import { useState, useEffect, useCallback } from 'react';
import { useConfig } from '../contexts/ConfigContext';
import {
  Settings as SettingsIcon, Server, Shield, Network, Mail, Calendar,
  HardDrive, GitBranch, Archive, Upload, Download, Trash2, RotateCcw,
  Save, ChevronDown, ChevronRight, CheckCircle, XCircle, AlertCircle,
  RefreshCw, Lock
} from 'lucide-react';
import { cellAPI } from '../services/api';

// ── helpers ──────────────────────────────────────────────────────────────────

function toast(msg, type = 'success') {
  // simple inline notification via a thrown CustomEvent consumed below
  window.dispatchEvent(new CustomEvent('settings-toast', { detail: { msg, type } }));
}

function Toast({ toasts }) {
  return (
    <div className="fixed bottom-4 right-4 z-50 space-y-2">
      {toasts.map((t) => (
        <div
          key={t.id}
          className={`px-4 py-3 rounded-lg shadow-lg text-sm text-white flex items-center gap-2 ${
            t.type === 'success' ? 'bg-green-600' : t.type === 'error' ? 'bg-red-600' : 'bg-yellow-600'
          }`}
        >
          {t.type === 'success' ? <CheckCircle className="h-4 w-4" /> : <XCircle className="h-4 w-4" />}
          {t.msg}
        </div>
      ))}
    </div>
  );
}

function useToasts() {
  const [toasts, setToasts] = useState([]);
  useEffect(() => {
    const handler = (e) => {
      const id = Date.now();
      setToasts((prev) => [...prev, { ...e.detail, id }]);
      setTimeout(() => setToasts((prev) => prev.filter((t) => t.id !== id)), 4000);
    };
    window.addEventListener('settings-toast', handler);
    return () => window.removeEventListener('settings-toast', handler);
  }, []);
  return toasts;
}

// ── Section wrapper ───────────────────────────────────────────────────────────

function Section({ icon: Icon, title, children, collapsible = false, defaultOpen = true }) {
  const [open, setOpen] = useState(defaultOpen);
  return (
    <div className="card mb-4">
      <button
        className="w-full flex items-center justify-between"
        onClick={() => collapsible && setOpen((v) => !v)}
        disabled={!collapsible}
      >
        <div className="flex items-center gap-2">
          <Icon className="h-5 w-5 text-primary-500" />
          <h3 className="text-base font-semibold text-gray-900">{title}</h3>
        </div>
        {collapsible && (open ? <ChevronDown className="h-4 w-4 text-gray-400" /> : <ChevronRight className="h-4 w-4 text-gray-400" />)}
      </button>
      {(!collapsible || open) && <div className="mt-4">{children}</div>}
    </div>
  );
}

// ── Field components ──────────────────────────────────────────────────────────

function Field({ label, children, hint }) {
  return (
    <div className="flex flex-col sm:flex-row sm:items-center gap-1 sm:gap-4">
      <label className="text-sm text-gray-600 sm:w-48 shrink-0">{label}</label>
      <div className="flex-1">{children}</div>
      {hint && <span className="text-xs text-gray-400">{hint}</span>}
    </div>
  );
}

function TextInput({ value, onChange, placeholder, type = 'text', readOnly }) {
  return (
    <input
      type={type}
      value={value ?? ''}
      onChange={(e) => onChange && onChange(e.target.value)}
      placeholder={placeholder}
      readOnly={readOnly}
      className={`w-full text-sm border rounded px-3 py-1.5 focus:outline-none focus:ring-2 focus:ring-primary-400 ${
        readOnly ? 'bg-gray-50 text-gray-500 cursor-default' : 'bg-white'
      }`}
    />
  );
}

function NumberInput({ value, onChange, min, max }) {
  return (
    <input
      type="number"
      value={value ?? ''}
      min={min}
      max={max}
      onChange={(e) => onChange && onChange(Number(e.target.value))}
      className="w-full text-sm border rounded px-3 py-1.5 focus:outline-none focus:ring-2 focus:ring-primary-400 bg-white"
    />
  );
}

