'use client';

import { useState, useEffect } from 'react';
import { workersAPI, Worker, settingsAPI, Settings } from '@/lib/api';

export default function Home() {
  const [workers, setWorkers] = useState<Worker[]>([]);
  const [newWorkerName, setNewWorkerName] = useState('');
  const [newPresenceDays, setNewPresenceDays] = useState('');
  const [nameError, setNameError] = useState(false);
  const [daysError, setDaysError] = useState(false);
  const [editingId, setEditingId] = useState<string | null>(null);
  const [editingDays, setEditingDays] = useState('');
  const [loading, setLoading] = useState(false);
  const [settings, setSettings] = useState<Settings>({ id: 1, totalPoints: 13, totalDays: 10 });
  const [showSettings, setShowSettings] = useState(false);
  const [showResetConfirm, setShowResetConfirm] = useState(false);
  const [editTotalPoints, setEditTotalPoints] = useState('');
  const [editTotalDays, setEditTotalDays] = useState('');

  const TOTAL_POINTS = settings.totalPoints;
  const TOTAL_DAYS = settings.totalDays;
  const POINTS_PER_DAY = TOTAL_POINTS / TOTAL_DAYS;

  useEffect(() => {
    loadWorkers();
    loadSettings();
  }, []);

  const loadWorkers = async () => {
    try {
      const data = await workersAPI.getAll();
      setWorkers(data);
    } catch (error) {
      console.error('Failed to load workers:', error);
      alert('Failed to load workers. Make sure json-server is running.');
    }
  };

  const loadSettings = async () => {
    try {
      const data = await settingsAPI.get();
      setSettings(data);
    } catch (error) {
      console.error('Failed to load settings:', error);
    }
  };

  const openSettings = () => {
    setEditTotalPoints(settings.totalPoints.toString());
    setEditTotalDays(settings.totalDays.toString());
    setShowSettings(true);
  };

  const closeSettings = () => {
    setShowSettings(false);
    setEditTotalPoints('');
    setEditTotalDays('');
  };

  const saveSettings = async () => {
    const points = parseInt(editTotalPoints);
    const days = parseInt(editTotalDays);

    if (isNaN(points) || points <= 0) {
      alert('Please enter a valid number of points greater than 0');
      return;
    }

    if (isNaN(days) || days <= 0) {
      alert('Please enter a valid number of days greater than 0');
      return;
    }

    try {
      setLoading(true);
      const updatedSettings = await settingsAPI.update({ totalPoints: points, totalDays: days });
      setSettings(updatedSettings);
      closeSettings();
    } catch (error) {
      console.error('Failed to save settings:', error);
      alert('Failed to save settings');
    } finally {
      setLoading(false);
    }
  };

  const addWorker = async () => {
    // Validate required fields
    const isNameEmpty = !newWorkerName.trim();
    const isDaysEmpty = !newPresenceDays.trim();

    setNameError(isNameEmpty);
    setDaysError(isDaysEmpty);

    if (isNameEmpty || isDaysEmpty) return;

    const days = parseInt(newPresenceDays);
    if (isNaN(days) || days < 0 || days > TOTAL_DAYS) {
      alert(`Please enter a valid number of days between 0 and ${TOTAL_DAYS}`);
      setDaysError(true);
      return;
    }

    try {
      setLoading(true);
      await workersAPI.create({
        name: newWorkerName.trim(),
        presenceDays: days,
      });
      await loadWorkers();
      setNewWorkerName('');
      setNewPresenceDays('');
      setNameError(false);
      setDaysError(false);
    } catch (error) {
      console.error('Failed to add worker:', error);
      alert('Failed to add worker');
    } finally {
      setLoading(false);
    }
  };

  const removeWorker = async (id: string) => {
    try {
      setLoading(true);
      await workersAPI.delete(id);
      await loadWorkers();
    } catch (error) {
      console.error('Failed to remove worker:', error);
      alert('Failed to remove worker');
    } finally {
      setLoading(false);
    }
  };

  const startEditing = (worker: Worker) => {
    setEditingId(worker.id);
    setEditingDays(worker.presenceDays.toString());
  };

  const cancelEditing = () => {
    setEditingId(null);
    setEditingDays('');
  };

