"""ANSI rendering for the minimal display."""

from __future__ import annotations

import os
import re
import shutil
import sys

_ESCAPES = re.compile(r"\x1b\[[0-9;]*m")


def color_safe() -> bool:
    """ANSI is enabled only for a colouring-capable terminal."""
    try:
        tty_ok = sys.stdout.isatty()
    except AttributeError:
        return False
    return tty_ok and not os.environ.get("NO_COLOR")


def terminal_width(default: int = 72) -> int:
    cols = shutil.get_terminal_size().columns
    return max(48, cols) if cols > 30 else default


def visible_len(s: str) -> int:
    """Length of ``s`` without ANSI escapes — what the user actually sees."""
    return len(_ESCAPES.sub("", s))


def fmt_time(seconds: float | None) -> str:
    if seconds is None or seconds < 0:
        return "--:--:--"
    total = int(seconds + 0.5)
    h, rem = divmod(total, 3600)
    m, s = divmod(rem, 60)
    return f"{h:02d}:{m:02d}:{s:02d}"


class C:  # noqa: N801
    """ANSI colour tokens; inert when disabled."""

    def __init__(self, on: bool = True):
        self.on = on
        self.reset = "\033[0m" if on else ""
        self.dim = "\033[90m" if on else ""
        self.cyan = "\033[1;96m" if on else ""
        self.green = "\033[92m" if on else ""
        self.amber = "\033[93m" if on else ""
        self.red = "\033[91m" if on else ""
        self.white = "\033[37m" if on else ""
        self.dark = "\033[38;5;6m" if on else ""
        self.vol = "\033[94m" if on else ""


class UI:
    def __init__(self, color: bool, width: int, bar_width: int):
        self.c = C(color)
        self.width = max(52, width)  # 52 keeps the bar row fitting with its time + volume
        self.bar_w = max(16, min(bar_width, self.width - 34))

    def _status(self, text: str, kind: str) -> str:
        if kind == "ok":
            return f"{self.c.green}{text}{self.c.reset}"
        if kind == "buffer":
            return f"{self.c.amber}{text}{self.c.reset}"
        if kind == "error":
            return f"{self.c.red}{text}{self.c.reset}"
        if kind == "pause":
            return f"{self.c.white}{text}{self.c.reset}"
        return f"{self.c.dim}{text}{self.c.reset}"

    def episode_line(self, number: int, status: str, kind: str) -> str:
        left = f"ASOT {number:04d}"
        max_status = self.width - len(left) - 1
        status = status[:max_status] if len(status) > max_status else status
        gap = self.width - len(left) - len(status)  # >= 1 by construction
        return f"{self.c.cyan}{left}{self.c.reset}{' ' * gap}{self._status(status, kind)}"

    def song_line(self, song: str, date: str) -> str:
        prefix = "    "
        d_raw = (date or "").strip()
        s_raw = (song or "").rstrip()
        if not s_raw or not s_raw.strip():
            s = f"{self.c.dim}(no track info){self.c.reset}"
        else:
            # reserve one column for the separator space before the date
            budget = max(0, self.width - len(prefix) - len(d_raw) - 1)
            if len(s_raw) > budget:
                s_raw = s_raw[:budget].rstrip()
            s = f"{self.c.white}{s_raw}{self.c.reset}"
        gap = self.width - len(prefix) - visible_len(s) - len(d_raw)  # >= 1
        d = f"{self.c.amber}{d_raw}{self.c.reset}" if d_raw else ""
        return prefix + s + " " * gap + d

    def bar_line(self, position, length, volume, paused):
        """Player bar row.  Exactly ``width`` characters in both colour modes."""
        w = self.bar_w
        filled = 0
        if length and length > 0 and position is not None and 0 <= position <= length:
            filled = int(round((position / length) * w))
        on = "\u2588" * filled
        off = "\u2591" * (w - filled)
        bar = f"[{self.c.green}{on}{self.c.reset}{self.c.dark}{off}{self.c.reset}]"

        pos_s = fmt_time(position)
        tot_s = fmt_time(length)
        vol_int = int(round(volume * 100))
        meter = ("█" * int(round(volume * 6)) + "░" * (6 - int(round(volume * 6))))
        vol_part = f"{vol_int:03d}% {meter}"
        right_time = f"{pos_s} / {tot_s}" if length and length > 0 else f"{pos_s} / ???"

        # gap is computed in *visible* characters, and includes the literal
        # single space between the time and the volume readout.
        gap = max(1, self.width - visible_len(bar) - len(right_time) - 1 - len(vol_part))
        return (f"{bar}{' ' * gap}{self.c.white}{right_time}{self.c.reset} "
                f"{self.c.vol}{vol_part}{self.c.reset}")

    def hint_line(self) -> str:
        text = "space play/pause   ←/→ ±15s   ↑/↓ volume   m mute   n next  p prev  q quit"
        if len(text) > self.width:
            text = text[:self.width]
        elif len(text) < self.width:
            text += " " * (self.width - len(text))
        return f"{self.c.dim}{text}{self.c.reset}"

    def render(
        self,
        number: int,
        song: str,
        date: str,
        status: str,
        kind: str,
        position,
        length,
        volume: float,
        paused: bool,
    ) -> str:
        lines = [
            self.episode_line(number, status, kind),
            self.song_line(song, date),
            self.bar_line(position, length, volume, paused),
            self.hint_line(),
        ]
        return "\033[H" + "\n".join(lines) + "\n"

    def plain_render(
        self,
        number: int,
        song: str,
        date: str,
        status: str,
        kind: str,
        position,
        length,
        volume: float,
        paused: bool,
    ) -> str:
        """Same layout without ANSI (non-tty / tests)."""
        lines = [
            self.episode_line(number, status, kind),
            self.song_line(song, date),
            self.bar_line(position, length, volume, paused),
            self.hint_line(),
        ]
        return "\n".join(lines) + "\n\n"