const ADJECTIVES = [
  'swift','calm','bold','keen','wise','warm','bright','silent','gentle','steady',
  'clever','vivid','nimble','serene','brave','quick','subtle','sharp','lucid','agile',
  'noble','witty','mellow','fierce','stout','deft','proud','fair','grand','cool'
]

const ANIMALS = [
  'fox','owl','wolf','bear','lynx','hare','deer','hawk','otter','raven',
  'crane','puma','seal','finch','cobra','bison','ibex','oriole','quail','gecko',
  'panda','tiger','eagle','badger','moose','robin','coral','falcon','heron','viper'
]

function hashToBytes(input) {
  const hex = input.replace(/[^0-9a-fA-F]/g, '')
  const bytes = []
  for (let i = 0; i < hex.length; i += 2) {
    bytes.push(parseInt(hex.substring(i, i + 2), 16))
  }
  return bytes
}

export function generatePseudonym(hash) {
  if (!hash || hash.length < 8) return 'Unknown'
  const bytes = hashToBytes(hash)
  const adj = ADJECTIVES[bytes[0] % ADJECTIVES.length]
  const animal = ANIMALS[bytes[1] % ANIMALS.length]
  const num = ((bytes[2] << 8) | bytes[3]) % 100
  const capitalAdj = adj.charAt(0).toUpperCase() + adj.slice(1)
  const capitalAnimal = animal.charAt(0).toUpperCase() + animal.slice(1)
  return `${capitalAdj}${capitalAnimal}${num}`
}

export function generateAvatar(hash, size = 64) {
  if (!hash || hash.length < 16) {
    return `<svg xmlns="http://www.w3.org/2000/svg" width="${size}" height="${size}" viewBox="0 0 64 64">
      <rect width="64" height="64" rx="32" fill="#A8A29E"/>
      <text x="32" y="40" text-anchor="middle" font-family="system-ui" font-size="24" fill="#fff">?</text>
    </svg>`
  }

  const bytes = hashToBytes(hash)

  const hues = [
    174, // teal (brand)
    210, // blue
    260, // purple
    330, // pink
    25,  // orange
    45,  // gold
    140, // green
    190, // cyan
  ]
  const hue = hues[bytes[4] % hues.length]
  const bg = `hsl(${hue}, 45%, 45%)`
  const fg = `hsl(${hue}, 30%, 85%)`

  const grid = 5
  const cellSize = 64 / grid
  let cells = ''

  for (let y = 0; y < grid; y++) {
    for (let x = 0; x < Math.ceil(grid / 2); x++) {
      const byteIndex = (y * 3 + x + 5) % bytes.length
      if (bytes[byteIndex] % 2 === 0) {
        const rx = x * cellSize
        const ry = y * cellSize
        cells += `<rect x="${rx}" y="${ry}" width="${cellSize}" height="${cellSize}" fill="${fg}"/>`
        const mirrorX = (grid - 1 - x) * cellSize
        if (mirrorX !== rx) {
          cells += `<rect x="${mirrorX}" y="${ry}" width="${cellSize}" height="${cellSize}" fill="${fg}"/>`
        }
      }
    }
  }

  return `<svg xmlns="http://www.w3.org/2000/svg" width="${size}" height="${size}" viewBox="0 0 64 64">
    <rect width="64" height="64" rx="32" fill="${bg}"/>
    ${cells}
  </svg>`
}