import { useState, useEffect, useRef, useCallback } from 'react';
import { api } from '../../api.js';
import { useAuth } from '../../context/AuthContext.jsx';

/* ── Icône œil (show/hide password) ───────────────────────────────────── */
function IconEye({ open }) {
  return open
    ? <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round"><path d="M1 12s4-8 11-8 11 8 11 8-4 8-11 8-11-8-11-8z"/><circle cx="12" cy="12" r="3"/></svg>
    : <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round"><path d="M17.94 17.94A10.07 10.07 0 0 1 12 20c-7 0-11-8-11-8a18.45 18.45 0 0 1 5.06-5.94M9.9 4.24A9.12 9.12 0 0 1 12 4c7 0 11 8 11 8a18.5 18.5 0 0 1-2.16 3.19m-6.72-1.07a3 3 0 1 1-4.24-4.24"/><line x1="1" y1="1" x2="23" y2="23"/></svg>;
}

/* ── Toggle switch ─────────────────────────────────────────────────────── */
function Toggle({ checked, onChange, id }) {
  return (
    <label htmlFor={id} style={{ cursor: 'pointer', display: 'flex', alignItems: 'center' }}>
      <input
        id={id}
        type="checkbox"
        checked={checked}
        onChange={e => onChange(e.target.checked)}
        style={{ display: 'none' }}
      />
      <span style={{
        display: 'inline-block',
        width: 44,
        height: 24,
        borderRadius: 12,
        background: checked ? 'var(--primary)' : 'var(--border)',
        position: 'relative',
        transition: 'background 0.2s',
        flexShrink: 0,
      }}>
        <span style={{
          position: 'absolute',
          top: 3,
          left: checked ? 23 : 3,
          width: 18,
          height: 18,
          borderRadius: '50%',
          background: '#fff',
          transition: 'left 0.2s',
          boxShadow: '0 1px 3px rgba(0,0,0,0.2)',
        }} />
      </span>
    </label>
  );
}

/* ── Ligne de paramètre ────────────────────────────────────────────────── */
function SettingRow({ label, description, children }) {
  return (
    <div style={{
      display: 'grid',
      gridTemplateColumns: '1fr 1fr',
      gap: '12px 24px',
      alignItems: 'center',
      padding: '18px 0',
      borderBottom: '1px solid var(--border)',
    }}>
      <div>
        <div style={{ fontWeight: 600, color: 'var(--text)', marginBottom: description ? 4 : 0 }}>{label}</div>
        {description && <div style={{ fontSize: '0.85rem', color: 'var(--text-muted)', lineHeight: 1.4 }}>{description}</div>}
      </div>
      <div style={{ display: 'flex', justifyContent: 'flex-end' }}>
        {children}
      </div>
    </div>
  );
}

const DEFAULT_STATE = {
  enabled:     false,
  host:        '',
  port:        587,
  secure:      false,
  email:       '',
  username:    '',
  password:    '',
  allowUnauth: false,
  appName:     'Crowdlending',
  appUrl:      '',
};

export default function SmtpSection() {
  const { user } = useAuth();
  const [form, setForm]             = useState(DEFAULT_STATE);
  const [hasPassword, setHasPassword] = useState(false);
  const [showPassword, setShowPassword] = useState(false);
  const passwordTyped = useRef(false); // true uniquement si l'utilisateur a tapé manuellement
  const [testEmail, setTestEmail]   = useState(user?.email || '');
  const [result, setResult]     = useState(null); // { ok, msg }
  const [testResult, setTestResult] = useState(null);
  const [loading, setLoading]       = useState(false);
  const [testing, setTesting]       = useState(false);
  const [loadingEnv, setLoadingEnv] = useState(false);
  const [saveStatus, setSaveStatus] = useState(null); // 'saving' | 'saved' | 'error'
  const debounceRef  = useRef(null);
  const isFirstLoad  = useRef(true);
  const hasPasswordRef = useRef(false);

  useEffect(() => {
    api.get('/admin/smtp').then(data => {
      setForm({
        enabled:     !!data.enabled,
        host:        data.host        || '',
        port:        data.port        || 587,
        secure:      !!data.secure,
        email:       data.email       || '',
        username:    data.username    || '',
        password:    '',
        allowUnauth: !!data.allowUnauth,
        appName:     data.appName     || 'Crowdlending',
        appUrl:      data.appUrl      || '',
      });
      setHasPassword(!!data.hasPassword);
      hasPasswordRef.current = !!data.hasPassword;
    });
  }, []);

  const doSave = useCallback(async (currentForm) => {
    setSaveStatus('saving');
    try {
      const payload = { ...currentForm };
      // N'envoyer le mot de passe que si l'utilisateur l'a tapé manuellement
      if (!payload.password || !passwordTyped.current) delete payload.password;
      await api.put('/admin/smtp', payload);
      if (payload.password) {
        setHasPassword(true);
        hasPasswordRef.current = true;
      }
      setSaveStatus('saved');
      setTimeout(() => setSaveStatus(null), 2500);
    } catch (e) {
      setSaveStatus('error');
      setResult({ ok: false, msg: e.message || 'Erreur lors de la sauvegarde.' });
    }
  }, []);

  const set = (key, value) => {
    setForm(f => {
      const next = { ...f, [key]: value };
      // Ne pas déclencher l'auto-save au chargement initial
      if (isFirstLoad.current) { isFirstLoad.current = false; return next; }
      clearTimeout(debounceRef.current);
      debounceRef.current = setTimeout(() => doSave(next), 1500);
      return next;
    });
  };

