"use client";

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

interface Task {
  id: string;
  headline: string;
  projectName: string;
  projectId: number;
  status: number;
  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 as { [key: string]: Task[] }).map(([projectName, tasks]) => ({
          projectName,
          tasks: tasks.sort((a: Task, b: Task) => {
            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 '';
    const date = new Date(dateString);
    return date.toLocaleDateString('en-US', {
      month: '2-digit',
      day: '2-digit',
      year: 'numeric'
    });
  };

  const getStatusInfo = (status: number): { label: string; className: string } => {
    switch (status) {
      case 1:
        return { label: 'New', className: 'bg-blue-600 text-white' };
      case 2:
        return { label: 'In Progress', className: 'bg-orange-400 text-white' };
      case 3:
        return { label: 'Done', className: 'bg-green-600 text-white' };
      case 4:
        return { label: 'Blocked', className: 'bg-red-600 text-white' };
      case 5:
        return { label: 'In Review', className: 'bg-purple-600 text-white' };
      case 6:
        return { label: 'To Be Validated', className: 'bg-yellow-600 text-white' };
      default:
        return { label: 'No Status', className: 'bg-gray-400 text-white' };
    }
  };

  const getMilestoneInfo = (milestone: string | null): { label: string; className: string } => {
    if (!milestone) return { label: 'No Milestone', className: 'bg-gray-200 text-gray-700' };
    
    // Map milestone/type to display names
    const milestoneMap: { [key: string]: string } = {
      'Marketing': 'Marketing',
      'Publication': 'Publication',
      'Development': 'Development',
      'Design': 'Design',
      'Research': 'Research'
    };

    return { 
      label: milestoneMap[milestone] || milestone, 
      className: 'bg-gray-200 text-gray-700' 
    };
  };

  const isOverdue = (dueDate: string | null): boolean => {
    if (!dueDate) return false;
    const today = new Date();
    today.setHours(0, 0, 0, 0);
    const taskDate = new Date(dueDate);
    taskDate.setHours(0, 0, 0, 0);
    return taskDate < today;
  };

  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">My ToDos</CardTitle>
        <div className="flex items-center gap-2">
          <Button variant="outline" size="sm">
            Group By: Due Date
          </Button>
          <Button variant="outline" size="sm">
            Filters
          </Button>
          <Button
            variant="ghost"
            size="icon"
            onClick={() => fetchTasks(true)}
            disabled={refreshing || !!retryTimeout}
            className={refreshing ? 'animate-spin' : ''}
          >
            <RefreshCw className="h-4 w-4" />
          </Button>
        </div>
      </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-4">
            <div className="flex items-center gap-2 text-red-500 font-medium">
              <span>🔥 Overdue</span>
              <span className="text-sm">({projectTasks.reduce((count, project) => 
                count + project.tasks.filter(task => isOverdue(task.dueDate)).length, 0
              )})</span>
            </div>
            <div className="space-y-2">
              {projectTasks.map((project) => (
                project.tasks.map((task) => {
                  const statusInfo = getStatusInfo(task.status);
                  const milestoneInfo = getMilestoneInfo(task.milestone);
                  if (!isOverdue(task.dueDate)) return null;
                  
                  return (
                    <div key={task.id} className="p-4 rounded-lg bg-white shadow-sm hover:bg-gray-50 transition-colors border-l-4 border-red-500">
                      <div className="flex items-start justify-between gap-4">
                        <div className="flex-1 min-w-0">
                          <div className="font-medium text-gray-900 mb-1">{project.projectName}</div>
                          <div className="text-sm text-blue-600">{task.headline}</div>
                          <div className="flex items-center gap-2 mt-2">
                            <span className="flex items-center gap-1 text-gray-500">
                              <Calendar className="h-4 w-4" />
                              {formatDate(task.dueDate)}
                            </span>
                          </div>
                        </div>
                        <div className="flex items-start gap-2">
                          <span className={`px-3 py-1 rounded-full text-xs font-medium ${milestoneInfo.className}`}>
                            {milestoneInfo.label}
                          </span>
                          <span className={`px-3 py-1 rounded-full text-xs font-medium ${statusInfo.className}`}>
                            {statusInfo.label}
                          </span>
                          <Button variant="ghost" size="icon" className="h-8 w-8">
                            <MoreVertical className="h-4 w-4" />
                          </Button>
                        </div>
                      </div>
                    </div>
                  );
                })
              ))}
            </div>
          </div>
        )}
      </CardContent>
    </Card>
  );
}