import React, { useState, useEffect } from 'react';
import {
  View,
  Text,
  StyleSheet,
  SafeAreaView,
  ScrollView,
  TouchableOpacity,
  RefreshControl,
  Alert,
  ActivityIndicator,
} from 'react-native';
import { KurdistanColors } from '../../theme/colors';
import { usePezkuwi } from '../../contexts/PezkuwiContext';

interface Proposal {
  id: string;
  title: string;
  description: string;
  proposer: string;
  status: 'active' | 'passed' | 'rejected' | 'expired';
  votesFor: number;
  votesAgainst: number;
  endBlock: number;
  deposit: string;
}

// Mock data removed - using real blockchain queries from democracy pallet

const ProposalsScreen: React.FC = () => {
  const { api, isApiReady, selectedAccount, error: connectionError } = usePezkuwi();

  const [proposals, setProposals] = useState<Proposal[]>([]);
  const [loading, setLoading] = useState(false);
  const [refreshing, setRefreshing] = useState(false);
  const [selectedFilter, setSelectedFilter] = useState<'all' | 'active' | 'passed' | 'rejected'>('all');

  const formatBalance = (balance: string, decimals: number = 12): string => {
    const value = BigInt(balance);
    const divisor = BigInt(10 ** decimals);
    const wholePart = value / divisor;
    return wholePart.toLocaleString();
  };

  const fetchProposals = async () => {
    if (!api || !isApiReady) return;

    try {
      setLoading(true);

      // Fetch democracy referenda
      if (api.query.democracy?.referendumInfoOf) {
        const referendaData = await api.query.democracy.referendumInfoOf.entries();
        const parsedProposals: Proposal[] = referendaData.map(([key, value]: any) => {
          const index = key.args[0].toNumber();
          const info = value.unwrap();

          if (info.isOngoing) {
            const ongoing = info.asOngoing;
            const ayeVotes = ongoing.tally?.ayes ? BigInt(ongoing.tally.ayes.toString()) : BigInt(0);
            const nayVotes = ongoing.tally?.nays ? BigInt(ongoing.tally.nays.toString()) : BigInt(0);

            return {
              id: `${index}`,
              title: `Referendum #${index}`,
              description: `Proposal hash: ${ongoing.proposalHash?.toString().slice(0, 20)}...`,
              proposer: 'Unknown',
              status: 'active' as const,
              votesFor: Number(ayeVotes / BigInt(10 ** 12)),
              votesAgainst: Number(nayVotes / BigInt(10 ** 12)),
              endBlock: ongoing.end?.toNumber() || 0,
              deposit: '0',
            };
          }

          return null;
        }).filter(Boolean) as Proposal[];

        setProposals(parsedProposals);
      }
    } catch (error) {
      console.error('Failed to load proposals:', error);
      Alert.alert('Error', 'Failed to load proposals from blockchain');
    } finally {
      setLoading(false);
      setRefreshing(false);
    }
  };

  useEffect(() => {
    fetchProposals();
    const interval = setInterval(fetchProposals, 30000);
    return () => clearInterval(interval);
  }, [api, isApiReady]);

  const handleRefresh = () => {
    setRefreshing(true);
    fetchProposals();
  };

  const handleProposalPress = (proposal: Proposal) => {
    Alert.alert(
      proposal.title,
      `${proposal.description}\n\nProposer: ${proposal.proposer.slice(0, 10)}...\nDeposit: ${proposal.deposit}`,
      [
        { text: 'Cancel', style: 'cancel' },
        { text: 'Vote', onPress: () => handleVote(proposal) },
      ]
    );
  };

  const handleVote = (proposal: Proposal) => {
    Alert.alert(
      'Cast Your Vote',
      `Vote on: ${proposal.title}`,
      [
        { text: 'Cancel', style: 'cancel' },
        { text: 'Vote Yes', onPress: () => submitVote(proposal, true) },
        { text: 'Vote No', onPress: () => submitVote(proposal, false) },
      ]
    );
  };

  const submitVote = async (proposal: Proposal, voteYes: boolean) => {
    Alert.alert('Success', `Voted ${voteYes ? 'YES' : 'NO'} on "${proposal.title}"`);
    // TODO: Submit vote to chain
  };

  const handleCreateProposal = () => {
    Alert.alert('Create Proposal', 'Create proposal form would open here');
  };

