import type { CertificateDesign, CertificateRenderData, CertificateSignatory } from '../types';

export function escapeHtml(input: unknown): string {
  return String(input ?? '').replace(/[&<>"']/g, (char) => {
    switch (char) {
      case '&':
        return '&amp;';
      case '<':
        return '&lt;';
      case '>':
        return '&gt;';
      case '"':
        return '&quot;';
      default:
        return '&#39;';
    }
  });
}

export function getYear(value: string | undefined | null): string {
  const match = String(value ?? '').match(/\b(19|20|21)\d{2}\b/);
  if (match) return match[0];

  return String(new Date().getFullYear());
}

export function shadeColor(hex: string, percent: number): string {
  const normalized = hex.startsWith('#') ? hex.slice(1) : hex;
  if (normalized.length !== 6) return hex;

  const numeric = parseInt(normalized, 16);
  if (Number.isNaN(numeric)) return hex;

  const offset = Math.round((percent / 100) * 255);
  const clamp = (value: number) => Math.max(0, Math.min(255, value));
  const red = clamp(((numeric >> 16) & 0xff) + offset);
  const green = clamp(((numeric >> 8) & 0xff) + offset);
  const blue = clamp((numeric & 0xff) + offset);
  const next = (red << 16) | (green << 8) | blue;

  return '#' + next.toString(16).padStart(6, '0');
}

export interface TemplateRenderArgs {
  design: CertificateDesign;
  data: CertificateRenderData;
}

export interface TemplateRenderOutput {
  body: string;
  styles: string;
}

export type TemplateRenderer = (args: TemplateRenderArgs) => TemplateRenderOutput;

export interface SignatoryBlockOptions {
  wrapperClass?: string;
  nameClass: string;
  roleClass: string;
  roleFirst?: boolean;
}

export function renderSignatoryBlock(sig: CertificateSignatory, options: SignatoryBlockOptions): string {
  if (sig.enabled === false) return '';

  const sigImg = sig.signatureUrl ? `<img class="sig-img" src="${escapeHtml(sig.signatureUrl)}" alt="" />` : '';

  const nameEl = `<div class="${options.nameClass}">${escapeHtml(sig.name)}</div>`;
  const roleEl = `<div class="${options.roleClass}">${escapeHtml(sig.role)}</div>`;
  const content = options.roleFirst ? `${roleEl}${nameEl}` : `${nameEl}${roleEl}`;
  const wrapperClass = options.wrapperClass ? ` class="${options.wrapperClass}"` : '';

  return `
    <div${wrapperClass}>
      <div class="sig-content">
        <div class="sig-img-slot">${sigImg}</div>
        <div class="sig-text">${content}</div>
      </div>
    </div>
  `;
}

export interface FooterMetaBlockOptions {
  wrapperClass?: string;
  labelClass: string;
  valueClass: string;
}

export function renderFooterMetaBlock(label: string, value: string, options: FooterMetaBlockOptions): string {
  const wrapperClass = options.wrapperClass ? ` class="${options.wrapperClass}"` : '';

  return `
    <div${wrapperClass}>
      <div class="sig-content">
        <div class="sig-img-slot"></div>
        <div class="sig-text">
          <div class="${options.labelClass}">${escapeHtml(label)}</div>
          <div class="${options.valueClass}">${escapeHtml(value)}</div>
        </div>
      </div>
    </div>
  `;
}

export const SIGNATURE_IMAGE_STYLES = `
  .sig-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    width: 100%;
  }
  .sig-img-slot {
    display: flex;
    align-items: flex-end;
    justify-content: center;
    width: 100%;
    height: 48px;
    min-height: 48px;
    margin-bottom: 6px;
    flex-shrink: 0;
  }
  .sig-text {
    display: flex;
    flex-direction: column;
    align-items: center;
    width: 100%;
    text-align: center;
  }
  .sig-img {
    display: block;
    max-height: 48px;
    max-width: 100%;
    width: auto;
    height: auto;
    object-fit: contain;
    background: transparent;
  }
`;

export const FONTS_LINK_HREF =
  'https://fonts.googleapis.com/css2?family=Cormorant+Garamond:ital,wght@0,300;0,400;0,500;0,600;0,700;1,400&family=Cinzel:wght@400;500;600;700&family=DM+Mono:wght@400;500&family=Bodoni+Moda:ital,wght@0,400;0,700;1,400&family=Archivo+Black&family=JetBrains+Mono:wght@400;500&family=Playfair+Display:ital,wght@0,400;0,700;0,900;1,400&family=Space+Grotesk:wght@400;500;700&display=swap';

export const BASE_STYLES = `
  *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
  html, body { width: 1100px; height: 780px; background: transparent; }
  body {
    -webkit-font-smoothing: antialiased;
    -webkit-print-color-adjust: exact;
    print-color-adjust: exact;
  }
  .cert { width: 1100px; height: 780px; position: relative; overflow: hidden; box-shadow: inset 0 0 0 3px rgba(0,0,0,0.12); }
`;