"""Tests for the engine kernel (SHARD-WP-0014 T1)."""

import pytest

from shard_wiki.engine import EngineKernel, extract_wikilinks
from shard_wiki.model import Identity


def test_write_creates_then_edits_as_history():
    k = EngineKernel("eng")
    p1 = k.write("Home", "first")
    assert p1.identity == Identity("eng", "Home")
    assert p1.envelope.source_rev == "1"
    p2 = k.write("Home", "second")
    assert p2.envelope.source_rev == "2"
    assert k.read("Home").body == "second"          # latest
    assert [v.body for v in k.history("Home")] == ["first", "second"]  # recoverable history


def test_read_missing_raises():
    k = EngineKernel("eng")
    with pytest.raises(KeyError):
        k.read("Nope")


def test_delete_is_recoverable():
    k = EngineKernel("eng")
    k.write("Doc", "v1")
    k.delete("Doc")
    assert not k.exists("Doc")
    with pytest.raises(KeyError):
        k.read("Doc")
    assert [v.body for v in k.history("Doc")] == ["v1"]   # history retained
    k.write("Doc", "v2")                                   # restore by writing
    assert k.exists("Doc") and k.read("Doc").body == "v2"


def test_keys_and_current_rev():
    k = EngineKernel("eng")
    k.write("A", "a")
    k.write("B", "b")
    k.write("A", "a2")
    assert set(k.keys()) == {"A", "B"}
    assert k.current_rev("A") == "2"
    assert k.current_rev("Missing") is None


def test_links_and_red_link_resolution():
    k = EngineKernel("eng")
    k.write("Home", "see [[Target]] and [[Other|labelled]] and [[Target]] again")
    k.write("Target", "exists")
    assert k.links("Home") == ["Target", "Other"]        # ordered, de-duped, label dropped
    assert k.resolve_link("Target") == Identity("eng", "Target")
    assert k.resolve_link("Other") is None               # red-link (not yet created)


def test_extract_wikilinks_helper():
    assert extract_wikilinks("none here") == []
    assert extract_wikilinks("[[A]] [[B|x]] [[A]]") == ["A", "B"]