import React, { useState, useEffect } from 'react';
import axios from 'axios';

const s = {
  overlay: {
    position: 'fixed', inset: 0, background: 'rgba(0,0,0,0.8)',
    zIndex: 2000, display: 'flex', alignItems: 'center', justifyContent: 'center',
  },
  modal: {
    background: '#111217', color: '#f8f9fa', width: '480px', maxWidth: '95vw',
    borderRadius: '10px', boxShadow: '0 8px 40px rgba(0,0,0,0.8)',
    border: '1px solid #222', overflow: 'hidden',
  },
  header: {
    background: 'linear-gradient(135deg, #000000, #151622)', color: 'white',
    padding: '18px 22px', display: 'flex', alignItems: 'center', justifyContent: 'space-between',
    borderBottom: '1px solid #222',
  },
  title: { fontSize: '15px', fontWeight: 700 },
  closeBtn: {
    background: 'none', border: 'none', color: 'white', fontSize: '20px',
    cursor: 'pointer', lineHeight: 1,
  },
  body: { padding: '22px' },
  tabs: { display: 'flex', gap: '4px', marginBottom: '20px' },
  tab: (active) => ({
    flex: 1, padding: '8px', borderRadius: '6px', cursor: 'pointer', fontSize: '12px',
    fontWeight: 700, textAlign: 'center', border: '1px solid',
    background: active ? '#1a1c2e' : 'none',
    borderColor: active ? '#667eea' : '#2a2b3a',
    color: active ? '#667eea' : '#777',
  }),
  label: { fontSize: '11px', color: '#9ca0b8', textTransform: 'uppercase', letterSpacing: '0.5px', marginBottom: '5px' },
  input: {
    width: '100%', background: '#0d0e14', border: '1px solid #2a2b3a', borderRadius: '6px',
    color: '#f8f9fa', padding: '9px 12px', fontSize: '13px', marginBottom: '14px',
    outline: 'none', boxSizing: 'border-box',
  },
  select: {
    width: '100%', background: '#0d0e14', border: '1px solid #2a2b3a', borderRadius: '6px',
    color: '#f8f9fa', padding: '9px 12px', fontSize: '13px', marginBottom: '14px',
    outline: 'none', boxSizing: 'border-box',
  },
  row: { display: 'flex', gap: '10px', justifyContent: 'flex-end', marginTop: '6px' },
  btn: (color, bg) => ({
    padding: '8px 18px', borderRadius: '6px', fontWeight: 700, fontSize: '13px',
    cursor: 'pointer', border: `1px solid ${color}`, color, background: bg || 'none',
  }),
  error: {
    background: '#3c1114', border: '1px solid #f5c6cb', borderRadius: '6px',
    padding: '10px 12px', fontSize: '12px', color: '#ffb3b8', marginBottom: '14px',
  },
  success: {
    background: '#0a2e1f', border: '1px solid #0f5132', borderRadius: '6px',
    padding: '10px 12px', fontSize: '12px', color: '#9ef7c1', marginBottom: '14px',
  },
  mergeWarning: {
    background: '#2a1f00', border: '1px solid #7a5000', borderRadius: '6px',
    padding: '12px', fontSize: '12px', color: '#ffc107', marginBottom: '14px', lineHeight: 1.5,
  },
};

export default function EditEmployeeModal({ employee, onClose, onSaved }) {
  const [tab, setTab] = useState('edit');

  // Edit state
  const [name, setName]             = useState(employee.name);
  const [department, setDepartment] = useState(employee.department || '');
  const [supervisor, setSupervisor] = useState(employee.supervisor || '');
  const [editError, setEditError]   = useState('');
  const [editSaving, setEditSaving] = useState(false);

