import React, { useEffect, useState } from 'react';
import {
  Check,
  CheckCircle2,
  Circle,
  Calendar,
  Trash2,
  RotateCcw,
  FileText,
  Tag,
  AlertCircle,
} from 'lucide-react';
import { Thought } from '../../lib/types';
import { api, triggerHaptic } from '../../lib/api';

interface TasksViewProps {
  onRefreshStats: () => void;
  onOpenDocument: (docId: string) => void;
}

export const TasksView: React.FC<TasksViewProps> = ({ onRefreshStats, onOpenDocument }) => {
  const [filter, setFilter] = useState<'open' | 'done' | 'discarded'>('open');
  const [tasks, setTasks] = useState<Thought[]>([]);
  const [discarded, setDiscarded] = useState<Thought[]>([]);
  const [loading, setLoading] = useState(true);

  const loadData = async () => {
    setLoading(true);
    try {
      const [allTasks, allDiscarded] = await Promise.all([
        api.getTasks(),
        api.getThoughts('discarded'),
      ]);
      setTasks(allTasks);
      setDiscarded(allDiscarded);
    } finally {
      setLoading(false);
    }
  };

  useEffect(() => {
    loadData();
  }, []);

  const handleToggleDone = async (task: Thought) => {
    triggerHaptic(15);
    const nextState = !task.isCompleted;
    setTasks((prev) =>
      prev.map((t) => (t.id === task.id ? { ...t, isCompleted: nextState } : t))
    );
    await api.updateThought(task.id, { isCompleted: nextState });
    onRefreshStats();
  };

  const handleDueDateChange = async (task: Thought, newDate: string) => {
    setTasks((prev) => prev.map((t) => (t.id === task.id ? { ...t, dueDate: newDate } : t)));
    await api.updateThought(task.id, { dueDate: newDate });
  };

  const handleConvertToDoc = async (task: Thought) => {
    triggerHaptic(20);
    const updated = await api.triageAction(task.id, 'keep', { convertTo: 'document' });
    onRefreshStats();
    if (updated.convertedRefId) {
      onOpenDocument(updated.convertedRefId);
    } else {
      loadData();
    }
  };

  const handleRestore = async (item: Thought) => {
    triggerHaptic(15);
    await api.triageAction(item.id, 'restore');
    await loadData();
    onRefreshStats();
  };

  const handleDeletePermanent = async (id: string) => {
    triggerHaptic(20);
    await api.deleteThought(id);
    await loadData();
    onRefreshStats();
  };

  const handlePurgeAllDiscarded = async () => {
    await api.purgeDiscarded();
    await loadData();
    onRefreshStats();
  };

  const openTasks = tasks.filter((t) => !t.isCompleted);
  const doneTasks = tasks.filter((t) => t.isCompleted);

  return (
    <div className="w-full space-y-2">
      {/* Filter Tabs */}
      <div className="flex flex-wrap items-center justify-between gap-2 mb-1">
        <div className="flex items-center border border-white/[0.08] bg-[#16171a]">
          <button
            onClick={() => setFilter('open')}
            className={`h-8 px-3.5 text-xs font-medium border-r border-white/[0.08] transition-colors ${
              filter === 'open'
                ? 'bg-[#222428] text-white'
                : 'text-zinc-400 hover:text-white hover:bg-white/[0.02]'
            }`}
          >
            Offen ({openTasks.length})
          </button>

          <button
            onClick={() => setFilter('done')}
            className={`h-8 px-3.5 text-xs font-medium border-r border-white/[0.08] transition-colors ${
              filter === 'done'
                ? 'bg-[#222428] text-white'
                : 'text-zinc-400 hover:text-white hover:bg-white/[0.02]'
            }`}
          >
            Erledigt ({doneTasks.length})
          </button>

          <button
            onClick={() => setFilter('discarded')}
            className={`h-8 px-3.5 text-xs font-medium transition-colors ${
              filter === 'discarded'
                ? 'bg-[#222428] text-white'
                : 'text-zinc-400 hover:text-white hover:bg-white/[0.02]'
            }`}
          >
            Papierkorb ({discarded.length})
          </button>
        </div>

        {filter === 'discarded' && discarded.length > 0 && (
          <button
            onClick={handlePurgeAllDiscarded}
            className="h-7 px-3 rounded-full bg-white/[0.06] hover:bg-white/[0.12] text-zinc-300 hover:text-white text-xs font-medium flex items-center gap-1.5 transition-colors"
          >
            <Trash2 className="w-3.5 h-3.5" />
            Papierkorb leeren
          </button>
        )}
      </div>

