"""CLI for ``tmuxp load`` subcommand."""

import argparse
import importlib
import logging
import os
import pathlib
import shutil
import sys
import typing as t

from libtmux.common import has_gte_version
from libtmux.server import Server
from libtmux.session import Session

from tmuxp import exc, log, util
from tmuxp._internal import config_reader
from tmuxp.types import StrPath
from tmuxp.workspace import loader
from tmuxp.workspace.builder import WorkspaceBuilder
from tmuxp.workspace.finders import find_workspace_file, get_workspace_dir

from .utils import prompt_choices, prompt_yes_no, style, tmuxp_echo

if t.TYPE_CHECKING:
    from typing_extensions import NotRequired, TypeAlias, TypedDict

    CLIColorsLiteral: TypeAlias = t.Literal[56, 88]

    class OptionOverrides(TypedDict):
        """Optional argument overrides for tmuxp load."""

        detached: NotRequired[bool]
        new_session_name: NotRequired[t.Optional[str]]


class CLILoadNamespace(argparse.Namespace):
    """Typed :class:`argparse.Namespace` for tmuxp load command."""

    workspace_files: t.List[str]
    socket_name: t.Optional[str]
    socket_path: t.Optional[str]
    tmux_config_file: t.Optional[str]
    new_session_name: t.Optional[str]
    answer_yes: t.Optional[bool]
    append: t.Optional[bool]
    colors: t.Optional["CLIColorsLiteral"]
    log_file: t.Optional[str]


def set_layout_hook(session: Session, hook_name: str) -> None:
    """Set layout hooks to normalize layout.

    References
    ----------
        - tmuxp issue: https://github.com/tmux-python/tmuxp/issues/309
        - tmux issue: https://github.com/tmux/tmux/issues/1106

    tmux 2.6+ requires that the window be viewed with the client before
    select-layout adjustments can take effect.

    To handle this, this function creates temporary hook for this session to
    iterate through all windows and select the layout.

    In order for layout changes to take effect, a client must at the very
    least be attached to the window (not just the session).

    hook_name is provided to allow this to set to multiple scenarios, such
    as 'client-attached' (which the user attaches the session). You may
    also want 'after-switch-client' for cases where the user loads tmuxp
    sessions inside tmux since tmuxp offers to switch for them.

    Also, the hooks are set immediately unbind after they're invoked via -u.

    Parameters
    ----------
    session : :class:`libtmux.session.Session`
        session to bind hook to
    hook_name : str
        hook name to bind to, e.g. 'client-attached'
    """
    assert session.id is not None
    cmd: t.List[str] = ["set-hook", hook_name]
    hook_cmd = []
    active_window = session.active_window
    for window in session.windows:
        # unfortunately, select-layout won't work unless
        # we've literally selected the window at least once
        # with the client
        hook_cmd.append(f"selectw -t {window.id}")
        # edit: removed -t, or else it won't respect main-pane-w/h
        hook_cmd.append("selectl")
        hook_cmd.append("selectw -p")

    # unset the hook immediately after executing
    hook_cmd.extend(
        (f"set-hook -u -t {session.id} {hook_name}", f"selectw -t {active_window.id}")
    )

    # join the hook's commands with semicolons
    _hook_cmd = "{}".format("; ".join(hook_cmd))

    # append the hook command
    cmd.append(_hook_cmd)

    # create the hook
    session.cmd(*cmd, target=session.id)


def load_plugins(session_config: t.Dict[str, t.Any]) -> t.List[t.Any]:
    """Load and return plugins in workspace."""
    plugins = []
    if "plugins" in session_config:
        for plugin in session_config["plugins"]:
            try:
                module_name = plugin.split(".")
                module_name = ".".join(module_name[:-1])
                plugin_name = plugin.split(".")[-1]
            except Exception as error:
                tmuxp_echo(
                    style("[Plugin Error] ", fg="red")
                    + f"Couldn't load {plugin}\n"
                    + style(f"{error}", fg="yellow"),
                )
                sys.exit(1)

