"""GitShardAdapter history adopt + cross-substrate integration (SHARD-WP-0012 T3)."""

import os
import subprocess

import pytest

from shard_wiki.adapters import FolderAdapter, GitShardAdapter
from shard_wiki.coordination import ApplyStatus
from shard_wiki.space import InformationSpace

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


def _git_repo(tmp_path, files, name="git"):
    repo = tmp_path / name
    repo.mkdir()
    _git(repo, "init", "--quiet")
    for rel, text in files.items():
        (repo / rel).parent.mkdir(parents=True, exist_ok=True)
        (repo / rel).write_text(text, encoding="utf-8")
        _git(repo, "add", rel)
    _git(repo, "commit", "-m", "seed")
    return repo


def _folder(tmp_path, name, files, writable=False):
    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")
    return FolderAdapter(name, root, writable=writable)


# -- history adopt -------------------------------------------------------------


def test_history_lists_commits_newest_first(tmp_path):
    repo = _git_repo(tmp_path, {"Home.md": "v1"})
    adapter = GitShardAdapter("git", repo, writable=True)
    adapter.write("Home", "v2")
    history = adapter.history("Home")
    assert len(history) == 2
    assert history[0].message == "write Home.md"  # newest first
    assert history[-1].message == "seed"
    assert all(rev.sha for rev in history)


def test_history_unknown_key_raises(tmp_path):
    adapter = GitShardAdapter("git", _git_repo(tmp_path, {"Home.md": "h"}))
    with pytest.raises(KeyError):
        adapter.history("Nope")


# -- cross-substrate integration ----------------------------------------------


def test_resolve_across_git_and_folder(tmp_path):
    space = InformationSpace("space")
    space.attach(GitShardAdapter("git", _git_repo(tmp_path, {"Home.md": "git home"})))
    space.attach(_folder(tmp_path, "notes", {"Daily.md": "folder daily"}))
    assert space.read("Home").body == "git home"  # resolved from the git shard
    assert space.read("Daily").body == "folder daily"  # resolved from the folder shard


def test_chorus_spans_substrates_with_divergence(tmp_path):
    space = InformationSpace("space")
    space.attach(GitShardAdapter("git", _git_repo(tmp_path, {"Shared.md": "from git"})))
    space.attach(_folder(tmp_path, "notes", {"Shared.md": "from folder"}))
    res = space.resolve("Shared")
    assert {p.body for p in res.pages} == {"from git", "from folder"}  # chorus across substrates
    git_page = next(p for p in res.pages if p.identity.shard == "git")
    assert git_page.envelope.divergence  # divergence recorded, not erased


def test_edit_through_git_shard_commits(tmp_path):
    repo = _git_repo(tmp_path, {"Home.md": "original"})
    space = InformationSpace("space")
    space.attach(GitShardAdapter("git", repo, writable=True))
    result = space.edit("Home", "edited via overlay")
    assert result.status is ApplyStatus.APPLIED  # write-through fast-forward on a git shard
    assert space.read("Home").body == "edited via overlay"
    assert int(_git(repo, "rev-list", "--count", "HEAD")) == 2  # the edit became a commit


def test_apply_under_drift_refuses_on_external_commit(tmp_path):
    repo = _git_repo(tmp_path, {"Home.md": "original"})
    space = InformationSpace("space")
    space.attach(GitShardAdapter("git", repo, writable=True))
    overlay = space.overlay("Home", "my draft")  # base_rev = current git sha
    # Another writer commits to the same path → the sha moves underneath the draft.
    (repo / "Home.md").write_text("someone else", encoding="utf-8")
    _git(repo, "add", "Home.md")
    _git(repo, "commit", "-m", "external")
    result = space.apply_overlay(overlay.overlay_id)
    assert result.status is ApplyStatus.REFUSED_DRIFT  # never clobber (sha drift detected)
    # The shard itself is untouched — the external commit stands; the draft remains a draft.
    assert space.union.shard("git").read("Home").body == "someone else"


def test_overlay_on_read_only_git_shard_kept_as_draft(tmp_path):
    space = InformationSpace("space")
    space.attach(GitShardAdapter("git", _git_repo(tmp_path, {"Home.md": "ro"}), writable=False))
    result = space.edit("Home", "wanted change")
    assert result.status is ApplyStatus.KEPT_DRAFT  # read-only target → overlay retained