import React, { useState, useEffect } from "react";
import { useQuery, useMutation, useQueryClient } from "@tanstack/react-query";
import { Button } from "@/components/ui/button";
import { Card, CardContent, CardDescription, CardHeader, CardTitle } from "@/components/ui/card";
import { Input } from "@/components/ui/input";
import { Table, TableBody, TableCell, TableHead, TableHeader, TableRow } from "@/components/ui/table";
import { PlusCircle, Search, Loader2, Edit, Trash2, Save, X, Plus } from "lucide-react";
import { Label } from "@/components/ui/label";
import CustomDialog from "@/components/CustomDialog";
import { featureApi } from "@/services/featureApi";
import { Feature, FeatureCreateRequest, FeatureUpdateRequest } from "@/types";
import Header from "@/components/layout/header";
import Sidebar from "@/components/layout/sidebar";
import { useIsMobile } from "@/hooks/use-mobile";
import { toast } from "@/lib/custom-toast";
import { Checkbox } from "@/components/ui/checkbox";
import { Badge } from "@/components/ui/badge";

const Features = () => {
  const queryClient = useQueryClient();
  const isMobile = useIsMobile();
  const [isSidebarOpen, setIsSidebarOpen] = useState(!isMobile);
  const [searchQuery, setSearchQuery] = useState("");
  const [isAddDialogOpen, setIsAddDialogOpen] = useState(false);
  const [newFeatureName, setNewFeatureName] = useState("");
  const [newFeatureDescription, setNewFeatureDescription] = useState("");
  const [newFeatureCategory, setNewFeatureCategory] = useState("");
  const [newFeatureStatus, setNewFeatureStatus] = useState(true);
  const [editingFeature, setEditingFeature] = useState<Feature | null>(null);
  const [editFeatureName, setEditFeatureName] = useState("");
  const [editFeatureDescription, setEditFeatureDescription] = useState("");
  const [editFeatureCategory, setEditFeatureCategory] = useState("");
  const [editFeatureStatus, setEditFeatureStatus] = useState(true);
  
  // Fetch features
  const { data: features = [], isLoading, error, refetch } = useQuery({
    queryKey: ["features"],
    queryFn: featureApi.getAll,
  });

  // Create feature mutation
  const createMutation = useMutation({
    mutationFn: featureApi.create,
    onSuccess: () => {
      toast.success("Feature created successfully");
      queryClient.invalidateQueries({ queryKey: ["features"] });
      setIsAddDialogOpen(false);
      setNewFeatureName("");
    },
    onError: (error) => {
      toast.error("Failed to create feature");
      console.error("Error creating feature:", error);
    }
  });

  // Update feature mutation
  const updateMutation = useMutation({
    mutationFn: ({ id, feature }: { id: number, feature: FeatureUpdateRequest }) => 
      featureApi.update(id, feature),
    onSuccess: () => {
      toast.success("Feature updated successfully");
      queryClient.invalidateQueries({ queryKey: ["features"] });
      setEditingFeature(null);
    },
    onError: (error) => {
      toast.error("Failed to update feature");
      console.error("Error updating feature:", error);
    }
  });

  // Delete feature mutation
  const deleteMutation = useMutation({
    mutationFn: featureApi.delete,
    onSuccess: () => {
      toast.success("Feature deleted successfully");
      queryClient.invalidateQueries({ queryKey: ["features"] });
    },
    onError: (error) => {
      toast.error("Failed to delete feature");
      console.error("Error deleting feature:", error);
    }
  });

  // Toggle sidebar
  const toggleSidebar = () => {
    setIsSidebarOpen(!isSidebarOpen);
  };

  // Handle create feature
  const handleCreateFeature = (e: React.FormEvent) => {
    e.preventDefault();
    e.stopPropagation();
    
    if (!newFeatureName.trim()) {
      toast.error("Feature name cannot be empty");
      return;
    }

    const newFeature: FeatureCreateRequest = {
      featureId: 0, // This will be assigned by the server
      featureName: newFeatureName.trim(),
      description: newFeatureDescription.trim(),
      category: newFeatureCategory.trim(),
      isActive: newFeatureStatus
    };

    createMutation.mutate(newFeature);
  };

  // Handle create feature input change
  const handleCreateChange = (e: React.ChangeEvent<HTMLInputElement>) => {
    const { name, value } = e.target;
    
    switch(name) {
      case 'featureName':
        setNewFeatureName(value);
        break;
      case 'featureDescription':
        setNewFeatureDescription(value);
        break;
      case 'featureCategory':
        setNewFeatureCategory(value);
        break;
      default:
        break;
    }
  };

