#!/usr/bin/env bash
# Changelog sync guard：按活动扫描配置提示本会话内尚未提交的项目改动。

emit_empty() {
    printf '{}\n'
}

cat >/dev/null

if [ -n "${CURSOR_SKIP_CHANGELOG:-}" ]; then
    emit_empty
    exit 0
fi

script_dir=$(CDPATH= cd -- "$(dirname -- "${BASH_SOURCE[0]}")" 2>/dev/null && pwd)
cursor_dir=$(dirname -- "$script_dir")
repo_root=$(dirname -- "$cursor_dir")
changelog="$cursor_dir/changelog/changelog-headlines.md"
ack_file="$cursor_dir/changelog/.changelog-ack"
session_marker="$cursor_dir/changelog/.session-start"
scan_config="$script_dir/changelog-scan.json"

if [ ! -f "$changelog" ] || [ ! -f "$scan_config" ]; then
    emit_empty
    exit 0
fi

if [ ! -f "$session_marker" ]; then
    emit_empty
    exit 0
fi

get_mtime() {
    stat -c %Y "$1" 2>/dev/null || stat -f %m "$1" 2>/dev/null
}

if [ -f "$ack_file" ]; then
    changelog_mtime=$(get_mtime "$changelog")
    ack_mtime=$(get_mtime "$ack_file")
    if [ -n "$changelog_mtime" ] && [ -n "$ack_mtime" ] &&
        [ "$ack_mtime" -ge "$changelog_mtime" ] 2>/dev/null; then
        emit_empty
        exit 0
    fi
fi

python_cmd=''
for candidate in python3 python; do
    if command -v "$candidate" >/dev/null 2>&1 &&
        "$candidate" -c 'import json' >/dev/null 2>&1; then
        python_cmd=$candidate
        break
    fi
done

if [ -z "$python_cmd" ]; then
    emit_empty
    exit 0
fi

result=$(
    "$python_cmd" - "$repo_root" "$changelog" "$session_marker" "$scan_config" <<'PY'
import json
import os
from pathlib import Path
import subprocess
import sys

repo_root = Path(sys.argv[1]).resolve()
changelog = Path(sys.argv[2])
session_marker = Path(sys.argv[3])
scan_config = Path(sys.argv[4])

def emit(value):
    print(json.dumps(value, ensure_ascii=False, separators=(",", ":")))

try:
    config = json.loads(scan_config.read_text(encoding="utf-8"))
    if config.get("schema_version") != 1:
        raise ValueError("unsupported schema")
    names = {
        value.casefold()
        for value in config.get("included_names", [])
        if isinstance(value, str) and value
    }
    extensions = {
        value.casefold()
        for value in config.get("included_extensions", [])
        if isinstance(value, str) and value
    }
    excluded = {
        value.casefold()
        for value in config.get("excluded_directories", [])
        if isinstance(value, str) and value
    }
    if not names and not extensions:
        emit({})
        raise SystemExit(0)

    status = subprocess.run(
        ["git", "-C", str(repo_root), "status", "--porcelain=v1",
         "--untracked-files=all", "--"],
        check=False,
        capture_output=True,
        text=True,
        encoding="utf-8",
    )
    if status.returncode != 0 or not status.stdout.strip():
        emit({})
        raise SystemExit(0)

    comparison_mtime = max(
        changelog.stat().st_mtime,
        session_marker.stat().st_mtime,
    )
    for current_root, directory_names, file_names in os.walk(repo_root):
        directory_names[:] = [
            name for name in directory_names if name.casefold() not in excluded
        ]
        current = Path(current_root)
        for file_name in file_names:
            candidate = current / file_name
            if (
                file_name.casefold() not in names
                and candidate.suffix.casefold() not in extensions
            ):
                continue
            try:
                if candidate.stat().st_mtime <= comparison_mtime:
                    continue
            except OSError:
                continue
            relative = candidate.relative_to(repo_root).as_posix()
            path_status = subprocess.run(
                ["git", "-C", str(repo_root), "status", "--porcelain=v1",
                 "--untracked-files=all", "--", relative],
                check=False,
                capture_output=True,
                text=True,
                encoding="utf-8",
            )
            if path_status.returncode == 0 and path_status.stdout.strip():
                message = (
                    "[Hook] Project source/config has an uncommitted change newer "
                    f"than this session and the changelog (e.g. {relative}). "
                    "Run dev-changelog Skill operation A now: add a fragment under "
                    ".cursor/changelog/entries/ and rebuild the changelog views."
                )
                emit({"followup_message": message})
                raise SystemExit(0)
    emit({})
except SystemExit:
    raise
except Exception:
    emit({})
PY
) || result='{}'

if [ -n "$result" ]; then
    printf '%s\n' "$result"
else
    emit_empty
fi

exit 0