import { api } from "./client";

export interface CategoryForecast {
  category_id: string;
  category_name: string;
  monthly_avg: number;
  algorithm: "sarima" | "holt_winters" | "average";
  actuals: { date: string; amount: number }[];
  forecast: { date: string; amount: number; lower: number; upper: number; lower_95: number; upper_95: number }[];
}

export interface SpendingForecastResponse {
  categories: CategoryForecast[];
}

export interface NetWorthProjectionResponse {
  history: { date: string; value: number }[];
  projections: {
    conservative: { date: string; value: number }[];
    base: { date: string; value: number }[];
    optimistic: { date: string; value: number }[];
  };
  insufficient_data: boolean;
}

export interface PercentilePath {
  date: string;
  value: number;
}

export interface MonteCarloMilestone {
  year: number;
  date: string;
  p10: number;
  p50: number;
  p90: number;
}

export interface MonteCarloResponse {
  dates: string[];
  percentiles: {
    p10: PercentilePath[];
    p25: PercentilePath[];
    p50: PercentilePath[];
    p75: PercentilePath[];
    p90: PercentilePath[];
  };
  current_value: number;
  expected_value: number;
  probability_of_gain: number;
  milestones: MonteCarloMilestone[];
  insufficient_data: boolean;
}

export interface BudgetForecastItem {
  category_id: string;
  category_name: string;
  budget_amount: number;
  spent_so_far: number;
  forecast_month_total: number;
  daily_velocity: number;
  probability_overspend: number;
  days_remaining: number;
}

export interface BudgetForecastResponse {
  forecasts: BudgetForecastItem[];
  message?: string;
}

export interface CashFlowDay {
  date: string;
  balance: number;
  upper: number;
  lower: number;
  avg_inflow: number;
  avg_outflow: number;
  negative_risk: boolean;
}

export interface UpcomingPayment {
  name: string;
  date: string;
  amount: number;
  at_risk: boolean;
}

export interface CashFlowResponse {
  current_balance: number;
  avg_daily_inflow: number;
  avg_daily_outflow: number;
  forecast: CashFlowDay[];
  negative_risk_days: string[];
  upcoming_payments: UpcomingPayment[];
  history_days: number;
}

export async function getSpendingForecast(): Promise<SpendingForecastResponse> {
  const res = await api.get("/predictions/spending");
  return res.data;
}

export async function getNetWorthProjection(years = 5): Promise<NetWorthProjectionResponse> {
  const res = await api.get("/predictions/net-worth", { params: { years } });
  return res.data;
}

export async function postMonteCarlo(params: {
  years?: number;
  n_simulations?: number;
  annual_contribution?: number;
}): Promise<MonteCarloResponse> {
  const res = await api.post("/predictions/monte-carlo", {
    years: params.years ?? 5,
    n_simulations: params.n_simulations ?? 1000,
    annual_contribution: params.annual_contribution ?? 0,
  });
  return res.data;
}

export async function getBudgetForecast(): Promise<BudgetForecastResponse> {
  const res = await api.get("/predictions/budget-forecast");
  return res.data;
}

export async function getCashFlowForecast(): Promise<CashFlowResponse> {
  const res = await api.get("/predictions/cashflow");
  return res.data;
}