function BoolToggle({ value, onChange, label }) {
  return (
    <label className="flex items-center gap-2 cursor-pointer select-none">
      <div
        onClick={() => onChange && onChange(!value)}
        className={`relative w-10 h-5 rounded-full transition-colors ${value ? 'bg-primary-500' : 'bg-gray-300'}`}
      >
        <span
          className={`absolute top-0.5 left-0.5 w-4 h-4 bg-white rounded-full shadow transition-transform ${value ? 'translate-x-5' : ''}`}
        />
      </div>
      <span className="text-sm text-gray-700">{label}</span>
    </label>
  );
}

function TagList({ value = [], onChange, placeholder }) {
  const [input, setInput] = useState('');
  const add = () => {
    const v = input.trim();
    if (v && !value.includes(v)) { onChange([...value, v]); setInput(''); }
  };
  return (
    <div className="space-y-1">
      <div className="flex gap-2 flex-wrap">
        {value.map((item) => (
          <span key={item} className="flex items-center gap-1 bg-primary-100 text-primary-700 text-xs rounded-full px-2 py-0.5">
            {item}
            <button onClick={() => onChange(value.filter((v) => v !== item))} className="hover:text-red-500">×</button>
          </span>
        ))}
      </div>
      <div className="flex gap-2">
        <input
          className="flex-1 text-sm border rounded px-3 py-1 focus:outline-none focus:ring-2 focus:ring-primary-400"
          value={input}
          onChange={(e) => setInput(e.target.value)}
          onKeyDown={(e) => e.key === 'Enter' && (e.preventDefault(), add())}
          placeholder={placeholder}
        />
        <button onClick={add} className="btn-secondary text-xs px-3 py-1">Add</button>
      </div>
    </div>
  );
}

// ── Service config forms ──────────────────────────────────────────────────────

function NetworkForm({ data, onChange }) {
  return (
    <div className="space-y-3">
      <Field label="DNS Port">
        <NumberInput value={data.dns_port} onChange={(v) => onChange({ ...data, dns_port: v })} min={1} max={65535} />
      </Field>
      <Field label="DHCP Range" hint="e.g. 10.0.0.100,10.0.0.200,12h">
        <TextInput value={data.dhcp_range} onChange={(v) => onChange({ ...data, dhcp_range: v })} placeholder="10.0.0.100,10.0.0.200,12h" />
      </Field>
      <Field label="NTP Servers">
        <TagList value={data.ntp_servers || []} onChange={(v) => onChange({ ...data, ntp_servers: v })} placeholder="0.pool.ntp.org" />
      </Field>
    </div>
  );
}

function WireguardForm({ data, onChange }) {
  return (
    <div className="space-y-3">
      <Field label="Listen Port">
        <NumberInput value={data.port} onChange={(v) => onChange({ ...data, port: v })} min={1} max={65535} />
      </Field>
      <Field label="Server Address" hint="CIDR, e.g. 10.0.0.1/24">
        <TextInput value={data.address} onChange={(v) => onChange({ ...data, address: v })} placeholder="10.0.0.1/24" />
      </Field>
      <Field label="Private Key">
        <TextInput value={data.private_key} onChange={(v) => onChange({ ...data, private_key: v })} placeholder="base64 private key" type="password" />
      </Field>
    </div>
  );
}

