import { useEffect, useMemo, useCallback } from 'react';
import { RefreshCw } from 'lucide-react';
import { type DateRange } from '@/services/dashboard.service';
import { useAuth, hasManagementAccess } from '@/contexts/AuthContext';

// Custom Hooks
import { useDashboardFilters } from './hooks/useDashboardFilters';
import { useDashboardPagination } from './hooks/useDashboardPagination';
import { useDashboardData } from './hooks/useDashboardData';
import { useDashboardExports } from './hooks/useDashboardExports';

// Components
import { DashboardHero } from './components/DashboardHero';
import { DashboardFiltersBar } from './components/DashboardFiltersBar';
import { AdminKPICards } from './components/sections/AdminKPICards';
import { UserKPICards } from './components/sections/UserKPICards';
import { CriticalAlertsSection } from './components/sections/CriticalAlertsSection';
import { RecentActivitySection } from './components/sections/RecentActivitySection';
import { AdminAnalyticsSection } from './components/sections/AdminAnalyticsSection';
import { UserMetricsSection } from './components/sections/UserMetricsSection';
import { PriorityDistributionReport } from './components/sections/PriorityDistributionReport';
import { TATBreachReport } from './components/sections/TATBreachReport';
import { UpcomingDeadlinesSection } from './components/sections/UpcomingDeadlinesSection';
import { AIRemarkUtilizationReport } from './components/sections/AIRemarkUtilizationReport';
import { ApproverPerformanceReport } from './components/sections/ApproverPerformanceReport';

// Utils
import { buildFilterUrl, getQuickActions } from './utils/dashboardNavigation';
import { getBreachedRequests, getUpcomingDeadlinesNotBreached } from './utils/dashboardCalculations';

interface DashboardProps {
  onNavigate?: (page: string) => void;
  onNewRequest?: () => void;
}


export function Dashboard({ onNavigate, onNewRequest }: DashboardProps) {
  const { user } = useAuth();
  
  // Determine user role
  const isAdmin = useMemo(() => hasManagementAccess(user), [user]);

  // Filters
  const filters = useDashboardFilters();
  const { dateRange, customStartDate, customEndDate, showCustomDatePicker, handleDateRangeChange, handleApplyCustomDate, resetCustomDates, setCustomStartDate, setCustomEndDate, setShowCustomDatePicker } = filters;

  // Pagination
  const pagination = useDashboardPagination();
  const {
    activity: activityPagination,
    critical: criticalPagination,
    deadlines: deadlinesPagination,
    approver: approverPagination,
    updateActivityPagination,
    updateCriticalPagination,
    updateDeadlinesPagination,
    updateApproverPagination,
    handleActivityPageChange,
    handleCriticalPageChange,
    handleDeadlinesPageChange,
    handleApproverPageChange,
  } = pagination;

  // Data fetching
  const dashboardData = useDashboardData({
    isAdmin,
    dateRange,
    customStartDate,
    customEndDate,
    onPaginationUpdate: {
      activity: updateActivityPagination,
      critical: updateCriticalPagination,
      deadlines: updateDeadlinesPagination,
      approver: updateApproverPagination,
    },
  });
  const {
    kpis,
    recentActivity,
    criticalRequests,
    departmentStats,
    priorityDistribution,
    upcomingDeadlines,
    aiRemarkUtilization,
    approverPerformance,
    loading,
    refreshing,
    fetchDashboardData,
    fetchRecentActivities,
    fetchCriticalRequests,
    fetchUpcomingDeadlines,
    fetchApproverPerformance,
  } = dashboardData;

  // Exports
  const exports = useDashboardExports();
  const { exportingDeptStats, exportingApproverPerformance, handleExportDepartmentStats, handleExportApproverPerformance } = exports;

  // Calculated values
  const breachedRequests = useMemo(() => getBreachedRequests(criticalRequests), [criticalRequests]);
  const upcomingDeadlinesNotBreached = useMemo(() => getUpcomingDeadlinesNotBreached(upcomingDeadlines), [upcomingDeadlines]);

