import hashlib
from gravityweave.pcp import create_entry, build_chain, inclusion_proof, head_hash, verify_inclusion


def test_create_and_chain_basic():
    ops = [("add-c1", "nodeA"), ("add-c2", "nodeB"), ("mutate-c1", "nodeA")]
    chain = build_chain(ops)
    assert len(chain) == 3
    # each entry hash should be a valid sha256 hex
    for e in chain:
        h = e.get("hash")
        assert isinstance(h, str) and len(h) == 64


def test_inclusion_proof_and_head():
    ops = [("op1", "A"), ("op2", "B"), ("op3", "C")]
    chain = build_chain(ops)
    head = head_hash(chain)
    # pick middle entry
    target = chain[1]
    proof = inclusion_proof(chain, target_entry_id=target["entry_id"])
    assert proof[0] == target["hash"]
    assert proof[-1] == head
    # verify inclusion using head-only verification (best-effort)
    assert verify_inclusion(head, proof)