"""Tests for GitShardAdapter write=commit + current_rev drift (SHARD-WP-0012 T2)."""

import os
import subprocess

from shard_wiki.adapters import GitShardAdapter, run_conformance
from shard_wiki.model import Verb

_ENV = {
    "GIT_AUTHOR_NAME": "t", "GIT_AUTHOR_EMAIL": "t@t",
    "GIT_COMMITTER_NAME": "t", "GIT_COMMITTER_EMAIL": "t@t",
    "PATH": os.environ.get("PATH", ""),
}


def _git(repo, *args, capture=False):
    return subprocess.run(
        ["git", "-C", str(repo), *args], check=True, capture_output=True, text=True, env=_ENV
    ).stdout.strip()


def _repo(tmp_path, files):
    repo = tmp_path / "repo"
    repo.mkdir()
    _git(repo, "init", "--quiet")
    for rel, text in files.items():
        (repo / rel).write_text(text, encoding="utf-8")
        _git(repo, "add", rel)
    _git(repo, "commit", "-m", "seed")
    return repo


def test_writable_profile_declares_write_and_version(tmp_path):
    profile = GitShardAdapter("git", _repo(tmp_path, {"Home.md": "h"}), writable=True).profile()
    assert profile.supports(Verb.WRITE)
    assert profile.supports(Verb.VERSION)
    profile.validate()  # PER_PAGE + WRITE is a consistent combination


def test_write_creates_a_commit(tmp_path):
    repo = _repo(tmp_path, {"Home.md": "old"})
    adapter = GitShardAdapter("git", repo, writable=True)
    before = _git(repo, "rev-list", "--count", "HEAD")
    page = adapter.write("Home", "new body")
    after = _git(repo, "rev-list", "--count", "HEAD")
    assert int(after) == int(before) + 1  # one new commit
    assert page.body == "new body"
    assert page.envelope.source_rev == _git(repo, "rev-parse", "HEAD")  # page is at the new sha


def test_write_advances_current_rev(tmp_path):
    repo = _repo(tmp_path, {"Home.md": "old"})
    adapter = GitShardAdapter("git", repo, writable=True)
    rev_before = adapter.current_rev("Home")
    adapter.write("Home", "changed")
    assert adapter.current_rev("Home") != rev_before  # sha moved → drift detectable


def test_write_new_key_tracks_it(tmp_path):
    repo = _repo(tmp_path, {"Home.md": "h"})
    adapter = GitShardAdapter("git", repo, writable=True)
    adapter.write("docs/New", "fresh page")
    assert "docs/New" in set(adapter.keys())
    assert adapter.read("docs/New").body == "fresh page"


def test_noop_write_creates_no_empty_commit(tmp_path):
    repo = _repo(tmp_path, {"Home.md": "same"})
    adapter = GitShardAdapter("git", repo, writable=True)
    before = _git(repo, "rev-list", "--count", "HEAD")
    adapter.write("Home", "same")  # identical body → nothing to commit
    assert _git(repo, "rev-list", "--count", "HEAD") == before


def test_current_rev_reflects_external_commit(tmp_path):
    repo = _repo(tmp_path, {"Home.md": "h"})
    adapter = GitShardAdapter("git", repo, writable=True)
    rev = adapter.current_rev("Home")
    # An out-of-band commit to the same path (another writer) moves the per-path sha.
    (repo / "Home.md").write_text("externally edited", encoding="utf-8")
    _git(repo, "add", "Home.md")
    _git(repo, "commit", "-m", "external")
    assert adapter.current_rev("Home") != rev


def test_conformance_positive_write_probe_passes(tmp_path):
    adapter = GitShardAdapter("git", _repo(tmp_path, {"Home.md": "body"}), writable=True)
    report = run_conformance(adapter)
    assert report.ok, report.diff()