  // Nettoyage du timer au démontage
  useEffect(() => () => clearTimeout(debounceRef.current), []);

  const handleTest = async () => {
    if (!testEmail) return;
    setTesting(true);
    setTestResult(null);
    try {
      const data = await api.post('/admin/smtp/test', { to: testEmail });
      setTestResult({ ok: data.ok, msg: data.msg });
    } catch (e) {
      setTestResult({ ok: false, msg: e.message || 'Erreur lors du test.' });
    } finally {
      setTesting(false);
    }
  };

  const handleLoadEnv = async () => {
    setLoadingEnv(true);
    try {
      const data = await api.get('/admin/smtp/env');
      setForm(f => {
        const next = {
          ...f,
          host:     data.host     || f.host,
          port:     data.port     || f.port,
          email:    data.email    || f.email,
          username: data.username || f.username,
          password: '',
        };
        clearTimeout(debounceRef.current);
        debounceRef.current = setTimeout(() => doSave(next), 1500);
        return next;
      });
      if (data.hasPassword) { setHasPassword(true); hasPasswordRef.current = true; }
    } catch (e) {
      setResult({ ok: false, msg: 'Impossible de charger les valeurs .env.' });
    } finally {
      setLoadingEnv(false);
    }
  };

  return (
    <div className="account-section">
      <div style={{ display: 'flex', alignItems: 'center', justifyContent: 'space-between', marginBottom: 4 }}>
        <h2 style={{ margin: 0 }}>SMTP</h2>
        <div style={{ display: 'flex', alignItems: 'center', gap: 12 }}>
          {saveStatus === 'saving' && (
            <span style={{ fontSize: '0.82rem', color: 'var(--text-muted)' }}>Sauvegarde…</span>
          )}
          {saveStatus === 'saved' && (
            <span style={{ fontSize: '0.82rem', color: 'var(--success, #15803d)' }}>✓ Sauvegardé</span>
          )}
          {saveStatus === 'error' && (
            <span style={{ fontSize: '0.82rem', color: 'var(--danger, #dc2626)' }}>Erreur</span>
          )}
          <button
            className="btn btn-secondary"
            onClick={() => handleLoadEnv()}
            disabled={loadingEnv}
            style={{ fontSize: '0.82rem' }}
          >
            {loadingEnv ? 'Chargement…' : 'Charger depuis .env'}
          </button>
        </div>
      </div>
      <p style={{ color: 'var(--text-muted)', marginBottom: 24 }}>
        Configuration du serveur de messagerie sortant. Utilisée pour les alertes, rapports et réinitialisation de mot de passe.
      </p>

      {result && (
        <div
          className={result.ok ? 'alert-success' : 'alert-error'}
          style={{
            padding: '10px 14px',
            borderRadius: 6,
            marginBottom: 16,
            background: result.ok ? 'var(--success-bg, #ecfdf5)' : 'var(--danger-bg, #fef2f2)',
            color: result.ok ? 'var(--success, #15803d)' : 'var(--danger, #dc2626)',
            border: `1px solid ${result.ok ? 'var(--success, #86efac)' : 'var(--danger, #fca5a5)'}`,
            display: 'flex',
            justifyContent: 'space-between',
            alignItems: 'center',
          }}
        >
          <span>{result.msg}</span>
          <button onClick={() => setResult(null)} style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'inherit', fontSize: 16 }}>×</button>
        </div>
      )}

      <div className="card" style={{ padding: '0 24px' }}>

        {/* Nom de la plateforme */}
        <SettingRow label="Nom de la plateforme" description="Affiché dans l'en-tête et le pied de page des emails envoyés.">
          <input
            className="form-input"
            type="text"
            value={form.appName}
            onChange={e => set('appName', e.target.value)}
            placeholder="Crowdlending"
            style={{ width: 280 }}
          />
        </SettingRow>

        {/* URL de la plateforme */}
        <SettingRow label="URL de la plateforme" description="Utilisée pour le bouton de redirection dans les emails. Inclure le protocole (https://).">
          <input
            className="form-input"
            type="url"
            value={form.appUrl}
            onChange={e => set('appUrl', e.target.value)}
            placeholder="https://monapp.example.com"
            style={{ width: 280 }}
          />
        </SettingRow>

        {/* Séparateur */}
        <div style={{ borderBottom: '1px solid var(--border)', margin: '4px 0' }} />

        {/* Activer */}
        <SettingRow
          label="Activer"
          description="Active SMTP. Activez ceci uniquement si vous avez saisi l'hôte, le port, le courriel, l'utilisateur et son mot de passe."
        >
          <Toggle id="smtp-enabled" checked={form.enabled} onChange={v => set('enabled', v)} />
        </SettingRow>