  const saveEditing = async (id: string) => {
    const days = parseInt(editingDays);
    if (isNaN(days) || days < 0 || days > TOTAL_DAYS) {
      alert(`Please enter a valid number of days between 0 and ${TOTAL_DAYS}`);
      return;
    }

    try {
      setLoading(true);
      await workersAPI.update(id, { presenceDays: days });
      await loadWorkers();
      setEditingId(null);
      setEditingDays('');
    } catch (error) {
      console.error('Failed to update worker:', error);
      alert('Failed to update worker');
    } finally {
      setLoading(false);
    }
  };

  const confirmResetAllPresences = async () => {
    try {
      setLoading(true);
      setShowResetConfirm(false);
      await workersAPI.resetAllPresences();
      await loadWorkers();
    } catch (error) {
      console.error('Failed to reset presences:', error);
      alert('Failed to reset presences');
    } finally {
      setLoading(false);
    }
  };

  const calculatePoints = (days: number): number => {
    return days * POINTS_PER_DAY;
  };

  const calculateUsedPoints = (days: number): number => {
    return TOTAL_POINTS - calculatePoints(days);
  };

  return (
    <main className="min-h-screen bg-gradient-to-br from-blue-50 to-indigo-100 p-8">
      <div className="max-w-4xl mx-auto">
        <div className="flex justify-between items-start mb-8">
          <div>
            <h1 className="text-4xl font-bold text-gray-800 mb-2">Worker Presence Manager</h1>
            <p className="text-gray-600">
              Sprint duration: {TOTAL_DAYS} working days | Total points per worker: {TOTAL_POINTS}
            </p>
          </div>
          <button
            onClick={openSettings}
            disabled={loading}
            className="px-4 py-2 bg-gray-600 text-white rounded-lg hover:bg-gray-700 transition-colors font-medium disabled:opacity-50 disabled:cursor-not-allowed"
          >
            Settings
          </button>
        </div>

        {/* Add Worker Form */}
        <div className="bg-white rounded-lg shadow-md p-6 mb-8">
          <h2 className="text-xl font-semibold text-gray-800 mb-4">Add Worker</h2>
          <div className="flex flex-col sm:flex-row gap-3">
            <input
              type="text"
              placeholder="Worker name"
              value={newWorkerName}
              onChange={(e) => {
                setNewWorkerName(e.target.value);
                if (nameError) setNameError(false);
              }}
              className={`flex-1 px-4 py-2 border rounded-lg focus:outline-none focus:ring-2 ${
                nameError
                  ? 'border-red-500 focus:ring-red-500'
                  : 'border-gray-300 focus:ring-blue-500'
              }`}
              onKeyPress={(e) => e.key === 'Enter' && addWorker()}
            />
            <input
              type="number"
              placeholder={`Presence days (0-${TOTAL_DAYS})`}
              value={newPresenceDays}
              onChange={(e) => {
                setNewPresenceDays(e.target.value);
                if (daysError) setDaysError(false);
              }}
              min="0"
              max={TOTAL_DAYS}
              className={`w-full sm:w-48 px-4 py-2 border rounded-lg focus:outline-none focus:ring-2 ${
                daysError
                  ? 'border-red-500 focus:ring-red-500'
                  : 'border-gray-300 focus:ring-blue-500'
              }`}
              onKeyPress={(e) => e.key === 'Enter' && addWorker()}
            />
            <button
              onClick={addWorker}
              disabled={loading}
              className="px-6 py-2 bg-blue-600 text-white rounded-lg hover:bg-blue-700 transition-colors font-medium disabled:opacity-50 disabled:cursor-not-allowed"
            >
              Add
            </button>
          </div>
        </div>

