#!/usr/bin/env python3

from collections import defaultdict

ORE  = "ORE"
FUEL = "FUEL"

class Reactor:
    def __init__(self, reactions, root=ORE):
        self.reactions = reactions
        self.root = root
        self.produced = defaultdict(int)
        self.leftover = defaultdict(int)

    def produce(self, el, n):
        if el == self.root:
            self.produced[el] += n
            return
        min = self.reactions[el][el]
        if type(min) == float:
            k = (n + min - 1) / min
        else:
            k = (n + min - 1) // min
        for el2, m in self.reactions[el].items():
            if el2 == el:
                continue
            self.get(el2, k * m)
        p = k*min
        self.produced[el] += p
        self.leftover[el] += p - n

    def get(self, el, n):
        n -= self.leftover[el]
        self.leftover[el] = 0
        if n <= 0:
            self.leftover[el] = -n
            return
        self.produce(el, n)

def parse(line):
    el = line.split()[-1]
    line = line.replace(" => ", ', ')
    return el, dict((m.split()[1], int(m.split()[0]))
                for m in line.split(', '))


def ore_per_fuel(reactions, n=1):
    reactor = Reactor(reactions)
    reactor.get(FUEL, n)
    return reactor.produced[ORE]

def ore_per_fuel_lim(reactions):
    float_recs = {}
    for el in reactions.keys():
        min = float(reactions[el][el])
        float_recs[el] = dict((el2, n/min) for el2, n in reactions[el].items())
    return ore_per_fuel(float_recs)

def search(f, target, best):
    step = best // 100
    i    = best
    while step > 0:
        while f(i) <= target:
            i += step
        i -= step
        step //= 10
    return i


def preproc(puzzle_input):
    return dict(map(parse, puzzle_input.split('\n')))

def partI(reactions):
    r = ore_per_fuel(reactions)
    return r

def partII(reactions):
    ore = 10**12
    best = int(ore // ore_per_fuel_lim(reactions))
    return search(lambda n: ore_per_fuel(reactions, n), ore, best)

from main import Tests

tests = Tests()
tests.add(
"""157 ORE => 5 NZVS
165 ORE => 6 DCFZ
44 XJWVT, 5 KHKGT, 1 QDVJ, 29 NZVS, 9 GPVTF, 48 HKGWZ => 1 FUEL
12 HKGWZ, 1 GPVTF, 8 PSHF => 9 QDVJ
179 ORE => 7 PSHF
177 ORE => 5 HKGWZ
7 DCFZ, 7 PSHF => 2 XJWVT
165 ORE => 2 GPVTF
3 DCFZ, 7 NZVS, 5 HKGWZ, 10 PSHF => 8 KHKGT""",
partI=13312)


tests.add(
"""2 VPVL, 7 FWMGM, 2 CXFTF, 11 MNCFX => 1 STKFG
17 NVRVD, 3 JNWZP => 8 VPVL
53 STKFG, 6 MNCFX, 46 VJHF, 81 HVMC, 68 CXFTF, 25 GNMV => 1 FUEL
22 VJHF, 37 MNCFX => 5 FWMGM
139 ORE => 4 NVRVD
144 ORE => 7 JNWZP
5 MNCFX, 7 RFSQX, 2 FWMGM, 2 VPVL, 19 CXFTF => 3 HVMC
5 VJHF, 7 MNCFX, 9 VPVL, 37 CXFTF => 6 GNMV
145 ORE => 6 MNCFX
1 NVRVD => 8 CXFTF
1 VJHF, 6 MNCFX => 4 RFSQX
176 ORE => 6 VJHF""",
partI=180697)

tests.add(
"""171 ORE => 8 CNZTR
7 ZLQW, 3 BMBT, 9 XCVML, 26 XMNCP, 1 WPTQ, 2 MZWV, 1 RJRHP => 4 PLWSL
114 ORE => 4 BHXH
14 VRPVC => 6 BMBT
6 BHXH, 18 KTJDG, 12 WPTQ, 7 PLWSL, 31 FHTLT, 37 ZDVW => 1 FUEL
6 WPTQ, 2 BMBT, 8 ZLQW, 18 KTJDG, 1 XMNCP, 6 MZWV, 1 RJRHP => 6 FHTLT
15 XDBXC, 2 LTCX, 1 VRPVC => 6 ZLQW
13 WPTQ, 10 LTCX, 3 RJRHP, 14 XMNCP, 2 MZWV, 1 ZLQW => 1 ZDVW
5 BMBT => 4 WPTQ
189 ORE => 9 KTJDG
1 MZWV, 17 XDBXC, 3 XCVML => 2 XMNCP
12 VRPVC, 27 CNZTR => 2 XDBXC
15 KTJDG, 12 BHXH => 5 XCVML
3 BHXH, 2 VRPVC => 7 MZWV
121 ORE => 7 VRPVC
7 XCVML => 6 RJRHP
5 BHXH, 4 VRPVC => 5 LTCX""",
partI=2210736)