  // Handlers
  const handleRefresh = useCallback(() => {
    if (dateRange === 'custom' && customStartDate && customEndDate) {
      fetchDashboardData(true);
    } else {
      fetchDashboardData(true);
    }
  }, [dateRange, customStartDate, customEndDate, fetchDashboardData]);

  const handleApplyCustomDateWrapper = useCallback(() => {
    handleApplyCustomDate(() => {
      if (customStartDate && customEndDate) {
        fetchDashboardData(false);
      }
    });
  }, [customStartDate, customEndDate, handleApplyCustomDate, fetchDashboardData]);

  const handleActivityPageChangeWrapper = useCallback((newPage: number) => {
    handleActivityPageChange(newPage, fetchRecentActivities);
  }, [handleActivityPageChange, fetchRecentActivities]);

  const handleCriticalPageChangeWrapper = useCallback((newPage: number) => {
    handleCriticalPageChange(newPage, fetchCriticalRequests);
  }, [handleCriticalPageChange, fetchCriticalRequests]);

  const handleDeadlinesPageChangeWrapper = useCallback((newPage: number) => {
    handleDeadlinesPageChange(newPage, fetchUpcomingDeadlines);
  }, [handleDeadlinesPageChange, fetchUpcomingDeadlines]);

  const handleApproverPageChangeWrapper = useCallback((newPage: number) => {
    handleApproverPageChange(newPage, () => fetchApproverPerformance(newPage));
  }, [handleApproverPageChange, fetchApproverPerformance]);

  useEffect(() => {
    if (dateRange === 'custom') {
      // Don't auto-fetch for custom dates until user applies them
      if (customStartDate && customEndDate) {
        fetchDashboardData(false);
      }
    } else {
      fetchDashboardData(false);
    }
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [dateRange, customStartDate, customEndDate]);

  // Quick actions
  const quickActions = useMemo(() => getQuickActions(isAdmin, onNewRequest, onNavigate), [isAdmin, onNewRequest, onNavigate]);

  // KPI click handler
  const handleKPIClick = useCallback((filters: {
    status?: string;
    priority?: string;
    slaCompliance?: string;
    department?: string;
    dateRange?: DateRange;
    startDate?: Date;
    endDate?: Date;
    targetPage?: 'requests' | 'open-requests' | 'my-requests';
  }) => {
    const url = buildFilterUrl(filters);
    onNavigate?.(url);
  }, [onNavigate]);

  if (loading) {
    return (
      <div className="flex items-center justify-center h-screen">
        <div className="flex flex-col items-center gap-4">
          <RefreshCw className="w-8 h-8 animate-spin text-blue-600" />
          <p className="text-muted-foreground">Loading dashboard...</p>
        </div>
      </div>
    );
  }

  return (
    <div className="space-y-4 sm:space-y-6 max-w-7xl mx-auto p-3 sm:p-4" data-testid="dashboard">
      <DashboardHero isAdmin={isAdmin} quickActions={quickActions} />
      
      <DashboardFiltersBar
        isAdmin={isAdmin}
        dateRange={dateRange}
        customStartDate={customStartDate}
        customEndDate={customEndDate}
        showCustomDatePicker={showCustomDatePicker}
        refreshing={refreshing}
        onDateRangeChange={handleDateRangeChange}
        onCustomStartDateChange={setCustomStartDate}
        onCustomEndDateChange={setCustomEndDate}
        onShowCustomDatePickerChange={setShowCustomDatePicker}
        onApplyCustomDate={handleApplyCustomDateWrapper}
        onResetCustomDates={resetCustomDates}
        onRefresh={handleRefresh}
      />

