// PoW Captcha Web Component
import { generateChallenge, solveChallenge, verifySolution } from '../services/pow-captcha.js'
import { t, i18n } from '../i18n.js'

export class PowCaptcha extends HTMLElement {
  constructor() {
    super()
    this.solved = false
    this.solving = false
    this.solution = null
    this.unsubscribe = null
  }

  connectedCallback() {
    this.render()
    this.unsubscribe = i18n.subscribe(() => this.render())
  }

  disconnectedCallback() {
    if (this.unsubscribe) this.unsubscribe()
  }

  render() {
    this.innerHTML = `
      <div class="pow-captcha ${this.solved ? 'pow-captcha--solved' : ''} ${this.solving ? 'pow-captcha--solving' : ''}">
        <label class="pow-captcha-label">
          <span class="pow-captcha-checkbox">
            ${this.solved 
              ? `<svg class="pow-captcha-check" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="3">
                   <polyline points="20 6 9 17 4 12"></polyline>
                 </svg>`
              : this.solving
                ? `<span class="pow-captcha-spinner"></span>`
                : ``
            }
          </span>
          <span class="pow-captcha-text">
            ${this.solved ? t('captcha.verified') : t('captcha.verify')}
          </span>
        </label>
      </div>
    `

    if (!this.solved && !this.solving) {
      this.querySelector('.pow-captcha-label').addEventListener('click', () => this.solve())
    }
  }

  async solve() {
    if (this.solving || this.solved) return

    this.solving = true
    this.render()

    try {
      const { challenge, difficulty, timestamp, signature, source } = await generateChallenge()

      const result = await solveChallenge(challenge, difficulty)

      const solution = {
        challenge,
        difficulty,
        nonce: result.nonce,
        signature,
        timestamp,
        source
      }

      const verification = await verifySolution(solution)
      if (!verification.ok) throw new Error('Verification failed')

      this.solution = { ...solution, token: verification.token }
      this.solving = false
      this.solved = true
      this.dispatchEvent(new CustomEvent('solved', { detail: this.solution }))
      this.render()

    } catch (error) {
      this.solving = false
      this.render()
      console.error('PoW Captcha error:', error)
    }
  }

  // Get solution for form submission
  getSolution() {
    return this.solution
  }

  // Check if solved
  isSolved() {
    return this.solved
  }

  // Reset captcha
  reset() {
    this.solved = false
    this.solution = null
    this.render()
  }
}

customElements.define('pow-captcha', PowCaptcha)

// Add styles
const style = document.createElement('style')
style.textContent = `
  .pow-captcha {
    display: inline-block;
    padding: var(--space-md) var(--space-lg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    background: var(--color-surface, var(--color-bg-secondary));
  }

  .pow-captcha-label {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    cursor: pointer;
    user-select: none;
  }

  .pow-captcha--solving .pow-captcha-label,
  .pow-captcha--solved .pow-captcha-label {
    cursor: default;
  }

  .pow-captcha-checkbox {
    width: 24px;
    height: 24px;
    border: 2px solid var(--color-border);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--color-bg);
    transition: all 0.2s ease;
  }

  .pow-captcha:hover:not(.pow-captcha--solved):not(.pow-captcha--solving) .pow-captcha-checkbox {
    border-color: var(--color-primary);
  }

  .pow-captcha--solved .pow-captcha-checkbox {
    background: var(--color-success, #22c55e);
    border-color: var(--color-success, #22c55e);
  }

  .pow-captcha-check {
    width: 16px;
    height: 16px;
    color: white;
  }

  .pow-captcha-spinner {
    width: 16px;
    height: 16px;
    border: 2px solid var(--color-border);
    border-top-color: var(--color-primary);
    border-radius: 50%;
    animation: pow-spin 0.8s linear infinite;
  }

  @keyframes pow-spin {
    to { transform: rotate(360deg); }
  }

  .pow-captcha-text {
    font-size: var(--font-size-sm);
    color: var(--color-text);
  }

  .pow-captcha--solved .pow-captcha-text {
    color: var(--color-success, #22c55e);
    font-weight: 500;
  }
`
document.head.appendChild(style)