import React, { useState, useEffect } from 'react';
import { Heart, Lock, Unlock, Key, Send, Copy, Check, Calendar, User } from 'lucide-react';

const LoveMessageSystem = () => {
  const [currentPartner, setCurrentPartner] = useState(null);
  const [partnershipId, setPartnershipId] = useState(null);
  const [messages, setMessages] = useState([]);
  const [newMessage, setNewMessage] = useState('');
  const [unlockKey, setUnlockKey] = useState('');
  const [inputUnlockKey, setInputUnlockKey] = useState('');
  const [showSetup, setShowSetup] = useState(true);
  const [partnerName, setPartnerName] = useState('');
  const [copied, setCopied] = useState(false);
  const [notification, setNotification] = useState('');

  // Initialize or load partnership
  useEffect(() => {
    const savedPartnerId = localStorage.getItem('partnerId');
    const savedPartnershipId = localStorage.getItem('partnershipId');
    
    if (savedPartnerId && savedPartnershipId) {
      setCurrentPartner(parseInt(savedPartnerId));
      setPartnershipId(savedPartnershipId);
      setShowSetup(false);
      loadMessages(savedPartnershipId);
      loadUnlockKey(savedPartnershipId, parseInt(savedPartnerId));
    }
  }, []);

  const generateId = () => {
    return Math.random().toString(36).substr(2, 9);
  };

  const generateUnlockKey = () => {
    return Math.random().toString(36).substr(2, 12).toUpperCase();
  };

  const createPartnership = async (partner) => {
    const newPartnershipId = generateId();
    const newUnlockKey = generateUnlockKey();
    
    setCurrentPartner(partner);
    setPartnershipId(newPartnershipId);
    setUnlockKey(newUnlockKey);
    
    localStorage.setItem('partnerId', partner.toString());
    localStorage.setItem('partnershipId', newPartnershipId);
    
    // Store in memory (simulating Supabase)
    const partnership = {
      id: newPartnershipId,
      partner1_unlock_key: partner === 1 ? newUnlockKey : null,
      partner2_unlock_key: partner === 2 ? newUnlockKey : null,
      created_at: new Date().toISOString()
    };
    
    localStorage.setItem(`partnership_${newPartnershipId}`, JSON.stringify(partnership));
    setShowSetup(false);
    showNotification(`Welcome, Partner ${partner}! Share this ID with your partner: ${newPartnershipId}`);
  };

  const joinPartnership = async (existingId, partner) => {
    const partnership = localStorage.getItem(`partnership_${existingId}`);
    
    if (partnership) {
      const newUnlockKey = generateUnlockKey();
      const partnershipData = JSON.parse(partnership);
      
      if (partner === 1) {
        partnershipData.partner1_unlock_key = newUnlockKey;
      } else {
        partnershipData.partner2_unlock_key = newUnlockKey;
      }
      
      localStorage.setItem(`partnership_${existingId}`, JSON.stringify(partnershipData));
      
      setCurrentPartner(partner);
      setPartnershipId(existingId);
      setUnlockKey(newUnlockKey);
      
      localStorage.setItem('partnerId', partner.toString());
      localStorage.setItem('partnershipId', existingId);
      
      setShowSetup(false);
      loadMessages(existingId);
      showNotification(`Successfully joined partnership!`);
    } else {
      showNotification('Partnership ID not found!');
    }
  };

  const loadMessages = (pId) => {
    const stored = localStorage.getItem(`messages_${pId}`);
    if (stored) {
      setMessages(JSON.parse(stored));
    }
  };

  const loadUnlockKey = (pId, partner) => {
    const partnership = localStorage.getItem(`partnership_${pId}`);
    if (partnership) {
      const data = JSON.parse(partnership);
      const key = partner === 1 ? data.partner1_unlock_key : data.partner2_unlock_key;
      setUnlockKey(key || '');
    }
  };

  const saveMessages = (pId, msgs) => {
    localStorage.setItem(`messages_${pId}`, JSON.stringify(msgs));
  };

