import React, { useEffect, useState } from "react";
import { useNavigate, useParams, Link } from "react-router-dom";
import { tasksApi, Task } from "@/services/tasksApi";
import { employeeApi } from "@/services/employeeApi";
import { toast } from "sonner";
import {
  ChevronRight,
  Home,
  Calendar,
  Clock,
  Edit,
  FileText,
  AlertCircle,
  CheckCircle,
  RefreshCw,
  Bug,
  Code,
  CheckSquare,
  XCircle,
  AlertTriangle,
  GitBranch,
  Link as LinkIcon,
  Monitor,
  Info,
  Paperclip,
  MessageSquare,
  History
} from "lucide-react";
import { Button } from "@/components/ui/button";
import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card";
import { Badge } from "@/components/ui/badge";
import { Avatar, AvatarFallback } from "@/components/ui/avatar";
import { format } from "date-fns";
import Layout from "../components/layout/layout";
import { useQuery } from "@tanstack/react-query";
import { Tabs, TabsContent, TabsList, TabsTrigger } from "@/components/ui/tabs";
import { Separator } from "@/components/ui/separator";
import TaskTimeLogCard from "@/components/tasks/TaskTimeLogCard";
import TaskCommentSection from "@/components/tasks/TaskCommentSection";
import TaskAttachmentsSection from "@/components/tasks/TaskAttachmentsSection";

const BugDetailPage = () => {
  const navigate = useNavigate();
  const { id } = useParams();
  const [bug, setBug] = useState<Task | undefined>();
  const [isLoading, setIsLoading] = useState(false);
  const [activeTab, setActiveTab] = useState("details");

  // Fetch employees data
  const {
    data: employees = [],
    isLoading: isLoadingEmployees
  } = useQuery({
    queryKey: ["employees"],
    queryFn: () => employeeApi.getAll(),
  });

  useEffect(() => {
    if (id) {
      fetchBug();
    }
  }, [id]);

  const fetchBug = async () => {
    try {
      setIsLoading(true);
      const bugData = await tasksApi.getById(Number(id));

      // Check if this is actually a bug type
      if (bugData && bugData.type === "Bug") {
        setBug(bugData);
      } else {
        toast.error("The requested item is not a bug");
        navigate("/bugs");
      }
    } catch (error) {
      console.error("Error fetching bug:", error);
      toast.error("Failed to load bug data");
    } finally {
      setIsLoading(false);
    }
  };

  const handleEdit = () => {
    navigate(`/bugs/${id}/edit`);
  };

  const handleBack = () => {
    navigate(-1);
  };

  // Get assignee information
  const getAssigneeInfo = (userId: number | null) => {
    if (!userId) return { initials: "NA", name: "Unassigned" };

    const userIdString = userId.toString();
    const employee = employees.find(emp => emp.id.toString() === userIdString);
    if (employee) {
      const initials = `${employee.firstName.charAt(0)}${employee.lastName.charAt(0)}`.toUpperCase();
      return {
        initials,
        name: `${employee.firstName} ${employee.lastName}`
      };
    }

    return { initials: "US", name: `User ${userId}` };
  };

  // Helper to get status badge
  const getStatusBadge = (status: string) => {
    switch (status) {
      case "Completed":
      case "Closed":
        return (
          <Badge variant="default" className="bg-green-500 hover:bg-green-600 text-white flex items-center gap-1">
            <CheckCircle className="h-3 w-3" />
            {status}
          </Badge>
        );
      case "In Progress":
        return (
          <Badge variant="default" className="bg-blue-500 hover:bg-blue-600 text-white flex items-center gap-1">
            <RefreshCw className="h-3 w-3" />
            {status}
          </Badge>
        );
      case "In Review":
        return (
          <Badge variant="default" className="bg-purple-500 hover:bg-purple-600 text-white flex items-center gap-1">
            <Clock className="h-3 w-3" />
            {status}
          </Badge>
        );
      case "New":
      default:
        return (
          <Badge variant="default" className="bg-gray-500 hover:bg-gray-600 text-white flex items-center gap-1">
            <AlertCircle className="h-3 w-3" />
            {status || "New"}
          </Badge>
        );
    }
  };

