# Convenience imports from pexpect
from __future__ import annotations

import os
import shlex
import signal
from typing import Any, Optional

from pexpect import EOF, TIMEOUT, is_executable_file  # type:ignore[attr-defined]
from pexpect import __file__ as PEXPECT_DIR

try:
    import pty

    from pexpect import spawn as pty_spawn
except ImportError:
    from pexpect.popen_spawn import PopenSpawn

    pty = None  # type: ignore[assignment]

__all__ = ["EOF", "PEXPECT_DIR", "TIMEOUT", "pty", "spawn", "spawnu", "which"]


def spawn(
    command: str,
    args: Any = None,
    timeout: int = 30,
    maxread: int = 2000,
    searchwindowsize: Any = None,
    logfile: Any = None,
    cwd: Any = None,
    env: Any = None,
    ignore_sighup: bool = True,
    echo: bool = True,
    encoding: str = "utf-8",
    **kwargs: Any,
) -> Any:
    """This is the main entry point for Pexpect. Use this function to start
    and control child applications.

    See https://github.com/pexpect/pexpect/blob/master/pexpect/pty_spawn.py
    for more information.
    """
    if args is None:
        args = []
    codec_errors = kwargs.get("codec_errors", kwargs.get("errors", "strict"))
    if pty is None:
        command = shlex.split(command, posix=os.name == "posix")  # type:ignore[unreachable]
        command += args
        child = PopenSpawn(
            command,
            timeout=timeout,
            maxread=maxread,
            searchwindowsize=searchwindowsize,
            logfile=logfile,
            cwd=cwd,
            env=env,
            encoding=encoding,
            codec_errors=codec_errors,
        )
        child.echo = echo
    else:
        try:
            # Signal handlers are inherited by forked processes, and we can't easily
            # reset it from the subprocess. Since kernelapp ignores SIGINT except in
            # message handlers, we need to temporarily reset the SIGINT handler here
            # so that the child and its children are interruptible.
            try:
                sig = signal.signal(signal.SIGINT, signal.SIG_DFL)
            except ValueError:
                # Only Main Thread can handle signals
                sig = None
            child = pty_spawn(
                command,
                args=args,
                timeout=timeout,
                maxread=maxread,
                searchwindowsize=searchwindowsize,
                logfile=logfile,
                cwd=cwd,
                env=env,
                encoding=encoding,
                codec_errors=codec_errors,
            )
        finally:
            if sig:
                signal.signal(signal.SIGINT, sig)
    return child


# For backwards compatibility
spawnu = spawn


def which(filename: str) -> str | None:
    """This takes a given filename; tries to find it in the environment path;
    then checks if it is executable. This returns the full path to the filename
    if found and executable. Otherwise this returns None."""

    # Special case where filename contains an explicit path.
    if os.path.dirname(filename) != "" and is_executable_file(filename):
        return filename
    if "PATH" not in os.environ or os.environ["PATH"] == "":
        p = os.defpath
    else:
        p = os.environ["PATH"]
    pathlist = p.split(os.pathsep)
    for path in pathlist:
        ff = os.path.join(path, filename)
        if pty is not None:
            if is_executable_file(ff):
                return ff
        else:
            pathext_str = os.environ.get("Pathext", ".exe;.com;.bat;.cmd")  # type:ignore[unreachable]
            pathext = pathext_str.split(os.pathsep) + [""]
            for ext in pathext:
                if os.access(ff + ext, os.X_OK):
                    return ff + ext
    return None
