fm.py

#!/usr/bin/env python3
"""fm - Interactive terminal chat for Apple's built-in Foundation Model."""

import asyncio
import sys

import apple_fm_sdk as fm

VERSION = "0.1.0"

HELP_TEXT = """\
fm

Interactive terminal chat for Apple's built-in Foundation Model.

Usage:
  fm
  fm --help
  fm --version

Commands in the REPL:
  :help   Show REPL help
  :reset  Start a fresh chat session
  :quit   Exit the program"""


def repl_help() -> str:
    return HELP_TEXT.split("\n\n")[-1]


def check_availability() -> bool:
    model = fm.SystemLanguageModel()
    is_available, reason = model.is_available()
    if is_available:
        return True
    print(f"Foundation Model is unavailable: {reason}", file=sys.stderr)
    return False


def make_session() -> fm.LanguageModelSession:
    return fm.LanguageModelSession(
        instructions=(
            "You are a concise terminal assistant. "
            "Keep responses practical and compact unless the user asks for detail."
        ),
    )


async def repl() -> None:
    session = make_session()

    while True:
        try:
            line = input("> ")
        except (EOFError, KeyboardInterrupt):
            print()
            break

        prompt = line.strip()
        if not prompt:
            continue

        if prompt in (":quit", ":exit"):
            break
        if prompt == ":help":
            print(repl_help())
            continue
        if prompt == ":reset":
            session = make_session()
            print("Conversation reset.")
            continue

        try:
            response = await session.respond(prompt)
            print(f"\n{response}\n")
        except Exception as e:
            print(f"Generation failed: {e}", file=sys.stderr)


def main() -> None:
    args = sys.argv[1:]

    if args:
        match args[0]:
            case "--help" | "-h":
                print(HELP_TEXT)
                return
            case "--version" | "-v":
                print(VERSION)
                return
            case other:
                print(f"Unknown argument: {other}\n", file=sys.stderr)
                print(HELP_TEXT)
                sys.exit(2)

    if not check_availability():
        sys.exit(1)

    print("Apple Foundation Model REPL")
    print("Type a prompt and press return.")
    print("Commands: :help, :reset, :quit")
    print()

    asyncio.run(repl())


if __name__ == "__main__":
    main()