"""Typer entry point.

Global options are parsed once in the callback, which builds the shared
:class:`~meshterm.context.AppContext`. Running with no subcommand launches the
interactive menu; otherwise the selected tool's subcommand runs. Both paths funnel
through :func:`run_tool_command` / :func:`run_menu`, so behavior stays identical.
"""

from __future__ import annotations

import asyncio
import logging
import sys
from pathlib import Path

import typer
from rich.console import Console

from .context import AppContext
from .core.admin_store import AdminStore
from .core.config import Settings
from .core.connection import DeviceCommandError, is_connection_lost
from .core.device_config import DeviceConfigError
from .core.device_store import DeviceStore
from .core.instancelock import InstanceBusy, hold_instance_lock
from .core.preferences import PreferenceError, Preferences
from .core.selection import DeviceSelectionError
from .persistence.logging import configure_logging, get_logger, level_from_name, log_path
from .persistence.repository import Repository
from .platforms import Resolution, resolve, set_platform
from .tools import all_tools
from .tools.base import Tool, ToolResult
from .ui.theme import make_console


def _unframe_help_panels() -> None:
    """Render Typer's help/error sections as coloured headings instead of boxed panels.

    Typer's rich help gives us the colour we want — yellow usage, cyan options, green
    switches — but wraps each Options/Commands/Error section in a rounded :class:`Panel`,
    the boxed framing scripted output is meant to be free of. There's no constant to drop
    that box, so we swap the ``Panel`` the help formatter calls for a thin stand-in that
    keeps the colour and the section title (as a bold heading, indigo like the app accent,
    red for errors) but no border — the same heading-over-content shape tool results use
    (see :func:`~meshterm.ui.surface._deframe`). The inner tables are already box-less.
    """
    import typer.rich_utils as rich_utils
    from rich.console import Group
    from rich.text import Text

    def _bare_panel(
        renderable: object,
        *,
        title: object = None,
        border_style: str = "",
        **_: object,
    ) -> Group:
        style = "bold red" if border_style == "red" else "bold #818cf8"
        heading = Text(str(title), style=style) if title else Text("")
        return Group(Text(""), heading, renderable)  # type: ignore[list-item]

    rich_utils.Panel = _bare_panel  # type: ignore[assignment,misc]


_unframe_help_panels()

app = typer.Typer(
    add_completion=False,
    no_args_is_help=False,
    # Rich help for its colour (usage, option flags, metavars), but with the boxed
    # section panels flattened to plain headings by _unframe_help_panels() above — a
    # splash of colour, none of the framing.
    rich_markup_mode="rich",
    # The one description, same as the package summary and the PyPI page. See
    # `meshterm.__doc__` — if this drifts from that, one of them is lying.
    help=(
        "MeshTerm is a full-featured TUI-based MeshCore client for your terminal. "
        "Supports USB, Bluetooth and TCP companion connection. "
        "For Windows, macOS and Linux."
    ),
)

# The context built by the callback and consumed by subcommands within one process.
_state: AppContext | None = None

# The platform resolution the callback made, for the ``platform`` diagnostic subcommand
# to report back (see :func:`platform_command`) without re-deriving it independently.
_platform_resolution: Resolution | None = None


@app.callback(invoke_without_command=True)
def main_callback(
    ctx: typer.Context,
    profile: str | None = typer.Option(None, "--profile", "-p", help="Device profile"),
    port: str | None = typer.Option(None, "--port", help="Serial port override"),
    ble: str | None = typer.Option(
        None, "--ble", help="Bluetooth address of a companion device (selects the BLE transport)"
    ),
    ble_pin: str | None = typer.Option(
        None, "--ble-pin", help="BLE pairing PIN, if the Bluetooth companion requires one"
    ),
    tcp: str | None = typer.Option(
        None,
        "--tcp",
        help="Network address host[:port] of a TCP companion (selects the TCP transport)",
    ),
    mock: bool = typer.Option(False, "--mock", help="Use the built-in simulator"),
    db_path: Path | None = typer.Option(None, "--db", help="SQLite database path"),
    json_output: bool = typer.Option(False, "--json", help="Machine-readable output"),
    quiet: bool = typer.Option(False, "--quiet", "-q", help="Suppress console logging"),
    platform: str | None = typer.Option(
        None,
        "--platform",
        help="Force the UI platform (regular|picocalc) instead of auto-detecting it",
    ),
) -> None:
    """Build the application context and dispatch to the menu or a subcommand.

