"""Multi-turn: same backend, two turns, context persists across the pair.

The backend fingerprints `messages[:-1]` against its pool of live PTYs.
After turn 1 finishes, we re-send the conversation with the assistant's
reply appended and one new user message — fingerprint matches, the same
process is reused, and the server-side prompt cache keeps the context
without us paying a fresh-spawn tax.

Run:
  python examples/multi_turn.py
"""

from __future__ import annotations

import asyncio
import os
from pathlib import Path
from typing import Any

from claude_code_api import (
    AssistantMessage,
    BackendOptions,
    ClaudeCodeBackend,
    ResultMessage,
    TextBlock,
)

CWD = Path(os.environ.get("CLAUDE_CODE_CWD", Path.cwd())).resolve()


def assistant_text(events: list[Any]) -> str:
    for ev in reversed(events):
        if isinstance(ev, AssistantMessage):
            return "".join(b.text for b in ev.content if isinstance(b, TextBlock)).strip()
    return ""


async def run_turn(
    backend: ClaudeCodeBackend, history: list[dict[str, Any]]
) -> str:
    events: list[Any] = []
    async for event in backend.complete(history):
        events.append(event)
        if isinstance(event, ResultMessage):
            print(f"  → stop_reason={event.stop_reason} duration_ms={event.duration_ms}")
    return assistant_text(events)


async def main() -> None:
    opts = BackendOptions(cwd=str(CWD), dangerously_skip_permissions=True)
    async with ClaudeCodeBackend(opts) as backend:
        history: list[dict[str, Any]] = [
            {"role": "user", "content": "Remember the codeword: Beaver. Reply OK."}
        ]
        print("[turn 1]")
        reply1 = await run_turn(backend, history)
        print(f"  [assistant] {reply1}")

        history += [
            {"role": "assistant", "content": [{"type": "text", "text": reply1}]},
            {"role": "user", "content": "What was the codeword? Reply with one word."},
        ]
        print("[turn 2]")
        reply2 = await run_turn(backend, history)
        print(f"  [assistant] {reply2}")


if __name__ == "__main__":
    asyncio.run(main())