function EmailForm({ data, onChange }) {
  return (
    <div className="space-y-3">
      <Field label="Mail Domain">
        <TextInput value={data.domain} onChange={(v) => onChange({ ...data, domain: v })} placeholder="mail.example.com" />
      </Field>
      <Field label="SMTP Port" hint="MTA-to-MTA (default 25)">
        <NumberInput value={data.smtp_port ?? 25} onChange={(v) => onChange({ ...data, smtp_port: v })} min={1} max={65535} />
      </Field>
      <Field label="Submission Port" hint="Client mail send (default 587)">
        <NumberInput value={data.submission_port ?? 587} onChange={(v) => onChange({ ...data, submission_port: v })} min={1} max={65535} />
      </Field>
      <Field label="IMAP Port" hint="Client mail fetch (default 993)">
        <NumberInput value={data.imap_port ?? 993} onChange={(v) => onChange({ ...data, imap_port: v })} min={1} max={65535} />
      </Field>
      <Field label="Webmail Port" hint="Rainloop webmail UI (default 8888)">
        <NumberInput value={data.webmail_port ?? 8888} onChange={(v) => onChange({ ...data, webmail_port: v })} min={1} max={65535} />
      </Field>
    </div>
  );
}

function CalendarForm({ data, onChange }) {
  return (
    <div className="space-y-3">
      <Field label="Radicale Port" hint="Internal port; clients use port 80 via Caddy">
        <NumberInput value={data.port} onChange={(v) => onChange({ ...data, port: v })} min={1} max={65535} />
      </Field>
      <Field label="Data Directory">
        <TextInput value={data.data_dir} onChange={(v) => onChange({ ...data, data_dir: v })} placeholder="/app/data/radicale" />
      </Field>
    </div>
  );
}

function FilesForm({ data, onChange }) {
  return (
    <div className="space-y-3">
      <Field label="WebDAV Port" hint="Host port for WebDAV (default 8080)">
        <NumberInput value={data.port ?? 8080} onChange={(v) => onChange({ ...data, port: v })} min={1} max={65535} />
      </Field>
      <Field label="File Manager Port" hint="Filegator host port (default 8082)">
        <NumberInput value={data.manager_port ?? 8082} onChange={(v) => onChange({ ...data, manager_port: v })} min={1} max={65535} />
      </Field>
      <Field label="Data Directory">
        <TextInput value={data.data_dir} onChange={(v) => onChange({ ...data, data_dir: v })} placeholder="/app/data/webdav" />
      </Field>
      <Field label="Default Quota (MB)">
        <NumberInput value={data.quota} onChange={(v) => onChange({ ...data, quota: v })} min={0} />
      </Field>
    </div>
  );
}

function RoutingForm({ data, onChange }) {
  return (
    <div className="space-y-3">
      <Field label="">
        <BoolToggle value={data.nat_enabled} onChange={(v) => onChange({ ...data, nat_enabled: v })} label="NAT Enabled" />
      </Field>
      <Field label="">
        <BoolToggle value={data.firewall_enabled} onChange={(v) => onChange({ ...data, firewall_enabled: v })} label="Firewall Enabled" />
      </Field>
    </div>
  );
}

function VaultForm({ data, onChange }) {
  return (
    <div className="space-y-3">
      <Field label="">
        <BoolToggle value={data.ca_configured} onChange={(v) => onChange({ ...data, ca_configured: v })} label="CA Configured" />
      </Field>
      <Field label="">
        <BoolToggle value={data.fernet_configured} onChange={(v) => onChange({ ...data, fernet_configured: v })} label="Fernet Encryption Configured" />
      </Field>
    </div>
  );
}

// service config meta
const SERVICE_DEFS = [
  { key: 'network',   label: 'Network (DNS/DHCP/NTP)', icon: Network,    Form: NetworkForm,    defaults: { dns_port: 53, dhcp_range: '', ntp_servers: [] } },
  { key: 'wireguard', label: 'WireGuard VPN',          icon: Shield,     Form: WireguardForm,  defaults: { port: 51820, address: '', private_key: '' } },
  { key: 'email',     label: 'Email (SMTP/IMAP)',       icon: Mail,       Form: EmailForm,      defaults: { domain: '', smtp_port: 25, submission_port: 587, imap_port: 993, webmail_port: 8888 } },
  { key: 'calendar',  label: 'Calendar (CalDAV)',        icon: Calendar,   Form: CalendarForm,   defaults: { port: 5232, data_dir: '' } },
  { key: 'files',     label: 'Files (WebDAV)',           icon: HardDrive,  Form: FilesForm,      defaults: { port: 8080, manager_port: 8082, data_dir: '', quota: 1024 } },
  { key: 'routing',   label: 'Routing & Firewall',      icon: GitBranch,  Form: RoutingForm,    defaults: { nat_enabled: true, firewall_enabled: true } },
  { key: 'vault',     label: 'Vault & Trust',           icon: Lock,       Form: VaultForm,      defaults: { ca_configured: false, fernet_configured: false } },
];