      {/* KPI Cards Section */}
      {isAdmin ? (
        <AdminKPICards
          kpis={kpis}
          priorityDistribution={priorityDistribution}
          dateRange={dateRange}
          customStartDate={customStartDate}
          customEndDate={customEndDate}
          onKPIClick={handleKPIClick}
        />
      ) : (
        <UserKPICards
          kpis={kpis}
          criticalRequests={criticalRequests}
          dateRange={dateRange}
          customStartDate={customStartDate}
          customEndDate={customEndDate}
          onKPIClick={handleKPIClick}
          onNavigate={onNavigate}
          userId={(user as any)?.userId}
          userDisplayName={(user as any)?.displayName || (user as any)?.email}
        />
      )}

      {/* Alerts and Activity Section */}
      <div className="grid grid-cols-1 lg:grid-cols-3 gap-4 sm:gap-6 h-[90vh] min-h-[720px] lg:h-[60vh] lg:min-h-[480px]" data-testid="dashboard-alerts-activity">
        <CriticalAlertsSection
          isAdmin={isAdmin}
          breachedRequests={breachedRequests}
          pagination={criticalPagination}
          onPageChange={handleCriticalPageChangeWrapper}
          onNavigate={onNavigate}
        />
        <RecentActivitySection
          isAdmin={isAdmin}
          recentActivity={recentActivity}
          pagination={activityPagination}
          refreshing={refreshing}
          onPageChange={handleActivityPageChangeWrapper}
          onRefresh={handleRefresh}
          onNavigate={onNavigate}
          currentUserId={(user as any)?.userId}
          currentUserDisplayName={(user as any)?.displayName}
          currentUserEmail={(user as any)?.email}
        />
      </div>

      {/* ADMIN - Additional Analytics */}
      {isAdmin && kpis && (
        <AdminAnalyticsSection
          kpis={kpis}
          upcomingDeadlines={upcomingDeadlines}
          criticalRequests={criticalRequests}
          departmentStats={departmentStats}
          dateRange={dateRange}
          customStartDate={customStartDate}
          customEndDate={customEndDate}
          exportingDeptStats={exportingDeptStats}
          onKPIClick={handleKPIClick}
          onExportDepartmentStats={handleExportDepartmentStats}
        />
      )}

      {/* NORMAL USER - Personal Metrics */}
      {!isAdmin && kpis && <UserMetricsSection kpis={kpis} />}

      {/* Priority Distribution Report */}
      {isAdmin && priorityDistribution.length > 0 && (
        <PriorityDistributionReport
          priorityDistribution={priorityDistribution}
          onNavigate={onNavigate}
        />
      )}

      {/* TAT Breach Report */}
      {isAdmin && breachedRequests.length > 0 && (
        <TATBreachReport
          breachedRequests={breachedRequests}
          pagination={criticalPagination}
          dateRange={dateRange}
          customStartDate={customStartDate}
          customEndDate={customEndDate}
          onPageChange={handleCriticalPageChangeWrapper}
          onKPIClick={handleKPIClick}
          onNavigate={onNavigate}
        />
      )}

      {/* Upcoming Deadlines / Workflow Aging */}
      {upcomingDeadlinesNotBreached.length > 0 && (
        <UpcomingDeadlinesSection
          isAdmin={isAdmin}
          upcomingDeadlines={upcomingDeadlinesNotBreached}
          pagination={deadlinesPagination}
          onPageChange={handleDeadlinesPageChangeWrapper}
          onNavigate={onNavigate}
        />
      )}

      {/* AI Remark Utilization Report (Admin Only) */}
      {isAdmin && aiRemarkUtilization && (
        <AIRemarkUtilizationReport aiRemarkUtilization={aiRemarkUtilization} />
      )}

      {/* Approver Performance Report (Admin Only) */}
      {isAdmin && approverPerformance.length > 0 && (
        <ApproverPerformanceReport
          approverPerformance={approverPerformance}
          pagination={approverPagination}
          dateRange={dateRange}
          customStartDate={customStartDate}
          customEndDate={customEndDate}
          loading={loading}
          exportingApproverPerformance={exportingApproverPerformance}
          onPageChange={handleApproverPageChangeWrapper}
          onExport={handleExportApproverPerformance}
          onNavigate={onNavigate}
        />
      )}
    </div>
  );
}