from collections import defaultdict
import re
import string
import pdb


def get_first(steps):
    for step, deps in steps.items():
        if len(deps) == 0:
            return step


with open('data/07.txt') as f:
    regexp = re.compile('Step (.) must be finished before step (.) can begin.')
    data = [regexp.match(line).groups() for line in f]


requires = {}
for before, after in data:
    if before not in requires:
        requires[before] = set()
    if after not in requires:
        requires[after] = set()
    requires[after].add(before)

workers = []


incomplete = {s: set(d) for s, d in requires.items()}
complete = []
available = set()
while len(incomplete):
    for step, deps in incomplete.items():
        if len(deps) == 0:
            available.add(step)

    s = sorted(available)[0]
    complete.append(s)
    for deps in incomplete.values():
        if s in deps:
            deps.remove(s)
    available.remove(s)
    del incomplete[s]

print(f'Part 1: {"".join(complete)}\n')


step_times = {c: 61 + i for i, c in enumerate(string.ascii_uppercase)}
unattempted = {s: set(d) for s, d in requires.items()}
complete = []
available = set()
running = set()
workers = [(None, 0) for i in range(5)]
time = -1
while len(unattempted) or len(running):
    time += 1
    for i, (s, t) in enumerate(workers):
        if s and (time - step_times[s] - t == 0):
            complete.append(s)
            running.remove(s)
            for deps in unattempted.values():
                if s in deps:
                    deps.remove(s)
            workers[i] = (None, 0)
   
    for step, deps in unattempted.items():
        if len(deps) == 0:
            available.add(step)

    ordered_steps = sorted(available)
    for i, (s, t) in enumerate(workers):
        if s is None:
            try:
                new_step = ordered_steps.pop(0)
                workers[i] = (new_step, time)
                del unattempted[new_step]
                available.remove(new_step)
                running.add(new_step)
            except IndexError:
                pass


print(f'Part 2: {time}\n')