/**
 * FinBot API Client
 * =================
 * Connects the Next.js frontend to the IRIS API proxy.
 * The proxy forwards to FastAPI when available and serves validated cached
 * Investor Relations responses when the backend process is warming up.
 */

export const BACKEND_URL = process.env.NEXT_PUBLIC_BACKEND_URL || '/api/proxy';

export interface Source {
  id: number;
  doc_name: string;
  page: number;
  support: string;
  image_url?: string;
}

export interface KPIRow {
  metric: string;
  current: string;
  previous: string;
  change: string;
  interpretation: string;
  direction: 'positive' | 'negative' | 'neutral';
  period?: string;
  value?: string;
}

export interface Driver {
  title: string;
  detail: string;
}

export interface VisualItem {
  id: string;
  page: number;
  image_url: string;
  alt: string;
}

export interface ChatResponse {
  response_type: 'ir_response' | 'unsupported' | 'insufficient';
  question: string;
  executive_summary?: string;
  sources: Source[];
  financial_kpis: KPIRow[];
  key_drivers_summary?: string;
  key_drivers: Driver[];
  visual_evidence: VisualItem[];
  latency_ms: number;
  model_used: string;
}

export interface Document {
  doc_id: string;
  name: string;
  doc_type: string;
  period: string;
  institution?: string;
  total_pages: number;
  status: string;
  filename: string;
  chunks_indexed?: number;
  tables_indexed?: number;
  colpali_pages?: number;
  pagemap_file?: string;
  page_section_map?: Record<string, string>;
  page_metadata_map?: Record<string, {
    slide: number;
    section: string;
    mapping_items: string[];
    kpis: string[];
    kpi_tags: string[];
    description: string;
    period: string;
    synonyms: string[];
    visual_layout: string;
  }>;
  retrieval_config?: string;
}

/** Check if the backend is reachable */
export async function checkBackendHealth(): Promise<boolean> {
  try {
    const res = await fetch(`${BACKEND_URL}/api/health`, {
      signal: AbortSignal.timeout(2000),
    });
    return res.ok;
  } catch {
    return false;
  }
}

/** Submit a question to the RAG pipeline */
export async function submitQuestion(
  question: string,
  docIds: string[],
): Promise<ChatResponse> {
  const res = await fetch(`${BACKEND_URL}/api/chat/query`, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ question, doc_ids: docIds }),
    signal: AbortSignal.timeout(120_000), // ColPali can take time
  });

  if (!res.ok) {
    const err = await res.text();
    throw new Error(`Backend error ${res.status}: ${err}`);
  }

  return res.json();
}

/** Get list of indexed documents */
export async function fetchDocuments(): Promise<Document[]> {
  const res = await fetch(`${BACKEND_URL}/api/documents/`, {
    signal: AbortSignal.timeout(5000),
  });
  if (!res.ok) throw new Error('Failed to fetch documents');
  return res.json();
}

/** Get the URL for a page image (rendered PDF page) */
export function getPageImageUrl(docId: string, pageNumber: number): string {
  return `${BACKEND_URL}/api/visuals/${docId}/${pageNumber}`;
}

/** Normalize legacy static page URLs to the backend visual route. */
export function normalizePageImageUrl(
  imageUrl: string | undefined,
  fallbackDocId: string,
  fallbackPage: number,
): string {
  if (!imageUrl) {
    return getPageImageUrl(fallbackDocId, fallbackPage);
  }

  const legacyPageMatch = imageUrl.match(
    /\/pages\/([^/]+)\/pages\/page_(\d{4})(?:_[^/.]+)?\.png$/,
  );
  if (legacyPageMatch) {
    return getPageImageUrl(legacyPageMatch[1], Number.parseInt(legacyPageMatch[2], 10));
  }

  if (imageUrl.startsWith('/api/visuals/')) {
    return `${BACKEND_URL}${imageUrl}`;
  }

  if (imageUrl.startsWith('/')) {
    return `${BACKEND_URL}${imageUrl}`;
  }

  return imageUrl;
}