  const getStatusColor = (status: string) => {
    switch (status) {
      case 'active':
        return KurdistanColors.kesk;
      case 'passed':
        return '#3B82F6';
      case 'rejected':
        return '#EF4444';
      case 'expired':
        return '#999';
      default:
        return '#666';
    }
  };

  const calculateVotePercentage = (proposal: Proposal) => {
    const total = proposal.votesFor + proposal.votesAgainst;
    if (total === 0) return { forPercentage: 0, againstPercentage: 0 };
    return {
      forPercentage: Math.round((proposal.votesFor / total) * 100),
      againstPercentage: Math.round((proposal.votesAgainst / total) * 100),
    };
  };

  const filteredProposals = selectedFilter === 'all'
    ? proposals
    : proposals.filter(p => p.status === selectedFilter);

  // Show error state
  if (connectionError && !api) {
    return (
      <SafeAreaView style={styles.container}>
        <View style={styles.centerContainer}>
          <Text style={styles.errorIcon}>⚠️</Text>
          <Text style={styles.errorTitle}>Connection Failed</Text>
          <Text style={styles.errorMessage}>{connectionError}</Text>
          <Text style={styles.errorHint}>
            • Check your internet connection{'\n'}
            • Connection will retry automatically
          </Text>
          <TouchableOpacity style={styles.retryButton} onPress={fetchProposals}>
            <Text style={styles.retryButtonText}>Retry Now</Text>
          </TouchableOpacity>
        </View>
      </SafeAreaView>
    );
  }

  // Show loading state
  if (!isApiReady || (loading && proposals.length === 0)) {
    return (
      <SafeAreaView style={styles.container}>
        <View style={styles.centerContainer}>
          <ActivityIndicator size="large" color={KurdistanColors.kesk} />
          <Text style={styles.loadingText}>Connecting to blockchain...</Text>
          <Text style={styles.loadingHint}>Please wait</Text>
        </View>
      </SafeAreaView>
    );
  }

  return (
    <SafeAreaView style={styles.container}>
      <ScrollView
        style={styles.scrollContent}
        refreshControl={<RefreshControl refreshing={refreshing} onRefresh={handleRefresh} />}
      >
        {/* Header */}
        <View style={styles.header}>
          <Text style={styles.headerTitle}>Proposals</Text>
          <Text style={styles.headerSubtitle}>Vote on governance proposals</Text>
        </View>

        {/* Create Proposal Button */}
        <TouchableOpacity style={styles.createButton} onPress={handleCreateProposal}>
          <Text style={styles.createButtonText}>➕ Create Proposal</Text>
        </TouchableOpacity>

        {/* Filter Tabs */}
        <View style={styles.filterTabs}>
          <TouchableOpacity
            style={[styles.filterTab, selectedFilter === 'all' && styles.filterTabActive]}
            onPress={() => setSelectedFilter('all')}
          >
            <Text style={[styles.filterTabText, selectedFilter === 'all' && styles.filterTabTextActive]}>
              All
            </Text>
          </TouchableOpacity>
          <TouchableOpacity
            style={[styles.filterTab, selectedFilter === 'active' && styles.filterTabActive]}
            onPress={() => setSelectedFilter('active')}
          >
            <Text style={[styles.filterTabText, selectedFilter === 'active' && styles.filterTabTextActive]}>
              Active
            </Text>
          </TouchableOpacity>
          <TouchableOpacity
            style={[styles.filterTab, selectedFilter === 'passed' && styles.filterTabActive]}
            onPress={() => setSelectedFilter('passed')}
          >
            <Text style={[styles.filterTabText, selectedFilter === 'passed' && styles.filterTabTextActive]}>
              Passed
            </Text>
          </TouchableOpacity>
          <TouchableOpacity
            style={[styles.filterTab, selectedFilter === 'rejected' && styles.filterTabActive]}
            onPress={() => setSelectedFilter('rejected')}
          >
            <Text style={[styles.filterTabText, selectedFilter === 'rejected' && styles.filterTabTextActive]}>
              Rejected
            </Text>
          </TouchableOpacity>
        </View>