  // Helper to get severity badge
  const getSeverityBadge = (severity: string) => {
    switch (severity?.toLowerCase()) {
      case "blocker":
        return (
          <Badge variant="outline" className="border-red-700 text-red-700 flex items-center gap-1">
            <AlertTriangle className="h-3 w-3 mr-1" />
            {severity}
          </Badge>
        );
      case "critical":
        return (
          <Badge variant="outline" className="border-red-500 text-red-500 flex items-center gap-1">
            <AlertTriangle className="h-3 w-3 mr-1" />
            {severity}
          </Badge>
        );
      case "major":
        return (
          <Badge variant="outline" className="border-orange-500 text-orange-500 flex items-center gap-1">
            <AlertCircle className="h-3 w-3 mr-1" />
            {severity}
          </Badge>
        );
      case "minor":
        return (
          <Badge variant="outline" className="border-yellow-500 text-yellow-500 flex items-center gap-1">
            <Info className="h-3 w-3 mr-1" />
            {severity}
          </Badge>
        );
      case "trivial":
        return (
          <Badge variant="outline" className="border-green-500 text-green-500 flex items-center gap-1">
            <Info className="h-3 w-3 mr-1" />
            {severity}
          </Badge>
        );
      default:
        return (
          <Badge variant="outline" className="border-gray-500 text-gray-500 flex items-center gap-1">
            {severity || "Not Set"}
          </Badge>
        );
    }
  };

  // Helper to get priority badge
  const getPriorityBadge = (priority: string) => {
    switch (priority?.toLowerCase()) {
      case "critical":
        return (
          <Badge variant="outline" className="border-red-600 text-red-600 flex items-center gap-1">
            <AlertCircle className="h-3 w-3 mr-1" />
            {priority}
          </Badge>
        );
      case "high":
        return (
          <Badge variant="outline" className="border-orange-600 text-orange-600 flex items-center gap-1">
            <AlertCircle className="h-3 w-3 mr-1" />
            {priority}
          </Badge>
        );
      case "medium":
        return (
          <Badge variant="outline" className="border-yellow-600 text-yellow-600 flex items-center gap-1">
            <Info className="h-3 w-3 mr-1" />
            {priority}
          </Badge>
        );
      case "low":
        return (
          <Badge variant="outline" className="border-green-600 text-green-600 flex items-center gap-1">
            <Info className="h-3 w-3 mr-1" />
            {priority}
          </Badge>
        );
      default:
        return (
          <Badge variant="outline" className="border-gray-500 text-gray-500 flex items-center gap-1">
            {priority || "Not Set"}
          </Badge>
        );
    }
  };

  // Helper to get bug type badge
  const getBugTypeBadge = (type: string) => {
    switch (type?.toLowerCase()) {
      case "bug":
        return (
          <Badge variant="outline" className="border-red-400 text-red-400 flex items-center gap-1">
            <Bug className="h-3 w-3 mr-1" />
            {type}
          </Badge>
        );
      case "feature":
        return (
          <Badge variant="outline" className="border-blue-400 text-blue-400 flex items-center gap-1">
            <Info className="h-3 w-3 mr-1" />
            {type}
          </Badge>
        );
      case "enhancement":
        return (
          <Badge variant="outline" className="border-green-400 text-green-400 flex items-center gap-1">
            <Info className="h-3 w-3 mr-1" />
            {type}
          </Badge>
        );
      case "task":
        return (
          <Badge variant="outline" className="border-purple-400 text-purple-400 flex items-center gap-1">
            <Info className="h-3 w-3 mr-1" />
            {type}
          </Badge>
        );
      default:
        return (
          <Badge variant="outline" className="border-gray-500 text-gray-500 flex items-center gap-1">
            {type || "Unknown"}
          </Badge>
        );
    }
  };

