import React from 'react';
import { Button } from '@/components/ui/button';
import { useConsent } from '@/contexts/consent';
import { useTranslation } from '../i18n/useTranslation';
import { isUploadPath, shouldShowAnalyticsNudge } from '../lib/analyticsConsent';

const PROMPT_STORAGE_KEY = 'fotospiel.guest.analyticsPrompt';
const SNOOZE_MS = 60 * 60 * 1000;
const ACTIVE_IDLE_LIMIT_MS = 20_000;

type PromptStorage = {
  snoozedUntil?: number | null;
};

function readSnoozedUntil(): number | null {
  if (typeof window === 'undefined') {
    return null;
  }

  try {
    const raw = window.localStorage.getItem(PROMPT_STORAGE_KEY);
    if (!raw) {
      return null;
    }
    const parsed = JSON.parse(raw) as PromptStorage;
    return typeof parsed.snoozedUntil === 'number' ? parsed.snoozedUntil : null;
  } catch {
    return null;
  }
}

function writeSnoozedUntil(value: number | null) {
  if (typeof window === 'undefined') {
    return;
  }

  try {
    const payload: PromptStorage = { snoozedUntil: value };
    window.localStorage.setItem(PROMPT_STORAGE_KEY, JSON.stringify(payload));
  } catch {
    // ignore storage failures
  }
}

function randomInt(min: number, max: number): number {
  const low = Math.ceil(min);
  const high = Math.floor(max);
  return Math.floor(Math.random() * (high - low + 1)) + low;
}

export default function GuestAnalyticsNudge({
  enabled,
  pathname,
}: {
  enabled: boolean;
  pathname: string;
}) {
  const { t } = useTranslation();
  const { decisionMade, preferences, savePreferences } = useConsent();
  const analyticsConsent = Boolean(preferences?.analytics);
  const [thresholdSeconds] = React.useState(() => randomInt(60, 120));
  const [thresholdRoutes] = React.useState(() => randomInt(2, 3));
  const [activeSeconds, setActiveSeconds] = React.useState(0);
  const [routeCount, setRouteCount] = React.useState(0);
  const [isOpen, setIsOpen] = React.useState(false);
  const [snoozedUntil, setSnoozedUntil] = React.useState<number | null>(() => readSnoozedUntil());
  const lastPathRef = React.useRef(pathname);
  const lastActivityAtRef = React.useRef(Date.now());
  const visibleRef = React.useRef(typeof document === 'undefined' ? true : document.visibilityState === 'visible');

  const isUpload = isUploadPath(pathname);

  React.useEffect(() => {
    const previousPath = lastPathRef.current;
    const currentPath = pathname;
    lastPathRef.current = currentPath;

    if (previousPath === currentPath) {
      return;
    }

    if (isUploadPath(previousPath) || isUploadPath(currentPath)) {
      return;
    }

    setRouteCount((count) => count + 1);
  }, [pathname]);

  React.useEffect(() => {
    if (typeof window === 'undefined') {
      return undefined;
    }

    const handleActivity = () => {
      lastActivityAtRef.current = Date.now();
    };

    const events: Array<keyof WindowEventMap> = [
      'pointerdown',
      'pointermove',
      'keydown',
      'scroll',
      'touchstart',
    ];

    events.forEach((event) => window.addEventListener(event, handleActivity, { passive: true }));

    return () => {
      events.forEach((event) => window.removeEventListener(event, handleActivity));
    };
  }, []);

  React.useEffect(() => {
    if (typeof document === 'undefined') {
      return undefined;
    }

    const handleVisibility = () => {
      visibleRef.current = document.visibilityState === 'visible';
    };

    document.addEventListener('visibilitychange', handleVisibility);

    return () => document.removeEventListener('visibilitychange', handleVisibility);
  }, []);

  React.useEffect(() => {
    if (typeof window === 'undefined') {
      return undefined;
    }

    const interval = window.setInterval(() => {
      const now = Date.now();

      if (!visibleRef.current) {
        return;
      }

      if (isUploadPath(lastPathRef.current)) {
        return;
      }

      if (now - lastActivityAtRef.current > ACTIVE_IDLE_LIMIT_MS) {
        return;
      }

      setActiveSeconds((seconds) => seconds + 1);
    }, 1000);

    return () => window.clearInterval(interval);
  }, []);

  React.useEffect(() => {
    if (!enabled || analyticsConsent || decisionMade) {
      setIsOpen(false);
      return;
    }

    const shouldOpen = shouldShowAnalyticsNudge({
      decisionMade,
      analyticsConsent,
      snoozedUntil,
      now: Date.now(),
      activeSeconds,
      routeCount,
      thresholdSeconds,
      thresholdRoutes,
      isUpload,
    });

    if (shouldOpen) {
      setIsOpen(true);
    }
  }, [
    enabled,
    analyticsConsent,
    decisionMade,
    snoozedUntil,
    activeSeconds,
    routeCount,
    thresholdSeconds,
    thresholdRoutes,
    isUpload,
  ]);

  React.useEffect(() => {
    if (isUpload) {
      setIsOpen(false);
    }
  }, [isUpload]);

  if (!enabled || decisionMade || analyticsConsent || !isOpen || isUpload) {
    return null;
  }

  const handleSnooze = () => {
    const until = Date.now() + SNOOZE_MS;
    setSnoozedUntil(until);
    writeSnoozedUntil(until);
    setIsOpen(false);
  };

  const handleAllow = () => {
    savePreferences({ analytics: true });
    writeSnoozedUntil(null);
    setIsOpen(false);
  };

  return (
    <div
      className="pointer-events-none fixed inset-x-0 z-40 px-4"
      style={{ bottom: 'calc(env(safe-area-inset-bottom, 0px) + 96px)' }}
    >
      <div className="pointer-events-auto mx-auto max-w-lg rounded-2xl border border-slate-200/80 bg-white/95 p-4 shadow-xl backdrop-blur dark:border-slate-700/60 dark:bg-slate-900/95">
        <div className="flex flex-col gap-3 sm:flex-row sm:items-center sm:justify-between">
          <div className="space-y-1">
            <p className="text-sm font-semibold text-foreground">
              {t('consent.analytics.title')}
            </p>
            <p className="text-xs text-muted-foreground">
              {t('consent.analytics.body')}
            </p>
          </div>
          <div className="flex flex-wrap items-center gap-2">
            <Button type="button" size="sm" variant="ghost" onClick={handleSnooze}>
              {t('consent.analytics.later')}
            </Button>
            <Button type="button" size="sm" onClick={handleAllow}>
              {t('consent.analytics.allow')}
            </Button>
          </div>
        </div>
      </div>
    </div>
  );
}