  // Merge state
  const [allEmployees, setAllEmployees] = useState([]);
  const [sourceId, setSourceId]         = useState('');
  const [mergeError, setMergeError]     = useState('');
  const [mergeResult, setMergeResult]   = useState(null);
  const [merging, setMerging]           = useState(false);

  useEffect(() => {
    if (tab === 'merge') {
      axios.get('/api/employees').then(r => setAllEmployees(r.data));
    }
  }, [tab]);

  const handleEdit = async () => {
    setEditError('');
    setEditSaving(true);
    try {
      await axios.patch(`/api/employees/${employee.id}`, { name, department, supervisor });
      onSaved();
      onClose();
    } catch (e) {
      setEditError(e.response?.data?.error || 'Failed to save changes');
    } finally {
      setEditSaving(false);
    }
  };

  const handleMerge = async () => {
    if (!sourceId) return setMergeError('Select an employee to merge in');
    setMergeError('');
    setMerging(true);
    try {
      const r = await axios.post(`/api/employees/${employee.id}/merge`, { source_id: parseInt(sourceId) });
      setMergeResult(r.data);
      onSaved(); // refresh dashboard / parent list
    } catch (e) {
      setMergeError(e.response?.data?.error || 'Merge failed');
    } finally {
      setMerging(false);
    }
  };

  const otherEmployees = allEmployees.filter(e => e.id !== employee.id);

  return (
    <div style={s.overlay} onClick={e => e.target === e.currentTarget && onClose()}>
      <div style={s.modal}>
        <div style={s.header}>
          <div style={s.title}>Edit Employee</div>
          <button style={s.closeBtn} onClick={onClose}>✕</button>
        </div>
        <div style={s.body}>
          <div style={s.tabs}>
            <button style={s.tab(tab === 'edit')}  onClick={() => setTab('edit')}>Edit Details</button>
            <button style={s.tab(tab === 'merge')} onClick={() => setTab('merge')}>Merge Duplicate</button>
          </div>

          {tab === 'edit' && (
            <>
              {editError && <div style={s.error}>{editError}</div>}
              <div style={s.label}>Full Name</div>
              <input style={s.input} value={name} onChange={e => setName(e.target.value)} />
              <div style={s.label}>Department</div>
              <input style={s.input} value={department} onChange={e => setDepartment(e.target.value)} placeholder="Optional" />
              <div style={s.label}>Supervisor</div>
              <input style={s.input} value={supervisor} onChange={e => setSupervisor(e.target.value)} placeholder="Optional" />
              <div style={s.row}>
                <button style={s.btn('#888')} onClick={onClose}>Cancel</button>
                <button style={s.btn('#fff', '#667eea')} onClick={handleEdit} disabled={editSaving}>
                  {editSaving ? 'Saving…' : 'Save Changes'}
                </button>
              </div>
            </>
          )}

          {tab === 'merge' && (
            <>
              {mergeResult ? (
                <div style={s.success}>
                  ✓ Merge complete — {mergeResult.violations_reassigned} violation{mergeResult.violations_reassigned !== 1 ? 's' : ''} reassigned
                  to <strong>{employee.name}</strong>. The duplicate record has been removed.
                </div>
              ) : (
                <>
                  <div style={s.mergeWarning}>
                    ⚠ This will reassign <strong>all violations</strong> from the selected employee into{' '}
                    <strong>{employee.name}</strong>, then permanently delete the duplicate record.
                    This cannot be undone.
                  </div>
                  {mergeError && <div style={s.error}>{mergeError}</div>}
                  <div style={s.label}>Duplicate to merge into {employee.name}</div>
                  <select style={s.select} value={sourceId} onChange={e => setSourceId(e.target.value)}>
                    <option value="">— select employee —</option>
                    {otherEmployees.map(e => (
                      <option key={e.id} value={e.id}>{e.name}{e.department ? ` (${e.department})` : ''}</option>
                    ))}
                  </select>
                  <div style={s.row}>
                    <button style={s.btn('#888')} onClick={onClose}>Cancel</button>
                    <button style={s.btn('#fff', '#c0392b')} onClick={handleMerge} disabled={merging || !sourceId}>
                      {merging ? 'Merging…' : 'Merge & Delete Duplicate'}
                    </button>
                  </div>
                </>
              )}
              {mergeResult && (
                <div style={s.row}>
                  <button style={s.btn('#fff', '#667eea')} onClick={onClose}>Done</button>
                </div>
              )}
            </>
          )}
        </div>
      </div>
    </div>
  );
}