  // Handle edit feature
  const handleEditFeature = (feature: Feature) => {
    setEditingFeature(feature);
    setEditFeatureName(feature.featureName);
    setEditFeatureDescription(feature.description || "");
    setEditFeatureCategory(feature.category || "");
    setEditFeatureStatus(feature.isActive !== undefined ? feature.isActive : true);
  };

  // Handle update feature
  const handleUpdateFeature = () => {
    if (!editingFeature) return;
    
    if (!editFeatureName.trim()) {
      toast.error("Feature name cannot be empty");
      return;
    }

    const updatedFeature: FeatureUpdateRequest = {
      featureId: editingFeature.featureId,
      featureName: editFeatureName.trim(),
      description: editFeatureDescription.trim(),
      category: editFeatureCategory.trim(),
      isActive: editFeatureStatus
    };

    updateMutation.mutate({ 
      id: editingFeature.featureId, 
      feature: updatedFeature 
    });
  };

  // Handle delete feature
  const handleDeleteFeature = (id: number) => {
    if (window.confirm("Are you sure you want to delete this feature?")) {
      deleteMutation.mutate(id);
    }
  };

  // Cancel editing
  const cancelEditing = () => {
    setEditingFeature(null);
  };

  // Filter features based on search query
  const filteredFeatures = features?.filter((feature: Feature) => {
    if (!searchQuery) return true;
    
    const query = searchQuery.toLowerCase();
    return feature.featureName.toLowerCase().includes(query);
  });

  // Function to ensure all standard features exist in the database
  const ensureAllMissingFeatures = async () => {
    try {
      const existingFeatures = await featureApi.getAll();
      
      // Define all required features with unique IDs (1-53)
      const requiredFeatures = [
        // Core features
        { featureId: 1, featureName: "Dashboard", description: "Main dashboard with overview statistics", category: "Core", isActive: true },
        { featureId: 2, featureName: "Projects", description: "Project management and tracking", category: "Core", isActive: true },
        { featureId: 3, featureName: "Deliverables", description: "Project deliverables management", category: "Project", isActive: true },
        { featureId: 4, featureName: "Teams", description: "Team management and organization", category: "Core", isActive: true },
        { featureId: 5, featureName: "Employees", description: "Employee management and profiles", category: "HR", isActive: true },
        
        // Admin features
        { featureId: 6, featureName: "Roles", description: "Role management and permissions", category: "Administration", isActive: true },
        { featureId: 7, featureName: "Permissions", description: "Permissions management", category: "Administration", isActive: true },
        { featureId: 8, featureName: "Role Features", description: "Manage feature access for roles", category: "Administration", isActive: true },
        
        // Project features
        { featureId: 9, featureName: "Backlog", description: "Product backlog management", category: "Project", isActive: true },
        { featureId: 10, featureName: "Issues", description: "Issue tracking and resolution", category: "Project", isActive: true },
        { featureId: 11, featureName: "Tasks", description: "Task tracking and assignment", category: "Project", isActive: true },
        { featureId: 12, featureName: "Time Logs", description: "Time tracking for tasks and projects", category: "Project", isActive: true },
        
        // Additional core features
        { featureId: 13, featureName: "Calendar", description: "Calendar view for events and deadlines", category: "Core", isActive: true },
        { featureId: 14, featureName: "Reports", description: "Reporting and analytics", category: "Management", isActive: true },
        { featureId: 15, featureName: "Messages", description: "Internal messaging system", category: "Communication", isActive: true },
        { featureId: 16, featureName: "Settings", description: "System settings and configuration", category: "Administration", isActive: true },
        { featureId: 17, featureName: "Notifications", description: "User notifications", category: "Core", isActive: true },
        { featureId: 18, featureName: "Audit Logs", description: "Audit logs and security tracking", category: "Administration", isActive: true },
        { featureId: 19, featureName: "Integrations", description: "Third-party system integrations", category: "Administration", isActive: true },
        { featureId: 20, featureName: "File Management", description: "Document and file storage system", category: "Core", isActive: true },
        
