import React, { useEffect, useRef, useState } from 'react';
import { createRoot } from 'react-dom/client';
import nacl from 'tweetnacl';

// ─── Provider config ──────────────────────────────────────────────────────────

const PROVIDERS = [
  {
    id: 'openai',
    name: 'OpenAI',
    placeholder: 'sk-...',
    models: ['gpt-4o', 'gpt-4o-mini', 'gpt-3.5-turbo'],
    docsUrl: 'https://platform.openai.com/api-keys',
  },
  {
    id: 'anthropic',
    name: 'Anthropic (Claude)',
    placeholder: 'sk-ant-...',
    models: ['claude-3-5-sonnet-20241022', 'claude-3-5-haiku-20241022', 'claude-3-opus-20240229'],
    docsUrl: 'https://console.anthropic.com/keys',
  },
  {
    id: 'groq',
    name: 'Groq (Free tier)',
    placeholder: 'gsk_...',
    models: ['llama-3.3-70b-versatile', 'llama-3.1-8b-instant', 'mixtral-8x7b-32768'],
    docsUrl: 'https://console.groq.com/keys',
  },
  {
    id: 'openrouter',
    name: 'OpenRouter (100+ models)',
    placeholder: 'sk-or-...',
    models: ['openai/gpt-4o-mini', 'anthropic/claude-3-5-haiku', 'meta-llama/llama-3.3-70b-instruct:free'],
    docsUrl: 'https://openrouter.ai/keys',
  },
];

// ─── Encryption helpers ───────────────────────────────────────────────────────

async function getOrCreateEncKey(): Promise<Uint8Array> {
  return new Promise((resolve) => {
    chrome.storage.local.get(['encKey'], (result) => {
      if (result.encKey) {
        resolve(Uint8Array.from(atob(result.encKey as string), c => c.charCodeAt(0)));
      } else {
        const key = nacl.randomBytes(32);
        const keyB64 = btoa(String.fromCharCode(...key));
        chrome.storage.local.set({ encKey: keyB64 });
        resolve(key);
      }
    });
  });
}

// ─── Styles ───────────────────────────────────────────────────────────────────

const styles = {
  page: {
    minHeight: '100vh',
    background: 'linear-gradient(135deg, #1e1e2e 0%, #181825 100%)',
    display: 'flex',
    alignItems: 'flex-start',
    justifyContent: 'center',
    padding: '40px 20px',
    fontFamily: '-apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif',
  } as React.CSSProperties,
  card: {
    background: 'rgba(30,30,46,0.95)',
    border: '1px solid rgba(205,214,244,0.12)',
    borderRadius: '16px',
    padding: '32px',
    width: '100%',
    maxWidth: '480px',
    boxShadow: '0 8px 48px rgba(0,0,0,0.4)',
    color: '#cdd6f4',
  } as React.CSSProperties,
  logoRow: {
    display: 'flex',
    alignItems: 'center',
    gap: '10px',
    marginBottom: '4px',
  } as React.CSSProperties,
  logo: {
    fontSize: '28px',
  } as React.CSSProperties,
  title: {
    fontSize: '22px',
    fontWeight: '800',
    color: '#89b4fa',
    margin: 0,
  } as React.CSSProperties,
  subtitle: {
    fontSize: '13px',
    color: '#6c7086',
    marginBottom: '28px',
    marginTop: '4px',
  } as React.CSSProperties,
  label: {
    display: 'block',
    fontSize: '13px',
    fontWeight: '600',
    color: '#a6adc8',
    marginBottom: '6px',
    textTransform: 'uppercase' as const,
    letterSpacing: '0.04em',
  } as React.CSSProperties,
  select: {
    width: '100%',
    padding: '10px 14px',
    borderRadius: '9px',
    border: '1px solid rgba(205,214,244,0.15)',
    background: 'rgba(49,50,68,0.7)',
    color: '#cdd6f4',
    fontSize: '14px',
    outline: 'none',
    cursor: 'pointer',
    marginBottom: '0',
  } as React.CSSProperties,
  input: {
    width: '100%',
    padding: '10px 14px',
    borderRadius: '9px',
    border: '1px solid rgba(205,214,244,0.15)',
    background: 'rgba(49,50,68,0.7)',
    color: '#cdd6f4',
    fontSize: '14px',
    outline: 'none',
    boxSizing: 'border-box' as const,
  } as React.CSSProperties,
  formGroup: {
    marginBottom: '20px',
  } as React.CSSProperties,
  hint: {
    fontSize: '12px',
    color: '#6c7086',
    marginTop: '6px',
    display: 'flex',
    alignItems: 'center',
    gap: '4px',
  } as React.CSSProperties,
  docsLink: {
    color: '#89b4fa',
    textDecoration: 'none',
    fontSize: '12px',
  } as React.CSSProperties,
  saveBtn: {
    width: '100%',
    padding: '12px',
    borderRadius: '10px',
    border: 'none',
    fontSize: '15px',
    fontWeight: '700',
    cursor: 'pointer',
    transition: 'all 0.2s ease',
    marginTop: '8px',
  } as React.CSSProperties,
  divider: {
    borderTop: '1px solid rgba(205,214,244,0.08)',
    margin: '24px 0',
  } as React.CSSProperties,
  statusBadge: {
    display: 'inline-flex',
    alignItems: 'center',
    gap: '6px',
    fontSize: '12px',
    padding: '4px 10px',
    borderRadius: '6px',
    marginTop: '12px',
  } as React.CSSProperties,
};