    Args:
        ctx: The Click/Typer context.
        profile: Named device profile to use.
        port: Explicit serial port, overriding the profile.
        ble: Explicit Bluetooth address, selecting the BLE transport.
        ble_pin: Optional BLE pairing PIN for the Bluetooth companion.
        tcp: Explicit network address ``host[:port]``, selecting the TCP transport.
        mock: Whether to use the simulator instead of real hardware.
        db_path: Override the database location.
        json_output: Request machine-readable output from tools.
        quiet: Suppress console logging (file logging continues).
        platform: Explicit ``--platform`` override; see :func:`meshterm.platforms.resolve`.
    """
    global _state, _platform_resolution

    # Resolved and installed first, before anything below it (make_console, the theme,
    # the eventual TuiSession) reads the active platform.
    try:
        _platform_resolution = resolve(platform)
    except ValueError as exc:
        raise typer.BadParameter(str(exc), param_hint="--platform") from exc
    set_platform(_platform_resolution.platform)

    settings = Settings.load()
    if db_path is not None:
        settings.db_path = db_path

    console = make_console()
    # Loaded before logging is configured, because how much goes in the file is one of
    # them — and handed to the context afterwards so the file is not read twice.
    prefs = Preferences.load(settings.config_dir / "preferences.yaml")
    configure_logging(
        console,
        settings.config_dir,
        level=logging.INFO,
        file_level=level_from_name(prefs.log_level),
        quiet=quiet or json_output,
    )

    app_ctx = AppContext(
        preferences=prefs,
        console=console,
        settings=settings,
        repo=Repository(settings.db_path),
        device_store=DeviceStore(settings.config_dir / "devices.json"),
        admin_store=AdminStore(settings.config_dir / "admin.json"),
        profile=settings.resolve_profile(profile),
        mock=mock,
        port_override=port,
        ble_override=ble,
        tcp_override=tcp,
        ble_pin=ble_pin,
        json_output=json_output,
        explicit_selection=(
            profile is not None or port is not None or ble is not None or tcp is not None
        ),
    )
    _state = app_ctx
    ctx.call_on_close(app_ctx.repo.close)

    if ctx.invoked_subcommand is None:
        from .ui.menu import run_menu

        # The interactive session is the one that holds the stores in memory and rewrites
        # them whole, so it is the one that claims the directory. One-shot subcommands are
        # brief and mostly read; blocking `meshterm contacts` because a menu is open in
        # another window would be an obstacle rather than a guard.
        try:
            with hold_instance_lock(settings.config_dir):
                asyncio.run(_drive(run_menu(app_ctx), app_ctx))
        except InstanceBusy as exc:
            console.print(f"[err]✗[/err] {exc}")
            raise typer.Exit(code=1) from None
        except Exception as exc:
            if type(exc).__name__ == "NoConsoleScreenBufferError":
                # prompt_toolkit needs a real Win32 console and reports its absence in the
                # language of its own internals. A traceback reads as "this app is broken"
                # when the answer is "open a different terminal", so answer that instead.
                get_logger().warning("no Windows console available: %s", exc)
                _report_no_windows_console(console)
                raise typer.Exit(code=1) from None
            # Logged before it is re-raised, and this is the case the log matters most for:
            # a session launched by double-clicking the executable owns its console window,
            # so when it dies the window closes with it and takes the traceback along. The
            # file is the only thing left to read afterwards.
            get_logger().exception("the interactive session raised an unhandled error")
            _report_log_location(console, settings.config_dir)
            raise