        // HR management features
        { featureId: 21, featureName: "Attendance", description: "Employee attendance tracking", category: "HR", isActive: true },
        { featureId: 22, featureName: "Leaves", description: "Employee leave requests", category: "HR", isActive: true },
        { featureId: 23, featureName: "Leaves Management", description: "Administrative leave management", category: "HR", isActive: true },
        { featureId: 24, featureName: "Leave Types", description: "Configure leave types and policies", category: "HR", isActive: true },
        { featureId: 42, featureName: "Leave Balances", description: "View your leave balances and history", category: "HR", isActive: true },
        
        // Productivity features
        { featureId: 25, featureName: "Todos", description: "Personal to-do list management", category: "Productivity", isActive: true },
        { featureId: 26, featureName: "Holidays", description: "Company holidays management", category: "HR", isActive: true },
        { featureId: 27, featureName: "Bugs", description: "Bug tracking and resolution", category: "Project", isActive: true },
        { featureId: 39, featureName: "Production Bugs", description: "Track and manage production bugs", category: "Project", isActive: true },
        { featureId: 40, featureName: "Test Cases", description: "Create and manage test cases", category: "Project", isActive: true },
        
        // Appraisal system features
        { featureId: 28, featureName: "My Appraisals", description: "Access to your own appraisals", category: "Appraisal", isActive: true },
        { featureId: 29, featureName: "Appraisal Cycles", description: "Manage appraisal cycle periods", category: "Appraisal", isActive: true },
        { featureId: 30, featureName: "Assessment Areas", description: "Manage assessment areas for appraisals", category: "Appraisal", isActive: true },
        { featureId: 31, featureName: "Competencies", description: "Manage competencies for appraisals", category: "Appraisal", isActive: true },
        { featureId: 32, featureName: "Manager Appraisals", description: "Access to team member appraisals for managers", category: "Appraisal", isActive: true },
        { featureId: 36, featureName: "Role Assessment Questions", description: "Configure assessment questions per role", category: "Appraisal", isActive: true },
        { featureId: 37, featureName: "HR Remarks", description: "HR comments on appraisals", category: "Appraisal", isActive: true },
        { featureId: 38, featureName: "Management Remarks", description: "Management comments on appraisals", category: "Appraisal", isActive: true },
        
        // Facilities features
        { featureId: 33, featureName: "Meeting Rooms", description: "Meeting room management", category: "Facilities", isActive: true },
        { featureId: 34, featureName: "Room Bookings", description: "Book and schedule meeting rooms", category: "Facilities", isActive: true },
        
        // Communication features
        { featureId: 35, featureName: "Communications", description: "Communication tools and channels", category: "Communication", isActive: true },
        
        // Other Project & Management features
        { featureId: 41, featureName: "My Profile", description: "Access and manage your personal profile", category: "Core", isActive: true },
        { featureId: 43, featureName: "Employee Projects", description: "Manage projects assigned to employees", category: "Project", isActive: true },
        { featureId: 44, featureName: "Health Dashboard", description: "System and project health overview", category: "Management", isActive: true },
        { featureId: 50, featureName: "Gantt Chart", description: "Visual project timeline and schedule", category: "Project", isActive: true },
        { featureId: 51, featureName: "Resource Allocation", description: "Manage and track resource distribution", category: "Project", isActive: true },
        
        // Asset Management features
        { featureId: 45, featureName: "Assets", description: "General asset management", category: "Asset Management", isActive: true },
        { featureId: 46, featureName: "System Details", description: "System and hardware details for assets", category: "Asset Management", isActive: true },
        { featureId: 47, featureName: "Asset Assignments", description: "Track asset assignments to employees", category: "Asset Management", isActive: true },
        { featureId: 48, featureName: "My Asset Requests", description: "Employee interface for requesting assets", category: "Asset Management", isActive: true },
        { featureId: 49, featureName: "Asset Request Management", description: "Admin interface for managing asset requests", category: "Asset Management", isActive: true },
        
