install.py

#!/usr/bin/env python3
from __future__ import annotations

import json
import platform
import shutil
from pathlib import Path


ROOT = Path(__file__).resolve().parent
CLAUDE_DIR = Path.home() / ".claude"
HOOKS_DIR = CLAUDE_DIR / "hooks"
COMMANDS_DIR = CLAUDE_DIR / "commands"
SETTINGS_PATH = CLAUDE_DIR / "settings.json"
SETTINGS_BACKUP_PATH = CLAUDE_DIR / "settings.userprompt-guard.backup.json"


def ensure_dirs() -> None:
    HOOKS_DIR.mkdir(parents=True, exist_ok=True)
    COMMANDS_DIR.mkdir(parents=True, exist_ok=True)


def load_settings() -> dict:
    if not SETTINGS_PATH.exists():
        return {}
    try:
        return json.loads(SETTINGS_PATH.read_text(encoding="utf-8"))
    except Exception:
        return {}


def write_settings(settings: dict) -> None:
    SETTINGS_PATH.parent.mkdir(parents=True, exist_ok=True)
    SETTINGS_PATH.write_text(json.dumps(settings, ensure_ascii=False, indent=2) + "\n", encoding="utf-8")


def backup_settings_if_needed() -> Path | None:
    if not SETTINGS_PATH.exists():
        return None
    if SETTINGS_BACKUP_PATH.exists():
        return None
    shutil.copy2(SETTINGS_PATH, SETTINGS_BACKUP_PATH)
    return SETTINGS_BACKUP_PATH


def hook_script_target() -> Path:
    return HOOKS_DIR / "claude_chat_audit.py"


def command_file_target() -> Path:
    return COMMANDS_DIR / "audit-chat.md"


def command_path_literal(path: Path) -> str:
    return path.as_posix()


def pick_python_command() -> str:
    if platform.system() == "Windows":
        return "python"
    return "python3"


def hook_command() -> str:
    return f'{pick_python_command()} "{command_path_literal(hook_script_target())}" hook-user'


def audit_chat_markdown() -> str:
    python_cmd = pick_python_command()
    script_path = command_path_literal(hook_script_target())
    return f"""---
description: Audit recent Claude chat content for local policy risk
argument-hint: Optional 'history' or 'doctor'
allowed-tools: Bash(python:*), Bash(python3:*)
---

Run this exact command once:

```bash
{python_cmd} "{script_path}" report --cwd "$PWD" $ARGUMENTS
```

Return the command output verbatim.
"""


def install_files() -> None:
    source_hook = ROOT / "hooks" / "claude_chat_audit.py"
    shutil.copy2(source_hook, hook_script_target())
    command_file_target().write_text(audit_chat_markdown(), encoding="utf-8")


def install_userprompt_hook(settings: dict) -> dict:
    hooks = settings.setdefault("hooks", {})
    entries = hooks.setdefault("UserPromptSubmit", [])

    if not isinstance(entries, list):
        entries = []
        hooks["UserPromptSubmit"] = entries

    command = hook_command()
    for entry in entries:
        hook_list = entry.get("hooks", [])
        if not isinstance(hook_list, list):
            continue
        for hook in hook_list:
            if hook.get("type") == "command" and hook.get("command") == command:
                return settings

    if entries:
        first = entries[0]
        hook_list = first.setdefault("hooks", [])
        if not isinstance(hook_list, list):
            first["hooks"] = []
            hook_list = first["hooks"]
        hook_list.append({"type": "command", "command": command})
    else:
        entries.append({"hooks": [{"type": "command", "command": command}]})

    return settings


def main() -> int:
    ensure_dirs()
    backup_path = backup_settings_if_needed()
    install_files()
    settings = install_userprompt_hook(load_settings())
    write_settings(settings)
    print("Installed Claude UserPrompt Guard.")
    print(f"Hook command: {hook_command()}")
    if backup_path:
        print(f"Settings backup: {backup_path}")
    print("Doctor check: /audit-chat doctor")
    print("Restart Claude Code to load the new hook.")
    return 0


if __name__ == "__main__":
    raise SystemExit(main())