  const sendMessage = async () => {
    if (!newMessage.trim()) return;

    const message = {
      id: generateId(),
      partnership_id: partnershipId,
      sender: currentPartner,
      content: newMessage,
      sent_at: new Date().toISOString(),
      unlocked: false
    };

    const updatedMessages = [...messages, message];
    setMessages(updatedMessages);
    saveMessages(partnershipId, updatedMessages);
    setNewMessage('');
    showNotification('Message sent! 💕');
  };

  const checkAutoUnlock = (sentDate) => {
    const sent = new Date(sentDate);
    const now = new Date();
    const daysDiff = Math.floor((now - sent) / (1000 * 60 * 60 * 24));
    return daysDiff >= 30;
  };

  const useUnlockKey = () => {
    if (!inputUnlockKey.trim()) {
      showNotification('Please enter an unlock key');
      return;
    }

    const partnership = localStorage.getItem(`partnership_${partnershipId}`);
    if (!partnership) return;

    const data = JSON.parse(partnership);
    const otherPartnerKey = currentPartner === 1 ? data.partner2_unlock_key : data.partner1_unlock_key;

    if (inputUnlockKey === otherPartnerKey) {
      // Unlock all messages
      const updatedMessages = messages.map(msg => ({
        ...msg,
        unlocked: true
      }));
      setMessages(updatedMessages);
      saveMessages(partnershipId, updatedMessages);

      // Invalidate the used key and generate new one for other partner
      if (currentPartner === 1) {
        data.partner2_unlock_key = generateUnlockKey();
      } else {
        data.partner1_unlock_key = generateUnlockKey();
      }
      localStorage.setItem(`partnership_${partnershipId}`, JSON.stringify(data));

      setInputUnlockKey('');
      showNotification('Messages unlocked! 🎉');
    } else {
      showNotification('Invalid unlock key!');
    }
  };

  const regenerateKey = () => {
    const newKey = generateUnlockKey();
    setUnlockKey(newKey);

    const partnership = localStorage.getItem(`partnership_${partnershipId}`);
    if (partnership) {
      const data = JSON.parse(partnership);
      if (currentPartner === 1) {
        data.partner1_unlock_key = newKey;
      } else {
        data.partner2_unlock_key = newKey;
      }
      localStorage.setItem(`partnership_${partnershipId}`, JSON.stringify(data));
      showNotification('New unlock key generated! 🔑');
    }
  };

  const copyToClipboard = (text) => {
    navigator.clipboard.writeText(text);
    setCopied(true);
    setTimeout(() => setCopied(false), 2000);
  };

  const showNotification = (msg) => {
    setNotification(msg);
    setTimeout(() => setNotification(''), 3000);
  };

  const myMessages = messages.filter(m => m.sender === currentPartner);
  const partnerMessages = messages.filter(m => m.sender !== currentPartner && m.sender !== null);

  if (showSetup) {
    return (
      <div className="min-h-screen bg-gradient-to-br from-pink-100 via-purple-50 to-rose-100 p-8">
        <div className="max-w-md mx-auto">
          <div className="text-center mb-8">
            <Heart className="w-16 h-16 text-rose-500 mx-auto mb-4" />
            <h1 className="text-4xl font-bold text-rose-600 mb-2">Love Messages</h1>
            <p className="text-gray-600">Connect with your partner</p>
          </div>

          <div className="bg-white rounded-2xl shadow-xl p-8 space-y-6">
            <div>
              <h2 className="text-2xl font-bold text-gray-800 mb-4">Create New Partnership</h2>
              <div className="space-y-3">
                <button
                  onClick={() => createPartnership(1)}
                  className="w-full bg-rose-500 text-white py-3 rounded-xl font-semibold hover:bg-rose-600 transition"
                >
                  I'm Partner 1
                </button>
                <button
                  onClick={() => createPartnership(2)}
                  className="w-full bg-purple-500 text-white py-3 rounded-xl font-semibold hover:bg-purple-600 transition"
                >
                  I'm Partner 2
                </button>
              </div>
            </div>