// ─── Safe chrome storage wrappers ────────────────────────────────────────────

function safeStorageGet(keys: string[], callback: (result: Record<string, string>) => void) {
  try {
    if (typeof chrome === 'undefined' || !chrome.runtime?.id) return;
    chrome.storage.local.get(keys, callback);
  } catch (err) {
    console.warn('LexAI: Extension context invalidated', err);
  }
}

function safeStorageSet(data: Record<string, string>, callback?: () => void) {
  try {
    if (typeof chrome === 'undefined' || !chrome.runtime?.id) return;
    if (callback) {
      chrome.storage.local.set(data, callback);
    } else {
      chrome.storage.local.set(data);
    }
  } catch (err) {
    console.warn('LexAI: Extension context invalidated', err);
  }
}

// ─── Component ────────────────────────────────────────────────────────────────

function OptionsPage() {
  const [provider, setProvider] = useState('openai');
  const [apiKey, setApiKey] = useState('');
  const [model, setModel] = useState('gpt-4o-mini');
  const [saveStatus, setSaveStatus] = useState<'idle' | 'saving' | 'saved' | 'error'>('idle');
  const [showKey, setShowKey] = useState(false);
  const [isEncrypted, setIsEncrypted] = useState(false);
  const apiKeyRef = useRef<HTMLInputElement>(null);

  useEffect(() => {
    safeStorageGet(['provider', 'apiKey', 'apiKeyEnc', 'encKey', 'model'], (result) => {
      if (result.provider) setProvider(result.provider);
      if (result.model) setModel(result.model);

      // Show placeholder if encrypted key exists
      if (result.apiKeyEnc && result.encKey) {
        setIsEncrypted(true);
        setApiKey(''); // don't show encrypted blob — show empty for re-entry or leave as is
      } else if (result.apiKey) {
        setApiKey(result.apiKey);
        setIsEncrypted(false);
      }
    });
  }, []);

  const currentProvider = PROVIDERS.find((p) => p.id === provider) ?? PROVIDERS[0];

  const handleProviderChange = (newProvider: string) => {
    setProvider(newProvider);
    const p = PROVIDERS.find((p) => p.id === newProvider);
    if (p) setModel(p.models[0]);
  };

  const handleSave = async () => {
    // If key is blank and we already have an encrypted key, don't overwrite
    if (!apiKey.trim() && !isEncrypted) {
      apiKeyRef.current?.focus();
      return;
    }
    if (!apiKey.trim() && isEncrypted) {
      // Only saving provider/model changes — preserve existing encrypted key
      setSaveStatus('saving');
      safeStorageSet({ provider, model }, () => {
        if (chrome.runtime.lastError) {
          setSaveStatus('error');
          setTimeout(() => setSaveStatus('idle'), 3000);
        } else {
          setSaveStatus('saved');
          setTimeout(() => setSaveStatus('idle'), 2500);
        }
      });
      return;
    }

    setSaveStatus('saving');

    try {
      const key = await getOrCreateEncKey();
      const nonce = nacl.randomBytes(24);
      const encoded = new TextEncoder().encode(apiKey.trim());
      const encrypted = nacl.secretbox(encoded, nonce, key);
      const combined = new Uint8Array(nonce.length + encrypted.length);
      combined.set(nonce);
      combined.set(encrypted, nonce.length);
      const apiKeyEncB64 = btoa(String.fromCharCode(...combined));

