import type { WidgetConfig, Doctor, TimeSlot } from './types';

let baseUrl = '';
let widgetKey = '';

export const initApi = (url: string, key: string) => {
    baseUrl = url;
    widgetKey = key;
};

const headers = () => ({
    'Content-Type': 'application/json',
    'X-Widget-Key': widgetKey,
});

export const fetchInit = async (): Promise<WidgetConfig> => {
    const res = await fetch(`${baseUrl}/api/widget/init?key=${widgetKey}`);
    if (!res.ok) throw new Error('Widget init failed');
    return res.json();
};

export const fetchDoctors = async (): Promise<Doctor[]> => {
    const res = await fetch(`${baseUrl}/api/widget/doctors?key=${widgetKey}`);
    if (!res.ok) throw new Error('Failed to load doctors');
    return res.json();
};

export const fetchSlots = async (doctorId: string, date: string): Promise<TimeSlot[]> => {
    const res = await fetch(`${baseUrl}/api/widget/slots?key=${widgetKey}&doctorId=${doctorId}&date=${date}`);
    if (!res.ok) throw new Error('Failed to load slots');
    return res.json();
};

export const submitBooking = async (data: any): Promise<{ appointmentId: string; reference: string }> => {
    const res = await fetch(`${baseUrl}/api/widget/book?key=${widgetKey}`, {
        method: 'POST', headers: headers(), body: JSON.stringify(data),
    });
    if (!res.ok) throw new Error('Booking failed');
    return res.json();
};

export const submitLead = async (data: any): Promise<{ leadId: string }> => {
    const res = await fetch(`${baseUrl}/api/widget/lead?key=${widgetKey}`, {
        method: 'POST', headers: headers(), body: JSON.stringify(data),
    });
    if (!res.ok) throw new Error('Submission failed');
    return res.json();
};

export const startChatSession = async (name: string, phone: string): Promise<{ leadId: string }> => {
    const res = await fetch(`${baseUrl}/api/widget/chat-start?key=${widgetKey}`, {
        method: 'POST', headers: headers(),
        body: JSON.stringify({ name, phone }),
    });
    if (!res.ok) throw new Error('Chat start failed');
    return res.json();
};

// Send the simplified {role, content: string}[] history to the backend.
// Backend responds with an SSE stream of UIMessageChunk events.
// branch (when set) is injected into the system prompt so the AI scopes
// tool calls to that branch.
type OutboundMessage = { role: 'user' | 'assistant'; content: string };
export const streamChat = async (
    leadId: string,
    messages: OutboundMessage[],
    branch: string | null,
): Promise<ReadableStream<Uint8Array>> => {
    const res = await fetch(`${baseUrl}/api/widget/chat?key=${widgetKey}`, {
        method: 'POST', headers: headers(),
        body: JSON.stringify({ leadId, messages, branch }),
    });
    if (!res.ok || !res.body) throw new Error('Chat failed');
    return res.body;
};