"""Claude CLI 后端 — 调用 claude CLI 子进程生成总结。

和 pi_client.py 对称的接口，复用 prompt 构建、PDF 文本提取、JSON 提取逻辑。
"""

from __future__ import annotations

import asyncio
import logging
import uuid

from app.config import settings

logger = logging.getLogger(__name__)


class ClaudeTimeoutError(Exception):
    pass


class ClaudeProcessError(Exception):
    def __init__(self, returncode: int, stderr: str):
        self.returncode = returncode
        self.stderr = stderr
        super().__init__(f"claude exited with code {returncode}: {stderr[:500]}")


async def call_claude(
    prompt: str,
    session_id: str | None = None,
    fix_errors: list[str] | None = None,
) -> tuple[str, str]:
    """调用 claude CLI print 模式，返回 (stdout 文本, session_id)。

    和 call_pi() 对称的接口，但 claude CLI 不需要文件路径和 pdf_mode——
    所有内容已在 prompt 中准备好。

    Args:
        prompt: 完整的 prompt 文本
        session_id: session ID（首次为 None 时自动生成）
        fix_errors: 上一轮验证错误列表（用于重试）
    """
    if session_id is None:
        session_id = f"claude-summary-{uuid.uuid4().hex[:8]}"

    cmd = [settings.CLAUDE_BIN, "-p", "--output-format", "text"]

    if fix_errors and session_id:
        # 重试：延续 session
        cmd += ["--session-id", session_id, "--continue"]
    else:
        cmd += ["--session-id", session_id]

    cmd.append(prompt)

    logger.info(
        "Calling claude (session=%s, fix=%s)",
        session_id,
        bool(fix_errors),
    )

    proc = await asyncio.create_subprocess_exec(
        *cmd,
        stdout=asyncio.subprocess.PIPE,
        stderr=asyncio.subprocess.PIPE,
    )
    try:
        stdout, stderr = await asyncio.wait_for(
            proc.communicate(),
            timeout=settings.SUMMARY_TIMEOUT_SECONDS,
        )
    except asyncio.TimeoutError:
        proc.kill()
        await proc.wait()
        raise ClaudeTimeoutError(
            f"claude timed out after {settings.SUMMARY_TIMEOUT_SECONDS}s"
        )

    if proc.returncode != 0:
        raise ClaudeProcessError(
            proc.returncode, stderr.decode("utf-8", errors="replace")
        )

    return stdout.decode("utf-8", errors="replace"), session_id