            try:
                plugin = getattr(importlib.import_module(module_name), plugin_name)
                plugins.append(plugin())
            except exc.TmuxpPluginException as error:
                if not prompt_yes_no(
                    "{}Skip loading {}?".format(
                        style(
                            str(error),
                            fg="yellow",
                        ),
                        plugin_name,
                    ),
                    default=True,
                ):
                    tmuxp_echo(
                        style("[Not Skipping] ", fg="yellow")
                        + "Plugin versions constraint not met. Exiting...",
                    )
                    sys.exit(1)
            except Exception as error:
                tmuxp_echo(
                    style("[Plugin Error] ", fg="red")
                    + f"Couldn't load {plugin}\n"
                    + style(f"{error}", fg="yellow"),
                )
                sys.exit(1)

    return plugins


def _reattach(builder: WorkspaceBuilder) -> None:
    """
    Reattach session (depending on env being inside tmux already or not).

    Parameters
    ----------
    builder: :class:`workspace.builder.WorkspaceBuilder`

    Notes
    -----
    If ``TMUX`` environmental variable exists in the environment this script is
    running, that means we're in a tmux client. So ``tmux switch-client`` will
    load the session.

    If not, ``tmux attach-session`` loads the client to the target session.
    """
    assert builder.session is not None
    for plugin in builder.plugins:
        plugin.reattach(builder.session)
        proc = builder.session.cmd("display-message", "-p", "'#S'")
        for line in proc.stdout:
            print(line)

    if "TMUX" in os.environ:
        builder.session.switch_client()

    else:
        builder.session.attach_session()


def _load_attached(builder: WorkspaceBuilder, detached: bool) -> None:
    """
    Load workspace in new session.

    Parameters
    ----------
    builder: :class:`workspace.builder.WorkspaceBuilder`
    detached : bool
    """
    builder.build()
    assert builder.session is not None

    if "TMUX" in os.environ:  # tmuxp ran from inside tmux
        # unset TMUX, save it, e.g. '/tmp/tmux-1000/default,30668,0'
        tmux_env = os.environ.pop("TMUX")

        if has_gte_version("2.6"):
            set_layout_hook(builder.session, "client-session-changed")

        builder.session.switch_client()  # switch client to new session

        os.environ["TMUX"] = tmux_env  # set TMUX back again
    else:
        if has_gte_version("2.6"):
            # if attaching for first time
            set_layout_hook(builder.session, "client-attached")

            # for cases where user switches client for first time
            set_layout_hook(builder.session, "client-session-changed")

        if not detached:
            builder.session.attach_session()


def _load_detached(builder: WorkspaceBuilder) -> None:
    """
    Load workspace in new session but don't attach.

    Parameters
    ----------
    builder: :class:`workspace.builder.WorkspaceBuilder`
    """
    builder.build()

    assert builder.session is not None

    if has_gte_version("2.6"):  # prepare for both cases
        set_layout_hook(builder.session, "client-attached")
        set_layout_hook(builder.session, "client-session-changed")

    print("Session created in detached state.")


def _load_append_windows_to_current_session(builder: WorkspaceBuilder) -> None:
    """
    Load workspace as new windows in current session.

    Parameters
    ----------
    builder: :class:`workspace.builder.WorkspaceBuilder`
    """
    current_attached_session = builder.find_current_attached_session()
    builder.build(current_attached_session, append=True)
    assert builder.session is not None
    if has_gte_version("2.6"):  # prepare for both cases
        set_layout_hook(builder.session, "client-attached")
        set_layout_hook(builder.session, "client-session-changed")


def _setup_plugins(builder: WorkspaceBuilder) -> Session:
    """Execute hooks for plugins running after ``before_script``.

