"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;
  projectId: number;
  status: string;
  dueDate: string | null;
  milestone: string | null;
  details: string | null;
}

interface ProjectTasks {
  projectName: string;
  tasks: Task[];
}

export function Flow() {
  const [projectTasks, setProjectTasks] = useState<ProjectTasks[]>([]);
  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)) {
        // Group tasks by project
        const groupedTasks = data.tasks.reduce((acc: { [key: string]: Task[] }, task: Task) => {
          if (!acc[task.projectName]) {
            acc[task.projectName] = [];
          }
          acc[task.projectName].push(task);
          return acc;
        }, {});

        // Convert to array and sort tasks by due date within each project
        const sortedProjectTasks = Object.entries(groupedTasks).map(([projectName, tasks]) => ({
          projectName,
          tasks: tasks.sort((a, b) => {
            if (!a.dueDate) return 1;
            if (!b.dueDate) return -1;
            return new Date(a.dueDate).getTime() - new Date(b.dueDate).getTime();
          }).slice(0, 6) // Limit to 6 tasks per project
        }));

        // Sort projects by earliest due date
        sortedProjectTasks.sort((a, b) => {
          const aEarliest = a.tasks[0]?.dueDate ? new Date(a.tasks[0].dueDate).getTime() : Infinity;
          const bEarliest = b.tasks[0]?.dueDate ? new Date(b.tasks[0].dueDate).getTime() : Infinity;
          return aEarliest - bEarliest;
        });

        setProjectTasks(sortedProjectTasks);
      } else {
        setProjectTasks([]);
      }
      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 formatDate = (dateString: string | null) => {
    if (!dateString) return 'No due date';
    const date = new Date(dateString);
    return date.toLocaleDateString('fr-FR', {
      day: 'numeric',
      month: 'short',
      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">Tasks</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>
        ) : projectTasks.length === 0 ? (
          <div className="text-center text-sm text-gray-500">No tasks found</div>
        ) : (
          <div className="space-y-6">
            {projectTasks.map((project) => (
              <div key={project.projectName} className="space-y-2">
                <h3 className="font-medium text-gray-900">{project.projectName}</h3>
                <div className="space-y-1">
                  {project.tasks.map((task) => (
                    <div key={task.id} className="flex items-center justify-between p-2 rounded-lg bg-white shadow-sm">
                      <span className="text-sm font-medium text-gray-700">
                        {task.headline}
                      </span>
                      <div className="flex items-center space-x-2">
                        <span className={`px-2 py-1 rounded-full text-xs font-medium ${
                          task.status === 'NEW' ? 'bg-blue-100 text-blue-800' :
                          task.status === 'INPROGRESS' ? 'bg-yellow-100 text-yellow-800' :
                          'bg-green-100 text-green-800'
                        }`}>
                          {task.status}
                        </span>
                        <span className="text-xs text-gray-500">
                          {formatDate(task.dueDate)}
                        </span>
                      </div>
                    </div>
                  ))}
                </div>
              </div>
            ))}
          </div>
        )}
      </CardContent>
    </Card>
  );
}