"""The colour palettes everything in the UI draws from.

Every colour in Beefy Player is a stock ANSI palette *name*, never RGB, so the
TUI adopts whatever colours the terminal is configured with.  A palette here is
therefore a short ladder of those names — the "gradient" is a quantised walk
from the quiet end to the hot end, not an interpolation.

The active palette drives the spectrum analyser, the album-art mosaic, the
provider wordmarks and the pane corners; `c` cycles through them and the
choice is remembered in the config file.
"""

from __future__ import annotations

#: Dark → hot ladders of ANSI names.  Sixteen of them: seven hue gradients, a
#: few near-monochromes, and the original spectrum.
PALETTES: dict[str, tuple[str, ...]] = {
    "spectrum": (
        "cyan",
        "blue",
        "magenta",
        "bright_magenta",
        "yellow",
        "bright_yellow",
        "red",
    ),
    "rainbow": (
        "red",
        "bright_yellow",
        "bright_green",
        "bright_cyan",
        "bright_blue",
        "bright_magenta",
    ),
    "ocean": (
        "bright_black",
        "blue",
        "bright_blue",
        "cyan",
        "bright_cyan",
        "bright_white",
    ),
    "ember": (
        "bright_black",
        "red",
        "bright_red",
        "yellow",
        "bright_yellow",
        "bright_white",
    ),
    "mint": (
        "bright_black",
        "green",
        "bright_green",
        "cyan",
        "bright_cyan",
        "bright_white",
    ),
    "sunset": ("magenta", "bright_magenta", "red", "bright_red", "yellow"),
    "violet": ("blue", "bright_blue", "magenta", "bright_magenta", "bright_white"),
    "acid": ("bright_black", "green", "bright_green", "yellow", "bright_yellow"),
    "neon": (
        "bright_magenta",
        "bright_red",
        "bright_yellow",
        "bright_green",
        "bright_cyan",
    ),
    "sand": ("bright_black", "yellow", "bright_yellow", "white", "bright_white"),
    "blood": ("bright_black", "red", "bright_red", "bright_magenta"),
    "forest": ("bright_black", "green", "bright_green", "yellow", "bright_white"),
    "ice": ("bright_white", "bright_cyan", "cyan", "bright_blue", "blue"),
    "steel": ("bright_black", "white", "bright_white", "bright_cyan"),
    "candy": ("magenta", "bright_magenta", "bright_cyan", "bright_yellow"),
    "mono": ("bright_black", "white", "bright_white"),
}

#: The stock names from dark to bright.  These are xterm's default values in
#: Rec. 601 luma order — the closest thing to a stock answer.  A theme may
#: disagree about the exact numbers, but the ordering is what the frame fades
#: need: a ladder is a *hue* walk, so where it ends says nothing about which
#: end is brighter.
BRIGHTNESS: tuple[str, ...] = (
    "black",
    "blue",
    "red",
    "bright_red",
    "magenta",
    "bright_magenta",
    "bright_blue",
    "green",
    "bright_black",
    "cyan",
    "bright_green",
    "bright_cyan",
    "yellow",
    "white",
    "bright_yellow",
    "bright_white",
)

_RANK = {name: rank for rank, name in enumerate(BRIGHTNESS)}

#: Cycle order for the palette key.
PALETTE_ORDER: tuple[str, ...] = tuple(PALETTES)

#: What you get until you press `c`.
DEFAULT_PALETTE = "spectrum"


def palette_stops(name: str | None) -> tuple[str, ...]:
    """The ladder for ``name``, falling back to the default palette."""
    key = (name or "").strip().lower()
    return PALETTES.get(key, PALETTES[DEFAULT_PALETTE])


def brightness(colour: str) -> int:
    """How bright a stock name is: 0 (black) to 15 (bright white)."""
    return _RANK.get(colour.strip().lower(), 0)