"""The product palette shared by build-time rasterization and both devices."""

from __future__ import annotations

import argparse
import json
import pathlib
import re

PALETTE_PATH = pathlib.Path(__file__).with_name('palette.json')
COLORS = json.loads(PALETTE_PATH.read_text(encoding='utf-8'))

def rgb(name: str) -> tuple[int, int, int]:
  value = COLORS[name]
  if not isinstance(value, str) or not re.fullmatch(r'#[0-9a-fA-F]{6}', value):
    raise ValueError(f'invalid palette color: {name}')
  return tuple(int(value[index:index + 2], 16) for index in (1, 3, 5))

def generate_header(destination: pathlib.Path) -> None:
  lines = ['#pragma once', '', 'namespace vamp_style {', '']
  for name in COLORS:
    if not re.fullmatch(r'[a-z][a-z_]*', name):
      raise ValueError(f'invalid palette name: {name}')
    r, g, b = rgb(name)
    lines.append(f'constexpr auto {name} = vamp_style::color{{{r}, {g}, {b}, 255}};')
  lines.extend(['', '}', ''])
  content = '\n'.join(lines)
  destination.parent.mkdir(parents=True, exist_ok=True)
  if not destination.exists() or destination.read_text() != content:
    destination.write_text(content, encoding='utf-8')

def main() -> None:
  parser = argparse.ArgumentParser(description=__doc__)
  parser.add_argument('--header', required=True, type=pathlib.Path)
  generate_header(parser.parse_args().header)

if __name__ == '__main__':
  main()