            <div className="border-t pt-6">
              <h2 className="text-2xl font-bold text-gray-800 mb-4">Join Existing</h2>
              <input
                type="text"
                placeholder="Enter Partnership ID"
                value={partnerName}
                onChange={(e) => setPartnerName(e.target.value)}
                className="w-full px-4 py-3 border border-gray-300 rounded-xl mb-3 focus:ring-2 focus:ring-rose-500 focus:border-transparent"
              />
              <div className="space-y-3">
                <button
                  onClick={() => joinPartnership(partnerName, 1)}
                  className="w-full bg-rose-400 text-white py-3 rounded-xl font-semibold hover:bg-rose-500 transition"
                >
                  Join as Partner 1
                </button>
                <button
                  onClick={() => joinPartnership(partnerName, 2)}
                  className="w-full bg-purple-400 text-white py-3 rounded-xl font-semibold hover:bg-purple-500 transition"
                >
                  Join as Partner 2
                </button>
              </div>
            </div>
          </div>
        </div>
      </div>
    );
  }

  return (
    <div className="min-h-screen bg-gradient-to-br from-pink-100 via-purple-50 to-rose-100 p-4 md:p-8">
      {notification && (
        <div className="fixed top-4 right-4 bg-white shadow-lg rounded-xl px-6 py-3 z-50 animate-pulse">
          <p className="text-gray-800 font-semibold">{notification}</p>
        </div>
      )}

      <div className="max-w-6xl mx-auto">
        <div className="text-center mb-8">
          <Heart className="w-12 h-12 text-rose-500 mx-auto mb-4" />
          <h1 className="text-3xl md:text-4xl font-bold text-rose-600 mb-2">
            Partner {currentPartner} Dashboard
          </h1>
          <p className="text-gray-600 text-sm">Partnership ID: {partnershipId}</p>
        </div>

        <div className="grid md:grid-cols-2 gap-6 mb-8">
          {/* Send Message Section */}
          <div className="bg-white rounded-2xl shadow-xl p-6">
            <h2 className="text-2xl font-bold text-gray-800 mb-4 flex items-center gap-2">
              <Send className="w-6 h-6 text-rose-500" />
              Send Love Message
            </h2>
            <textarea
              value={newMessage}
              onChange={(e) => setNewMessage(e.target.value)}
              placeholder="Write your daily love message..."
              className="w-full h-32 px-4 py-3 border border-gray-300 rounded-xl mb-4 focus:ring-2 focus:ring-rose-500 focus:border-transparent resize-none"
            />
            <button
              onClick={sendMessage}
              className="w-full bg-rose-500 text-white py-3 rounded-xl font-semibold hover:bg-rose-600 transition flex items-center justify-center gap-2"
            >
              <Heart className="w-5 h-5" />
              Send Message
            </button>
          </div>

          {/* Unlock Key Section */}
          <div className="bg-white rounded-2xl shadow-xl p-6">
            <h2 className="text-2xl font-bold text-gray-800 mb-4 flex items-center gap-2">
              <Key className="w-6 h-6 text-purple-500" />
              Your Unlock Key
            </h2>
            <div className="bg-purple-50 rounded-xl p-4 mb-4">
              <p className="text-sm text-gray-600 mb-2">Share this key with your partner:</p>
              <div className="flex items-center gap-2">
                <code className="flex-1 bg-white px-4 py-2 rounded-lg font-mono text-lg font-bold text-purple-600">
                  {unlockKey}
                </code>
                <button
                  onClick={() => copyToClipboard(unlockKey)}
                  className="bg-purple-500 text-white p-2 rounded-lg hover:bg-purple-600 transition"
                >
                  {copied ? <Check className="w-5 h-5" /> : <Copy className="w-5 h-5" />}
                </button>
              </div>
            </div>
            <button
              onClick={regenerateKey}
              className="w-full bg-purple-500 text-white py-3 rounded-xl font-semibold hover:bg-purple-600 transition mb-4"
            >
              Generate New Key
            </button>

