const { test } = require('node:test')
const assert = require('node:assert/strict')
const fs = require('node:fs')
const path = require('node:path')
const crypto = require('node:crypto')
const postcss = require('postcss')

const root = path.resolve(__dirname, '..')
const source = fs.readFileSync(path.join(root, 'src/renderer/src/styles/nanumSquare.css'), 'utf8')
const css = postcss.parse(source)
const faces = []
css.walkAtRules('font-face', rule => {
  faces.push(Object.fromEntries(rule.nodes.filter(node => node.type === 'decl').map(node => [node.prop, node.value])))
})

function codepoints(range) {
  const result = new Set()
  let previous = -1
  for (const entry of range.split(',')) {
    const match = entry.trim().match(/^U\+([0-9A-F]+)(?:-([0-9A-F]+))?$/)
    assert.ok(match, `Invalid unicode-range: ${entry}`)
    const start = parseInt(match[1], 16)
    const end = parseInt(match[2] ?? match[1], 16)
    assert.ok(start > previous && end >= start && end <= 0x10ffff)
    for (let code = start; code <= end; code++) result.add(code)
    previous = end
  }
  return result
}

test('coverage is tied to the original bundled font bytes for all four weights', () => {
  assert.equal(faces.length, 4)
  assert.deepEqual(faces.map(face => face['font-weight']), ['300', '400', '700', '800'])
  for (const face of faces) {
    assert.equal(face['font-family'], "'NanumSquare'")
    assert.equal(face['font-display'], 'swap')
    const filename = face.src.match(/\/([^/]+\.woff2)'/)[1]
    const hash = crypto.createHash('sha256').update(fs.readFileSync(path.join(root, 'src/renderer/public/assets/fonts', filename))).digest('hex')
    assert.ok(source.includes(`${filename} sha256: ${hash}`), 'Regenerate coverage if a font changes')
  }
})

for (const face of faces) {
  test(`weight ${face['font-weight']} preserves visible Hangul and lets blank glyphs fall back`, () => {
    const included = codepoints(face['unicode-range'])
    assert.equal([...included].filter(code => code >= 0xac00 && code <= 0xd7a3).length, 2479)
    for (const char of '가모한글학생SLAM0123 →') assert.ok(included.has(char.codePointAt(0)), `Keep ${char}`)
    for (const char of ['몯', '힣', '\u2022']) assert.equal(included.has(char.codePointAt(0)), false, `Let ${char} use fallback`)
    for (const code of [0x20, 0x3000, 0x3164]) assert.ok(included.has(code), 'Preserve intentional spacing')
  })
}

test('UI keeps its original default font and native fallback without Neo', () => {
  const entry = fs.readFileSync(path.join(root, 'src/renderer/src/index.css'), 'utf8')
  assert.match(entry, /@import "\.\/styles\/nanumSquare\.css"/)
  assert.match(entry, /font-family: 'NanumSquare', Inter, system-ui, sans-serif/)
  assert.doesNotMatch(entry + source, /NanumSquareNeo/)
  const directFaces = []
  postcss.parse(entry).walkAtRules('font-face', rule => directFaces.push(rule))
  assert.equal(directFaces.length, 0, 'Unrestricted duplicate faces would suppress fallback')
})