import React, { useState, useEffect, useCallback } from 'react';
import { X, Loader, AlertCircle, Send, RefreshCw } from 'lucide-react';

const API_BASE = process.env.REACT_APP_API_BASE || 'http://localhost:3001/api';

// ---------------------------------------------------------------------------
// Styles — matches dark theme tactical intelligence aesthetic
// ---------------------------------------------------------------------------
const STYLES = {
  overlay: {
    position: 'fixed',
    inset: 0,
    zIndex: 100,
    display: 'flex',
    alignItems: 'center',
    justifyContent: 'center',
  },
  backdrop: {
    position: 'fixed',
    inset: 0,
    background: 'rgba(0,0,0,0.7)',
    backdropFilter: 'blur(4px)',
  },
  content: {
    position: 'relative',
    background: 'linear-gradient(135deg, #1E293B, #0F172A)',
    border: '1px solid rgba(14, 165, 233, 0.25)',
    borderRadius: '16px',
    padding: '2rem',
    width: '90%',
    maxWidth: '560px',
    maxHeight: '85vh',
    overflowY: 'auto',
    zIndex: 101,
  },
  header: {
    display: 'flex',
    alignItems: 'flex-start',
    justifyContent: 'space-between',
    marginBottom: '1.25rem',
  },
  title: {
    fontFamily: 'monospace',
    fontSize: '0.8rem',
    fontWeight: 700,
    color: '#A855F7',
    textTransform: 'uppercase',
    letterSpacing: '0.1em',
  },
  subtitle: {
    fontFamily: 'monospace',
    fontSize: '0.7rem',
    color: '#94A3B8',
    marginTop: '0.35rem',
    overflow: 'hidden',
    textOverflow: 'ellipsis',
    whiteSpace: 'nowrap',
    maxWidth: '400px',
  },
  closeBtn: {
    background: 'none',
    border: 'none',
    color: '#64748B',
    cursor: 'pointer',
    padding: '0.25rem',
    borderRadius: '4px',
    display: 'flex',
    alignItems: 'center',
    justifyContent: 'center',
  },
  textarea: {
    width: '100%',
    boxSizing: 'border-box',
    minHeight: '100px',
    background: 'rgba(15, 23, 42, 0.8)',
    border: '1px solid rgba(14, 165, 233, 0.2)',
    borderRadius: '8px',
    padding: '0.75rem',
    color: '#F8FAFC',
    fontSize: '0.85rem',
    fontFamily: 'monospace',
    resize: 'vertical',
    outline: 'none',
  },
  charCounter: {
    fontFamily: 'monospace',
    fontSize: '0.6rem',
    color: '#64748B',
    textAlign: 'right',
    marginTop: '0.25rem',
  },
  submitBtn: {
    padding: '0.5rem 1rem',
    borderRadius: '8px',
    border: '1px solid rgba(168, 85, 247, 0.4)',
    background: 'rgba(168, 85, 247, 0.15)',
    color: '#C084FC',
    cursor: 'pointer',
    fontSize: '0.8rem',
    fontWeight: 600,
    display: 'inline-flex',
    alignItems: 'center',
    gap: '0.4rem',
    transition: 'all 0.2s',
  },
  submitBtnDisabled: {
    opacity: 0.4,
    cursor: 'not-allowed',
  },
  noteItem: {
    padding: '0.75rem',
    marginBottom: '0.5rem',
    background: 'rgba(14, 165, 233, 0.04)',
    border: '1px solid rgba(14, 165, 233, 0.1)',
    borderRadius: '8px',
  },
  noteMeta: {
    fontFamily: 'monospace',
    fontSize: '0.6rem',
    color: '#64748B',
    marginBottom: '0.35rem',
    display: 'flex',
    gap: '0.5rem',
  },
  noteText: {
    fontFamily: 'monospace',
    fontSize: '0.75rem',
    color: '#CBD5E1',
    lineHeight: 1.5,
    whiteSpace: 'pre-wrap',
    wordBreak: 'break-word',
  },
  error: {
    display: 'flex',
    alignItems: 'center',
    gap: '0.5rem',
    padding: '0.5rem 0.75rem',
    background: 'rgba(239, 68, 68, 0.08)',
    border: '1px solid rgba(239, 68, 68, 0.2)',
    borderRadius: '0.5rem',
    marginBottom: '0.75rem',
  },
  errorText: {
    fontFamily: 'monospace',
    fontSize: '0.7rem',
    color: '#FCA5A5',
  },
  emptyState: {
    textAlign: 'center',
    padding: '1.5rem 0',
    fontFamily: 'monospace',
    fontSize: '0.7rem',
    color: '#475569',
  },
  divider: {
    height: '1px',
    background: 'rgba(14, 165, 233, 0.1)',
    margin: '1rem 0',
  },
  retryBtn: {
    padding: '0.4rem 0.75rem',
    borderRadius: '6px',
    border: '1px solid rgba(14, 165, 233, 0.3)',
    background: 'rgba(14, 165, 233, 0.1)',
    color: '#7DD3FC',
    cursor: 'pointer',
    fontSize: '0.7rem',
    fontWeight: 600,
    display: 'inline-flex',
    alignItems: 'center',
    gap: '0.3rem',
    marginTop: '0.5rem',
  },
};

// ---------------------------------------------------------------------------
// RemediationModal — add and view remediation notes for a queue item
// ---------------------------------------------------------------------------
export default function RemediationModal({ item, onClose, onNoteAdded }) {
  const [notes, setNotes] = useState([]);
  const [newNoteText, setNewNoteText] = useState('');
  const [loading, setLoading] = useState(true);
  const [saving, setSaving] = useState(false);
  const [error, setError] = useState(null);
  const [fetchError, setFetchError] = useState(null);

