"""Claude client abstraction. SDK preferred, `claude -p` CLI fallback."""

from __future__ import annotations

import os
import shutil
import subprocess
from typing import Callable

LLMCaller = Callable[..., str]  # (prompt, *, model, max_tokens) -> response text


def _have_anthropic_sdk() -> bool:
    try:
        import anthropic  # noqa: F401
        return True
    except ImportError:
        return False


def _have_claude_cli() -> bool:
    return shutil.which("claude") is not None


def _call_via_sdk(prompt: str, model: str, max_tokens: int) -> str:
    import anthropic
    client = anthropic.Anthropic()
    response = client.messages.create(
        model=model,
        max_tokens=max_tokens,
        messages=[{"role": "user", "content": prompt}],
    )
    return response.content[0].text


def _call_via_cli(prompt: str, model: str, max_tokens: int) -> str:
    """Shell out to Claude Code CLI. max_tokens is ignored (CLI handles defaults)."""
    result = subprocess.run(
        ["claude", "-p", prompt, "--model", model],
        capture_output=True,
        text=True,
        check=True,
        timeout=60,
    )
    return result.stdout.strip()


def call_claude(
    prompt: str,
    *,
    model: str = "claude-haiku-4-5",
    max_tokens: int = 1000,
) -> str:
    """Send a prompt to Claude.

    Tries the anthropic SDK first (requires ANTHROPIC_API_KEY), falls back to
    the `claude -p` CLI if available. Raises RuntimeError if neither works.
    """
    if _have_anthropic_sdk() and os.getenv("ANTHROPIC_API_KEY"):
        return _call_via_sdk(prompt, model, max_tokens)
    if _have_claude_cli():
        return _call_via_cli(prompt, model, max_tokens)
    raise RuntimeError(
        "No Claude client available. Either:\n"
        "  - Install the `anthropic` SDK and set ANTHROPIC_API_KEY, or\n"
        "  - Install Claude Code CLI (`claude` on PATH)"
    )