```javascript
class StockfolioAPI {
    static async getMarketSummary() {
        try {
            const response = await axios.get('/api/market-summary');
            return response.data;
        } catch (error) {
            console.error('Error fetching market summary:', error);
            return {
                kse100: 42500.75,
                change_percent: 0.45,
                volume: 125600000,
                value: 8450000000
            };
        }
    }

    static async getTopStocks() {
        try {
            const response = await axios.get('/api/companies?limit=4');
            return response.data;
        } catch (error) {
            console.error('Error fetching top stocks:', error);
            return [
                {
                    symbol: "OGDC",
                    name: "Oil & Gas Development Company",
                    sector: "Oil & Gas",
                    price: 86.45,
                    change: 1.25,
                    volume: 12500000
                },
                {
                    symbol: "LUCK",
                    name: "Lucky Cement",
                    sector: "Cement",
                    price: 650.20,
                    change: -2.35,
                    volume: 850000
                },
                {
                    symbol: "HBL",
                    name: "Habib Bank Limited",
                    sector: "Banking",
                    price: 125.75,
                    change: 0.85,
                    volume: 4500000
                },
                {
                    symbol: "ENGRO",
                    name: "Engro Corporation",
                    sector: "Chemical",
                    price: 320.50,
                    change: 3.15,
                    volume: 2200000
                }
            ];
        }
    }

    static async getCompanies() {
        try {
            const response = await axios.get('/api/companies');
            return response.data;
        } catch (error) {
            console.error('Error fetching companies:', error);
            return [];
        }
    }

    static async getSectors() {
        try {
            const response = await axios.get('/api/sectors');
            return response.data;
        } catch (error) {
            console.error('Error fetching sectors:', error);
            return [];
        }
    }

    static async getUACReports(userId) {
        try {
            const response = await axios.get(`/api/uac-reports/${userId}`);
            return response.data;
        } catch (error) {
            console.error('Error fetching UAC reports:', error);
            return [];
        }
    }
}
```