import qrcode from './vendor/qrcode.mjs'

export function drawQr(canvas, text) {
  const qr = qrcode(0, 'M'); qr.addData(text); qr.make()
  const count = qr.getModuleCount(), scale = 5, margin = 4
  canvas.width = canvas.height = (count + margin * 2) * scale
  const ctx = canvas.getContext('2d'); ctx.fillStyle = '#fff'; ctx.fillRect(0, 0, canvas.width, canvas.height)
  ctx.fillStyle = '#000'
  for (let y = 0; y < count; y++) for (let x = 0; x < count; x++)
    if (qr.isDark(y, x)) ctx.fillRect((x + margin) * scale, (y + margin) * scale, scale, scale)
}

export class InviteScanner {
  constructor(video, onCode) { this.video = video; this.onCode = onCode; this.epoch = 0; this.canvas = document.createElement('canvas') }
  decode(source, width, height) {
    if (!width || !height) return null
    const scale = Math.min(1, 1280 / Math.max(width, height))
    this.canvas.width = Math.round(width * scale); this.canvas.height = Math.round(height * scale)
    const ctx = this.canvas.getContext('2d', { willReadFrequently: true })
    ctx.drawImage(source, 0, 0, this.canvas.width, this.canvas.height)
    const pixels = ctx.getImageData(0, 0, this.canvas.width, this.canvas.height)
    return globalThis.jsQR(pixels.data, pixels.width, pixels.height)?.data
  }
  async image(file) {
    this.stop(); const epoch = this.epoch
    if (!file || file.size > 8 * 1024 * 1024) throw new Error('QR resmi en fazla 8 MB olabilir.')
    const bitmap = await createImageBitmap(file)
    let result
    try { result = this.decode(bitmap, bitmap.width, bitmap.height) } finally { bitmap.close() }
    if (epoch !== this.epoch) return
    if (!result) throw new Error('Resimde QR okunamadı; daha net bir görüntü deneyin.')
    await this.onCode(result)
  }
  async start() {
    this.stop(); const epoch = this.epoch
    const stream = await navigator.mediaDevices.getUserMedia({ video: { facingMode: 'environment' }, audio: false })
    if (epoch !== this.epoch) { stream.getTracks().forEach(t => t.stop()); return }
    this.stream = stream; this.video.srcObject = stream; this.video.hidden = false
    try {
      await this.video.play()
      if (epoch !== this.epoch) return
      this.timer = setInterval(() => {
        const result = this.decode(this.video, this.video.videoWidth, this.video.videoHeight)
        if (result) { this.stop(); void this.onCode(result).catch(error => this.onError?.(error)) }
      }, 250)
      this.limit = setTimeout(() => this.stop(), 60000)
    } catch (error) { this.stop(); throw error }
  }
  stop() { this.epoch++; clearInterval(this.timer); clearTimeout(this.limit); this.stream?.getTracks().forEach(t => t.stop()); this.stream = null; this.video.srcObject = null; this.video.hidden = true }
}