import React, { CSSProperties, useState } from 'react';
import { useNode, UserComponent } from '@craftjs/core';
import { cssPropsToString } from '../../utils/style-helpers';
import { escapeHtml, escapeAttr } from '../../utils/escape';

interface TabItem {
  label: string;
  content: string;
}

interface TabsProps {
  tabs?: TabItem[];
  style?: CSSProperties;
  activeTabBg?: string;
  activeTabColor?: string;
  inactiveTabBg?: string;
  inactiveTabColor?: string;
  contentBg?: string;
  anchorId?: string;
}

const defaultTabs: TabItem[] = [
  { label: 'Overview', content: 'Welcome to our platform. We provide the tools you need to build, launch, and grow your online presence. Our intuitive interface makes it simple to get started in minutes.' },
  { label: 'Features', content: 'Drag-and-drop editor, responsive templates, custom domains, analytics dashboard, SEO tools, and integrations with your favorite services. Everything you need in one place.' },
  { label: 'Support', content: 'Our dedicated support team is available 24/7 to help you with any questions. Access our knowledge base, community forums, or reach out directly via live chat or email.' },
];

export const Tabs: UserComponent<TabsProps> = ({
  tabs = defaultTabs,
  style = {},
  activeTabBg = '#3b82f6',
  activeTabColor = '#ffffff',
  inactiveTabBg = '#f1f5f9',
  inactiveTabColor = '#64748b',
  contentBg = '#ffffff',
  anchorId,
}) => {
  const {
    connectors: { connect, drag },
    selected,
  } = useNode((node) => ({
    selected: node.events.selected,
  }));

  const [activeIndex, setActiveIndex] = useState(0);

  return (
    <section
      ref={(ref: HTMLElement | null): void => { if (ref) connect(drag(ref)); }}
      id={anchorId || undefined}
      style={{
        padding: '60px 20px',
        backgroundColor: '#ffffff',
        outline: selected ? '2px solid #3b82f6' : 'none',
        ...style,
      }}
    >
      <div style={{ maxWidth: '800px', margin: '0 auto' }}>
        {/* Tab buttons */}
        <div style={{ display: 'flex', gap: '2px', borderBottom: '2px solid #e2e8f0' }}>
          {tabs.map((tab, i) => (
            <button
              key={i}
              onClick={() => setActiveIndex(i)}
              style={{
                padding: '12px 24px',
                fontSize: '14px',
                fontWeight: '600',
                border: 'none',
                borderTopLeftRadius: '8px',
                borderTopRightRadius: '8px',
                cursor: 'pointer',
                backgroundColor: i === activeIndex ? activeTabBg : inactiveTabBg,
                color: i === activeIndex ? activeTabColor : inactiveTabColor,
                transition: 'background-color 0.2s, color 0.2s',
              }}
            >
              {tab.label}
            </button>
          ))}
        </div>
        {/* Content panel */}
        <div
          style={{
            padding: '24px',
            backgroundColor: contentBg,
            border: '1px solid #e2e8f0',
            borderTop: 'none',
            borderBottomLeftRadius: '8px',
            borderBottomRightRadius: '8px',
            fontSize: '14px',
            lineHeight: '1.7',
            color: '#4b5563',
            minHeight: '100px',
          }}
        >
          {tabs[activeIndex]?.content || ''}
        </div>
      </div>
    </section>
  );
};

/* ---------- Craft config ---------- */

Tabs.craft = {
  displayName: 'Tabs',
  props: {
    tabs: defaultTabs,
    style: { backgroundColor: '#ffffff' },
    activeTabBg: '#3b82f6',
    activeTabColor: '#ffffff',
    inactiveTabBg: '#f1f5f9',
    inactiveTabColor: '#64748b',
    contentBg: '#ffffff',
    anchorId: '',
  },
  rules: {
    canDrag: () => true,
    canMoveIn: () => false,
    canMoveOut: () => true,
  },
};

/* ---------- HTML export ---------- */

/**
 * Deterministic (non-cryptographic) string hash -- djb2 -- used to derive a
 * stable id scope from existing prop data instead of Math.random/Date.now.
 * Same input always produces the same output across export runs.
 */
function stableHash(seed: string): string {
  let h = 5381;
  for (let i = 0; i < seed.length; i++) {
    h = ((h << 5) + h + seed.charCodeAt(i)) | 0;
  }
  return (h >>> 0).toString(36);
}