// ── Main component ────────────────────────────────────────────────────────────

function Settings() {
  const toasts = useToasts();
  const { refresh: refreshConfig } = useConfig();

  // identity
  const [identity, setIdentity] = useState({ cell_name: '', domain: '', ip_range: '', wireguard_port: 51820 });
  const [identityDirty, setIdentityDirty] = useState(false);
  const [identitySaving, setIdentitySaving] = useState(false);

  // service configs
  const [serviceConfigs, setServiceConfigs] = useState({});
  const [serviceDirty, setServiceDirty] = useState({});
  const [serviceSaving, setServiceSaving] = useState({});

  // backups
  const [backups, setBackups] = useState([]);
  const [backupsLoading, setBackupsLoading] = useState(false);
  const [backupCreating, setBackupCreating] = useState(false);

  const [isLoading, setIsLoading] = useState(true);

  const loadAll = useCallback(async () => {
    setIsLoading(true);
    try {
      const [cfgRes, bkRes] = await Promise.all([
        cellAPI.getConfig(),
        cellAPI.listBackups(),
      ]);
      const cfg = cfgRes.data;
      setIdentity({
        cell_name: cfg.cell_name || '',
        domain: cfg.domain || '',
        ip_range: cfg.ip_range || '',
        wireguard_port: cfg.wireguard_port || 51820,
      });
      setServiceConfigs(cfg.service_configs || {});
      setBackups(bkRes.data || []);
    } catch (err) {
      toast('Failed to load configuration', 'error');
    } finally {
      setIsLoading(false);
    }
  }, []);

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

  const _applyResult = (res, label) => {
    const { restarted = [], warnings = [] } = res.data || {};
    if (restarted.length > 0) {
      toast(`${label} saved — restarted: ${restarted.join(', ')}`);
    } else {
      toast(`${label} saved`);
    }
    warnings.forEach((w) => toast(w, 'warning'));
  };

  // identity save
  const saveIdentity = async () => {
    setIdentitySaving(true);
    try {
      const res = await cellAPI.updateConfig(identity);
      setIdentityDirty(false);
      _applyResult(res, 'Cell identity');
      refreshConfig();
    } catch {
      toast('Failed to save identity', 'error');
    } finally {
      setIdentitySaving(false);
    }
  };

  // service config save
  const saveService = async (key) => {
    setServiceSaving((s) => ({ ...s, [key]: true }));
    try {
      const res = await cellAPI.updateConfig({ [key]: serviceConfigs[key] });
      setServiceDirty((d) => ({ ...d, [key]: false }));
      _applyResult(res, key);
    } catch {
      toast(`Failed to save ${key} config`, 'error');
    } finally {
      setServiceSaving((s) => ({ ...s, [key]: false }));
    }
  };

  const updateServiceConfig = (key, data) => {
    setServiceConfigs((prev) => ({ ...prev, [key]: data }));
    setServiceDirty((d) => ({ ...d, [key]: true }));
  };