        {/* Proposals List */}
        <View style={styles.proposalsList}>
          {filteredProposals.length === 0 ? (
            <View style={styles.emptyContainer}>
              <Text style={styles.emptyIcon}>📋</Text>
              <Text style={styles.emptyText}>No proposals found</Text>
            </View>
          ) : (
            filteredProposals.map((proposal) => {
              const { forPercentage, againstPercentage } = calculateVotePercentage(proposal);
              return (
                <TouchableOpacity
                  key={proposal.id}
                  style={styles.proposalCard}
                  onPress={() => handleProposalPress(proposal)}
                >
                  {/* Proposal Header */}
                  <View style={styles.proposalHeader}>
                    <Text style={styles.proposalTitle}>{proposal.title}</Text>
                    <View style={[styles.statusBadge, { backgroundColor: `${getStatusColor(proposal.status)}15` }]}>
                      <Text style={[styles.statusBadgeText, { color: getStatusColor(proposal.status) }]}>
                        {proposal.status.toUpperCase()}
                      </Text>
                    </View>
                  </View>

                  {/* Description */}
                  <Text style={styles.proposalDescription} numberOfLines={2}>
                    {proposal.description}
                  </Text>

                  {/* Proposer */}
                  <Text style={styles.proposer}>
                    By: {proposal.proposer.slice(0, 10)}...{proposal.proposer.slice(-6)}
                  </Text>

                  {/* Vote Progress Bar */}
                  <View style={styles.voteProgressContainer}>
                    <View style={styles.voteProgressBar}>
                      <View style={[styles.voteProgressFor, { width: `${forPercentage}%` }]} />
                    </View>
                    <View style={styles.voteStats}>
                      <View style={styles.voteStat}>
                        <Text style={styles.voteStatIcon}>✅</Text>
                        <Text style={styles.voteStatText}>{proposal.votesFor.toLocaleString()} ({forPercentage}%)</Text>
                      </View>
                      <View style={styles.voteStat}>
                        <Text style={styles.voteStatIcon}>❌</Text>
                        <Text style={styles.voteStatText}>{proposal.votesAgainst.toLocaleString()} ({againstPercentage}%)</Text>
                      </View>
                    </View>
                  </View>

                  {/* Metadata */}
                  <View style={styles.proposalMetadata}>
                    <Text style={styles.metadataItem}>📦 Deposit: {proposal.deposit}</Text>
                    <Text style={styles.metadataItem}>⏰ Block: {proposal.endBlock.toLocaleString()}</Text>
                  </View>

                  {/* Vote Button */}
                  {proposal.status === 'active' && (
                    <TouchableOpacity
                      style={styles.voteButton}
                      onPress={() => handleVote(proposal)}
                    >
                      <Text style={styles.voteButtonText}>Vote Now</Text>
                    </TouchableOpacity>
                  )}
                </TouchableOpacity>
              );
            })
          )}
        </View>

        {/* Info Note */}
        <View style={styles.infoNote}>
          <Text style={styles.infoNoteIcon}>ℹ️</Text>
          <Text style={styles.infoNoteText}>
            Creating a proposal requires a deposit that will be returned if the proposal passes. Only citizens can vote.
          </Text>
        </View>
      </ScrollView>
    </SafeAreaView>
  );
};

