import { create } from 'zustand';
import { invoke } from '@tauri-apps/api/core';

/**
 * Mempool statistics from the network
 */
export interface MempoolStats {
  txCount: number;
  totalSizeBytes: number;
  totalFees: number;
  minFeeRate: number;     // sompi per byte
  avgFeeRate: number;
  maxFeeRate: number;
  percentile10: number;   // fee rate at 10th percentile
  percentile50: number;   // fee rate at 50th percentile (median)
  percentile90: number;   // fee rate at 90th percentile
  lastUpdated: number;    // unix timestamp
}

/**
 * Fee tier recommendation
 */
export interface FeeRecommendation {
  tier: 'economy' | 'standard' | 'priority' | 'instant';
  feeRate: number;        // sompi per byte
  estimatedBlocks: number;
  estimatedTimeSecs: number;
  description: string;
}

/**
 * Historical fee data point for charting
 */
export interface FeeHistoryPoint {
  timestamp: number;
  avgFeeRate: number;
  minFeeRate: number;
  maxFeeRate: number;
  blockHeight: number;
}

/**
 * Full fee analytics data
 */
export interface FeeAnalytics {
  mempool: MempoolStats;
  recommendations: FeeRecommendation[];
  feeHistory: FeeHistoryPoint[];
  networkCongestion: 'low' | 'medium' | 'high';
  blockTargetTimeSecs: number;
}

interface FeeAnalyticsState {
  // State
  analytics: FeeAnalytics | null;
  selectedTier: FeeRecommendation['tier'];
  isLoading: boolean;
  error: string | null;
  autoRefresh: boolean;
  refreshIntervalMs: number;

  // Actions
  fetchAnalytics: () => Promise<void>;
  setSelectedTier: (tier: FeeRecommendation['tier']) => void;
  setAutoRefresh: (enabled: boolean) => void;
  calculateFee: (txSizeBytes: number) => Promise<number>;
}

// Transform snake_case backend response to camelCase
function transformMempoolStats(data: any): MempoolStats {
  return {
    txCount: data.tx_count,
    totalSizeBytes: data.total_size_bytes,
    totalFees: data.total_fees,
    minFeeRate: data.min_fee_rate,
    avgFeeRate: data.avg_fee_rate,
    maxFeeRate: data.max_fee_rate,
    percentile10: data.percentile_10,
    percentile50: data.percentile_50,
    percentile90: data.percentile_90,
    lastUpdated: data.last_updated,
  };
}

function transformRecommendation(data: any): FeeRecommendation {
  return {
    tier: data.tier as FeeRecommendation['tier'],
    feeRate: data.fee_rate,
    estimatedBlocks: data.estimated_blocks,
    estimatedTimeSecs: data.estimated_time_secs,
    description: data.description,
  };
}

function transformFeeHistory(data: any): FeeHistoryPoint {
  return {
    timestamp: data.timestamp,
    avgFeeRate: data.avg_fee_rate,
    minFeeRate: data.min_fee_rate,
    maxFeeRate: data.max_fee_rate,
    blockHeight: data.block_height,
  };
}

function transformAnalytics(data: any): FeeAnalytics {
  return {
    mempool: transformMempoolStats(data.mempool),
    recommendations: data.recommendations.map(transformRecommendation),
    feeHistory: data.fee_history.map(transformFeeHistory),
    networkCongestion: data.network_congestion as FeeAnalytics['networkCongestion'],
    blockTargetTimeSecs: data.block_target_time_secs,
  };
}

export const useFeeAnalyticsStore = create<FeeAnalyticsState>()((set, get) => ({
  // Initial state
  analytics: null,
  selectedTier: 'standard',
  isLoading: false,
  error: null,
  autoRefresh: true,
  refreshIntervalMs: 30000, // 30 seconds

  // Fetch all analytics data
  fetchAnalytics: async () => {
    set({ isLoading: true, error: null });

    try {
      const data = await invoke<any>('fee_get_analytics');
      const analytics = transformAnalytics(data);
      set({ analytics, isLoading: false });
    } catch (error) {
      const message = error instanceof Error ? error.message : 'Failed to fetch fee analytics';
      set({ error: message, isLoading: false });
    }
  },

  // Set selected fee tier
  setSelectedTier: (tier) => {
    set({ selectedTier: tier });
  },

  // Toggle auto-refresh
  setAutoRefresh: (enabled) => {
    set({ autoRefresh: enabled });
  },

  // Calculate fee for a transaction
  calculateFee: async (txSizeBytes) => {
    const { selectedTier } = get();
    try {
      const fee = await invoke<number>('fee_calculate', {
        txSizeBytes,
        tier: selectedTier,
      });
      return fee;
    } catch (error) {
      // Fallback calculation
      const { analytics } = get();
      const recommendation = analytics?.recommendations.find((r) => r.tier === selectedTier);
      const feeRate = recommendation?.feeRate || 1.0;
      return Math.ceil(txSizeBytes * feeRate);
    }
  },
}));

/**
 * Get the selected recommendation
 */
export function useSelectedRecommendation(): FeeRecommendation | null {
  const { analytics, selectedTier } = useFeeAnalyticsStore();
  return analytics?.recommendations.find((r) => r.tier === selectedTier) || null;
}

/**
 * Get congestion color class
 */
export function getCongestionColor(congestion: FeeAnalytics['networkCongestion']): string {
  switch (congestion) {
    case 'low':
      return 'text-green-400';
    case 'medium':
      return 'text-yellow-400';
    case 'high':
      return 'text-red-400';
    default:
      return 'text-gray-400';
  }
}

/**
 * Get congestion background color
 */
export function getCongestionBgColor(congestion: FeeAnalytics['networkCongestion']): string {
  switch (congestion) {
    case 'low':
      return 'bg-green-500/20 border-green-500/30';
    case 'medium':
      return 'bg-yellow-500/20 border-yellow-500/30';
    case 'high':
      return 'bg-red-500/20 border-red-500/30';
    default:
      return 'bg-gray-500/20 border-gray-500/30';
  }
}

/**
 * Format time duration in human readable format
 */
export function formatDuration(seconds: number): string {
  if (seconds < 60) {
    return `~${seconds}s`;
  } else if (seconds < 3600) {
    const mins = Math.floor(seconds / 60);
    return `~${mins}m`;
  } else {
    const hours = Math.floor(seconds / 3600);
    return `~${hours}h`;
  }
}

/**
 * Format fee rate
 */
export function formatFeeRate(rate: number): string {
  return `${rate.toFixed(2)} sompi/byte`;
}