import { SpanStatusCode, trace } from "@opentelemetry/api";
import { currentAccessToken } from "../auth/oidc";
import type {
  WWIKpi,
  WWIReorderRecommendation,
  WWISupplierScore,
  WWIBusinessEvent,
  WWIWhatIfResult,
  WWIScenario,
} from "./types";

const API_BASE = import.meta.env.VITE_API_BASE_URL ?? "http://localhost:8000";
const tracer = trace.getTracer("wwi-frontend-api");

function authHeaders(): Record<string, string> {
  const token = currentAccessToken();
  return token ? { Authorization: `Bearer ${token}` } : {};
}

async function get<T>(path: string, spanName: string): Promise<T> {
  return tracer.startActiveSpan(spanName, async (span) => {
    try {
      const resp = await fetch(`${API_BASE}${path}`, {
        headers: { Accept: "application/json", ...authHeaders() },
      });
      if (!resp.ok) {
        const body = await resp.text();
        throw new Error(`HTTP ${resp.status}: ${body}`);
      }
      span.setAttribute("http.status_code", resp.status);
      span.setStatus({ code: SpanStatusCode.OK });
      return (await resp.json()) as T;
    } catch (err) {
      span.recordException(err as Error);
      span.setStatus({ code: SpanStatusCode.ERROR, message: String(err) });
      throw err;
    } finally {
      span.end();
    }
  });
}

async function post<T>(path: string, body: unknown, spanName: string): Promise<T> {
  return tracer.startActiveSpan(spanName, async (span) => {
    try {
      const resp = await fetch(`${API_BASE}${path}`, {
        method: "POST",
        headers: {
          "Content-Type": "application/json",
          Accept: "application/json",
          ...authHeaders(),
        },
        body: JSON.stringify(body),
      });
      if (!resp.ok) {
        const text = await resp.text();
        throw new Error(`HTTP ${resp.status}: ${text}`);
      }
      span.setAttribute("http.status_code", resp.status);
      span.setStatus({ code: SpanStatusCode.OK });
      return (await resp.json()) as T;
    } catch (err) {
      span.recordException(err as Error);
      span.setStatus({ code: SpanStatusCode.ERROR, message: String(err) });
      throw err;
    } finally {
      span.end();
    }
  });
}

export const getWWIKpis = () =>
  get<WWIKpi>("/api/wwi/sales/kpis", "frontend.wwi.sales_kpis");

export const getWWIReorderRecommendations = () =>
  get<WWIReorderRecommendation[]>(
    "/api/wwi/stock/recommendations",
    "frontend.wwi.reorder_recommendations",
  );

export const getWWISupplierScores = (topN = 10) =>
  get<WWISupplierScore[]>(
    `/api/wwi/suppliers/scores?top_n=${topN}`,
    "frontend.wwi.supplier_scores",
  );

export const getWWIBusinessEvents = (limit = 100) =>
  get<WWIBusinessEvent[]>(
    `/api/wwi/events?limit=${limit}`,
    "frontend.wwi.business_events",
  );

export const createWWIScenario = (
  stockItemKey: number,
  demandMultiplier: number,
) =>
  post<WWIWhatIfResult>(
    "/api/wwi/scenarios",
    { stock_item_key: stockItemKey, demand_multiplier: demandMultiplier },
    "frontend.wwi.create_scenario",
  );

export const getWWIScenarios = (limit = 20) =>
  get<WWIScenario[]>(
    `/api/wwi/scenarios?limit=${limit}`,
    "frontend.wwi.list_scenarios",
  );