"""Tests for the ext.struct built-in extension (SHARD-WP-0014 T6)."""

import pytest

from shard_wiki import InformationSpace
from shard_wiki.adapters import assert_conformant
from shard_wiki.engine import ExtensionRuntime, build_engine_shard
from shard_wiki.engine.extensions import StructExt, parse_frontmatter
from shard_wiki.model import PageShape, Verb

_STRUCT_PAGE = "---\ntitle: Spec\nstatus: draft\n---\nbody text"


def test_parse_frontmatter():
    fields, has = parse_frontmatter(_STRUCT_PAGE)
    assert has and fields == {"title": "Spec", "status": "draft"}
    assert parse_frontmatter("just prose") == ({}, False)
    assert parse_frontmatter("---\nunterminated") == ({}, False)


def _runtime(allowed=None):
    rt = ExtensionRuntime()
    rt.register(StructExt(allowed_fields=allowed))
    return rt


def test_feature_absent_when_extension_off():
    shard = build_engine_shard("off", ExtensionRuntime(), activate=set())
    shard.write("Spec", _STRUCT_PAGE)
    assert shard.read("Spec").shape is PageShape.PROSE          # kernel: opaque prose
    assert not shard.profile().supports(Verb.STRUCTURED_PAYLOAD)  # honest absence


def test_feature_present_when_extension_on():
    shard = build_engine_shard("on", _runtime(), activate={"ext.struct"})
    shard.write("Spec", _STRUCT_PAGE)
    assert shard.read("Spec").shape is PageShape.TYPED_RECORD   # tagged by ext.struct
    assert shard.read("Spec").body.endswith("body text")        # content preserved (in-text)
    assert shard.profile().supports(Verb.STRUCTURED_PAYLOAD)    # profile reflects activation (E-5)
    assert_conformant(shard)                                     # still conformant


def test_plain_page_is_not_tagged_even_when_on():
    shard = build_engine_shard("on", _runtime(), activate={"ext.struct"})
    shard.write("Plain", "no frontmatter here")
    assert shard.read("Plain").shape is PageShape.PROSE


def test_allowed_fields_validation_rejects_disallowed():
    shard = build_engine_shard("v", _runtime(allowed={"title"}), activate={"ext.struct"})
    with pytest.raises(ValueError, match="disallowed fields"):
        shard.write("Bad", "---\ntitle: ok\nsecret: no\n---\nx")
    shard.write("Good", "---\ntitle: ok\n---\nx")               # allowed field passes
    assert shard.read("Good").shape is PageShape.TYPED_RECORD


def test_through_information_space_edit():
    space = InformationSpace("team")
    space.attach(build_engine_shard("wikiE", _runtime(), activate={"ext.struct"}))
    space.union.shard("wikiE").write("Doc", "---\ntitle: T\n---\nv1")
    res = space.edit("Doc", "---\ntitle: T2\n---\nv2")           # overlay→apply→write-through
    assert res.status.value == "applied"
    page = space.read("Doc")
    assert page.shape is PageShape.TYPED_RECORD and "v2" in page.body