import { useState, useMemo, useEffect, useCallback } from 'react';
import { useTranslation } from 'react-i18next';
import DOMPurify from 'dompurify';
import type {
  AppConfig,
  LocalizedText,
  RemnawaveAppClient,
  RemnawavePlatformData,
  RemnawaveButtonClient,
} from '@/types';
import { CardsBlock, TimelineBlock, AccordionBlock, MinimalBlock } from './blocks';
import type { BlockRendererProps } from './blocks';

const platformOrder = ['ios', 'android', 'windows', 'macos', 'linux', 'androidTV', 'appleTV'];

// eslint-disable-next-line no-script-url
const dangerousSchemes = ['javascript:', 'data:', 'vbscript:', 'file:'];

function isValidDeepLink(url: string | undefined): boolean {
  if (!url) return false;
  const lowerUrl = url.toLowerCase().trim();
  if (dangerousSchemes.some((s) => lowerUrl.startsWith(s))) return false;
  return lowerUrl.includes('://');
}

function isValidExternalUrl(url: string | undefined): boolean {
  if (!url) return false;
  const lowerUrl = url.toLowerCase().trim();
  if (dangerousSchemes.some((s) => lowerUrl.startsWith(s))) return false;
  return lowerUrl.startsWith('http://') || lowerUrl.startsWith('https://');
}

function detectPlatform(): string | null {
  if (typeof window === 'undefined' || !navigator?.userAgent) return null;
  const ua = navigator.userAgent.toLowerCase();
  if (/iphone|ipad|ipod/.test(ua)) return 'ios';
  if (/android/.test(ua)) return /tv|television/.test(ua) ? 'androidTV' : 'android';
  if (/macintosh|mac os x/.test(ua)) return 'macos';
  if (/windows/.test(ua)) return 'windows';
  if (/linux/.test(ua)) return 'linux';
  return null;
}

const RENDERERS: Record<string, React.ComponentType<BlockRendererProps>> = {
  cards: CardsBlock,
  timeline: TimelineBlock,
  accordion: AccordionBlock,
  minimal: MinimalBlock,
};

// Icons
const CopyIcon = () => (
  <svg className="h-4 w-4" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={1.5}>
    <path
      strokeLinecap="round"
      strokeLinejoin="round"
      d="M8 16H6a2 2 0 01-2-2V6a2 2 0 012-2h8a2 2 0 012 2v2m-6 12h8a2 2 0 002-2v-8a2 2 0 00-2-2h-8a2 2 0 00-2 2v8a2 2 0 002 2z"
    />
  </svg>
);

const CheckIcon = () => (
  <svg className="h-4 w-4" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={2}>
    <path strokeLinecap="round" strokeLinejoin="round" d="M5 13l4 4L19 7" />
  </svg>
);

const BackIcon = () => (
  <svg className="h-6 w-6" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={2}>
    <path strokeLinecap="round" strokeLinejoin="round" d="M15 19l-7-7 7-7" />
  </svg>
);

interface Props {
  appConfig: AppConfig;
  onOpenDeepLink: (url: string) => void;
  isTelegramWebApp: boolean;
  onGoBack: () => void;
}

export default function InstallationGuide({
  appConfig,
  onOpenDeepLink,
  isTelegramWebApp,
  onGoBack,
}: Props) {
  const { t, i18n } = useTranslation();

  const detectedPlatform = useMemo(() => detectPlatform(), []);
  const isMobile = typeof window !== 'undefined' && window.innerWidth < 768;

  const [activePlatformKey, setActivePlatformKey] = useState<string | null>(null);
  const [selectedApp, setSelectedApp] = useState<RemnawaveAppClient | null>(null);
  const [copied, setCopied] = useState(false);