    Parameters
    ----------
    builder: :class:`workspace.builder.WorkspaceBuilder`
    """
    assert builder.session is not None
    for plugin in builder.plugins:
        plugin.before_script(builder.session)

    return builder.session


def load_workspace(
    workspace_file: StrPath,
    socket_name: t.Optional[str] = None,
    socket_path: None = None,
    tmux_config_file: t.Optional[str] = None,
    new_session_name: t.Optional[str] = None,
    colors: t.Optional[int] = None,
    detached: bool = False,
    answer_yes: bool = False,
    append: bool = False,
) -> t.Optional[Session]:
    """Entrypoint for ``tmuxp load``, load a tmuxp "workspace" session via config file.

    Parameters
    ----------
    workspace_file : list of str
        paths or session names to workspace files
    socket_name : str, optional
        ``tmux -L <socket-name>``
    socket_path: str, optional
        ``tmux -S <socket-path>``
    new_session_name: str, options
        ``tmux new -s <new_session_name>``
    colors : str, optional
        '-2'
            Force tmux to support 256 colors
    detached : bool
        Force detached state. default False.
    answer_yes : bool
        Assume yes when given prompt to attach in new session.
        Default False.
    append : bool
       Assume current when given prompt to append windows in same session.
       Default False.

    Notes
    -----
    tmuxp will check and load a workspace file. The file will use ConfigReader
    to load a JSON/YAML into a :py:obj:`dict`. Then :func:`loader.expand` and
    :func:`loader.trickle` will be used to expand any shorthands, template
    variables, or file paths relative to where the config/script is executed
    from.

    :func:`loader.expand` accepts the directory of the config file, so the
    user's workspace can resolve absolute paths relative to where the
    workspace file is. In otherwords, if a workspace file at */var/moo/hi.yaml*
    has *./* in its workspaces, we want to be sure any file path with *./* is
    relative to */var/moo*, not the user's PWD.

    A :class:`libtmux.Server` object is created. No tmux server is started yet,
    just the object.

    The prepared workspace and its server object is passed into an instance
    of :class:`~tmuxp.workspace.builder.WorkspaceBuilder`.

    A sanity check against :meth:`libtmux.common.which` is ran. It will raise
    an exception if tmux isn't found.

    If a tmux session under the same name as ``session_name`` in the tmuxp
    workspace exists, tmuxp offers to attach the session. Currently, tmuxp
    does not allow appending a workspace / incremental building on top of a
    current session (pull requests are welcome!).

    :meth:`~tmuxp.workspace.builder.build` will build the session in
    the background via using tmux's detached state (``-d``).

    After the session (workspace) is built, unless the user decided to load
    the session in the background via ``tmuxp -d`` (which is in the spirit
    of tmux's ``-d``), we need to prompt the user to attach the session.

    If the user is already inside a tmux client, which we detect via the
    ``TMUX`` environment variable bring present, we will prompt the user to
    switch their current client to it.

    If they're outside of tmux client - in a plain-old PTY - we will
    automatically ``attach``.

    If an exception is raised during the building of the workspace, tmuxp will
    prompt to cleanup (``$ tmux kill-session``) the session on the user's
    behalf. An exception raised during this process means it's not easy to
    predict how broken the session is.

    .. versionchanged:: tmux 2.6+

        In tmux 2.6, the way layout and proportion's work when interfacing
        with tmux in a detached state (outside of a client) changed. Since
        tmuxp builds workspaces in a detached state, the WorkspaceBuilder isn't
        able to rely on functionality requiring awarness of session geometry,
        e.g. ``set-layout``.

        Thankfully, tmux is able to defer commands to run after the user
        performs certain actions, such as loading a client via
        ``attach-session`` or ``switch-client``.

        Upon client switch, ``client-session-changed`` is triggered [1]_.

