"""Full-screen keyboard help."""

from __future__ import annotations

import sys
import textwrap
from typing import TYPE_CHECKING, cast

from rich.console import Group
from rich.table import Table
from rich.text import Text
from textual.app import ComposeResult
from textual.screen import ModalScreen
from textual.widgets import Static

from .common import SPECTRUM_STOPS, gradient

if TYPE_CHECKING:
    from ..app import BeefyPlayerApp

HELP_ROWS: tuple[tuple[str, str], ...] = (
    ("↑ / ↓  j / k", "move through the station list"),
    ("enter", "tune in to the selected station"),
    ("space", "play / pause the current station"),
    ("s", "stop playback"),
    ("] / [", "next / previous station (tunes immediately)"),
    ("+ / -", "volume up / down"),
    ("m", "mute / unmute"),
    ("f", "favourite — favourites float to the top"),
    ("/", "filter stations by title, genre or description"),
    ("esc", "clear the filter / close overlays"),
    (
        "v",
        "cycle visualiser: mirror → bars → wave → waterfall → radial → braille",
    ),
    ("r", "refresh station list and song history"),
    ("g / G", "jump to the top / bottom of the list"),
    ("? ", "this help"),
    ("q", "quit"),
)

ABOUT_LINUX = (
    (
        "The spectrum captures your actual PulseAudio/PipeWire output with "
        "parec (SYNC); otherwise it falls back to a muted ffmpeg stream tap "
        "(FFT, can drift) or a synthesized display (SIM)."
    ),
    (
        "The desktop picks us up over MPRIS as a "
        "beefyplayer media player — try `playerctl -l` / `playerctl metadata`."
    ),
)

ABOUT_MACOS = (
    (
        "The spectrum captures your Mac's real audio output (SYNC) with a "
        "native Core Audio process tap — nothing to install. macOS asks for "
        "System Audio Recording permission the first time; without it the "
        "analyser falls back to a muted ffmpeg stream tap (FFT, can drift) "
        "or a synthesized display (SIM)."
    ),
    (
        "mpv publishes what is playing to the macOS Now Playing session, so "
        "Control Center and the keyboard media keys control this app."
    ),
)


class HelpScreen(ModalScreen[None]):
    def compose(self) -> ComposeResult:
        provider = cast("BeefyPlayerApp", self.app).provider
        about = (
            f"Stations and song history come from {provider.name} "
            f"({provider.station_source} + {provider.history_source}).",
        ) + (ABOUT_MACOS if sys.platform == "darwin" else ABOUT_LINUX)

        table = Table.grid(padding=(0, 2), expand=False)
        table.add_column(style="bold cyan", no_wrap=True, justify="right")
        table.add_column(style="")
        for key, description in HELP_ROWS:
            table.add_row(key, description)

        header = Text()
        header.append("◤ ", style=f"bold {gradient(SPECTRUM_STOPS, 0.9)}")
        header.append("BEEFY PLAYER", style=f"bold {gradient(SPECTRUM_STOPS, 0.55)}")
        header.append("  keyboard & credits", style="dim")

        footer = Text()
        for paragraph in about:
            for line in textwrap.wrap(paragraph, width=70):
                footer.append(line + "\n", style="dim")

        body = Group(header, Text(""), table, Text(""), footer)
        yield Static(body, id="help")

    def on_key(self, event) -> None:
        event.stop()
        self.dismiss(None)