"""tmux 裸终端运行时（零依赖，最轻量）。

每个 member 对应一个 tmux 会话（session = rig 名，window = member id）。
启动：tmux new-session -d -s <rig> -n <member> '<command>'
停止：tmux kill-session -t <rig>:<member>
"""
from __future__ import annotations

import shutil
import subprocess
from dataclasses import dataclass


class TmuxNotFoundError(RuntimeError):
    pass


def _tmux(*args: str) -> str:
    if not shutil.which("tmux"):
        raise TmuxNotFoundError("tmux 未安装")
    r = subprocess.run(["tmux", *args], capture_output=True, text=True, timeout=10)
    if r.returncode != 0:
        raise RuntimeError(f"tmux {' '.join(args)} 失败: {r.stderr.strip()}")
    return r.stdout.strip()


@dataclass
class TmuxSession:
    rig: str
    member: str
    command: str

    @property
    def target(self) -> str:
        return f"{self.rig}:{self.member}"

    def exists(self) -> bool:
        try:
            _tmux("has-session", "-t", self.target)
            return True
        except (RuntimeError, Exception):
            return False

    def start(self):
        if self.exists():
            return
        _tmux("new-session", "-d", "-s", self.rig, "-n", self.member, self.command)

    def stop(self):
        try:
            _tmux("kill-window", "-t", self.target)
        except (RuntimeError, Exception):
            pass

    def capture(self, lines: int = 20) -> str:
        """抓最后 N 行输出。"""
        if not self.exists():
            return ""
        try:
            return _tmux("capture-pane", "-t", self.target, "-p", "-S", f"-{lines}")
        except (RuntimeError, Exception):
            return ""


class TerminalRuntime:
    """tmux 裸终端运行时管理器。"""

    def __init__(self, rig_name: str):
        self.rig_name = rig_name

    def start(self, member_id: str, command: str, cwd: str = ".") -> TmuxSession:
        sess = TmuxSession(rig=self.rig_name, member=member_id, command=command)
        if cwd != ".":
            command = f"cd {cwd} && {command}"
        sess.command = command
        sess.start()
        return sess

    def stop(self, member_id: str):
        TmuxSession(rig=self.rig_name, member=member_id, command="").stop()

    def stop_all(self):
        try:
            _tmux("kill-session", "-t", self.rig_name)
        except (RuntimeError, Exception):
            pass

    def status(self, member_id: str) -> str:
        sess = TmuxSession(rig=self.rig_name, member=member_id, command="")
        return "running" if sess.exists() else "stopped"