const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: '#F8F9FA',
  },
  scrollContent: {
    flex: 1,
  },
  header: {
    padding: 20,
    paddingBottom: 16,
  },
  headerTitle: {
    fontSize: 28,
    fontWeight: 'bold',
    color: '#333',
    marginBottom: 4,
  },
  headerSubtitle: {
    fontSize: 14,
    color: '#666',
  },
  createButton: {
    backgroundColor: KurdistanColors.kesk,
    marginHorizontal: 16,
    marginBottom: 20,
    paddingVertical: 14,
    borderRadius: 12,
    alignItems: 'center',
  },
  createButtonText: {
    fontSize: 16,
    fontWeight: '600',
    color: '#FFFFFF',
  },
  filterTabs: {
    flexDirection: 'row',
    paddingHorizontal: 16,
    marginBottom: 20,
    gap: 8,
  },
  filterTab: {
    paddingHorizontal: 16,
    paddingVertical: 8,
    borderRadius: 20,
    backgroundColor: '#E5E5E5',
  },
  filterTabActive: {
    backgroundColor: KurdistanColors.kesk,
  },
  filterTabText: {
    fontSize: 14,
    fontWeight: '600',
    color: '#666',
  },
  filterTabTextActive: {
    color: '#FFFFFF',
  },
  proposalsList: {
    paddingHorizontal: 16,
  },
  emptyContainer: {
    padding: 40,
    alignItems: 'center',
  },
  emptyIcon: {
    fontSize: 64,
    marginBottom: 16,
  },
  emptyText: {
    fontSize: 16,
    color: '#666',
    textAlign: 'center',
  },
  proposalCard: {
    backgroundColor: '#FFFFFF',
    borderRadius: 16,
    padding: 16,
    marginBottom: 16,
    shadowColor: '#000',
    shadowOffset: { width: 0, height: 2 },
    shadowOpacity: 0.05,
    shadowRadius: 4,
    elevation: 2,
  },
  proposalHeader: {
    flexDirection: 'row',
    justifyContent: 'space-between',
    alignItems: 'flex-start',
    marginBottom: 12,
  },
  proposalTitle: {
    flex: 1,
    fontSize: 16,
    fontWeight: 'bold',
    color: '#333',
    marginRight: 8,
  },
  statusBadge: {
    paddingHorizontal: 10,
    paddingVertical: 4,
    borderRadius: 12,
  },
  statusBadgeText: {
    fontSize: 10,
    fontWeight: '700',
  },
  proposalDescription: {
    fontSize: 14,
    color: '#666',
    lineHeight: 20,
    marginBottom: 8,
  },
  proposer: {
    fontSize: 12,
    color: '#999',
    fontFamily: 'monospace',
    marginBottom: 16,
  },
  voteProgressContainer: {
    marginBottom: 12,
  },
  voteProgressBar: {
    height: 8,
    backgroundColor: '#FEE2E2',
    borderRadius: 4,
    overflow: 'hidden',
    marginBottom: 8,
  },
  voteProgressFor: {
    height: '100%',
    backgroundColor: KurdistanColors.kesk,
  },
  voteStats: {
    flexDirection: 'row',
    justifyContent: 'space-between',
  },
  voteStat: {
    flexDirection: 'row',
    alignItems: 'center',
    gap: 4,
  },
  voteStatIcon: {
    fontSize: 14,
  },
  voteStatText: {
    fontSize: 13,
    color: '#666',
    fontWeight: '500',
  },
  proposalMetadata: {
    flexDirection: 'row',
    justifyContent: 'space-between',
    marginBottom: 12,
    paddingTop: 12,
    borderTopWidth: 1,
    borderTopColor: '#F0F0F0',
  },
  metadataItem: {
    fontSize: 12,
    color: '#999',
  },
  voteButton: {
    backgroundColor: KurdistanColors.kesk,
    paddingVertical: 10,
    borderRadius: 12,
    alignItems: 'center',
  },
  voteButtonText: {
    fontSize: 14,
    fontWeight: '600',
    color: '#FFFFFF',
  },
  infoNote: {
    flexDirection: 'row',
    backgroundColor: '#FEF3C7',
    marginHorizontal: 16,
    marginTop: 16,
    marginBottom: 24,
    padding: 16,
    borderRadius: 12,
    gap: 12,
  },
  infoNoteIcon: {
    fontSize: 20,
  },
  infoNoteText: {
    flex: 1,
    fontSize: 12,
    color: '#92400E',
    lineHeight: 18,
  },
  // Error & Loading States
  centerContainer: {
    flex: 1,
    justifyContent: 'center',
    alignItems: 'center',
    padding: 32,
  },
  errorIcon: {
    fontSize: 64,
    marginBottom: 16,
  },
  errorTitle: {
    fontSize: 20,
    fontWeight: 'bold',
    color: '#333',
    marginBottom: 8,
  },
  errorMessage: {
    fontSize: 14,
    color: '#666',
    textAlign: 'center',
    marginBottom: 16,
  },
  errorHint: {
    fontSize: 12,
    color: '#999',
    textAlign: 'center',
    lineHeight: 20,
    marginBottom: 24,
  },
  retryButton: {
    backgroundColor: KurdistanColors.kesk,
    paddingHorizontal: 24,
    paddingVertical: 12,
    borderRadius: 8,
  },
  retryButtonText: {
    color: '#FFFFFF',
    fontSize: 14,
    fontWeight: '600',
  },
  loadingText: {
    fontSize: 16,
    color: '#333',
    marginTop: 16,
  },
  loadingHint: {
    fontSize: 12,
    color: '#999',
    marginTop: 8,
  },
});

export default ProposalsScreen;