def _report_log_location(console: Console, config_dir: Path) -> None:
    """Point at the log after a fault, since it is the copy that outlives the terminal."""
    console.print()
    console.print(f"[muted]The details are in {log_path(config_dir)}[/muted]")
    console.print("[muted]Attach it to a bug report. For more detail next time, raise[/muted]")
    console.print("[muted]'Log detail' on the Preferences page.[/muted]")


def _report_no_windows_console(console: Console) -> None:
    """Explain a console MeshTerm cannot draw in, and how to get one it can.

    Reached when prompt_toolkit finds no Win32 console screen buffer: a Git Bash, MSYS or
    Cygwin shell — which announce themselves as ``xterm`` and are not Windows consoles at
    all — or a process whose output has been redirected away from one.
    """
    console.print("[err]✗[/err] MeshTerm needs a Windows console, and could not find one.")
    console.print()
    console.print("That usually means one of two things:")
    console.print()
    console.print("  • You are in Git Bash, MSYS or Cygwin. Those are not Windows consoles.")
    console.print("    Open [accent]Windows Terminal[/accent] or [accent]PowerShell[/accent]")
    console.print("    and run it from there.")
    console.print("  • The output is piped or redirected somewhere. The full-screen menu")
    console.print("    needs the terminal itself.")
    console.print()
    console.print("Every screen also has a subcommand, and those pipe fine —")
    console.print("try [accent]meshterm --help[/accent].")


@app.command(name="platform")
def platform_command() -> None:
    """Print the resolved platform and every input the resolution looked at.

    A diagnostic for the platform seam (see ``meshterm/platforms.py``): confirms which
    flavour a given invocation would run as, and why — the ``--platform``/
    ``MESHTERM_PLATFORM`` inputs, what ``/proc/device-tree/model`` reports (``None`` off
    the actual hardware), and which of those decided it.
    """
    assert _platform_resolution is not None  # set by the callback that always runs first
    r = _platform_resolution
    console = make_console()
    console.print(f"platform: [accent]{r.platform.name}[/accent]  (source: {r.source})")
    console.print(f"  --platform:              {r.flag or '(not passed)'}")
    console.print(f"  MESHTERM_PLATFORM:       {r.env or '(not set)'}")
    console.print(f"  /proc/device-tree/model: {r.detected_model or '(unavailable)'}")


@app.command(name="specimen")
def specimen_command() -> None:
    """Print the visual-language specimen for the active platform.

    Every mark, icon funnel, colour scale and fold on one card, drawn through the same
    theme and glyph machinery the TUI uses — so on the PicoCalc console it is the
    font/palette acceptance screen, and with ``--platform picocalc`` on a desktop it
    previews that flavour. See :mod:`meshterm.ui.specimen`.
    """
    from .ui.specimen import specimen_lines

    console = make_console()
    for line in specimen_lines():
        console.print(line)


def run_tool_command(tool: Tool, params: dict) -> None:
    """Execute a tool from a CLI subcommand and render its result.

    Builds and tears down the device connection within a single event loop so the
    ``meshcore`` client is never used across loops.

