"""Tests for the RecentChanges merged feed (SHARD-WP-0010 T3)."""

import os
from datetime import datetime, timezone

from shard_wiki.adapters import FolderAdapter
from shard_wiki.coordination import DecisionLog, EventType
from shard_wiki.union import UnionGraph
from shard_wiki.views import recent_changes


def _shard(tmp_path, name, files, mtime=None):
    root = tmp_path / name
    for rel, text in files.items():
        p = root / rel
        p.parent.mkdir(parents=True, exist_ok=True)
        p.write_text(text, encoding="utf-8")
        if mtime is not None:
            os.utime(p, (mtime, mtime))
    return FolderAdapter(name, root)


def test_edit_and_alias_both_appear_newest_first(tmp_path):
    # Page edit signal pinned to an old mtime; the alias decision happens "now" → alias is newest.
    old = datetime(2020, 1, 1, tzinfo=timezone.utc).timestamp()
    u = UnionGraph("space")
    u.attach(_shard(tmp_path, "shardA", {"Home.md": "home"}, mtime=old))
    log = DecisionLog()
    log.append("space", EventType.ALIAS_SET, {"alias": "Start", "target": "shardA:Home"})

    feed = recent_changes(u, log, "space")
    kinds = [e.kind for e in feed]
    assert "edit" in kinds and "alias" in kinds
    assert feed[0].kind == "alias"  # newest first
    assert feed[-1].kind == "edit"
    # Monotonic non-increasing by time.
    assert all(feed[i].when >= feed[i + 1].when for i in range(len(feed) - 1))


def test_per_shard_attribution_present(tmp_path):
    u = UnionGraph("space")
    u.attach(_shard(tmp_path, "shardA", {"A.md": "a"}))
    u.attach(_shard(tmp_path, "shardB", {"B.md": "b"}))
    feed = recent_changes(u, DecisionLog(), "space")
    edits = {e.ref: e.source for e in feed if e.kind == "edit"}
    assert edits["shardA:A"] == "shardA"
    assert edits["shardB:B"] == "shardB"  # each edit attributed to its shard


def test_coordination_entries_carry_actor_and_ref(tmp_path):
    u = UnionGraph("space")
    u.attach(_shard(tmp_path, "shardA", {"Doc.md": "x"}))
    log = DecisionLog()
    log.append(
        "space", EventType.PAGE_FORKED, {"source": "shardA:Doc", "fork": "shardB:Doc"}, actor="ana"
    )
    fork = next(e for e in recent_changes(u, log, "space") if e.kind == "fork")
    assert fork.source == "coordination"
    assert fork.actor == "ana"
    assert fork.ref == "shardA:Doc→shardB:Doc"


def test_limit_truncates_to_newest(tmp_path):
    u = UnionGraph("space")
    u.attach(_shard(tmp_path, "shardA", {"A.md": "a", "B.md": "b", "C.md": "c"}))
    feed = recent_changes(u, DecisionLog(), "space", limit=2)
    assert len(feed) == 2