  // Format date for display
  const formatDate = (dateString: string | null) => {
    if (!dateString) return "Not set";
    try {
      return format(new Date(dateString), "MMM dd, yyyy");
    } catch (error) {
      return "Invalid date";
    }
  };

  if (isLoading || isLoadingEmployees) {
    return (
      <Layout>
        <div className="h-full flex items-center justify-center p-4">
          <div className="flex flex-col items-center gap-2">
            <div className="animate-spin rounded-full h-8 w-8 border-b-2 border-primary"></div>
            <p className="text-sm text-muted-foreground">Loading bug details...</p>
          </div>
        </div>
      </Layout>
    );
  }

  if (!bug) {
    return (
      <Layout>
        <div className="h-full flex flex-col items-center justify-center p-4">
          <h2 className="text-2xl font-bold mb-2">Bug Not Found</h2>
          <p className="text-muted-foreground mb-4">
            The bug you're looking for doesn't exist or has been removed.
          </p>
          <Button onClick={handleBack}>Back to Bugs</Button>
        </div>
      </Layout>
    );
  }

  // Get assignee details
  const { initials: assigneeInitials, name: assigneeName } = getAssigneeInfo(bug.assignedTo);

  return (
    <Layout>
      <div className="pb-6 w-full animate-fadeIn">
        {/* Breadcrumb Navigation */}
        <nav className="flex items-center space-x-2 text-sm text-muted-foreground overflow-x-auto pb-2 mb-4 px-4 md:px-6">
          <Link to="/" className="flex items-center hover:text-foreground transition-colors flex-shrink-0">
            <Home className="h-4 w-4 mr-1" />
            Home
          </Link>
          <ChevronRight className="h-4 w-4 flex-shrink-0" />
          <Link to="/bugs" className="hover:text-foreground transition-colors flex-shrink-0">
            Bugs
          </Link>
          <ChevronRight className="h-4 w-4 flex-shrink-0" />
          <span className="text-foreground font-medium flex-shrink-0">Bug Details</span>
        </nav>

        <div className="px-4 md:px-6 space-y-6 max-w-7xl mx-auto">
          {/* Header Section with background */}
          <div className="bg-white dark:bg-gray-800 rounded-xl shadow-sm p-4 sm:p-6">
            <div className="flex flex-col gap-4">
              <div className="flex flex-col sm:flex-row sm:justify-between sm:flex-wrap gap-4">
                <div className="space-y-1 flex-1">
                  <div className="flex flex-wrap items-center gap-2">
                    <h1 className="text-xl md:text-3xl font-bold tracking-tight break-words">{bug.title}</h1>
                  </div>
                  <div className="flex flex-wrap items-center gap-2 mt-2">
                    {getStatusBadge(bug.status)}
                    {getBugTypeBadge(bug.type)}
                    {bug.priority && getPriorityBadge(bug.priority)}
                    {bug.severity && getSeverityBadge(bug.severity)}
                    <span className="text-sm text-muted-foreground ml-2">
                      {bug.taskCode || `BUG-${bug.id}`}
                    </span>
                  </div>
                </div>
                <div className="flex items-center gap-2 shrink-0">
                  <Button variant="outline" onClick={handleBack} className="flex-1 sm:flex-auto">
                    Back
                  </Button>
                  <Button onClick={handleEdit} className="bg-blue-600 hover:bg-blue-700 flex-1 sm:flex-auto">
                    <Edit className="h-4 w-4 mr-2" />
                    Edit Bug
                  </Button>
                </div>
              </div>

              <div className="grid grid-cols-1 sm:grid-cols-2 md:grid-cols-4 gap-3">
                <div className="flex items-center gap-3 px-3 sm:px-4 py-2 bg-gray-50 dark:bg-gray-900 rounded-lg">
                  <Avatar className="h-10 w-10 border-2 border-primary/10">
                    <AvatarFallback className="bg-primary/10 text-primary">
                      {assigneeInitials}
                    </AvatarFallback>
                  </Avatar>
                  <div>
                    <p className="text-xs text-muted-foreground">Assigned To</p>
                    <p className="font-medium">{assigneeName}</p>
                  </div>
                </div>