(Tabs as any).toHtml = (props: TabsProps, _childrenHtml: string) => {
  const sectionStyle = cssPropsToString({
    padding: '60px 20px',
    ...props.style,
  });
  const idAttr = props.anchorId ? ` id="${escapeAttr(props.anchorId)}"` : '';
  const tabs = props.tabs || defaultTabs;
  const activeTabBg = props.activeTabBg || '#3b82f6';
  const activeTabColor = props.activeTabColor || '#ffffff';
  const inactiveTabBg = props.inactiveTabBg || '#f1f5f9';
  const inactiveTabColor = props.inactiveTabColor || '#64748b';
  const contentBg = props.contentBg || '#ffffff';

  // tabId scopes the functional wiring (onclick/getElementById) as well as
  // the ARIA tab<->panel linking ids. It must be deterministic (no
  // Math.random) because aria-controls/aria-labelledby need to reference
  // the SAME id across repeated exports of the same content -- derived from
  // anchorId when present, otherwise a stable hash of the tab labels (pure
  // function of the props, not time/randomness).
  const scopeSeed = props.anchorId || tabs.map((t) => t.label).join('|') + '::' + tabs.length;
  const tabId = 'tabs_' + stableHash(scopeSeed);

  const tabButtons = tabs.map((tab, i) => {
    const isActive = i === 0;
    return `<button onclick="${tabId}_switch(${i})" id="${tabId}_btn_${i}" role="tab" aria-selected="${isActive ? 'true' : 'false'}" aria-controls="${tabId}_panel_${i}" tabindex="${isActive ? '0' : '-1'}" style="padding:12px 24px;font-size:14px;font-weight:600;border:none;border-top-left-radius:8px;border-top-right-radius:8px;cursor:pointer;background-color:${isActive ? activeTabBg : inactiveTabBg};color:${isActive ? activeTabColor : inactiveTabColor}">${escapeHtml(tab.label)}</button>`;
  }).join('\n      ');

  const tabPanels = tabs.map((tab, i) => {
    return `<div id="${tabId}_panel_${i}" role="tabpanel" aria-labelledby="${tabId}_btn_${i}" tabindex="0" style="padding:24px;background-color:${contentBg};border:1px solid #e2e8f0;border-top:none;border-bottom-left-radius:8px;border-bottom-right-radius:8px;font-size:14px;line-height:1.7;color:#4b5563;min-height:100px;${i !== 0 ? 'display:none' : ''}">${escapeHtml(tab.content)}</div>`;
  }).join('\n    ');

  const switchScript = `<script>
function ${tabId}_switch(idx){
  var total=${tabs.length};
  for(var i=0;i<total;i++){
    document.getElementById('${tabId}_panel_'+i).style.display=i===idx?'':'none';
    var btn=document.getElementById('${tabId}_btn_'+i);
    btn.style.backgroundColor=i===idx?'${activeTabBg}':'${inactiveTabBg}';
    btn.style.color=i===idx?'${activeTabColor}':'${inactiveTabColor}';
    btn.setAttribute('aria-selected', i===idx ? 'true' : 'false');
    btn.setAttribute('tabindex', i===idx ? '0' : '-1');
  }
}
(function(){
  var total=${tabs.length};
  for(var i=0;i<total;i++){
    (function(idx){
      var btn=document.getElementById('${tabId}_btn_'+idx);
      btn.addEventListener('keydown', function(e){
        var next=null;
        if(e.key==='ArrowRight'){ next=(idx+1)%total; }
        else if(e.key==='ArrowLeft'){ next=(idx-1+total)%total; }
        else if(e.key==='Home'){ next=0; }
        else if(e.key==='End'){ next=total-1; }
        if(next!==null){
          e.preventDefault();
          ${tabId}_switch(next);
          document.getElementById('${tabId}_btn_'+next).focus();
        }
      });
    })(i);
  }
})();
</script>`;

  return {
    html: `<section${idAttr}${sectionStyle ? ` style="${sectionStyle}"` : ''}>
  <div style="max-width:800px;margin:0 auto">
    <div role="tablist" style="display:flex;gap:2px;border-bottom:2px solid #e2e8f0">
      ${tabButtons}
    </div>
    ${tabPanels}
  </div>
  ${switchScript}
</section>`,
  };
};