        {/* Hôte */}
        <SettingRow label="Hôte" description="Nom du serveur SMTP">
          <input
            className="form-input"
            type="text"
            value={form.host}
            onChange={e => set('host', e.target.value)}
            placeholder="smtp.example.com"
            style={{ width: 280 }}
          />
        </SettingRow>

        {/* Port */}
        <SettingRow label="Port" description="Port du serveur SMTP">
          <input
            className="form-input"
            type="number"
            value={form.port}
            onChange={e => set('port', parseInt(e.target.value, 10) || 587)}
            min={1}
            max={65535}
            style={{ width: 120 }}
          />
        </SettingRow>

        {/* Connexion sécurisée (TLS) */}
        <SettingRow label="Connexion sécurisée (TLS)" description="Utiliser TLS dès la connexion (port 465). Désactivez pour STARTTLS (port 587).">
          <Toggle id="smtp-secure" checked={form.secure} onChange={v => set('secure', v)} />
        </SettingRow>

        {/* Courriel */}
        <SettingRow label="Courriel" description="Adresse email à partir de laquelle les courriels sont envoyés">
          <input
            className="form-input"
            type="email"
            value={form.email}
            onChange={e => set('email', e.target.value)}
            placeholder="no-reply@example.com"
            style={{ width: 280 }}
          />
        </SettingRow>

        {/* Nom d'utilisateur */}
        <SettingRow label="Nom d'utilisateur" description="Nom d'utilisateur du serveur SMTP">
          <input
            className="form-input"
            type="text"
            value={form.username}
            onChange={e => set('username', e.target.value)}
            placeholder="user@example.com"
            autoComplete="off"
            style={{ width: 280 }}
          />
        </SettingRow>

        {/* Mot de passe */}
        <SettingRow
          label="Mot de passe"
          description={hasPassword && !form.password ? 'Un mot de passe est déjà enregistré. Laissez vide pour le conserver.' : 'Mot de passe du serveur SMTP'}
        >
          <div style={{ position: 'relative', width: 280 }}>
            <input
              className="form-input"
              type={showPassword ? 'text' : 'password'}
              value={form.password}
              onChange={e => { passwordTyped.current = true; set('password', e.target.value); }}
              placeholder={hasPassword ? '••••••••' : 'Mot de passe'}
              autoComplete="new-password"
              style={{ width: '100%', paddingRight: 36 }}
            />
            <button
              type="button"
              onClick={() => setShowPassword(s => !s)}
              style={{
                position: 'absolute', right: 10, top: '50%', transform: 'translateY(-50%)',
                background: 'none', border: 'none', cursor: 'pointer',
                color: 'var(--text-muted)', padding: 0, display: 'flex',
              }}
              tabIndex={-1}
            >
              <IconEye open={showPassword} />
            </button>
          </div>
        </SettingRow>

        {/* Certificats non autorisés */}
        <SettingRow
          label="Faire confiance aux certificats de serveurs SMTP non autorisés"
          description="Ne permettez ceci que si vous avez besoin de faire confiance aux certificats autosignés."
        >
          <Toggle id="smtp-allowUnauth" checked={form.allowUnauth} onChange={v => set('allowUnauth', v)} />
        </SettingRow>

      </div>


      {/* Section email de test */}
      <div className="card" style={{ marginTop: 24, padding: '20px 24px' }}>
        <h3 style={{ margin: '0 0 12px' }}>Envoyer un email de test</h3>
        <p style={{ color: 'var(--text-muted)', marginBottom: 16, fontSize: '0.9rem' }}>
          Vérifiez que votre configuration SMTP fonctionne en envoyant un email de test. Sauvegardez d'abord vos paramètres.
        </p>
        {testResult && (
          <div style={{
            padding: '10px 14px',
            borderRadius: 6,
            marginBottom: 14,
            background: testResult.ok ? 'var(--success-bg, #ecfdf5)' : 'var(--danger-bg, #fef2f2)',
            color: testResult.ok ? 'var(--success, #15803d)' : 'var(--danger, #dc2626)',
            border: `1px solid ${testResult.ok ? 'var(--success, #86efac)' : 'var(--danger, #fca5a5)'}`,
            display: 'flex',
            justifyContent: 'space-between',
            alignItems: 'center',
          }}>
            <span>{testResult.msg}</span>
            <button onClick={() => setTestResult(null)} style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'inherit', fontSize: 16 }}>×</button>
          </div>
        )}
        <div style={{ display: 'flex', gap: 10, alignItems: 'center' }}>
          <input
            className="form-input"
            type="email"
            value={testEmail}
            onChange={e => setTestEmail(e.target.value)}
            placeholder="destinataire@example.com"
            style={{ flex: 1, maxWidth: 320 }}
            onKeyDown={e => e.key === 'Enter' && handleTest()}
          />
          <button
            className="btn btn-secondary"
            onClick={() => handleTest()}
            disabled={testing || !testEmail}
          >
            {testing ? 'Envoi…' : 'Envoyer un courriel de test'}
          </button>
        </div>
      </div>
    </div>
  );
}