        // New Admin features
        { featureId: 52, featureName: "Feature Management", description: "System features and functionality management", category: "Administration", isActive: true },
        { featureId: 53, featureName: "Role Permissions", description: "Manage permissions for system roles", category: "Administration", isActive: true },
      ];
      
      let createdCount = 0;
      
      for (const reqFeature of requiredFeatures) {
        const exists = existingFeatures.some(f => f.featureId === reqFeature.featureId);
        if (!exists) {
          console.log(`Creating missing feature: ${reqFeature.featureName}`);
          await featureApi.create(reqFeature);
          createdCount++;
        }
      }
      
      queryClient.invalidateQueries({ queryKey: ["features"] });
      
      if (createdCount > 0) {
        toast.success(`Added ${createdCount} missing features`, {
          description: "All standard features have been added to the system."
        });
      } else {
        toast.info("All features already exist", {
          description: "No new features were added."
        });
      }
    } catch (error) {
      console.error("Error ensuring features:", error);
      toast.error("Failed to create features", {
        description: "An error occurred while creating the required features."
      });
    }
  };

  return (
    <div className="flex min-h-screen flex-col">
      <Header toggleSidebar={toggleSidebar} isSidebarOpen={isSidebarOpen} />
      <Sidebar isOpen={isSidebarOpen} setIsOpen={setIsSidebarOpen} />
      
      <main className={`flex-1 p-6 pt-20 md:p-10 md:pt-24 ${isSidebarOpen ? "md:ml-64" : ""} transition-all duration-300`}>
        <div className="mx-auto max-w-6xl">
          <div className="flex flex-col sm:flex-row items-start sm:items-center justify-between mb-8 gap-4">
            <div>
              <h2 className="text-3xl font-bold tracking-tight">Features</h2>
              <p className="text-muted-foreground">
                System features and functionality
              </p>
            </div>
            <div className="flex flex-wrap gap-2">
              <Button onClick={() => ensureAllMissingFeatures()}>
                <Plus className="mr-2 h-4 w-4" />
                Add All Missing Features
              </Button>
              <Button onClick={(e) => {
                e.stopPropagation();
                setIsAddDialogOpen(true);
              }}>
                <PlusCircle className="mr-2 h-4 w-4" />
                Add Feature
              </Button>
            </div>

            <CustomDialog
              isOpen={isAddDialogOpen}
              onClose={() => !createMutation.isPending && setIsAddDialogOpen(false)}
              title="Create New Feature"
              description="Add a new feature to the system"
              allowClose={!createMutation.isPending}
              isPending={createMutation.isPending}
            >
              <form onSubmit={handleCreateFeature}>
                <div className="grid gap-4 py-4">
                  <div className="space-y-2">
                    <Label htmlFor="featureName">Feature Name*</Label>
                    <Input
                      id="featureName"
                      name="featureName"
                      value={newFeatureName}
                      onChange={handleCreateChange}
                      placeholder="Dashboard, Projects, Teams, etc."
                      required
                    />
                  </div>
                  <div className="space-y-2">
                    <Label htmlFor="featureDescription">Feature Description</Label>
                    <Input
                      id="featureDescription"
                      name="featureDescription"
                      value={newFeatureDescription}
                      onChange={handleCreateChange}
                      placeholder="Brief description of this feature"
                    />
                  </div>
                  <div className="space-y-2">
                    <Label htmlFor="featureCategory">Category</Label>
                    <Input
                      id="featureCategory"
                      name="featureCategory"
                      value={newFeatureCategory}
                      onChange={handleCreateChange}
                      placeholder="Admin, User, Reports, etc."
                    />
                  </div>
                  <div className="flex items-center space-x-2">
                    <Checkbox 
                      id="featureStatus" 
                      checked={newFeatureStatus}
                      onCheckedChange={(checked) => setNewFeatureStatus(checked as boolean)}
                    />
                    <Label htmlFor="featureStatus">Active</Label>
                  </div>
                </div>
                <div className="flex justify-end gap-2 mt-4">
                  <Button type="button" variant="outline" onClick={() => !createMutation.isPending && setIsAddDialogOpen(false)}>
                    Cancel
                  </Button>
                  <Button type="submit" disabled={createMutation.isPending || !newFeatureName.trim()}>
                    {createMutation.isPending ? (
                      <>
                        <Loader2 className="mr-2 h-4 w-4 animate-spin" />
                        Creating...
                      </>
                    ) : "Create Feature"}
                  </Button>
                </div>
              </form>
            </CustomDialog>
          </div>
          
          <Card>
            <CardHeader>
              <div className="flex flex-col sm:flex-row items-start sm:items-center justify-between gap-4">
                <div>
                  <CardTitle>Feature Management</CardTitle>
                  <CardDescription>
                    {features?.length || 0} features defined in the system
                  </CardDescription>
                </div>
                