        {/* Workers List */}
        {workers.length > 0 ? (
          <div className="bg-white rounded-lg shadow-md overflow-hidden">
            <div className="overflow-x-auto">
              <table className="w-full">
                <thead className="bg-gray-50 border-b border-gray-200">
                  <tr>
                    <th className="px-6 py-3 text-left text-xs font-medium text-gray-500 uppercase tracking-wider">
                      Worker Name
                    </th>
                    <th className="px-6 py-3 text-left text-xs font-medium text-gray-500 uppercase tracking-wider">
                      Presence Days
                    </th>
                    <th className="px-6 py-3 text-left text-xs font-medium text-gray-500 uppercase tracking-wider">
                      Points Earned
                    </th>
                    <th className="px-6 py-3 text-left text-xs font-medium text-gray-500 uppercase tracking-wider">
                      Points Used
                    </th>
                    <th className="px-6 py-3 text-left text-xs font-medium text-gray-500 uppercase tracking-wider">
                      Remaining Points
                    </th>
                    <th className="px-6 py-3 text-right text-xs font-medium text-gray-500 uppercase tracking-wider">
                      Actions
                    </th>
                  </tr>
                </thead>
                <tbody className="bg-white divide-y divide-gray-200">
                  {workers.map((worker) => {
                    const pointsEarned = calculatePoints(worker.presenceDays);
                    const pointsUsed = calculateUsedPoints(worker.presenceDays);
                    const remainingPoints = TOTAL_POINTS - pointsUsed;
                    const isEditing = editingId === worker.id;

                    return (
                      <tr key={worker.id} className="hover:bg-gray-50">
                        <td className="px-6 py-4 whitespace-nowrap text-sm font-medium text-gray-900">
                          {worker.name}
                        </td>
                        <td className="px-6 py-4 whitespace-nowrap text-sm text-gray-700">
                          {isEditing ? (
                            <input
                              type="number"
                              value={editingDays}
                              onChange={(e) => setEditingDays(e.target.value)}
                              min="0"
                              max={TOTAL_DAYS}
                              className="w-20 px-2 py-1 border border-blue-300 rounded focus:outline-none focus:ring-2 focus:ring-blue-500"
                              onKeyPress={(e) => {
                                if (e.key === 'Enter') saveEditing(worker.id);
                                if (e.key === 'Escape') cancelEditing();
                              }}
                              autoFocus
                            />
                          ) : (
                            `${worker.presenceDays} / ${TOTAL_DAYS}`
                          )}
                        </td>
                        <td className="px-6 py-4 whitespace-nowrap text-sm text-green-600 font-medium">
                          {pointsEarned.toFixed(2)}
                        </td>
                        <td className="px-6 py-4 whitespace-nowrap text-sm text-red-600 font-medium">
                          {pointsUsed.toFixed(2)}
                        </td>
                        <td className="px-6 py-4 whitespace-nowrap text-sm text-gray-700 font-medium">
                          {remainingPoints.toFixed(2)} / {TOTAL_POINTS}
                        </td>
                        <td className="px-6 py-4 whitespace-nowrap text-right text-sm font-medium">
                          {isEditing ? (
                            <div className="flex gap-2 justify-end">
                              <button
                                onClick={() => saveEditing(worker.id)}
                                className="text-green-600 hover:text-green-900 transition-colors"
                              >
                                Save
                              </button>
                              <button
                                onClick={cancelEditing}
                                className="text-gray-600 hover:text-gray-900 transition-colors"
                              >
                                Cancel
                              </button>
                            </div>
                          ) : (
                            <div className="flex gap-2 justify-end">
                              <button
                                onClick={() => startEditing(worker)}
                                className="p-2 text-blue-600 hover:text-blue-900 hover:bg-blue-50 rounded transition-colors"
                                title="Edit"
                              >
                                <svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" strokeWidth={1.5} stroke="currentColor" className="w-5 h-5">
                                  <path strokeLinecap="round" strokeLinejoin="round" d="m16.862 4.487 1.687-1.688a1.875 1.875 0 1 1 2.652 2.652L10.582 16.07a4.5 4.5 0 0 1-1.897 1.13L6 18l.8-2.685a4.5 4.5 0 0 1 1.13-1.897l8.932-8.931Zm0 0L19.5 7.125M18 14v4.75A2.25 2.25 0 0 1 15.75 21H5.25A2.25 2.25 0 0 1 3 18.75V8.25A2.25 2.25 0 0 1 5.25 6H10" />
                                </svg>
                              </button>
                              <button
                                onClick={() => removeWorker(worker.id)}
                                className="p-2 text-red-600 hover:text-red-900 hover:bg-red-50 rounded transition-colors"
                                title="Remove"
                              >
                                <svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" strokeWidth={1.5} stroke="currentColor" className="w-5 h-5">
                                  <path strokeLinecap="round" strokeLinejoin="round" d="m14.74 9-.346 9m-4.788 0L9.26 9m9.968-3.21c.342.052.682.107 1.022.166m-1.022-.165L18.16 19.673a2.25 2.25 0 0 1-2.244 2.077H8.084a2.25 2.25 0 0 1-2.244-2.077L4.772 5.79m14.456 0a48.108 48.108 0 0 0-3.478-.397m-12 .562c.34-.059.68-.114 1.022-.165m0 0a48.11 48.11 0 0 1 3.478-.397m7.5 0v-.916c0-1.18-.91-2.164-2.09-2.201a51.964 51.964 0 0 0-3.32 0c-1.18.037-2.09 1.022-2.09 2.201v.916m7.5 0a48.667 48.667 0 0 0-7.5 0" />
                                </svg>
                              </button>
                            </div>
                          )}
                        </td>
                      </tr>
                    );
                  })}
                </tbody>
              </table>
            </div>

