/**
 * Checks that the packaged Google Sans Flex subset still carries the variable axes the CSS uses.
 *
 * Run from the repository root with `npm run check:font` (or `node bin/check-font.mjs [woff2]`).
 * tests/Feature/FontTest.php runs it through the configured `node` binary as well, because PHP
 * cannot open a woff2 without the Brotli extension.
 *
 *   wght  400–700 — every typescale weight (font.css `font-weight: 400 700`, type.css's regular,
 *                   medium and bold reference tokens).
 *   ROND  0–100   — the roundness axis every `type-emphasized-*` utility sets to 100. Re-subset
 *                   the font without it and the emphasized styles quietly stop being round.
 *
 * Output is one JSON object on stdout — {file, postscriptName, numGlyphs, axes: {tag: {name, min,
 * default, max}}} — and the exit status is 1, with the reason on stderr, when an axis is missing
 * or narrower than the range above.
 */
import { openSync } from 'fontkit'
import { fileURLToPath } from 'node:url'

/** The axes the stylesheets depend on, and the range each one has to cover. */
const REQUIRED = {
    wght: { min: 400, max: 700 },
    ROND: { min: 0, max: 100 },
}

const file = process.argv[2] ?? fileURLToPath(new URL('../resources/fonts/google-sans-flex/GoogleSansFlex-Latin.woff2', import.meta.url))

let font

try {
    font = openSync(file)
} catch (error) {
    process.stderr.write(`${file}: ${error.message}\n`)
    process.exit(1)
}

const axes = font.variationAxes ?? {}
const problems = Object.entries(REQUIRED).flatMap(([tag, range]) => {
    const axis = axes[tag]

    if (!axis) {
        return [`${tag} is missing; the subset has ${Object.keys(axes).join(', ') || 'no variable axes'}.`]
    }

    return axis.min > range.min || axis.max < range.max
        ? [`${tag} covers ${axis.min}–${axis.max}, not the ${range.min}–${range.max} the stylesheets ask for.`]
        : []
})

process.stdout.write(`${JSON.stringify({
    file,
    postscriptName: font.postscriptName,
    numGlyphs: font.numGlyphs,
    axes,
})}\n`)

if (problems.length > 0) {
    process.stderr.write(`${file}\n${problems.map((problem) => `  ${problem}`).join('\n')}\n`)
    process.exit(1)
}