    References
    ----------
    .. [1] cmd-switch-client.c hook. GitHub repo for tmux.

       https://github.com/tmux/tmux/blob/2.6/cmd-switch-client.c#L132.
       Accessed April 8th, 2018.
    """
    # get the canonical path, eliminating any symlinks
    if isinstance(workspace_file, (str, os.PathLike)):
        workspace_file = pathlib.Path(workspace_file)

    tmuxp_echo(
        style("[Loading] ", fg="green")
        + style(str(workspace_file), fg="blue", bold=True),
    )

    # ConfigReader allows us to open a yaml or json file as a dict
    raw_workspace = config_reader.ConfigReader._from_file(workspace_file) or {}

    # shapes workspaces relative to config / profile file location
    expanded_workspace = loader.expand(
        raw_workspace,
        cwd=os.path.dirname(workspace_file),
    )

    # Overridden session name
    if new_session_name:
        expanded_workspace["session_name"] = new_session_name

    # propagate workspace inheritance (e.g. session -> window, window -> pane)
    expanded_workspace = loader.trickle(expanded_workspace)

    t = Server(  # create tmux server object
        socket_name=socket_name,
        socket_path=socket_path,
        config_file=tmux_config_file,
        colors=colors,
    )

    shutil.which("tmux")  # raise exception if tmux not found

    try:  # load WorkspaceBuilder object for tmuxp workspace / tmux server
        builder = WorkspaceBuilder(
            session_config=expanded_workspace,
            plugins=load_plugins(expanded_workspace),
            server=t,
        )
    except exc.EmptyWorkspaceException:
        tmuxp_echo("%s is empty or parsed no workspace data" % workspace_file)
        return None

    session_name = expanded_workspace["session_name"]

    # if the session already exists, prompt the user to attach
    if builder.session_exists(session_name) and not append:
        if not detached and (
            answer_yes
            or prompt_yes_no(
                "%s is already running. Attach?" % style(session_name, fg="green"),
                default=True,
            )
        ):
            _reattach(builder)
        return None

    try:
        if detached:
            _load_detached(builder)
            return _setup_plugins(builder)

        if append:
            if "TMUX" in os.environ:  # tmuxp ran from inside tmux
                _load_append_windows_to_current_session(builder)
            else:
                _load_attached(builder, detached)

            return _setup_plugins(builder)

        # append and answer_yes have no meaning if specified together
        if answer_yes:
            _load_attached(builder, detached)
            return _setup_plugins(builder)

        if "TMUX" in os.environ:  # tmuxp ran from inside tmux
            msg = (
                "Already inside TMUX, switch to session? yes/no\n"
                "Or (a)ppend windows in the current active session?\n[y/n/a]"
            )
            options = ["y", "n", "a"]
            choice = prompt_choices(msg, choices=options)

            if choice == "y":
                _load_attached(builder, detached)
            elif choice == "a":
                _load_append_windows_to_current_session(builder)
            else:
                _load_detached(builder)
        else:
            _load_attached(builder, detached)

    except exc.TmuxpException as e:
        import traceback

        tmuxp_echo(traceback.format_exc())
        tmuxp_echo(str(e))

        choice = prompt_choices(
            "Error loading workspace. (k)ill, (a)ttach, (d)etach?",
            choices=["k", "a", "d"],
            default="k",
        )

        if choice == "k":
            if builder.session is not None:
                builder.session.kill()
                tmuxp_echo("Session killed.")
        elif choice == "a":
            _reattach(builder)
        else:
            sys.exit()

    return _setup_plugins(builder)


def create_load_subparser(parser: argparse.ArgumentParser) -> argparse.ArgumentParser:
    """Augment :class:`argparse.ArgumentParser` with ``load`` subcommand."""
    workspace_files = parser.add_argument(
        "workspace_files",
        nargs="+",
        metavar="workspace-file",
        help="filepath to session or filename of session in tmuxp workspace directory",
    )
    parser.add_argument(
        "-L",
        dest="socket_name",
        metavar="socket_name",
        action="store",
        help="passthru to tmux(1) -L",
    )
    parser.add_argument(
        "-S",
        dest="socket_path",
        metavar="socket_path",
        action="store",
        help="passthru to tmux(1) -S",
    )

