import { getApp, getApps, initializeApp } from 'firebase/app';
import { getAuth, signInAnonymously } from 'firebase/auth';
import type { DemoLocale } from './types';

type FirebaseEnvConfig = {
  apiKey: string;
  authDomain: string;
  projectId: string;
  appId: string;
  messagingSenderId?: string;
  storageBucket?: string;
};

type VoiceRole = 'assistant' | 'system';

export type LiveVoiceMessage = {
  role: VoiceRole;
  text: string;
};

export type LiveVoiceToolAction = {
  label?: string;
  prompt?: string;
  href?: string;
  auto?: boolean;
};

export type LiveVoiceToolUi = {
  kind?: string;
  title?: string;
  description?: string;
  items?: Array<Record<string, unknown>>;
  actions?: LiveVoiceToolAction[];
  [key: string]: unknown;
};

export type LiveVoiceAssistantResponse = {
  messages?: LiveVoiceMessage[];
  ui?: LiveVoiceToolUi;
};

export type LiveVoiceToolResponse = {
  messages?: LiveVoiceMessage[];
  ui?: LiveVoiceToolUi;
};

export type LiveMarketingStreamEvent =
  | { type: 'text'; text: string }
  | { type: 'image'; base64: string; mimeType?: string }
  | { type: 'done' }
  | { type: 'error'; message: string };

export type LiveInvoiceItem = {
  description?: string;
  quantity?: number;
  unitPrice?: number;
  lineTotal?: number;
};

export type LiveInvoiceExtraction = {
  provider?: 'gemini' | 'mock' | string;
  model?: string;
  confidence?: number;
  warnings?: string[];
  rawText?: string;
  invoice?: {
    direction?: 'sale' | 'purchase' | string;
    status?: 'draft' | 'open' | 'paid' | 'overdue' | string;
    invoiceNumber?: string;
    counterpartyName?: string;
    description?: string;
    currency?: string;
    total?: number;
    paid?: number;
    issueDate?: string;
    dueDate?: string;
    deliveryDate?: string;
    items?: LiveInvoiceItem[];
  };
};

export type LiveInvoiceScanResponse = {
  extraction?: LiveInvoiceExtraction;
  created?: { id?: string } | null;
};

const DEMO_USER_ID = (import.meta.env.VITE_DEMO_USER_ID as string | undefined)?.trim() || '';
const HF_DEMO_API_KEY = (import.meta.env.VITE_HF_DEMO_API_KEY as string | undefined)?.trim() || '';

const firebaseConfig: FirebaseEnvConfig = {
  apiKey: (import.meta.env.VITE_FIREBASE_API_KEY as string | undefined)?.trim() || '',
  authDomain: (import.meta.env.VITE_FIREBASE_AUTH_DOMAIN as string | undefined)?.trim() || '',
  projectId: (import.meta.env.VITE_FIREBASE_PROJECT_ID as string | undefined)?.trim() || '',
  appId: (import.meta.env.VITE_FIREBASE_APP_ID as string | undefined)?.trim() || '',
  messagingSenderId: (import.meta.env.VITE_FIREBASE_MESSAGING_SENDER_ID as string | undefined)?.trim() || undefined,
  storageBucket: (import.meta.env.VITE_FIREBASE_STORAGE_BUCKET as string | undefined)?.trim() || undefined,
};

let authTokenPromise: Promise<string | null> | null = null;

function getLiveApiBaseUrl(): string {
  const raw =
    (import.meta.env.VITE_DEMO_API_BASE_URL as string | undefined)?.trim() ||
    (import.meta.env.VITE_API_BASE_URL as string | undefined)?.trim() ||
    '';

  if (!raw) {
    throw new Error('Missing `VITE_DEMO_API_BASE_URL` for live mode.');
  }

  return raw.endsWith('/api') ? raw.slice(0, -4) : raw.replace(/\/$/, '');
}

function hasFirebaseConfig(config: FirebaseEnvConfig): boolean {
  return Boolean(config.apiKey && config.authDomain && config.projectId && config.appId);
}

async function getIdToken(): Promise<string | null> {
  if (!hasFirebaseConfig(firebaseConfig)) return null;
  if (!authTokenPromise) {
    authTokenPromise = (async () => {
      const app = getApps().some((entry) => entry.name === 'hf-demo-app')
        ? getApp('hf-demo-app')
        : initializeApp(firebaseConfig, 'hf-demo-app');
      const auth = getAuth(app);
      if (!auth.currentUser) {
        await signInAnonymously(auth);
      }
      return auth.currentUser ? await auth.currentUser.getIdToken(true) : null;
    })();
  }
  return authTokenPromise;
}

