer_per_genre.html', {
        'customers': customers,
        'customer': customer,
        'data': data,
        'selected_customer_id': selected_customer_id,
    })


def invoice_per_customer_after_date(request):
    customers = Customer.objects.all()
    selected_customer_id = request.GET.get('customer_id')
    selected_date = request.GET.get('invoice_date', '2000-01-01')
    data = []
    sum = 0
    customer = None

    if selected_customer_id:
        customer = Customer.objects.filter(customer_id=selected_customer_id).first()
        if selected_date:
            query = """
                SELECT c.first_name, c.last_name, i.invoice_date::date, i.total
                FROM customer c
                JOIN invoice i ON c.customer_id = i.customer_id
                WHERE c.customer_id = %s AND i.invoice_date > %s
                ORDER BY i.invoice_date
            """
            with connection.cursor() as cursor:
                cursor.execute(query, [selected_customer_id, selected_date])
                rows = cursor.fetchall()
                for r in rows:
                    sum += r[3]

                data = [{'first_name': row[0], 'last_name': row[1], 'invoice_date': row[2], 'total': row[3]} for row in
                        rows]
        else:
            query = """
                            SELECT c.first_name, c.last_name, i.invoice_date::date, i.total
                            FROM customer c
                            JOIN invoice i ON c.customer_id = i.customer_id
                            WHERE c.customer_id = %s
                            ORDER BY i.invoice_date
                        """
            with connection.cursor() as cursor:
                cursor.execute(query, [selected_customer_id])
                rows = cursor.fetchall()
                for r in rows:
                    sum += r[3]

                data = [{'first_name': row[0], 'last_name': row[1], 'invoice_date': row[2], 'total': row[3]}
                        for row in
                        rows]

    return render(request, 'invoices_per_customer_after_date.html', {
        'customers': customers,
        'total_sum': sum,
        'data': data,
        'customer': customer,
        'selected_customer_id': selected_customer_id,
    })