  // --- Helpers ---

  const getLocalizedText = useCallback(
    (text: LocalizedText | undefined): string => {
      if (!text) return '';
      const lang = i18n.language || 'en';
      return text[lang] || text['en'] || text['ru'] || Object.values(text)[0] || '';
    },
    [i18n.language],
  );

  const getBaseTranslation = useCallback(
    (key: string, i18nKey: string): string => {
      const bt = appConfig.baseTranslations;
      if (bt && key in bt) {
        const text = getLocalizedText(bt[key as keyof typeof bt] as LocalizedText);
        if (text) return text;
      }
      return t(i18nKey);
    },
    [appConfig.baseTranslations, getLocalizedText, t],
  );

  const getSvgHtml = useCallback(
    (svgKey: string | undefined): string => {
      if (!svgKey || !appConfig.svgLibrary?.[svgKey]) return '';
      const entry = appConfig.svgLibrary[svgKey];
      const raw = typeof entry === 'string' ? entry : entry.svgString;
      if (!raw) return '';
      return DOMPurify.sanitize(raw, { USE_PROFILES: { svg: true, svgFilters: true } });
    },
    [appConfig.svgLibrary],
  );

  // --- Available platforms ---

  const availablePlatforms = useMemo(() => {
    if (!appConfig.platforms) return [];
    const available = platformOrder.filter((key) => {
      const data = appConfig.platforms[key] as RemnawavePlatformData | undefined;
      return data && data.apps && data.apps.length > 0;
    });
    if (detectedPlatform && available.includes(detectedPlatform)) {
      return [detectedPlatform, ...available.filter((p) => p !== detectedPlatform)];
    }
    return available;
  }, [appConfig.platforms, detectedPlatform]);

  // --- Auto-select platform & app ---

  useEffect(() => {
    if (selectedApp || !availablePlatforms.length) return;
    const platform = availablePlatforms[0];
    const data = appConfig.platforms[platform] as RemnawavePlatformData | undefined;
    if (!data?.apps?.length) return;
    const app = data.apps.find((a) => a.featured) || data.apps[0];
    if (app) {
      setSelectedApp(app);
      setActivePlatformKey(platform);
    }
  }, [appConfig.platforms, availablePlatforms, selectedApp]);

  // --- Copy ---

  const handleCopy = useCallback(async (url: string) => {
    try {
      await navigator.clipboard.writeText(url);
    } catch {
      const textarea = document.createElement('textarea');
      textarea.value = url;
      document.body.appendChild(textarea);
      textarea.select();
      document.execCommand('copy');
      document.body.removeChild(textarea);
    }
    setCopied(true);
    setTimeout(() => setCopied(false), 2000);
  }, []);

  // --- Button renderer (passed to block renderers) ---

  const renderBlockButtons = useCallback(
    (buttons: RemnawaveButtonClient[] | undefined, variant: 'light' | 'subtle') => {
      if (!buttons || buttons.length === 0) return null;

      const baseClass =
        variant === 'light'
          ? 'rounded-xl border border-accent-500/40 px-4 py-2 text-sm font-medium text-accent-400 transition-all hover:bg-accent-500/10'
          : 'rounded-xl px-3 py-1.5 text-sm font-medium text-dark-300 transition-all hover:bg-dark-700/50';

      return (
        <div className="mt-3 flex flex-wrap gap-2">
          {buttons.map((btn, idx) => {
            const btnText = getLocalizedText(btn.text);
            const btnSvg = getSvgHtml(btn.svgIconKey);
            const btnIcon = btnSvg ? (
              <div
                className="h-4 w-4 [&>svg]:h-full [&>svg]:w-full"
                dangerouslySetInnerHTML={{ __html: btnSvg }}
              />
            ) : null;

            if (btn.type === 'subscriptionLink') {
              const url =
                btn.resolvedUrl ||
                btn.url ||
                btn.link ||
                selectedApp?.deepLink ||
                appConfig.subscriptionUrl;
              if (!url || !isValidDeepLink(url)) return null;
              return (
                <button
                  key={idx}
                  onClick={() => onOpenDeepLink(url)}
                  className={`flex items-center gap-2 ${baseClass}`}
                >
                  {btnIcon}
                  {btnText || getBaseTranslation('openApp', 'subscription.connection.openLink')}
                </button>
              );
            }