      safeStorageSet({ apiKeyEnc: apiKeyEncB64, provider, model }, () => {
        if (chrome.runtime.lastError) {
          setSaveStatus('error');
          setTimeout(() => setSaveStatus('idle'), 3000);
        } else {
          // Remove plaintext key if it existed
          chrome.storage.local.remove('apiKey');
          setIsEncrypted(true);
          setApiKey('');
          setSaveStatus('saved');
          setTimeout(() => setSaveStatus('idle'), 2500);
        }
      });
    } catch (err) {
      console.error('LexAI: Encryption failed', err);
      setSaveStatus('error');
      setTimeout(() => setSaveStatus('idle'), 3000);
    }
  };

  const saveBtnStyle: React.CSSProperties = {
    ...styles.saveBtn,
    background: saveStatus === 'saved'
      ? '#a6e3a1'
      : saveStatus === 'error'
      ? '#f38ba8'
      : 'linear-gradient(135deg, #89b4fa 0%, #b4befe 100%)',
    color: '#1e1e2e',
  };

  return (
    <div style={styles.page}>
      <div style={styles.card}>
        {/* Header */}
        <div style={styles.logoRow}>
          <span style={styles.logo}>⚡</span>
          <h1 style={styles.title}>LexAI Settings</h1>
        </div>
        <p style={styles.subtitle}>
          Configure your LLM provider and API key. Your key is encrypted and stored locally.
        </p>

        <div style={styles.divider} />

        {/* Provider */}
        <div style={styles.formGroup}>
          <label style={styles.label}>LLM Provider</label>
          <select
            style={styles.select}
            value={provider}
            onChange={(e) => handleProviderChange(e.target.value)}
          >
            {PROVIDERS.map((p) => (
              <option key={p.id} value={p.id}>{p.name}</option>
            ))}
          </select>
        </div>

        {/* Model */}
        <div style={styles.formGroup}>
          <label style={styles.label}>Model</label>
          <select
            style={styles.select}
            value={model}
            onChange={(e) => setModel(e.target.value)}
          >
            {currentProvider.models.map((m) => (
              <option key={m} value={m}>{m}</option>
            ))}
          </select>
        </div>

        {/* API Key */}
        <div style={styles.formGroup}>
          <label style={styles.label}>
            API Key{' '}
            {isEncrypted && (
              <span
                title="API key is encrypted with TweetNaCl secretbox"
                style={{ fontSize: '14px', marginLeft: '4px', verticalAlign: 'middle' }}
              >
                🔒
              </span>
            )}
          </label>
          <div style={{ position: 'relative' }}>
            <input
              ref={apiKeyRef}
              type={showKey ? 'text' : 'password'}
              value={apiKey}
              onChange={(e) => {
                setApiKey(e.target.value);
                if (isEncrypted && e.target.value) setIsEncrypted(false);
              }}
              placeholder={isEncrypted ? '••••••• (encrypted — enter new key to change)' : currentProvider.placeholder}
              style={{ ...styles.input, paddingRight: '42px' }}
              onKeyDown={(e) => e.key === 'Enter' && handleSave()}
            />
            <button
              onClick={() => setShowKey((s) => !s)}
              style={{
                position: 'absolute',
                right: '10px',
                top: '50%',
                transform: 'translateY(-50%)',
                background: 'none',
                border: 'none',
                color: '#6c7086',
                cursor: 'pointer',
                fontSize: '14px',
                padding: '4px',
              }}
              title={showKey ? 'Hide key' : 'Show key'}
            >
              {showKey ? '🙈' : '👁'}
            </button>
          </div>
          <div style={styles.hint}>
            <span>🔒 Encrypted with TweetNaCl on your device.</span>
            <span>·</span>
            <a
              href={currentProvider.docsUrl}
              target="_blank"
              rel="noopener noreferrer"
              style={styles.docsLink}
            >
              Get API key →
            </a>
          </div>
        </div>

        {/* Save */}
        <button style={saveBtnStyle} onClick={handleSave} disabled={saveStatus === 'saving'}>
          {saveStatus === 'saving'
            ? '⏳ Saving…'
            : saveStatus === 'saved'
            ? '✓ Settings Saved!'
            : saveStatus === 'error'
            ? '✕ Save Failed — Try Again'
            : '💾 Save Settings'}
        </button>

        <div style={styles.divider} />

        {/* Info */}
        <div style={{ fontSize: '12px', color: '#6c7086', lineHeight: '1.6' }}>
          <strong style={{ color: '#a6adc8' }}>How to use LexAI:</strong>
          <ol style={{ margin: '8px 0 0 16px', padding: 0 }}>
            <li>Select any text on a webpage</li>
            <li>Click Fix, Rephrase, Shorten, Expand, or Tone</li>
            <li>Accept or replace the suggestion</li>
          </ol>
        </div>
      </div>
    </div>
  );
}

createRoot(document.getElementById('app')!).render(<OptionsPage />);