"use client";

import { useEffect, useState } from "react";
import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card";
import { Button } from "@/components/ui/button";
import { RefreshCw } from "lucide-react";

interface Task {
  id: string;
  headline: string;
  projectName: string;
  status: string;
  dueDate: string | null;
  milestone: string | null;
}

export function Flow() {
  const [tasks, setTasks] = useState<Task[]>([]);
  const [error, setError] = useState<string | null>(null);
  const [loading, setLoading] = useState(true);
  const [refreshing, setRefreshing] = useState(false);
  const [retryTimeout, setRetryTimeout] = useState<NodeJS.Timeout | null>(null);

  const fetchTasks = async (isRefresh = false) => {
    try {
      if (isRefresh) {
        setRefreshing(true);
      }
      const response = await fetch('/api/leantime/tasks');
      
      if (response.status === 429) {
        const retryAfter = parseInt(response.headers.get('retry-after') || '60');
        const timeout = setTimeout(() => fetchTasks(), retryAfter * 1000);
        setRetryTimeout(timeout);
        setError(`Rate limit exceeded. Retrying in ${retryAfter} seconds...`);
        return;
      }

      if (!response.ok) {
        throw new Error('Failed to fetch tasks');
      }

      const data = await response.json();
      if (data.tasks && Array.isArray(data.tasks)) {
        setTasks(data.tasks);
      } else {
        setTasks([]);
      }
      setError(null);
    } catch (err) {
      console.error('Error fetching tasks:', err);
      setError('Failed to fetch tasks');
    } finally {
      setLoading(false);
      setRefreshing(false);
    }
  };

  useEffect(() => {
    fetchTasks();
    return () => {
      if (retryTimeout) {
        clearTimeout(retryTimeout);
      }
    };
  }, []);

  const getStatusClass = (status: string): string => {
    switch (status.toLowerCase()) {
      case 'new':
        return 'bg-blue-100 text-blue-800';
      case 'in_progress':
        return 'bg-yellow-100 text-yellow-800';
      case 'done':
        return 'bg-green-100 text-green-800';
      default:
        return 'bg-gray-100 text-gray-800';
    }
  };

  const formatDate = (dateString: string | null): string => {
    if (!dateString) return 'No due date';
    const date = new Date(dateString);
    return date.toLocaleDateString('en-US', {
      month: '2-digit',
      day: '2-digit',
      year: 'numeric'
    });
  };

  return (
    <Card className="transition-transform duration-500 ease-in-out transform hover:scale-105">
      <CardHeader className="flex flex-row items-center justify-between pb-2">
        <CardTitle className="text-lg font-medium">Flow</CardTitle>
        <Button
          variant="ghost"
          size="icon"
          onClick={() => fetchTasks(true)}
          disabled={refreshing || !!retryTimeout}
          className={refreshing ? 'animate-spin' : ''}
        >
          <RefreshCw className="h-4 w-4" />
        </Button>
      </CardHeader>
      <CardContent>
        {loading ? (
          <div className="flex items-center justify-center py-4">
            <div className="h-4 w-4 animate-spin rounded-full border-2 border-primary border-t-transparent" />
          </div>
        ) : error ? (
          <div className="text-center text-sm text-red-500">{error}</div>
        ) : tasks.length === 0 ? (
          <div className="text-center text-sm text-gray-500">No tasks found</div>
        ) : (
          <div className="space-y-6">
            {tasks.map((task) => (
              <div key={task.id} className="border rounded-lg p-4 bg-white shadow-sm">
                <div className="flex items-start justify-between">
                  <div className="space-y-1">
                    <div className="text-sm font-medium text-gray-600">{task.projectName}</div>
                    <div className="text-base font-medium text-blue-600 hover:text-blue-800">
                      {task.headline}
                    </div>
                    <div className="flex items-center space-x-3 text-sm text-gray-500">
                      <div className="flex items-center space-x-1">
                        <span className="w-4 h-4">🗓️</span>
                        <span>{formatDate(task.dueDate)}</span>
                      </div>
                      {task.milestone && (
                        <div className="flex items-center space-x-1">
                          <span className="px-2 py-1 rounded-full bg-gray-100">
                            {task.milestone}
                          </span>
                        </div>
                      )}
                    </div>
                  </div>
                  <div className={`px-3 py-1 rounded-full text-xs font-medium ${getStatusClass(task.status)}`}>
                    {task.status.toUpperCase()}
                  </div>
                </div>
              </div>
            ))}
          </div>
        )}
      </CardContent>
    </Card>
  );
}