            if (btn.type === 'copyButton') {
              if (appConfig.hideLink) return null;
              const url = btn.resolvedUrl || appConfig.subscriptionUrl;
              if (!url) return null;
              return (
                <button
                  key={idx}
                  onClick={() => handleCopy(url)}
                  className={`flex items-center gap-2 ${
                    copied
                      ? 'rounded-xl border border-success-500 bg-success-500/10 px-4 py-2 text-sm font-medium text-success-400'
                      : baseClass
                  }`}
                >
                  {copied ? <CheckIcon /> : btnIcon || <CopyIcon />}
                  {copied
                    ? t('subscription.connection.copied')
                    : btnText || getBaseTranslation('copyLink', 'subscription.connection.copyLink')}
                </button>
              );
            }

            // external
            const href = btn.link || btn.url || '';
            if (!isValidExternalUrl(href)) return null;
            return (
              <a
                key={idx}
                href={href}
                target="_blank"
                rel="noopener noreferrer"
                className={`inline-flex items-center gap-2 ${baseClass}`}
              >
                {btnIcon}
                {btnText}
              </a>
            );
          })}
        </div>
      );
    },
    [
      selectedApp,
      appConfig,
      copied,
      getSvgHtml,
      getLocalizedText,
      getBaseTranslation,
      handleCopy,
      onOpenDeepLink,
      t,
    ],
  );

  // --- Current platform data ---

  const currentPlatformKey = activePlatformKey || availablePlatforms[0];
  const currentPlatformData = currentPlatformKey
    ? (appConfig.platforms[currentPlatformKey] as RemnawavePlatformData | undefined)
    : undefined;
  const currentPlatformApps = currentPlatformData?.apps || [];

  // Platform display name
  const getPlatformDisplayName = useCallback(
    (key: string): string => {
      const data = appConfig.platforms[key] as RemnawavePlatformData | undefined;
      if (data?.displayName) {
        const name = getLocalizedText(data.displayName);
        if (name) return name;
      }
      if (appConfig.platformNames?.[key]) {
        return getLocalizedText(appConfig.platformNames[key]);
      }
      const fallback: Record<string, string> = {
        ios: 'iOS',
        android: 'Android',
        windows: 'Windows',
        macos: 'macOS',
        linux: 'Linux',
        androidTV: 'Android TV',
        appleTV: 'Apple TV',
      };
      return fallback[key] || key;
    },
    [appConfig.platforms, appConfig.platformNames, getLocalizedText],
  );

  // Platform SVG icon for dropdown
  const currentPlatformSvg = getSvgHtml(currentPlatformData?.svgIconKey);

  // Block renderer
  const blockType = appConfig.uiConfig?.installationGuidesBlockType || 'cards';
  const Renderer = RENDERERS[blockType] || CardsBlock;

