Zitap/zitap/helpers.py

import datetime
from .models import Participant, Date, Event


def slots2string( participant : Participant, n_slots : int ) -> str :
    """ Convert the slots of a participant to a string. """

    # Get the slots of the participant
    byte_array = participant.slots

    # Convert the slots to a string
    string_value = bin(int.from_bytes(byte_array, byteorder='big'))[2:]

    # Pad the string with 0s if necessary
    return '0' * (n_slots - len(string_value)) + string_value

def string2slots( string : str, n_slots : int ) -> bytes :
    """ Convert a string to a byte array. """
    if len(string) != n_slots:
        raise ValueError(f"Invalid string length: {len(string)} (expected {n_slots})")

    # Convert the string to a byte array
    return int(string, 2).to_bytes((n_slots + 7) // 8, byteorder='big')

def get_slot_count( event ) -> int :
    """ Get the number of slots in an event. """

    # Get the timespan of the event
    start_time = datetime.datetime.combine(datetime.date.today(), event.start_time)
    end_time = datetime.datetime.combine(datetime.date.today(), event.end_time)
    timespan = abs(end_time - start_time)

    # Get the number of slots in the event
    days = event.date_set.count()
    slots_per_day = int(timespan.total_seconds() // event.slot_interval.total_seconds())
    return days * slots_per_day

def slots2grid( event : Event ) -> dict :
    """ Convert the slots of an event to data for the grid. """

    # Get the number of slots in the event
    n_slots = get_slot_count(event)

    data = {
        'rows': [],
        'days': [],
        'colors': [],
        'n_days': event.date_set.count(),
    }
    # Get the timespan of the event
    start_time = datetime.datetime.combine(datetime.date.today(), event.start_time)
    end_time = datetime.datetime.combine(datetime.date.today(), event.end_time)
    timespan = abs(end_time - start_time)
    
    # Get the slots in a day
    slots_per_day = int(timespan.total_seconds() // event.slot_interval.total_seconds())

    # Get the slots of each day
    participants = event.participant_set.all()
    participant_slot_strings = [slots2string(participant, n_slots) for participant in participants]
    max_occupancy = 1

    for n, date in enumerate(event.date_set.all()):
        # Get participants for each slot
        slot_participants = [[] for i in range(slots_per_day)]
        for i, participant in enumerate(participants):
            for j in range(slots_per_day):
                if participant_slot_strings[i][n*slots_per_day + j] == '1':
                    slot_participants[j].append(participant)
        # Fill the slots of the day
        slots = []
        last_hour = None
        last_half_hour = None
        for j, ps in enumerate(slot_participants):
            slot_begin = (start_time + j * event.slot_interval).strftime('%H:%M')
            slot_end = (start_time + (j+1) * event.slot_interval).strftime('%H:%M')
            current_time = start_time + j * event.slot_interval
            slots.append({
                'tooltip': f"{slot_begin} - {slot_end} \n{', '.join([p.user.username for p in ps])}",
                'offset': n*slots_per_day + j,
                'date': date.date,
                'time': current_time,
                'class': f'color_{len(ps)}',
                'is_full_hour': current_time.hour != last_hour,
                'is_half_hour': current_time.minute // 30 != last_half_hour,
            })
            max_occupancy = max(max_occupancy, len(ps))
            last_hour = current_time.hour
            last_half_hour = current_time.minute // 30
        
        day = {
            'date': date.date,
            'slots': slots,
        }
        data['days'].append(day)

    # Fill the rows of the grid
    last_hour = None
    for i in range(slots_per_day):
        current_time = start_time + i * event.slot_interval
        data['rows'].append({
            'time': current_time,
            'is_full_hour': current_time.hour != last_hour,
        })
        last_hour = current_time.hour

    data['rows'].append({
        'time': end_time,
        'is_full_hour': True,
    })

    # create a color for each slot from white to dark green
    for i in range(max_occupancy+1):
        data['colors'].append({
            'color': f"hsl(120, 100%, {100 - 70 * i / max_occupancy}%)",
            'name': f'color_{i}'
        })
    return data