            {/* Summary */}
            <div className="bg-gray-50 px-6 py-4 border-t border-gray-200">
              <div className="flex flex-wrap items-center justify-between gap-4">
                <div className="flex flex-wrap gap-6 text-sm">
                  <div>
                    <span className="text-gray-600">Total Workers: </span>
                    <span className="font-semibold text-gray-900">{workers.length}</span>
                  </div>
                  <div>
                    <span className="text-gray-600">Avg Presence Days: </span>
                    <span className="font-semibold text-gray-900">
                      {workers.length > 0
                        ? (workers.reduce((sum, w) => sum + w.presenceDays, 0) / workers.length).toFixed(1)
                        : '0'}
                    </span>
                  </div>
                  <div>
                    <span className="text-gray-600">Total Presence Days: </span>
                    <span className="font-semibold text-gray-900">
                      {workers.reduce((sum, w) => sum + w.presenceDays, 0)}
                    </span>
                  </div>
                </div>
                  <div>
                    <span className="text-gray-600">Total Points in the sprint: </span>
                    <span className="font-semibold text-blue-600">
                      {workers.reduce((sum, w) => sum + calculatePoints(w.presenceDays), 0).toFixed(2)}
                    </span>
                  </div>
                <button
                  onClick={() => setShowResetConfirm(true)}
                  disabled={loading}
                  className="p-2 bg-orange-600 text-white rounded-lg hover:bg-orange-700 transition-colors disabled:opacity-50 disabled:cursor-not-allowed"
                  title="Reset All Presences"
                >
                  <svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" strokeWidth={1.5} stroke="currentColor" className="w-5 h-5">
                    <path strokeLinecap="round" strokeLinejoin="round" d="M16.023 9.348h4.992v-.001M2.985 19.644v-4.992m0 0h4.992m-4.993 0 3.181 3.183a8.25 8.25 0 0 0 13.803-3.7M4.031 9.865a8.25 8.25 0 0 1 13.803-3.7l3.181 3.182m0-4.991v4.99" />
                  </svg>
                </button>
              </div>
            </div>
          </div>
        ) : (
          <div className="bg-white rounded-lg shadow-md p-12 text-center">
            <p className="text-gray-500 text-lg">No workers added yet. Add your first worker above.</p>
          </div>
        )}

        {/* Info Box */}
        <div className="mt-8 bg-blue-50 border border-blue-200 rounded-lg p-4">
          <h3 className="font-semibold text-blue-900 mb-2">How it works:</h3>
          <ul className="text-sm text-blue-800 space-y-1">
            <li>• Each worker has {TOTAL_POINTS} points for a sprint ({TOTAL_DAYS} working days)</li>
            <li>• Each presence day equals {POINTS_PER_DAY.toFixed(2)} points</li>
            <li>• Points Earned = Presence Days × {POINTS_PER_DAY.toFixed(2)}</li>
            <li>• Points Used = {TOTAL_POINTS} - Points Earned (days not present)</li>
            <li>• Remaining Points = Points Earned</li>
          </ul>
        </div>

        {/* Settings Modal */}
        {showSettings && (
          <div className="fixed inset-0 bg-black bg-opacity-50 flex items-center justify-center p-4 z-50">
            <div className="bg-white rounded-lg shadow-xl max-w-md w-full p-6">
              <h2 className="text-2xl font-bold text-gray-800 mb-4">Settings</h2>