  // ---------------------------------------------------------------------------
  // Fetch existing notes on mount
  // ---------------------------------------------------------------------------
  const fetchNotes = useCallback(async () => {
    setLoading(true);
    setFetchError(null);
    try {
      const res = await fetch(`${API_BASE}/ivanti/todo-queue/${item.id}/notes`, {
        credentials: 'include',
      });
      if (!res.ok) {
        const data = await res.json().catch(() => ({}));
        throw new Error(data.error || `HTTP ${res.status}`);
      }
      const data = await res.json();
      setNotes(data);
    } catch (e) {
      setFetchError(e.message || 'Failed to load notes.');
    } finally {
      setLoading(false);
    }
  }, [item.id]);

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

  // ---------------------------------------------------------------------------
  // Submit new note
  // ---------------------------------------------------------------------------
  const handleSubmit = useCallback(async () => {
    if (!newNoteText.trim() || saving) return;

    setSaving(true);
    setError(null);
    try {
      const res = await fetch(`${API_BASE}/ivanti/todo-queue/${item.id}/notes`, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        credentials: 'include',
        body: JSON.stringify({ note_text: newNoteText }),
      });
      const data = await res.json();
      if (!res.ok) {
        throw new Error(data.error || `HTTP ${res.status}`);
      }
      // Prepend new note to list (most recent first)
      setNotes((prev) => [data, ...prev]);
      setNewNoteText('');
      if (onNoteAdded) onNoteAdded();
    } catch (e) {
      setError(e.message || 'Failed to save note.');
    } finally {
      setSaving(false);
    }
  }, [newNoteText, saving, item.id, onNoteAdded]);

  // ---------------------------------------------------------------------------
  // Format date as YYYY-MM-DD
  // ---------------------------------------------------------------------------
  const formatDate = (dateStr) => {
    try {
      const d = new Date(dateStr);
      return d.toISOString().slice(0, 10);
    } catch {
      return '—';
    }
  };

  const canSubmit = newNoteText.trim().length > 0 && !saving;
  const remaining = 5000 - newNoteText.length;

  return (
    <div style={STYLES.overlay}>
      <div style={STYLES.backdrop} onClick={onClose} />
      <div style={STYLES.content}>
        {/* Header */}
        <div style={STYLES.header}>
          <div>
            <div style={STYLES.title}>Remediation Notes</div>
            <div style={STYLES.subtitle} title={item.finding_title || item.finding_id}>
              {item.finding_title || item.finding_id}
            </div>
            <div style={{ ...STYLES.subtitle, fontSize: '0.6rem', color: '#64748B' }}>
              ID: {item.finding_id}
            </div>
          </div>
          <button onClick={onClose} style={STYLES.closeBtn} aria-label="Close modal">
            <X style={{ width: '18px', height: '18px' }} />
          </button>
        </div>

        {/* New note input */}
        <div style={{ marginBottom: '1rem' }}>
          <textarea
            value={newNoteText}
            onChange={(e) => setNewNoteText(e.target.value)}
            maxLength={5000}
            placeholder="Describe what remediation steps were taken…"
            style={STYLES.textarea}
            disabled={saving}
          />
          <div style={STYLES.charCounter}>
            {remaining} characters remaining
          </div>
        </div>

        {/* Error message */}
        {error && (
          <div style={STYLES.error}>
            <AlertCircle style={{ width: '14px', height: '14px', color: '#EF4444', flexShrink: 0 }} />
            <span style={STYLES.errorText}>{error}</span>
          </div>
        )}

        {/* Submit button */}
        <div style={{ marginBottom: '1rem' }}>
          <button
            onClick={handleSubmit}
            disabled={!canSubmit}
            style={{
              ...STYLES.submitBtn,
              ...(canSubmit ? {} : STYLES.submitBtnDisabled),
            }}
          >
            <Send style={{ width: '14px', height: '14px' }} />
            {saving ? 'Saving...' : 'Add Note'}
          </button>
        </div>

        <div style={STYLES.divider} />

        {/* Notes list */}
        {loading && (
          <div style={{ textAlign: 'center', padding: '1.5rem 0' }}>
            <Loader style={{ width: '20px', height: '20px', color: '#0EA5E9', animation: 'spin 1s linear infinite', margin: '0 auto' }} />
            <div style={{ fontFamily: 'monospace', fontSize: '0.7rem', color: '#475569', marginTop: '0.5rem' }}>
              Loading notes...
            </div>
          </div>
        )}

        {fetchError && !loading && (
          <div style={STYLES.error}>
            <AlertCircle style={{ width: '14px', height: '14px', color: '#EF4444', flexShrink: 0 }} />
            <span style={STYLES.errorText}>{fetchError}</span>
            <button onClick={fetchNotes} style={STYLES.retryBtn}>
              <RefreshCw style={{ width: '12px', height: '12px' }} />
              Retry
            </button>
          </div>
        )}

        {!loading && !fetchError && notes.length === 0 && (
          <div style={STYLES.emptyState}>
            No remediation notes yet.
          </div>
        )}

        {!loading && !fetchError && notes.length > 0 && (
          <div>
            {notes.map((note) => (
              <div key={note.id} style={STYLES.noteItem}>
                <div style={STYLES.noteMeta}>
                  <span style={{ color: '#A855F7', fontWeight: 600 }}>{note.username}</span>
                  <span>{formatDate(note.created_at)}</span>
                </div>
                <div style={STYLES.noteText}>{note.note_text}</div>
              </div>
            ))}
          </div>
        )}
      </div>
    </div>
  );
}