    tmux_config_file = parser.add_argument(
        "-f",
        dest="tmux_config_file",
        metavar="tmux_config_file",
        help="passthru to tmux(1) -f",
    )

    parser.add_argument(
        "-s",
        dest="new_session_name",
        metavar="new_session_name",
        help="start new session with new session name",
    )
    parser.add_argument(
        "--yes",
        "-y",
        dest="answer_yes",
        action="store_true",
        help="always answer yes",
    )
    parser.add_argument(
        "-d",
        dest="detached",
        action="store_true",
        help="load the session without attaching it",
    )
    parser.add_argument(
        "-a",
        "--append",
        dest="append",
        action="store_true",
        help="load workspace, appending windows to the current session",
    )
    colorsgroup = parser.add_mutually_exclusive_group()

    colorsgroup.add_argument(
        "-2",
        dest="colors",
        action="store_const",
        const=256,
        help="force tmux to assume the terminal supports 256 colours.",
    )

    colorsgroup.add_argument(
        "-8",
        dest="colors",
        action="store_const",
        const=88,
        help="like -2, but indicates that the terminal supports 88 colours.",
    )
    parser.set_defaults(colors=None)

    log_file = parser.add_argument(
        "--log-file",
        metavar="file_path",
        action="store",
        help="file to log errors/output to",
    )

    try:
        import shtab

        workspace_files.complete = shtab.FILE  # type: ignore
        tmux_config_file.complete = shtab.FILE  # type: ignore
        log_file.complete = shtab.FILE  # type: ignore
    except ImportError:
        pass

    return parser


def command_load(
    args: CLILoadNamespace,
    parser: t.Optional[argparse.ArgumentParser] = None,
) -> None:
    """Load a tmux workspace from each WORKSPACE_FILE.

    WORKSPACE_FILE is a specifier for a workspace file.

    If WORKSPACE_FILE is a path to a directory, tmuxp will search it for
    ".tmuxp.{yaml,yml,json}".

    If WORKSPACE_FILE is has no directory component and only a filename, e.g.
    "myworkspace.yaml", tmuxp will search the users's workspace directory for that
    file.

    If WORKSPACE_FILE has no directory component, and only a name with no extension,
    e.g. "myworkspace", tmuxp will search the users's workspace directory for any
    file with the extension ".yaml", ".yml", or ".json" that matches that name.

    If multiple workspace files that match a given WORKSPACE_FILE are found, tmuxp
    will warn and pick the first one found.

    If multiple WORKSPACE_FILEs are provided, workspaces will be created for all of
    them. The last one provided will be attached. The others will be created in
    detached mode.
    """
    util.oh_my_zsh_auto_title()

    if args.log_file:
        logfile_handler = logging.FileHandler(args.log_file)
        logfile_handler.setFormatter(log.LogFormatter())
        from . import logger

        logger.addHandler(logfile_handler)

    tmux_options = {
        "socket_name": args.socket_name,
        "socket_path": args.socket_path,
        "tmux_config_file": args.tmux_config_file,
        "new_session_name": args.new_session_name,
        "answer_yes": args.answer_yes,
        "colors": args.colors,
        "detached": args.detached,
        "append": args.append,
    }

    if args.workspace_files is None or len(args.workspace_files) == 0:
        tmuxp_echo("Enter at least one config")
        if parser is not None:
            parser.print_help()
        sys.exit()
        return

    last_idx = len(args.workspace_files) - 1
    original_detached_option = tmux_options.pop("detached")
    original_new_session_name = tmux_options.pop("new_session_name")

    for idx, workspace_file in enumerate(args.workspace_files):
        workspace_file = find_workspace_file(
            workspace_file,
            workspace_dir=get_workspace_dir(),
        )

        detached = original_detached_option
        new_session_name = original_new_session_name

        if last_idx > 0 and idx < last_idx:
            detached = True
            new_session_name = None

        load_workspace(
            workspace_file,
            detached=detached,
            new_session_name=new_session_name,
            **tmux_options,
        )