            <div className="border-t pt-4">
              <p className="text-sm text-gray-600 mb-2">Use partner's key to unlock:</p>
              <input
                type="text"
                value={inputUnlockKey}
                onChange={(e) => setInputUnlockKey(e.target.value)}
                placeholder="Enter unlock key"
                className="w-full px-4 py-2 border border-gray-300 rounded-xl mb-2 focus:ring-2 focus:ring-purple-500 focus:border-transparent"
              />
              <button
                onClick={useUnlockKey}
                className="w-full bg-green-500 text-white py-3 rounded-xl font-semibold hover:bg-green-600 transition flex items-center justify-center gap-2"
              >
                <Unlock className="w-5 h-5" />
                Unlock Messages
              </button>
            </div>
          </div>
        </div>

        {/* Messages Display */}
        <div className="grid md:grid-cols-2 gap-6">
          {/* My Messages */}
          <div className="bg-white rounded-2xl shadow-xl p-6">
            <h2 className="text-2xl font-bold text-gray-800 mb-4 flex items-center gap-2">
              <User className="w-6 h-6 text-rose-500" />
              My Messages ({myMessages.length})
            </h2>
            <div className="space-y-3 max-h-96 overflow-y-auto">
              {myMessages.map((msg) => (
                <div key={msg.id} className="bg-rose-50 rounded-xl p-4 border-2 border-rose-200">
                  <div className="flex items-center justify-between mb-2">
                    <span className="text-xs text-gray-500 flex items-center gap-1">
                      <Calendar className="w-3 h-3" />
                      {new Date(msg.sent_at).toLocaleDateString()}
                    </span>
                  </div>
                  <p className="text-gray-800">{msg.content}</p>
                </div>
              ))}
              {myMessages.length === 0 && (
                <p className="text-gray-400 text-center py-8">No messages sent yet</p>
              )}
            </div>
          </div>

          {/* Partner's Messages */}
          <div className="bg-white rounded-2xl shadow-xl p-6">
            <h2 className="text-2xl font-bold text-gray-800 mb-4 flex items-center gap-2">
              <Heart className="w-6 h-6 text-purple-500" />
              Partner's Messages ({partnerMessages.length})
            </h2>
            <div className="space-y-3 max-h-96 overflow-y-auto">
              {partnerMessages.map((msg) => {
                const autoUnlock = checkAutoUnlock(msg.sent_at);
                const isUnlocked = msg.unlocked || autoUnlock;
                const daysRemaining = 30 - Math.floor((new Date() - new Date(msg.sent_at)) / (1000 * 60 * 60 * 24));

                return (
                  <div
                    key={msg.id}
                    className={`rounded-xl p-4 border-2 ${
                      isUnlocked ? 'bg-green-50 border-green-200' : 'bg-gray-100 border-gray-300'
                    }`}
                  >
                    <div className="flex items-center justify-between mb-2">
                      <span className="text-xs text-gray-500 flex items-center gap-1">
                        <Calendar className="w-3 h-3" />
                        {new Date(msg.sent_at).toLocaleDateString()}
                      </span>
                      {isUnlocked ? (
                        <Unlock className="w-4 h-4 text-green-500" />
                      ) : (
                        <Lock className="w-4 h-4 text-gray-500" />
                      )}
                    </div>
                    {isUnlocked ? (
                      <p className="text-gray-800">{msg.content}</p>
                    ) : (
                      <div className="text-center py-4">
                        <Lock className="w-8 h-8 text-gray-400 mx-auto mb-2" />
                        <p className="text-gray-500 text-sm">
                          Unlocks in {daysRemaining} days
                        </p>
                        <p className="text-gray-400 text-xs mt-1">
                          Or use unlock key
                        </p>
                      </div>
                    )}
                  </div>
                );
              })}
              {partnerMessages.length === 0 && (
                <p className="text-gray-400 text-center py-8">
                  Waiting for partner's messages...
                </p>
              )}
            </div>
          </div>
        </div>
      </div>
    </div>
  );
};

export default LoveMessageSystem;