from __future__ import annotations

import os
import shlex
from uuid import uuid4
import subprocess
from dataclasses import dataclass

from .registry import repository_paths, validate_targets


class TmuxError(RuntimeError):
    pass


@dataclass
class Endpoint:
    session: str
    pid: int
    repos: list[str]
    instance_id: str = ""

    @property
    def endpoint_id(self) -> str:
        return f"tmux-amq-{self.pid}"

    @property
    def instance_key(self) -> str:
        return self.instance_id or self.endpoint_id


class TmuxManager:
    def __init__(self, session: str = "tamq"):
        self.session = session

    def _run(self, *args: str, check: bool = True) -> str:
        result = subprocess.run(["tmux", *args], text=True, capture_output=True, check=False)
        if check and result.returncode:
            raise TmuxError(result.stderr.strip() or "tmux command failed")
        return result.stdout.strip()

    def ensure(self, repos: list[str], command: str = "codex") -> Endpoint:
        if not repos:
            raise TmuxError("at least one repository is required")
        try:
            validate_targets(repos)
        except Exception as exc:
            raise TmuxError(str(exc)) from exc
        result = subprocess.run(["tmux", "has-session", "-t", self.session], capture_output=True)
        if result.returncode != 0:
            self._run("new-session", "-d", "-s", self.session, "-n", "__tamq_boot", "-c", os.getcwd(), "sleep", "infinity")
        pid_text = self._run("display-message", "-p", "-t", self.session, "#{pid}")
        try:
            pid = int(pid_text)
        except ValueError as exc:
            raise TmuxError(f"unable to determine tmux PID: {pid_text!r}") from exc
        endpoint = Endpoint(self.session, pid, list(dict.fromkeys(repos)), f"tmux-amq-{pid}-{uuid4().hex[:12]}")
        paths = repository_paths()
        windows = self._run("list-windows", "-t", self.session, "-F", "#{window_name}").splitlines()
        for index, repo in enumerate(endpoint.repos):
            if repo not in windows:
                if index == 0 and "__tamq_boot" in windows:
                    self._run("rename-window", "-t", f"{self.session}:__tamq_boot", repo)
                    windows[windows.index("__tamq_boot")] = repo
                else:
                    try:
                        repo_path = paths[repo]
                    except KeyError as exc:
                        raise TmuxError(f"gita path missing for registered repository: {repo}") from exc
                    self._run("new-window", "-d", "-t", self.session, "-n", repo, "-c", repo_path, "sleep", "infinity")
                tap = ["tamq", "tap", "--repo", repo, "--endpoint", endpoint.endpoint_id, "--", command]
                self._run("send-keys", "-t", f"{self.session}:{repo}", shell_join(tap), "C-m")
        return endpoint


def shell_join(parts: list[str]) -> str:
    return " ".join(shlex.quote(part) for part in parts)