    Args:
        tool: The tool to run.
        params: Parameters parsed from the subcommand's options.
    """
    assert _state is not None  # set by the callback before any subcommand runs
    try:
        asyncio.run(_drive(_execute_and_render(tool, params, _state), _state))
    except (DeviceSelectionError, DeviceConfigError, DeviceCommandError, PreferenceError) as exc:
        # Expected user-facing error (ambiguous/absent device, a bad config or preference
        # value, or a transient command failure): show the message, not a traceback. Logged
        # at warning because it is a thing that went wrong, even though it is an ordinary
        # one — a log that only holds crashes cannot answer "what happened before it".
        get_logger().warning("%s failed: %s", tool.name, exc)
        _state.console.print(f"[err]✗[/err] {exc}")
        raise typer.Exit(1) from exc
    except Exception as exc:
        # A dropped serial link (device unplugged/powered off mid-command) can't be recovered
        # from in a one-shot scripted run the way the interactive menu offers — but it should
        # still read as a clean message, not a traceback.
        if is_connection_lost(exc):
            get_logger().warning("%s lost the device connection: %s", tool.name, exc)
            _state.console.print(
                "[err]✗[/err] the connection to your device was lost "
                "(it may have been unplugged or powered off)."
            )
            raise typer.Exit(1) from exc
        # Anything else is a real fault. It still reaches the terminal as a traceback,
        # because a person looking at one wants to see it — but it also lands in the log,
        # which is the copy that survives the terminal being closed and is the one thing
        # worth attaching to a bug report.
        get_logger().exception("%s raised an unhandled error", tool.name)
        _report_log_location(_state.console, _state.settings.config_dir)
        raise


async def _drive(coro, ctx: AppContext) -> None:
    """Await a coroutine then disconnect the device (but keep the repo open).

    Args:
        coro: The coroutine to run (a tool execution or the menu loop).
        ctx: The application context whose device should be closed afterward.
    """
    try:
        await coro
    finally:
        if ctx._device is not None:
            try:
                await ctx._device.disconnect()
            except Exception:  # noqa: BLE001 - a dead/lost link must not crash teardown
                pass
            ctx._device = None


async def _execute_and_render(tool: Tool, params: dict, ctx: AppContext) -> ToolResult:
    """Run a tool and print its closing message and artifact list.

    Args:
        tool: The tool to execute.
        params: Parameters for the tool.
        ctx: The application context.

    Returns:
        The tool's :class:`ToolResult`.
    """
    result = await tool.execute(ctx, params)
    if result.message:
        ctx.console.print(result.message)
    for artifact in result.artifacts:
        ctx.console.print(f"[ok]●[/ok] wrote [accent]{artifact}[/accent]")
    return result


def _register_all() -> None:
    """Register every tool's CLI subcommand with the Typer app."""
    for tool in all_tools():
        tool.register_cli(app)


_register_all()


def _owns_its_console() -> bool:
    """Whether this process is the only one on its console — i.e. it was double-clicked.

    Windows gives a console to a process launched from Explorer and destroys it the moment
    that process ends, so an error message is displayed and erased in the same instant.
    Launched from a shell instead, the console belongs to the shell and survives.

    ``GetConsoleProcessList`` tells the two apart: it reports how many processes are
    attached to this console. One is us, alone, holding a window that dies with us.

    Returns:
        ``True`` only on Windows, and only when nothing else shares the console.
    """
    if sys.platform != "win32":
        return False
    try:
        import ctypes

        buffer = (ctypes.c_uint * 4)()
        count = ctypes.windll.kernel32.GetConsoleProcessList(buffer, 4)  # type: ignore[attr-defined]
    except Exception:  # pragma: no cover - no console at all, or a stubbed kernel32
        return False
    return count == 1


def main() -> None:
    """Console-script entry point.

    Holds the window open after a failure when MeshTerm owns it, because otherwise the
    error is drawn and destroyed together and the person who needs to read it sees a
    flash. Only on that path: a successful run should not make anyone press a key, and a
    run from a shell leaves its output on the screen anyway.
    """
    try:
        app()
    except SystemExit as exit_request:
        if exit_request.code and _owns_its_console():
            _wait_before_the_window_closes()
        raise
    except BaseException:
        if _owns_its_console():
            _wait_before_the_window_closes()
        raise


def _wait_before_the_window_closes() -> None:
    """Ask for a keypress so a message stays readable, and never fail doing it."""
    try:
        print()
        print("-- Press Enter to close this window --")
        input()
    except Exception:  # pragma: no cover - stdin closed, redirected, or gone
        pass


if __name__ == "__main__":
    main()