function getAuthHeader(): string {
    const token = localStorage.getItem('token');
    return token ? `Bearer ${token}` : '';
}

async function apiGet(url: string): Promise<Response> {
    return fetch(`/api${url}`, {
        headers: {
            'Authorization': getAuthHeader(),
            'Content-Type': 'application/json'
        }
    });
}

async function apiPost(url: string, data?: unknown): Promise<Response> {
    return fetch(`/api${url}`, {
        method: 'POST',
        headers: {
            'Authorization': getAuthHeader(),
            'Content-Type': 'application/json'
        },
        body: data ? JSON.stringify(data) : undefined
    });
}

async function apiPut(url: string, data?: unknown): Promise<Response> {
    return fetch(`/api${url}`, {
        method: 'PUT',
        headers: {
            'Authorization': getAuthHeader(),
            'Content-Type': 'application/json'
        },
        body: data ? JSON.stringify(data) : undefined
    });
}

async function apiDelete(url: string): Promise<Response> {
    return fetch(`/api${url}`, {
        method: 'DELETE',
        headers: {
            'Authorization': getAuthHeader()
        }
    });
}

async function apiPatch(url: string, data?: unknown): Promise<Response> {
    return fetch(`/api${url}`, {
        method: 'PATCH',
        headers: {
            'Authorization': getAuthHeader(),
            'Content-Type': 'application/json'
        },
        body: data ? JSON.stringify(data) : undefined
    });
}

async function handleResponse<T>(response: Response): Promise<T> {
    if (!response.ok) {
        const errorData = await response.json().catch(() => ({ error: 'Unknown error' }));
        throw new Error(errorData.error || `HTTP ${response.status}`);
    }
    return response.json();
}

async function handleVoidResponse(response: Response): Promise<void> {
    if (!response.ok) {
        const errorData = await response.json().catch(() => ({ error: 'Unknown error' }));
        throw new Error(errorData.error || `HTTP ${response.status}`);
    }
}

function handleError(error: unknown, context: string): void {
    console.error(`${context}:`, error);
    const message = error instanceof Error ? error.message : 'An unexpected error occurred';
    if ((window as any).showToast?.error) {
        (window as any).showToast.error(message);
    }
}

(window as any).api = {
    get: apiGet,
    post: apiPost,
    put: apiPut,
    delete: apiDelete,
    patch: apiPatch,
    handleResponse,
    handleVoidResponse,
    handleError
};

export {
    getAuthHeader,
    apiGet,
    apiPost,
    apiPut,
    apiDelete,
    apiPatch,
    handleResponse,
    handleVoidResponse,
    handleError
};