"""Commodore VIC-20 (VIC 6560/6561) 16-colour palette.

Calibrated against MAME's `vic20`: a display-setup cartridge cycled the global
background ($900F bits 4-7) over all 16 values while a blank-character cell was
sampled with the emulator's screen pixel reader (NORMAL mode -- $900F bit 3 = 1;
with bit 3 = 0 the chip is in REVERSE mode and blank cells show the foreground).

The VIC has 16 colours but the per-cell *foreground* (colour RAM, 3 bits) is
limited to the first 8; the global background / border / auxiliary may be any of
the 16.  Colours 8-15 are lighter variants of 0-7.
"""

from __future__ import annotations

import numpy as np

from ..palette import srgb_to_lab

VIC = np.array([
    (0x00, 0x00, 0x00),   # 0  black
    (0xFF, 0xFF, 0xFF),   # 1  white
    (0xF0, 0x00, 0x00),   # 2  red
    (0x00, 0xF0, 0xF0),   # 3  cyan
    (0x60, 0x00, 0x60),   # 4  purple
    (0x00, 0xA0, 0x00),   # 5  green
    (0x00, 0x00, 0xF0),   # 6  blue
    (0xD0, 0xD0, 0x00),   # 7  yellow
    (0xC0, 0xA0, 0x00),   # 8  orange
    (0xFF, 0xA0, 0x00),   # 9  light orange
    (0xF0, 0x80, 0x80),   # 10 pink
    (0x00, 0xFF, 0xFF),   # 11 light cyan
    (0xFF, 0x00, 0xFF),   # 12 light purple
    (0x00, 0xFF, 0x00),   # 13 light green
    (0x00, 0xA0, 0xFF),   # 14 light blue
    (0xFF, 0xFF, 0x00),   # 15 light yellow
], dtype=np.float64)

# Foreground (colour RAM, 3-bit) is limited to the first 8 colours.
FG_USABLE = list(range(8))
# Background / border / auxiliary may be any of the 16.
BG_USABLE = list(range(16))


def get_palette() -> np.ndarray:
    return VIC


def palette_lab() -> np.ndarray:
    return srgb_to_lab(VIC)