  // backups
  const createBackup = async () => {
    setBackupCreating(true);
    try {
      await cellAPI.createBackup();
      toast('Backup created');
      const res = await cellAPI.listBackups();
      setBackups(res.data || []);
    } catch {
      toast('Failed to create backup', 'error');
    } finally {
      setBackupCreating(false);
    }
  };

  const restoreBackup = async (id) => {
    if (!confirm(`Restore backup ${id}? Current config will be overwritten.`)) return;
    try {
      await cellAPI.restoreBackup(id);
      toast('Configuration restored — reloading…');
      setTimeout(() => loadAll(), 500);
    } catch {
      toast('Failed to restore backup', 'error');
    }
  };

  const deleteBackup = async (id) => {
    if (!confirm(`Delete backup ${id}?`)) return;
    try {
      await cellAPI.deleteBackup(id);
      setBackups((prev) => prev.filter((b) => b.backup_id !== id));
      toast('Backup deleted');
    } catch {
      toast('Failed to delete backup', 'error');
    }
  };

  // export
  const exportConfig = async () => {
    try {
      const res = await cellAPI.exportConfig('json');
      const blob = new Blob([res.data.config], { type: 'application/json' });
      const url = URL.createObjectURL(blob);
      const a = document.createElement('a');
      a.href = url;
      a.download = `pic-config-${new Date().toISOString().slice(0, 10)}.json`;
      a.click();
      URL.revokeObjectURL(url);
    } catch {
      toast('Export failed', 'error');
    }
  };

  // import
  const importConfig = async (e) => {
    const file = e.target.files?.[0];
    if (!file) return;
    const text = await file.text();
    if (!confirm('Import this config? Current settings will be replaced.')) { e.target.value = ''; return; }
    try {
      await cellAPI.importConfig(text, 'json');
      toast('Config imported — reloading…');
      setTimeout(() => loadAll(), 500);
    } catch {
      toast('Import failed', 'error');
    } finally {
      e.target.value = '';
    }
  };

  if (isLoading) {
    return (
      <div className="flex items-center justify-center h-64">
        <div className="animate-spin rounded-full h-8 w-8 border-b-2 border-primary-600" />
      </div>
    );
  }

  return (
    <div>
      <Toast toasts={toasts} />
      <div className="mb-6">
        <h1 className="text-2xl font-bold text-gray-900">Settings</h1>
        <p className="mt-1 text-gray-500 text-sm">Configure your Personal Internet Cell</p>
      </div>

      {/* Cell Identity */}
      <Section icon={Server} title="Cell Identity">
        <div className="space-y-3">
          <Field label="Cell Name">
            <TextInput
              value={identity.cell_name}
              onChange={(v) => { setIdentity((i) => ({ ...i, cell_name: v })); setIdentityDirty(true); }}
              placeholder="mycell"
            />
          </Field>
          <Field label="Domain">
            <TextInput
              value={identity.domain}
              onChange={(v) => { setIdentity((i) => ({ ...i, domain: v })); setIdentityDirty(true); }}
              placeholder="cell.local"
            />
          </Field>
          <Field label="IP Range" hint="Docker bridge subnet">
            <TextInput
              value={identity.ip_range}
              onChange={(v) => { setIdentity((i) => ({ ...i, ip_range: v })); setIdentityDirty(true); }}
              placeholder="172.20.0.0/16"
            />
          </Field>
          <Field label="WireGuard Port">
            <NumberInput
              value={identity.wireguard_port}
              onChange={(v) => { setIdentity((i) => ({ ...i, wireguard_port: v })); setIdentityDirty(true); }}
              min={1} max={65535}
            />
          </Field>
        </div>
        <div className="flex justify-end mt-4">
          <button
            onClick={saveIdentity}
            disabled={!identityDirty || identitySaving}
            className="btn-primary flex items-center gap-2 text-sm disabled:opacity-50"
          >
            {identitySaving ? <RefreshCw className="h-4 w-4 animate-spin" /> : <Save className="h-4 w-4" />}
            Save Identity
          </button>
        </div>
        <p className="text-xs text-gray-400 mt-2">
          IP Range and port changes update the .env file and mark affected containers for restart.
          Use the banner above to apply when ready.
        </p>
      </Section>

