"use client";

import React, { useState, useEffect } from "react";
import { db } from "@/lib/firebase";
import { collection, onSnapshot, addDoc, updateDoc, deleteDoc, doc, query, orderBy } from "firebase/firestore";
import { motion, AnimatePresence } from "framer-motion";
import { Plus, Trash2, CheckCircle2, Circle, Clock } from "lucide-react";

interface Task {
  id: string;
  title: string;
  status: "todo" | "doing" | "done";
  priority: "low" | "medium" | "high";
}

export default function TasksPage() {
  const [tasks, setTasks] = useState<Task[]>([]);
  const [newTask, setNewTask] = useState("");

  useEffect(() => {
    const unsub = onSnapshot(collection(db, "tasks"), (snap) => {
      setTasks(snap.docs.map(doc => ({ id: doc.id, ...doc.data() } as Task)));
    });
    return () => unsub();
  }, []);

  const addTask = async (e: React.FormEvent) => {
    e.preventDefault();
    if (!newTask.trim()) return;
    await addDoc(collection(db, "tasks"), {
      title: newTask,
      status: "todo",
      priority: "medium",
      createdAt: new Date()
    });
    setNewTask("");
  };

  const toggleStatus = async (task: Task) => {
    const nextStatus = task.status === "todo" ? "doing" : task.status === "doing" ? "done" : "todo";
    await updateDoc(doc(db, "tasks", task.id), { status: nextStatus });
  };

  return (
    <div className="p-10 max-w-6xl mx-auto">
      <header className="mb-12">
        <h1 className="text-5xl font-black italic tracking-tighter mb-2">TASKS / SYSTEM</h1>
        <p className="text-gray-500 font-medium">Gestión de flujo de trabajo corporativo</p>
      </header>

      <form onSubmit={addTask} className="mb-12 relative group">
        <input 
          type="text" 
          placeholder="Escribe una nueva tarea y pulsa Enter..."
          value={newTask}
          onChange={(e) => setNewTask(e.target.value)}
          className="w-full bg-white/5 border border-white/10 rounded-3xl px-8 py-6 outline-none focus:border-blue-500/40 transition-all text-xl font-medium placeholder:text-gray-700 backdrop-blur-md"
        />
        <button type="submit" className="absolute right-4 top-1/2 -translate-y-1/2 p-3 bg-blue-600 rounded-2xl hover:bg-blue-500 transition-all">
          <Plus size={24} />
        </button>
      </form>

      <div className="grid grid-cols-1 md:grid-cols-3 gap-8">
        <TaskColumn title="Pendientes" status="todo" tasks={tasks.filter(t => t.status === "todo")} onToggle={toggleStatus} />
        <TaskColumn title="En Proceso" status="doing" tasks={tasks.filter(t => t.status === "doing")} onToggle={toggleStatus} />
        <TaskColumn title="Completadas" status="done" tasks={tasks.filter(t => t.status === "done")} onToggle={toggleStatus} />
      </div>
    </div>
  );
}

function TaskColumn({ title, status, tasks, onToggle }: { title: string, status: string, tasks: Task[], onToggle: (t: Task) => void }) {
  return (
    <div className="space-y-6">
      <div className="flex items-center justify-between px-4">
        <h2 className="text-xs font-black uppercase tracking-[0.2em] text-gray-500">{title}</h2>
        <span className="text-xs font-mono bg-white/10 px-2 py-1 rounded-md">{tasks.length}</span>
      </div>
      
      <div className="space-y-4">
        <AnimatePresence mode="popLayout">
          {tasks.map((task) => (
            <motion.div
              key={task.id}
              layout
              initial={{ scale: 0.8, opacity: 0 }}
              animate={{ scale: 1, opacity: 1 }}
              exit={{ scale: 0.8, opacity: 0 }}
              className="bg-white/5 border border-white/5 rounded-2xl p-5 hover:bg-white/10 hover:border-white/20 transition-all cursor-pointer group"
              onClick={() => onToggle(task)}
            >
              <div className="flex items-start gap-4">
                <div className="mt-1">
                  {status === "done" ? <CheckCircle2 className="text-green-400" size={18} /> : 
                   status === "doing" ? <Clock className="text-orange-400" size={18} /> : 
                   <Circle className="text-gray-600" size={18} />}
                </div>
                <div className="flex-1">
                  <p className={`font-semibold text-sm ${status === "done" ? 'line-through text-gray-600' : 'text-gray-200'}`}>
                    {task.title}
                  </p>
                  <div className="flex gap-2 mt-3">
                    <span className={`text-[8px] font-black uppercase px-2 py-0.5 rounded-full border ${
                      task.priority === 'high' ? 'border-red-500/40 text-red-400 bg-red-500/10' :
                      task.priority === 'medium' ? 'border-orange-500/40 text-orange-400 bg-orange-500/10' :
                      'border-gray-500/40 text-gray-400 bg-gray-500/10'
                    }`}>
                      {task.priority || 'medium'}
                    </span>
                  </div>
                </div>
                <button 
                  onClick={(e) => { e.stopPropagation(); deleteDoc(doc(db, "tasks", task.id)); }}
                  className="opacity-0 group-hover:opacity-100 p-2 hover:bg-red-500/20 text-red-400 rounded-lg transition-all"
                >
                  <Trash2 size={14} />
                </button>
              </div>
            </motion.div>
          ))}
        </AnimatePresence>
      </div>
    </div>
  );
}