              <div className="space-y-4">
                <div>
                  <label className="block text-sm font-medium text-gray-700 mb-2">
                    Points per Worker per Sprint
                  </label>
                  <input
                    type="number"
                    value={editTotalPoints}
                    onChange={(e) => setEditTotalPoints(e.target.value)}
                    min="1"
                    className="w-full px-4 py-2 border border-gray-300 rounded-lg focus:outline-none focus:ring-2 focus:ring-blue-500"
                    placeholder="e.g., 13"
                  />
                  <p className="mt-1 text-sm text-gray-500">
                    Total points allocated to each worker for the sprint
                  </p>
                </div>

                <div>
                  <label className="block text-sm font-medium text-gray-700 mb-2">
                    Number of Days in Sprint
                  </label>
                  <input
                    type="number"
                    value={editTotalDays}
                    onChange={(e) => setEditTotalDays(e.target.value)}
                    min="1"
                    className="w-full px-4 py-2 border border-gray-300 rounded-lg focus:outline-none focus:ring-2 focus:ring-blue-500"
                    placeholder="e.g., 10"
                  />
                  <p className="mt-1 text-sm text-gray-500">
                    Total working days in the sprint
                  </p>
                </div>

                <div className="bg-gray-50 rounded p-3 text-sm text-gray-600">
                  <p>
                    <strong>Points per day:</strong>{' '}
                    {editTotalPoints && editTotalDays && parseInt(editTotalPoints) > 0 && parseInt(editTotalDays) > 0
                      ? (parseInt(editTotalPoints) / parseInt(editTotalDays)).toFixed(2)
                      : 'N/A'}
                  </p>
                </div>
              </div>

              <div className="flex gap-3 mt-6">
                <button
                  onClick={saveSettings}
                  disabled={loading}
                  className="flex-1 px-4 py-2 bg-blue-600 text-white rounded-lg hover:bg-blue-700 transition-colors font-medium disabled:opacity-50 disabled:cursor-not-allowed"
                >
                  Save
                </button>
                <button
                  onClick={closeSettings}
                  disabled={loading}
                  className="flex-1 px-4 py-2 bg-gray-200 text-gray-800 rounded-lg hover:bg-gray-300 transition-colors font-medium disabled:opacity-50 disabled:cursor-not-allowed"
                >
                  Cancel
                </button>
              </div>
            </div>
          </div>
        )}

        {/* Reset Confirmation Modal */}
        {showResetConfirm && (
          <div className="fixed inset-0 bg-black bg-opacity-50 flex items-center justify-center p-4 z-50">
            <div className="bg-white rounded-lg shadow-xl max-w-md w-full p-6">
              <div className="flex items-center gap-3 mb-4">
                <div className="p-3 bg-orange-100 rounded-full">
                  <svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" strokeWidth={1.5} stroke="currentColor" className="w-6 h-6 text-orange-600">
                    <path strokeLinecap="round" strokeLinejoin="round" d="M12 9v3.75m-9.303 3.376c-.866 1.5.217 3.374 1.948 3.374h14.71c1.73 0 2.813-1.874 1.948-3.374L13.949 3.378c-.866-1.5-3.032-1.5-3.898 0L2.697 16.126ZM12 15.75h.007v.008H12v-.008Z" />
                  </svg>
                </div>
                <h2 className="text-xl font-bold text-gray-800">Reset All Presences</h2>
              </div>

              <p className="text-gray-600 mb-6">
                Are you sure you want to reset all worker presences to 0? This action cannot be undone.
              </p>

              <div className="flex gap-3">
                <button
                  onClick={() => setShowResetConfirm(false)}
                  disabled={loading}
                  className="flex-1 px-4 py-2 bg-gray-200 text-gray-800 rounded-lg hover:bg-gray-300 transition-colors font-medium disabled:opacity-50 disabled:cursor-not-allowed"
                >
                  Cancel
                </button>
                <button
                  onClick={confirmResetAllPresences}
                  disabled={loading}
                  className="flex-1 px-4 py-2 bg-orange-600 text-white rounded-lg hover:bg-orange-700 transition-colors font-medium disabled:opacity-50 disabled:cursor-not-allowed"
                >
                  Reset All
                </button>
              </div>
            </div>
          </div>
        )}
      </div>
    </main>
  );
}