"""The trust dial's hard wall, on a real Gitea (D4, D5; M3.3): with the
protection a `merge: approved` project has, the agent's own token can't
merge its PR until an operator approves the PR as it is now; it can then;
and a commit pushed after the approval needs approving again: at once by the
agent's own check, and by Gitea once it has dismissed the approval."""

import base64
import time
import uuid
from pathlib import Path

import pytest
from e2e_support import fresh_repo, operator_gitea

from nisse_core.gitea import GiteaClient, GiteaError
from nisse_dev.config import AgentConfig

pytestmark = pytest.mark.integration

# How long Gitea gets to dismiss an approval after a push (#162).
DISMISS_WAIT_S = 30.0


def add_file(gitea: GiteaClient, repo: str, branch: str, path: str) -> None:
    gitea._request(
        "POST",
        f"/repos/{repo}/contents/{path}",
        json={
            "content": base64.b64encode(f"{path}\n".encode()).decode(),
            "message": f"add {path}",
            "branch": branch,
        },
    )


def approve(operator: GiteaClient, repo: str, pr: int) -> None:
    operator._request(
        "POST", f"/repos/{repo}/pulls/{pr}/reviews", json={"event": "APPROVED"}
    )


def wait_for_dismissal(gitea: GiteaClient, repo: str, pr: int) -> None:
    """Gitea dismisses a stale approval in a job it queues on the push, not
    in the push itself, and its merge check counts what isn't dismissed yet.
    A merge tried before that job has run can still go through (#162)."""
    deadline = time.monotonic() + DISMISS_WAIT_S
    while gitea.approvals(repo, pr):  # dismissed ones aren't listed
        assert time.monotonic() < deadline, (
            f"Gitea didn't dismiss the approval within {DISMISS_WAIT_S}s"
        )
        time.sleep(0.5)


def test_merging_needs_the_operators_approval_of_the_pr_as_it_is(
    tmp_path: Path, live_config: AgentConfig, gitea: GiteaClient
) -> None:
    operator = operator_gitea(live_config.gitea_url)
    run = uuid.uuid4().hex[:8]
    with fresh_repo(operator, run, tmp_path / "keys", agent=gitea.whoami()) as repo:
        name = repo.name
        # The agent's PR, its branch made through the API.
        gitea.branch_with_file(
            name, base="main", branch="m-1", path="a.txt", text="a\n", message="a"
        )
        pr = gitea.open_pull_request(name, head="m-1", base="main", title="a", body="")
        with pytest.raises(GiteaError):
            gitea.merge_pull_request(name, pr.number)  # no approval yet

        approve(operator, name, pr.number)
        [approval] = gitea.approvals(name, pr.number)
        head = gitea.pull_request(name, pr.number).head_sha
        assert (approval.author, approval.commit) == (operator.whoami(), head)
        gitea.merge_pull_request(name, pr.number)  # approved: the agent may
        assert gitea.pull_request(name, pr.number).merged

        # Approved, then changed: the approval no longer stands.
        gitea.branch_with_file(
            name, base="main", branch="m-2", path="b.txt", text="b\n", message="b"
        )
        second = gitea.open_pull_request(
            name, head="m-2", base="main", title="b", body=""
        )
        approve(operator, name, second.number)
        approved = gitea.pull_request(name, second.number).head_sha
        add_file(gitea, name, "m-2", "c.txt")  # a fix pushed after the approval
        # At once, with no waiting: the PR's head is read from the branch,
        # so the agent sees the new commit, and the approval is for the old
        # one. Its own check (an approval at the head, not stale) holds off.
        after = gitea.pull_request(name, second.number).head_sha
        assert after != approved
        assert not [
            a
            for a in gitea.approvals(name, second.number)
            if a.commit == after and not a.stale
        ]
        # Gitea's own refusal comes once it has dismissed the approval.
        wait_for_dismissal(gitea, name, second.number)
        with pytest.raises(GiteaError):
            gitea.merge_pull_request(name, second.number)