                <div className="flex items-center gap-3 px-3 sm:px-4 py-2 bg-gray-50 dark:bg-gray-900 rounded-lg">
                  <div className="h-10 w-10 rounded-full bg-primary/10 flex items-center justify-center">
                    <Calendar className="h-5 w-5 text-primary" />
                  </div>
                  <div>
                    <p className="text-xs text-muted-foreground">Created</p>
                    <p className="font-medium">{formatDate(bug.createdAt || "")}</p>
                  </div>
                </div>

                <div className="flex items-center gap-3 px-3 sm:px-4 py-2 bg-gray-50 dark:bg-gray-900 rounded-lg">
                  <div className="h-10 w-10 rounded-full bg-primary/10 flex items-center justify-center">
                    <GitBranch className="h-5 w-5 text-primary" />
                  </div>
                  <div>
                    <p className="text-xs text-muted-foreground">Version</p>
                    <p className="font-medium">{bug.version || "Not specified"}</p>
                  </div>
                </div>

                <div className="flex items-center gap-3 px-3 sm:px-4 py-2 bg-gray-50 dark:bg-gray-900 rounded-lg">
                  <div className="h-10 w-10 rounded-full bg-primary/10 flex items-center justify-center">
                    <Monitor className="h-5 w-5 text-primary" />
                  </div>
                  <div>
                    <p className="text-xs text-muted-foreground">Environment</p>
                    <p className="font-medium">{bug.environment || "Not specified"}</p>
                  </div>
                </div>
              </div>
            </div>
          </div>

          {/* Tab Content Section */}
          <Tabs defaultValue="details" className="w-full" onValueChange={setActiveTab}>
            <TabsList className="grid grid-cols-3 md:grid-cols-6 mb-4 overflow-x-auto">
              <TabsTrigger value="details" className="text-xs md:text-sm">
                <FileText className="h-4 w-4 mr-1 md:mr-2" />
                Details
              </TabsTrigger>
              <TabsTrigger value="steps" className="text-xs md:text-sm">
                <CheckSquare className="h-4 w-4 mr-1 md:mr-2" />
                Steps
              </TabsTrigger>
              <TabsTrigger value="resolution" className="text-xs md:text-sm">
                <Bug className="h-4 w-4 mr-1 md:mr-2" />
                Resolution
              </TabsTrigger>
              <TabsTrigger value="attachments" className="text-xs md:text-sm">
                <Paperclip className="h-4 w-4 mr-1 md:mr-2" />
                Files
              </TabsTrigger>
              <TabsTrigger value="timelogs" className="text-xs md:text-sm">
                <History className="h-4 w-4 mr-1 md:mr-2" />
                Time Logs
              </TabsTrigger>
              <TabsTrigger value="discussion" className="text-xs md:text-sm">
                <MessageSquare className="h-4 w-4 mr-1 md:mr-2" />
                Discussion
              </TabsTrigger>
            </TabsList>

            <TabsContent value="details" className="space-y-4">
              <Card>
                <CardHeader>
                  <CardTitle className="text-md flex items-center">
                    <FileText className="h-4 w-4 mr-2" />
                    Bug Description
                  </CardTitle>
                </CardHeader>
                <CardContent>
                  <div className="prose dark:prose-invert max-w-none">
                    {bug.description ? (
                      <div className="whitespace-pre-wrap">{bug.description}</div>
                    ) : (
                      <p className="text-muted-foreground italic">No description provided.</p>
                    )}
                  </div>
                </CardContent>
              </Card>

              {bug.url && (
                <Card>
                  <CardHeader>
                    <CardTitle className="text-md flex items-center">
                      <LinkIcon className="h-4 w-4 mr-2" />
                      Related URL
                    </CardTitle>
                  </CardHeader>
                  <CardContent>
                    <a
                      href={bug.url.startsWith('http') ? bug.url : `https://${bug.url}`}
                      target="_blank"
                      rel="noopener noreferrer"
                      className="text-blue-600 dark:text-blue-400 hover:underline"
                    >
                      {bug.url}
                    </a>
                  </CardContent>
                </Card>
              )}