      {loading ? (
        <div className="p-6 text-center text-zinc-500 text-sm">Lade Aufgaben…</div>
      ) : filter === 'discarded' ? (
        <div className="bg-[#222428] border border-white/[0.08] divide-y divide-white/[0.06]">
          {discarded.length === 0 ? (
            <div className="px-4 py-6 text-center text-zinc-400 text-sm">
              Keine verworfenen Gedanken im Papierkorb.
            </div>
          ) : (
            discarded.map((item) => (
              <div
                key={item.id}
                className="px-3 py-2 flex items-center justify-between gap-3 hover:bg-white/[0.02]"
              >
                <div className="flex items-center gap-2.5 min-w-0 flex-1">
                  <Trash2 className="w-4 h-4 text-zinc-500 flex-shrink-0" />
                  <p className="text-sm text-zinc-400 line-through truncate">{item.content}</p>
                </div>
                <div className="flex items-center gap-2 flex-shrink-0">
                  <button
                    onClick={() => handleRestore(item)}
                    className="h-7 px-2.5 rounded-full bg-[#16171a] hover:bg-[#2b2d33] border border-white/[0.06] text-xs text-[#1d8cf8] flex items-center gap-1.5 transition-colors"
                  >
                    <RotateCcw className="w-3 h-3" /> Zurück
                  </button>
                  <button
                    onClick={() => handleDeletePermanent(item.id)}
                    className="w-7 h-7 rounded-full bg-[#16171a] hover:bg-white/[0.1] text-zinc-400 hover:text-white flex items-center justify-center transition-colors"
                  >
                    <Trash2 className="w-3 h-3" />
                  </button>
                </div>
              </div>
            ))
          )}
        </div>
      ) : (
        <div className="bg-[#222428] border border-white/[0.08] divide-y divide-white/[0.06]">
          {(filter === 'open' ? openTasks : doneTasks).length === 0 ? (
            <div className="px-4 py-6 text-center text-zinc-400 text-sm">
              {filter === 'open'
                ? 'Keine offenen Aufgaben vorhanden.'
                : 'Noch keine erledigten Aufgaben.'}
            </div>
          ) : (
            (filter === 'open' ? openTasks : doneTasks).map((task) => (
              <div
                key={task.id}
                className={`px-3 py-2 flex flex-col sm:flex-row sm:items-center justify-between gap-2 transition-colors hover:bg-white/[0.02] ${
                  task.isCompleted ? 'opacity-65' : ''
                }`}
              >
                <div className="flex items-center gap-3 min-w-0 flex-1">
                  {/* Square minimalist checkbox */}
                  <button
                    onClick={() => handleToggleDone(task)}
                    className={`w-4 h-4 flex items-center justify-center flex-shrink-0 transition-colors border ${
                      task.isCompleted
                        ? 'bg-[#1d8cf8] border-[#1d8cf8] text-white'
                        : 'border-zinc-500 hover:border-[#1d8cf8] text-transparent'
                    }`}
                    title={task.isCompleted ? 'Als offen markieren' : 'Als erledigt abhaken'}
                  >
                    <Check className="w-3 h-3 stroke-[3]" />
                  </button>

                  <div className="min-w-0 flex-1">
                    <p
                      className={`text-sm break-words leading-tight ${
                        task.isCompleted ? 'line-through text-zinc-500' : 'text-white'
                      }`}
                    >
                      {task.content}
                    </p>

                    <div className="flex flex-wrap items-center gap-1.5 mt-0.5 empty:hidden">
                      {task.priority === 'urgent' && (
                        <span className="px-1.5 py-0.2 border border-[#1d8cf8] text-[#1d8cf8] text-[10px] font-semibold">
                          Dringend
                        </span>
                      )}
                      {task.priority === 'high' && (
                        <span className="px-1.5 py-0.2 border border-white/20 text-zinc-300 text-[10px] font-medium">
                          Wichtig
                        </span>
                      )}
                      {task.tags?.map((tag) => (
                        <span
                          key={tag}
                          className="px-1.5 py-0.2 bg-[#16171a] text-zinc-400 text-[10px]"
                        >
                          #{tag}
                        </span>
                      ))}
                    </div>
                  </div>
                </div>

                {/* Action Controls */}
                <div className="flex items-center gap-2 self-end sm:self-center flex-shrink-0">
                  <div className="relative flex items-center">
                    <Calendar className="w-3 h-3 text-zinc-400 absolute left-2 pointer-events-none" />
                    <input
                      type="date"
                      value={task.dueDate || ''}
                      onChange={(e) => handleDueDateChange(task, e.target.value)}
                      className="h-7 pl-6 pr-2 bg-[#16171a] text-white text-xs border border-white/[0.08] focus:outline-none focus:border-[#1d8cf8] transition-colors"
                    />
                  </div>

                  <button
                    onClick={() => handleConvertToDoc(task)}
                    title="Als Notiz / Projekt vertiefen"
                    className="h-7 px-2.5 rounded-full bg-[#16171a] hover:bg-[#2b2d33] border border-white/[0.06] text-xs text-zinc-300 hover:text-white flex items-center gap-1.5 transition-colors"
                  >
                    <FileText className="w-3 h-3 text-[#1d8cf8]" />
                    <span className="hidden md:inline">Vertiefen</span>
                  </button>

                  <button
                    onClick={() => handleDeletePermanent(task.id)}
                    title="Löschen"
                    className="w-7 h-7 rounded-full bg-[#16171a] hover:bg-white/[0.1] text-zinc-400 hover:text-white flex items-center justify-center transition-colors"
                  >
                    <Trash2 className="w-3 h-3" />
                  </button>
                </div>
              </div>
            ))
          )}
        </div>
      )}
    </div>
  );
};