"""Catalogue picker: switch between SomaFM, tilderadio and whatever comes next."""

from __future__ import annotations

from rich.console import Group
from rich.text import Text
from textual.app import ComposeResult
from textual.containers import VerticalScroll
from textual.screen import ModalScreen
from textual.widgets import Static

from ..providers import PROVIDERS, available_providers
from .common import active_stops, gradient, truncate


class ProviderScreen(ModalScreen[str | None]):
    """A list of catalogues; enter selects, esc leaves everything as it was."""

    def __init__(self, current_id: str = "") -> None:
        super().__init__()
        self.slugs: tuple[str, ...] = available_providers()
        self.current_id = current_id
        self.index = self.slugs.index(current_id) if current_id in self.slugs else 0

    def compose(self) -> ComposeResult:
        # A scroll container keeps thirteen catalogues navigable on a short
        # terminal; the body is given its exact line count so it measures.
        with VerticalScroll(id="providers"):
            yield Static(self._body(), id="providers-body")

    def on_mount(self) -> None:
        body = self.query_one("#providers-body", Static)
        body.styles.height = len(self.slugs) + 5  # heading, blank, rows, footer

    def _body(self) -> Group:
        header = Text()
        header.append("◤ ", style=f"bold {gradient(active_stops(self.app), 0.9)}")
        header.append("CATALOGUES", style=f"bold {gradient(active_stops(self.app), 0.55)}")
        header.append("  ·  pick a station catalogue", style="dim")

        name_width = (
            max(
                (
                    len(PROVIDERS[slug].name)
                    for slug in self.slugs
                    if slug in PROVIDERS
                ),
                default=12,
            )
            + 2
        )

        rows: list[Text] = []
        for index, slug in enumerate(self.slugs):
            provider = PROVIDERS[slug]
            selected = index == self.index
            row = Text(no_wrap=True)
            row.append(
                "▶ " if selected else "  ", style="bold magenta" if selected else ""
            )
            row.append(f"{index + 1:>2}  ", style="dim")
            row.append(
                f"{truncate(provider.name, name_width - 2):<{name_width}}",
                style="bold underline" if selected else "bold",
            )
            row.append("  ")
            # marker(2) + number(5) + name + gap(2) + tagline + current dot(3)
            room = max(8, 58 - 2 - 5 - name_width - 2 - 3)
            row.append(truncate(provider.tagline, room), style="italic dim")
            if slug == self.current_id:
                row.append("  ●", style="bold green")
            rows.append(row)

        current = PROVIDERS.get(self.current_id)
        footer = Text()
        footer.append("\n")
        if current is not None:
            line = truncate(f"now: {current.name} — {current.station_source}", 58)
            footer.append(line + "\n", style="dim")
        footer.append(
            "↑ ↓ choose · enter switch · esc cancel",
            style="dim",
        )
        return Group(header, Text(""), *rows, footer)

    # -- interaction ----------------------------------------------------- #

    def _move(self, delta: int) -> None:
        self.index = (self.index + delta) % len(self.slugs)
        body = self.query_one("#providers-body", Static)
        body.update(self._body())

        box = self.query_one("#providers", VerticalScroll)

        def follow() -> None:
            visible = max(1, box.size.height)
            target = max(0, 2 + self.index - (visible - 3) // 2)
            box.scroll_to(y=target, animate=False)

        box.call_after_refresh(follow)

    def on_key(self, event) -> None:
        key = event.key
        if key in ("up", "k", "shift+tab"):
            self._move(-1)
        elif key in ("down", "j", "tab"):
            self._move(1)
        elif key in ("enter", "space"):
            self.dismiss(self.slugs[self.index])
        elif key == "escape" or key == "q":
            self.dismiss(None)
        elif key.isdigit() and key != "0":
            choice = int(key) - 1
            if 0 <= choice < len(self.slugs):
                self.dismiss(self.slugs[choice])
        else:
            return
        event.stop()