              {bug.inputs && (
                <Card>
                  <CardHeader>
                    <CardTitle className="text-md flex items-center">
                      <Code className="h-4 w-4 mr-2" />
                      Test Data / Inputs
                    </CardTitle>
                  </CardHeader>
                  <CardContent>
                    <div className="bg-muted p-3 rounded-md font-mono text-sm whitespace-pre-wrap">
                      {bug.inputs}
                    </div>
                  </CardContent>
                </Card>
              )}
            </TabsContent>

            <TabsContent value="steps" className="space-y-4">
              <Card>
                <CardHeader>
                  <CardTitle className="text-md flex items-center">
                    <CheckSquare className="h-4 w-4 mr-2" />
                    Steps to Reproduce
                  </CardTitle>
                </CardHeader>
                <CardContent>
                  {bug.stepsToReproduce ? (
                    <div className="whitespace-pre-wrap">{bug.stepsToReproduce}</div>
                  ) : (
                    <p className="text-muted-foreground italic">No reproduction steps provided.</p>
                  )}
                </CardContent>
              </Card>

              <div className="grid grid-cols-1 md:grid-cols-2 gap-4">
                <Card>
                  <CardHeader>
                    <CardTitle className="text-md flex items-center">
                      <CheckCircle className="h-4 w-4 mr-2" />
                      Expected Behavior
                    </CardTitle>
                  </CardHeader>
                  <CardContent>
                    {bug.expectedBehavior ? (
                      <div className="whitespace-pre-wrap">{bug.expectedBehavior}</div>
                    ) : (
                      <p className="text-muted-foreground italic">No expected behavior specified.</p>
                    )}
                  </CardContent>
                </Card>

                <Card>
                  <CardHeader>
                    <CardTitle className="text-md flex items-center">
                      <XCircle className="h-4 w-4 mr-2" />
                      Actual Behavior
                    </CardTitle>
                  </CardHeader>
                  <CardContent>
                    {bug.actualBehavior ? (
                      <div className="whitespace-pre-wrap">{bug.actualBehavior}</div>
                    ) : (
                      <p className="text-muted-foreground italic">No actual behavior specified.</p>
                    )}
                  </CardContent>
                </Card>
              </div>
            </TabsContent>

            <TabsContent value="resolution" className="space-y-4">
              <Card>
                <CardHeader>
                  <CardTitle className="text-md flex items-center">
                    <AlertCircle className="h-4 w-4 mr-2" />
                    Root Cause
                  </CardTitle>
                </CardHeader>
                <CardContent>
                  {bug.rootCause ? (
                    <div className="whitespace-pre-wrap">{bug.rootCause}</div>
                  ) : (
                    <p className="text-muted-foreground italic">Root cause analysis not provided yet.</p>
                  )}
                </CardContent>
              </Card>

              <Card>
                <CardHeader>
                  <CardTitle className="text-md flex items-center">
                    <CheckCircle className="h-4 w-4 mr-2" />
                    Resolution
                  </CardTitle>
                </CardHeader>
                <CardContent>
                  {bug.resolution ? (
                    <div className="whitespace-pre-wrap">{bug.resolution}</div>
                  ) : (
                    <p className="text-muted-foreground italic">Resolution details not provided yet.</p>
                  )}
                </CardContent>
              </Card>
            </TabsContent>

            <TabsContent value="attachments" className="space-y-4">
              <TaskAttachmentsSection taskId={bug.id} />
            </TabsContent>

            <TabsContent value="timelogs" className="space-y-4">
              <TaskTimeLogCard taskId={bug.id} />
            </TabsContent>

            <TabsContent value="discussion" className="space-y-4">
              <TaskCommentSection taskId={bug.id} />
            </TabsContent>
          </Tabs>
        </div>
      </div>
    </Layout>
  );
};

export default BugDetailPage;