async function parseErrorResponse(response: Response): Promise<string> {
  try {
    const json = (await response.json()) as { error?: string; message?: string; hint?: string };
    return json.message || json.error || `Request failed with status ${response.status}`;
  } catch {
    const text = await response.text().catch(() => '');
    return text || `Request failed with status ${response.status}`;
  }
}

async function requestJson<T>(path: string, init: RequestInit = {}): Promise<T> {
  const baseUrl = getLiveApiBaseUrl();
  const token = await getIdToken();
  const headers = new Headers(init.headers || {});
  if (!headers.has('Content-Type')) {
    headers.set('Content-Type', 'application/json');
  }
  if (token) {
    headers.set('Authorization', `Bearer ${token}`);
  }
  if (HF_DEMO_API_KEY) {
    headers.set('x-hf-demo-key', HF_DEMO_API_KEY);
  }
  const response = await fetch(`${baseUrl}${path}`, {
    ...init,
    headers,
  });
  if (!response.ok) {
    const message = await parseErrorResponse(response);
    throw new Error(message);
  }
  return (await response.json()) as T;
}

function withDemoUser<T extends Record<string, unknown>>(body: T): T {
  if (!DEMO_USER_ID) return body;
  return { ...body, userId: DEMO_USER_ID };
}

export function parseDataUrl(dataUrl: string): { base64: string; mimeType: string } {
  const trimmed = dataUrl.trim();
  const match = trimmed.match(/^data:([^;]+);base64,(.+)$/);
  if (!match) {
    return { base64: trimmed, mimeType: 'image/png' };
  }
  return { mimeType: match[1], base64: match[2] };
}

export async function sendVoiceAssistantMessage(params: {
  message: string;
  locale: DemoLocale;
  pageRoute?: string;
  pageContext?: string;
}): Promise<LiveVoiceAssistantResponse> {
  return await requestJson<LiveVoiceAssistantResponse>(
    '/api/voice/assistant',
    {
      method: 'POST',
      body: JSON.stringify(
        withDemoUser({
          message: params.message,
          locale: params.locale,
          pageRoute: params.pageRoute,
          pageContext: params.pageContext,
        })
      ),
    }
  );
}

export async function callVoiceTool(params: {
  name: string;
  args?: Record<string, unknown>;
  locale: DemoLocale;
}): Promise<LiveVoiceToolResponse> {
  return await requestJson<LiveVoiceToolResponse>(
    '/api/voice/tool',
    {
      method: 'POST',
      body: JSON.stringify(
        withDemoUser({
          name: params.name,
          args: params.args || {},
          locale: params.locale,
        })
      ),
    }
  );
}

export async function scanInvoiceImage(params: {
  dataBase64: string;
  mimeType?: string;
  locale: DemoLocale;
  createInvoice: boolean;
}): Promise<LiveInvoiceScanResponse> {
  return await requestJson<LiveInvoiceScanResponse>(
    '/api/invoices/scan',
    {
      method: 'POST',
      body: JSON.stringify({
        dataBase64: params.dataBase64,
        mimeType: params.mimeType,
        locale: params.locale,
        createInvoice: params.createInvoice,
      }),
    }
  );
}

export async function streamMarketingGeneration(params: {
  prompt: string;
  locale: DemoLocale;
  product: { name: string; category: string; description?: string };
  image?: { base64: string; mimeType: string };
  signal?: AbortSignal;
  onEvent: (event: LiveMarketingStreamEvent) => void;
}): Promise<void> {
  const baseUrl = getLiveApiBaseUrl();
  const token = await getIdToken();
  const headers = new Headers({ 'Content-Type': 'application/json' });
  if (token) {
    headers.set('Authorization', `Bearer ${token}`);
  }
  if (HF_DEMO_API_KEY) {
    headers.set('x-hf-demo-key', HF_DEMO_API_KEY);
  }

  const response = await fetch(`${baseUrl}/api/marketing/generate-stream`, {
    method: 'POST',
    headers,
    signal: params.signal,
    body: JSON.stringify({
      prompt: params.prompt,
      language: params.locale,
      product: params.product,
      image: params.image,
    }),
  });

  if (!response.ok || !response.body) {
    const message = await parseErrorResponse(response);
    throw new Error(message);
  }

  const reader = response.body.getReader();
  const decoder = new TextDecoder('utf-8');
  let buffer = '';

  while (true) {
    const { value, done } = await reader.read();
    if (done) break;
    buffer += decoder.decode(value, { stream: true });
    const lines = buffer.split('\n');
    buffer = lines.pop() ?? '';

    for (const line of lines) {
      const trimmed = line.trim();
      if (!trimmed) continue;
      try {
        const event = JSON.parse(trimmed) as LiveMarketingStreamEvent;
        params.onEvent(event);
      } catch {
        // Ignore malformed chunks from network boundaries.
      }
    }
  }
}