"""Logic for the `pr` domain. Transport-agnostic (D-263)."""

from __future__ import annotations

import shutil
from pathlib import Path

from tooling.core import config, process
from tooling.core.errors import ReachError

LOGIN = "schweitz"
REPO = "jpmschweitzer/settled-reach"

# Paths whose change means the committed systems.db may be stale. The generator
# set is read from the registry rather than restated, so this list cannot drift
# from tooling/generator_sources.py (T-1067).
EXTRA_WATCHED = (
    "tooling/domains/atlas/planet/import_heightmaps.py",
    "tooling/domains/atlas/planet/import_province_boundaries.py",
    "server/data/systems-schema.sql",
    "wiki/star-systems/",
    "wiki/economics/",
)


def comment(number: str, body_or_path: str) -> None:
    """Post a comment on a Gitea PR or issue.

    `@path` reads the body from a file — the form that exists because a long
    comment inline would need a `$(...)` subshell, and a subshell breaks the
    permission gate's prefix matching (.claude/rules/tea-cli.md).

    Every flag is explicit for the same reason the rule gives: omitting
    `--login` or `--repo` sends `tea` interactive, and an interactive prompt
    with no TTY does not wait — it crashes.
    """
    body = _resolve_body(body_or_path)

    tea = shutil.which("tea")
    if tea is None:
        raise ReachError(
            "the tea CLI is not on PATH",
            fix="tea is symlinked into ~/.local/bin — check that, rather than "
            "calling the linuxbrew path directly, which breaks the Bash(tea *) rule",
        )

    process.run(
        [tea, "comment", "--login", LOGIN, "--repo", REPO, number, body],
        cwd=config.repo_root(),
        fix=f"check that PR/issue {number} exists and the login is authorised",
    )


def watchlist_diff(base: str, head: str) -> list[str]:
    """Files changed in the range that would make the committed systems.db stale."""
    from tooling import generator_sources

    root = config.repo_root()
    registered = sorted(
        {
            str(path.relative_to(root))
            for paths in generator_sources.GENERATOR_SOURCES.values()
            for path in paths
        }
    )
    watched = [*registered, *EXTRA_WATCHED]
    if not watched:
        # The original checked this too: an empty registry would diff nothing
        # and report a clean watchlist, which is the answer that lets a stale DB
        # through.
        raise ReachError(
            "the generator-source registry is empty",
            fix="tooling/generator_sources.py should list every generator input",
        )

    result = process.run(
        ["git", "diff", "--name-only", f"{base}...{head}", "--", *watched],
        cwd=config.repo_root(),
        check=False,
    )
    return [line for line in (result.stdout or "").splitlines() if line]


def _resolve_body(body_or_path: str) -> str:
    if not body_or_path.startswith("@"):
        return body_or_path
    path = Path(body_or_path[1:])
    if not path.is_file():
        raise ReachError(
            f"comment body file not found: {path}",
            fix="write the comment to a file first, then pass @that-path",
        )
    return path.read_text(encoding="utf-8")