'use client';

import { useEffect, useState } from 'react';
import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card';
import { Button } from '@/components/ui/button';
import { Alert, AlertDescription } from '@/components/ui/alert';
import { Save, Download, Upload, RefreshCw, Check, X } from 'lucide-react';
import CodeMirror from '@uiw/react-codemirror';
import { json } from '@codemirror/lang-json';
import { oneDark } from '@codemirror/theme-one-dark';

export function ConfigEditor() {
  const [config, setConfig] = useState<any>(null);
  const [editing, setEditing] = useState(false);
  const [editValue, setEditValue] = useState('');
  const [saving, setSaving] = useState(false);
  const [loading, setLoading] = useState(true);
  const [message, setMessage] = useState<{ type: 'success' | 'error'; text: string } | null>(null);

  const fetchConfig = async () => {
    setLoading(true);
    try {
      const response = await fetch('/api/config');
      const data = await response.json();
      setConfig(data);
      setEditValue(JSON.stringify(data, null, 2));
    } catch (error) {
      setMessage({ type: 'error', text: 'Failed to load config' });
    } finally {
      setLoading(false);
    }
  };

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

  const handleSave = async () => {
    setSaving(true);
    setMessage(null);

    try {
      // Validate JSON
      const parsed = JSON.parse(editValue);

      const response = await fetch('/api/config', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify(parsed),
      });

      const result = await response.json();

      if (result.success) {
        setMessage({ type: 'success', text: result.message || 'Config saved successfully!' });
        setConfig(parsed);
        setEditing(false);
      } else {
        setMessage({ type: 'error', text: result.message || 'Failed to save config' });
      }
    } catch (error) {
      setMessage({ type: 'error', text: 'Invalid JSON format' });
    } finally {
      setSaving(false);
    }
  };

  const handleCancel = () => {
    setEditValue(JSON.stringify(config, null, 2));
    setEditing(false);
    setMessage(null);
  };

  const handleDownload = () => {
    const blob = new Blob([JSON.stringify(config, null, 2)], { type: 'application/json' });
    const url = URL.createObjectURL(blob);
    const a = document.createElement('a');
    a.href = url;
    a.download = 'openclaw-config.json';
    a.click();
    URL.revokeObjectURL(url);
  };

  const handleUpload = (e: React.ChangeEvent<HTMLInputElement>) => {
    const file = e.target.files?.[0];
    if (!file) return;

    const reader = new FileReader();
    reader.onload = (event) => {
      try {
        const content = event.target?.result as string;
        JSON.parse(content); // Validate
        setEditValue(content);
        setEditing(true);
        setMessage(null);
      } catch {
        setMessage({ type: 'error', text: 'Invalid JSON file' });
      }
    };
    reader.readAsText(file);
  };

  if (loading) {
    return (
      <div className="flex items-center justify-center h-64">
        <RefreshCw className="w-8 h-8 animate-spin text-orange-400" />
      </div>
    );
  }

  return (
    <div className="space-y-4">
      {/* Actions */}
      <div className="flex flex-wrap gap-2 items-center">
        <Button
          onClick={() => setEditing(true)}
          disabled={editing}
          className="bg-orange-500 hover:bg-orange-600"
        >
          Edit Config
        </Button>
        <Button
          variant="outline"
          onClick={fetchConfig}
          disabled={loading}
          className="border-zinc-700 hover:bg-zinc-800"
        >
          <RefreshCw className={`w-4 h-4 mr-2 ${loading ? 'animate-spin' : ''}`} />
          Reload
        </Button>
        <Button
          variant="outline"
          onClick={handleDownload}
          className="border-zinc-700 hover:bg-zinc-800"
        >
          <Download className="w-4 h-4 mr-2" />
          Export
        </Button>
        <Button
          variant="outline"
          onClick={() => document.getElementById('config-upload')?.click()}
          className="border-zinc-700 hover:bg-zinc-800"
        >
          <Upload className="w-4 h-4 mr-2" />
          Import
        </Button>
        <input
          id="config-upload"
          type="file"
          accept=".json"
          onChange={handleUpload}
          className="hidden"
        />
      </div>

      {/* Message */}
      {message && (
        <Alert variant={message.type === 'error' ? 'destructive' : 'default'} className={
          message.type === 'success' ? 'bg-green-500/10 border-green-500/20 text-green-400' : ''
        }>
          {message.type === 'success' ? (
            <Check className="h-4 w-4" />
          ) : (
            <X className="h-4 w-4" />
          )}
          <AlertDescription>{message.text}</AlertDescription>
        </Alert>
      )}

      {/* Editor */}
      <Card className="bg-zinc-900/50 border-zinc-800">
        <CardHeader>
          <CardTitle>openclaw.json</CardTitle>
        </CardHeader>
        <CardContent>
          <div className="rounded-lg overflow-hidden border border-zinc-700">
            <CodeMirror
              value={editValue}
              height="600px"
              theme={oneDark}
              extensions={[json()]}
              editable={editing}
              onChange={setEditValue}
              className="text-sm"
            />
          </div>
          {editing && (
            <div className="flex justify-end gap-2 mt-4">
              <Button
                variant="outline"
                onClick={handleCancel}
                disabled={saving}
                className="border-zinc-700 hover:bg-zinc-800"
              >
                Cancel
              </Button>
              <Button
                onClick={handleSave}
                disabled={saving}
                className="bg-green-600 hover:bg-green-700"
              >
                {saving ? (
                  <>
                    <RefreshCw className="w-4 h-4 mr-2 animate-spin" />
                    Saving...
                  </>
                ) : (
                  <>
                    <Save className="w-4 h-4 mr-2" />
                    Save & Apply
                  </>
                )}
              </Button>
            </div>
          )}
        </CardContent>
      </Card>

      <div className="text-sm text-zinc-500">
        <p>⚠️ Warning: Editing the config directly restarts the Gateway to apply changes.</p>
      </div>
    </div>
  );
}