import pickle
from random import randrange
from subprocess import check_output

from common import set_

BITS = 10


def mask(height: int) -> int:
    return ((1 << height.bit_length()) - 1) >> BITS


def valid(commit: str, height: int) -> bool:
    expected = int.from_bytes(bytes.fromhex(commit), "little")
    return mask(height) & (height ^ expected) == 0


# args = []
args = ["--topo-order"]
original_commits = check_output(["git", "log", "--pretty=%H", *args], text=True).splitlines()
N = len(original_commits)
total_changes: dict[str, tuple[int, int]] = {}
chosen_parents: dict[str, str | None] = {}
heights: dict[str, int] = {}
nheights: dict[str, int] = {}
included = set()
for i, commit in enumerate(reversed(original_commits)):
    print(f"C={i / N:6f}", flush=True)
    parents = check_output(["git", "log", "--pretty=%P", "-n", "1", commit], text=True).split()
    parents = [parent for parent in parents if parent in heights]
    chosen_parent = None
    height = 1 + max((heights[parent] for parent in parents), default=0)
    nheight = 1 + min((nheights[parent] for parent in parents), default=0)
    if nheight > mask(height) or valid(commit, height):
        included.add(commit)
        nheight = 0
        ctr = set_(commit)
        changes = len(ctr), 1
        for parent in parents:
            if parent in included:
                _parent = parent
            else:
                _parent = chosen_parents[parent]
                if _parent is None:
                    continue
            assert _parent in included
            pctr = set_(_parent)
            pcc, pch = total_changes[parent]
            maybe_changes = len(pctr - ctr) + len(ctr - pctr) + pcc, pch + 1
            if maybe_changes > changes:
                changes = maybe_changes
                chosen_parent = parent
    else:
        changes = 0, 1
        for parent in parents:
            pcc, pch = total_changes[parent]
            maybe_changes = pcc, pch + 1
            if maybe_changes > changes:
                changes = maybe_changes
                chosen_parent = parent
    total_changes[commit] = changes
    if chosen_parent is not None and chosen_parent not in included:
        chosen_parent = chosen_parents[chosen_parent]
    assert chosen_parent is None or chosen_parent in included
    chosen_parents[commit] = chosen_parent
    heights[commit] = height
    nheights[commit] = nheight
commit = original_commits[0]
commits = []
while commit is not None:
    commits.append(commit)
    commit = chosen_parents[commit]
with open("/code/commits.dat", "wb") as file:
    pickle.dump(commits, file)