  return (
    <div className="space-y-6 pb-6">
      {/* Header + platform dropdown */}
      <div className="flex items-center gap-3">
        {!isTelegramWebApp && (
          <button
            onClick={onGoBack}
            className="flex h-10 w-10 items-center justify-center rounded-xl border border-dark-700 bg-dark-800 transition-colors hover:border-dark-600"
          >
            <BackIcon />
          </button>
        )}
        <h2 className="flex-1 text-lg font-bold text-dark-100">
          {getBaseTranslation('installationGuideHeader', 'subscription.connection.title')}
        </h2>
        {availablePlatforms.length > 1 && (
          <div className="relative flex items-center">
            {currentPlatformSvg && (
              <div
                className="pointer-events-none absolute left-3 z-10 h-5 w-5 text-dark-400 [&>svg]:h-full [&>svg]:w-full"
                dangerouslySetInnerHTML={{ __html: currentPlatformSvg }}
              />
            )}
            <select
              value={currentPlatformKey || ''}
              onChange={(e) => {
                const newPlatform = e.target.value;
                setActivePlatformKey(newPlatform);
                const data = appConfig.platforms[newPlatform] as RemnawavePlatformData | undefined;
                if (data?.apps?.length) {
                  const app = data.apps.find((a) => a.featured) || data.apps[0];
                  if (app) setSelectedApp(app);
                }
              }}
              className={`appearance-none rounded-xl border border-dark-700 bg-dark-800 py-2 pr-8 text-sm font-medium text-dark-200 outline-none transition-colors hover:border-dark-600 ${
                currentPlatformSvg ? 'pl-10' : 'pl-4'
              }`}
            >
              {availablePlatforms.map((p) => (
                <option key={p} value={p}>
                  {getPlatformDisplayName(p)}
                </option>
              ))}
            </select>
            <div className="pointer-events-none absolute right-2.5 text-dark-400">
              <svg
                className="h-4 w-4"
                fill="none"
                viewBox="0 0 24 24"
                stroke="currentColor"
                strokeWidth={2}
              >
                <path strokeLinecap="round" strokeLinejoin="round" d="M8 9l4-4 4 4M8 15l4 4 4-4" />
              </svg>
            </div>
          </div>
        )}
      </div>

      {/* App chips */}
      {currentPlatformApps.length > 0 && (
        <div className="flex flex-wrap gap-2">
          {currentPlatformApps.map((app, idx) => {
            const isSelected = selectedApp?.name === app.name;
            const appIconSvg = getSvgHtml(app.svgIconKey);
            return (
              <button
                key={app.name + idx}
                onClick={() => setSelectedApp(app)}
                className={`relative flex min-w-[calc(50%-0.25rem)] items-center gap-2 overflow-hidden rounded-xl px-4 py-2 text-sm font-medium transition-all active:scale-[0.97] ${
                  isSelected
                    ? 'bg-accent-500/15 text-accent-400 ring-1 ring-accent-500/40'
                    : 'border border-dark-700/50 bg-dark-800/80 text-dark-200 hover:border-dark-600/50 hover:bg-dark-700/80'
                }`}
              >
                {app.featured && <span className="h-2 w-2 shrink-0 rounded-full bg-amber-400" />}
                <span className="relative z-10 truncate">{app.name}</span>
                {appIconSvg && (
                  <div
                    className="ml-auto h-7 w-7 shrink-0 opacity-30 [&>svg]:h-full [&>svg]:w-full"
                    dangerouslySetInnerHTML={{ __html: appIconSvg }}
                  />
                )}
              </button>
            );
          })}
        </div>
      )}

      {/* Tutorial button */}
      {appConfig.baseSettings?.isShowTutorialButton && appConfig.baseSettings?.tutorialUrl && (
        <a
          href={appConfig.baseSettings.tutorialUrl}
          target="_blank"
          rel="noopener noreferrer"
          className="btn-secondary w-full justify-center"
        >
          <svg
            className="h-5 w-5"
            fill="none"
            viewBox="0 0 24 24"
            stroke="currentColor"
            strokeWidth={1.5}
          >
            <path
              strokeLinecap="round"
              strokeLinejoin="round"
              d="M12 6.042A8.967 8.967 0 006 3.75c-1.052 0-2.062.18-3 .512v14.25A8.987 8.987 0 016 18c2.305 0 4.408.867 6 2.292m0-14.25a8.966 8.966 0 016-2.292c1.052 0 2.062.18 3 .512v14.25A8.987 8.987 0 0018 18a8.967 8.967 0 00-6 2.292m0-14.25v14.25"
            />
          </svg>
          {getBaseTranslation('tutorial', 'subscription.connection.tutorial')}
        </a>
      )}

      {/* Blocks */}
      {selectedApp && (
        <Renderer
          blocks={selectedApp.blocks}
          isMobile={isMobile}
          getLocalizedText={getLocalizedText}
          getSvgHtml={getSvgHtml}
          renderBlockButtons={renderBlockButtons}
        />
      )}
    </div>
  );
}