      {/* Service Configurations */}
      <div className="mb-2">
        <h2 className="text-lg font-semibold text-gray-800">Service Configuration</h2>
      </div>
      {SERVICE_DEFS.map(({ key, label, icon: Icon, Form, defaults }) => {
        const data = { ...defaults, ...(serviceConfigs[key] || {}) };
        const dirty = serviceDirty[key];
        const saving = serviceSaving[key];
        return (
          <Section key={key} icon={Icon} title={label} collapsible defaultOpen={false}>
            <Form data={data} onChange={(d) => updateServiceConfig(key, d)} />
            <div className="flex items-center justify-between mt-4">
              <span className="text-xs text-gray-400">Port/directory changes take effect after container restart.</span>
              <button
                onClick={() => saveService(key)}
                disabled={!dirty || saving}
                className="btn-primary flex items-center gap-2 text-sm disabled:opacity-50"
              >
                {saving ? <RefreshCw className="h-4 w-4 animate-spin" /> : <Save className="h-4 w-4" />}
                Save
              </button>
            </div>
          </Section>
        );
      })}

      {/* Backup & Restore */}
      <Section icon={Archive} title="Backup & Restore" collapsible defaultOpen>
        <div className="flex justify-between items-center mb-3">
          <span className="text-sm text-gray-600">{backups.length} backup{backups.length !== 1 ? 's' : ''} stored</span>
          <button
            onClick={createBackup}
            disabled={backupCreating}
            className="btn-secondary flex items-center gap-2 text-sm"
          >
            {backupCreating ? <RefreshCw className="h-4 w-4 animate-spin" /> : <Archive className="h-4 w-4" />}
            Create Backup
          </button>
        </div>
        {backups.length === 0 ? (
          <p className="text-sm text-gray-400 text-center py-4">No backups yet</p>
        ) : (
          <div className="overflow-x-auto">
            <table className="w-full text-sm">
              <thead>
                <tr className="text-left text-xs text-gray-500 border-b">
                  <th className="pb-2 font-medium">Backup ID</th>
                  <th className="pb-2 font-medium">Timestamp</th>
                  <th className="pb-2 font-medium">Services</th>
                  <th className="pb-2" />
                </tr>
              </thead>
              <tbody className="divide-y divide-gray-100">
                {backups.map((b) => (
                  <tr key={b.backup_id} className="hover:bg-gray-50">
                    <td className="py-2 font-mono text-xs text-gray-700">{b.backup_id}</td>
                    <td className="py-2 text-gray-600">{new Date(b.timestamp).toLocaleString()}</td>
                    <td className="py-2 text-gray-500">{(b.services || []).length} services</td>
                    <td className="py-2">
                      <div className="flex gap-2 justify-end">
                        <button
                          onClick={() => restoreBackup(b.backup_id)}
                          className="text-blue-600 hover:text-blue-800 flex items-center gap-1 text-xs"
                          title="Restore"
                        >
                          <RotateCcw className="h-3.5 w-3.5" /> Restore
                        </button>
                        <button
                          onClick={() => deleteBackup(b.backup_id)}
                          className="text-red-500 hover:text-red-700 flex items-center gap-1 text-xs"
                          title="Delete"
                        >
                          <Trash2 className="h-3.5 w-3.5" /> Delete
                        </button>
                      </div>
                    </td>
                  </tr>
                ))}
              </tbody>
            </table>
          </div>
        )}
      </Section>

      {/* Export / Import */}
      <Section icon={Download} title="Export & Import">
        <div className="flex flex-wrap gap-3">
          <button onClick={exportConfig} className="btn-secondary flex items-center gap-2 text-sm">
            <Download className="h-4 w-4" /> Export JSON
          </button>
          <label className="btn-secondary flex items-center gap-2 text-sm cursor-pointer">
            <Upload className="h-4 w-4" /> Import JSON
            <input type="file" accept=".json" className="hidden" onChange={importConfig} />
          </label>
        </div>
        <p className="text-xs text-gray-400 mt-2">
          Export downloads all service configs as JSON. Import replaces current service configs.
        </p>
      </Section>
    </div>
  );
}

export default Settings;