                <div className="w-full sm:w-auto relative">
                  <Search className="absolute left-3 top-1/2 -translate-y-1/2 h-4 w-4 text-muted-foreground" />
                  <Input
                    placeholder="Search features..."
                    className="pl-9 w-full sm:w-[250px]"
                    value={searchQuery}
                    onChange={(e) => setSearchQuery(e.target.value)}
                  />
                </div>
              </div>
            </CardHeader>
            <CardContent>
              {isLoading ? (
                <div className="flex justify-center items-center h-64">
                  <Loader2 className="h-8 w-8 animate-spin text-primary" />
                </div>
              ) : error ? (
                <div className="flex justify-center items-center h-64 text-destructive">
                  <p>Error loading features. Please try again later.</p>
                </div>
              ) : filteredFeatures?.length === 0 ? (
                <div className="flex justify-center items-center h-64 text-muted-foreground">
                  <p>No features found.</p>
                </div>
              ) : (
                <div className="rounded-md border">
                  <Table>
                    <TableHeader>
                      <TableRow>
                        <TableHead>ID</TableHead>
                        <TableHead>Feature Name</TableHead>
                        <TableHead>Description</TableHead>
                        <TableHead>Category</TableHead>
                        <TableHead>Status</TableHead>
                        <TableHead className="w-24 text-right">Actions</TableHead>
                      </TableRow>
                    </TableHeader>
                    <TableBody>
                      {filteredFeatures?.map((feature: Feature) => (
                        <TableRow key={feature.featureId}>
                          <TableCell>{feature.featureId}</TableCell>
                          {editingFeature?.featureId === feature.featureId ? (
                            <TableCell>
                              <Input
                                value={editFeatureName}
                                onChange={(e) => setEditFeatureName(e.target.value)}
                                className="w-full"
                              />
                            </TableCell>
                          ) : (
                            <TableCell className="font-medium">{feature.featureName}</TableCell>
                          )}
                          
                          {editingFeature?.featureId === feature.featureId ? (
                            <TableCell>
                              <Input
                                value={editFeatureDescription}
                                onChange={(e) => setEditFeatureDescription(e.target.value)}
                                className="w-full"
                              />
                            </TableCell>
                          ) : (
                            <TableCell>{feature.description || "-"}</TableCell>
                          )}
                          
                          {editingFeature?.featureId === feature.featureId ? (
                            <TableCell>
                              <Input
                                value={editFeatureCategory}
                                onChange={(e) => setEditFeatureCategory(e.target.value)}
                                className="w-full"
                              />
                            </TableCell>
                          ) : (
                            <TableCell>{feature.category || "-"}</TableCell>
                          )}
                          
                          {editingFeature?.featureId === feature.featureId ? (
                            <TableCell>
                              <div className="flex items-center space-x-2">
                                <Checkbox 
                                  id={`edit-status-${feature.featureId}`}
                                  checked={editFeatureStatus}
                                  onCheckedChange={(checked) => setEditFeatureStatus(checked as boolean)}
                                />
                                <Label htmlFor={`edit-status-${feature.featureId}`}>Active</Label>
                              </div>
                            </TableCell>
                          ) : (
                            <TableCell>
                              <Badge variant={feature.isActive ? "success" : "secondary"}>
                                {feature.isActive ? "Active" : "Inactive"}
                              </Badge>
                            </TableCell>
                          )}
                          
                          <TableCell className="text-right">
                            {editingFeature?.featureId === feature.featureId ? (
                              <div className="flex justify-end gap-2">
                                <Button 
                                  size="sm" 
                                  variant="outline" 
                                  onClick={cancelEditing}
                                >
                                  <X className="h-4 w-4" />
                                </Button>
                                <Button 
                                  size="sm" 
                                  onClick={handleUpdateFeature}
                                >
                                  <Save className="h-4 w-4" />
                                </Button>
                              </div>
                            ) : (
                              <div className="flex justify-end gap-2">
                                <Button 
                                  size="sm" 
                                  variant="outline" 
                                  onClick={() => handleEditFeature(feature)}
                                >
                                  <Edit className="h-4 w-4" />
                                </Button>
                                <Button 
                                  size="sm" 
                                  variant="destructive" 
                                  onClick={() => handleDeleteFeature(feature.featureId)}
                                >
                                  <Trash2 className="h-4 w-4" />
                                </Button>
                              </div>
                            )}
                          </TableCell>
                        </TableRow>
                      ))}
                    </TableBody>
                  </Table>
                </div>
              )}
            </CardContent>
          </Card>
        </div>
      </main>
    </div>
  );
};

export default Features;