"""Tests for overlay-aware union read (SHARD-WP-0008 T5)."""

from shard_wiki.adapters import FolderAdapter
from shard_wiki.coordination import DecisionLog, OverlayEngine
from shard_wiki.model import Identity
from shard_wiki.policy import Policy
from shard_wiki.provenance import OverlayState
from shard_wiki.union import ResolutionKind, UnionGraph


def _union(tmp_path, files, policy=None):
    for rel, text in files.items():
        (tmp_path / rel).write_text(text, encoding="utf-8")
    log = DecisionLog()
    u = UnionGraph("space", log=log, policy=policy) if policy else UnionGraph("space", log=log)
    u.attach(FolderAdapter("wikiA", tmp_path))
    return u, OverlayEngine("space", log)


def test_no_overlay_reads_clean(tmp_path):
    u, _ = _union(tmp_path, {"Home.md": "canon"})
    page = u.resolve("Home").single()
    assert page.body == "canon"
    assert page.envelope.overlay_state is OverlayState.NONE


def test_open_overlay_surfaces_draft_and_projects_body(tmp_path):
    u, eng = _union(tmp_path, {"Home.md": "canon"})
    eng.draft(Identity("wikiA", "Home"), "my draft", base_rev=None)
    page = u.resolve("Home").single()
    assert page.envelope.overlay_state is OverlayState.DRAFT  # never hidden
    assert page.body == "my draft"  # projected (show_drafts default True)


def test_show_drafts_false_keeps_canonical_body_but_still_flags(tmp_path):
    u, eng = _union(tmp_path, {"Home.md": "canon"}, policy=Policy(show_drafts=False))
    eng.draft(Identity("wikiA", "Home"), "my draft", base_rev=None)
    page = u.resolve("Home").single()
    assert page.body == "canon"  # not projected
    assert page.envelope.overlay_state is OverlayState.DRAFT  # but still surfaced (I-4)


def test_draft_only_new_page_becomes_resolvable(tmp_path):
    u, eng = _union(tmp_path, {"Home.md": "x"})
    assert u.resolve("Brand").is_red_link  # nothing yet
    eng.draft(Identity("wikiA", "Brand"), "drafted into being", base_rev=None)
    res = u.resolve("Brand")
    assert res.kind is ResolutionKind.SINGLE
    assert res.single().body == "drafted into being"
    assert res.single().envelope.overlay_state is OverlayState.DRAFT