find free time where you can

timeblocks.py

from datetime import date, datetime, time


class Block:
    """
    Base class to represent a block of time.

    Instantiation can be like:
    
    # Use datetime objects directly

    Block(datetime(2019,4,2,10,14,55), datetime(2019,4,2,12,15,30))

    # If you just want times and don't need accurate dates 
    # (i.e. your time blocks won't span midnight)

    # Hours are in the 0-23 range.

    Block('10:35', '12:12')
    """
    def __init__(self, start_time, end_time):
        if isinstance(start_time, str):
            hour, minute = start_time.split(':')
            self.start_time = datetime.combine(date.min, time(int(hour), int(minute)))
        elif isinstance(start_time, datetime):
            self.start_time = start_time
        else:
            raise Exception

        if isinstance(end_time, str):
            hour, minute = end_time.split(':')
            self.end_time = datetime.combine(date.min, time(int(hour), int(minute)))
        elif isinstance(end_time, datetime):
            self.end_time = end_time
        else:
            raise Exception

        self.duration = self.end_time-self.start_time

    def __repr__(self):
        return 'start: {} | end: {} | dur: {}'.format(self.start_time, self.end_time, self.duration)


class BusyBlock(Block):
    pass


class FreeBlock(Block):
    pass


def process_blocks(blocks):
    assert len(blocks) > 1

    blocks = sorted(blocks, key=lambda b:b.start_time)

    free_blocks = []

    for idx, block in enumerate(blocks[0:-1]):
        next_block = blocks[idx+1]
        if next_block.start_time > block.end_time:
            free_blocks.append(FreeBlock(block.end_time, next_block.start_time))

    return free_blocks


test_blocks = [
    BusyBlock('00:37', '12:34'),
    BusyBlock('12:34', '23:59'),
]