import { z } from 'zod';

export const CommodityType = z.enum([
  // Energy commodities
  'natural_gas',
  'wti_crude',
  'coal',
  // Petroleum
  'brent_crude',
  'dubai_crude',
  'gasoline',
  'diesel',
  'heating_oil',
  // Natural gas futures
  'ng_futures_1',
  'ng_futures_2',
  'ng_futures_3',
  'ng_futures_4',
  // Market indicators
  'ovx',
  'vix',
  'dxy',
  'financial_stress',
  // Supply metrics
  'spr_level',
  'us_crude_production',
  // Geopolitical risk
  'gpr_daily',
]);
export type CommodityType = z.infer<typeof CommodityType>;

export const CommodityPriceSchema = z.object({
  commodity: CommodityType,
  price: z.number(),
  unit: z.string(),
  timestamp: z.date(),
  source: z.string(),
});
export type CommodityPrice = z.infer<typeof CommodityPriceSchema>;

export const COMMODITY_UNITS: Record<CommodityType, string> = {
  natural_gas: '$/Million BTU',
  wti_crude: '$/Barrel',
  coal: '$/Metric Ton',
  brent_crude: '$/Barrel',
  dubai_crude: '$/Barrel',
  gasoline: '$/Gallon',
  diesel: '$/Gallon',
  heating_oil: '$/Gallon',
  ng_futures_1: '$/Million BTU',
  ng_futures_2: '$/Million BTU',
  ng_futures_3: '$/Million BTU',
  ng_futures_4: '$/Million BTU',
  ovx: 'Index',
  vix: 'Index',
  dxy: 'Index',
  financial_stress: 'Index',
  spr_level: 'Million Barrels',
  us_crude_production: 'Million Barrels/Day',
  gpr_daily: 'Index',
};

export const COMMODITY_DISPLAY_NAMES: Record<CommodityType, string> = {
  natural_gas: 'Natural Gas',
  wti_crude: 'WTI Crude',
  coal: 'Coal',
  brent_crude: 'Brent Crude',
  dubai_crude: 'Dubai Crude',
  gasoline: 'Gasoline',
  diesel: 'Diesel',
  heating_oil: 'Heating Oil',
  ng_futures_1: 'NG Futures (Month 1)',
  ng_futures_2: 'NG Futures (Month 2)',
  ng_futures_3: 'NG Futures (Month 3)',
  ng_futures_4: 'NG Futures (Month 4)',
  ovx: 'Oil Volatility (OVX)',
  vix: 'Market Volatility (VIX)',
  dxy: 'US Dollar Index',
  financial_stress: 'Financial Stress',
  spr_level: 'SPR Level',
  us_crude_production: 'US Crude Production',
  gpr_daily: 'Geopolitical Risk',
};

export const COMMODITY_CATEGORIES = {
  petroleum: ['wti_crude', 'brent_crude', 'dubai_crude', 'gasoline', 'diesel', 'heating_oil'],
  energy_commodity: ['natural_gas', 'coal'],
  futures: ['ng_futures_1', 'ng_futures_2', 'ng_futures_3', 'ng_futures_4'],
  market_indicator: ['ovx', 'vix', 'dxy', 'financial_stress'],
  supply: ['spr_level', 'us_crude_production'],
  geopolitical: ['gpr_daily'],
} as const;

/** Coerce EIA string values to numbers, treating empty/null as null */
const eiaNumericValue = z.union([z.string(), z.number(), z.null()]).transform((val): number | null => {
  if (val === null || val === '') return null;
  const num = Number(val);
  return Number.isNaN(num) ? null : num;
});

/**
 * EIA natural gas price row.
 * Endpoint: /v2/natural-gas/pri/fut/data/
 * Series: RNGWHHD (Henry Hub Natural Gas Spot Price)
 */
export const eiaNaturalGasRowSchema = z.object({
  period: z.string(),
  'series-description': z.string(),
  value: eiaNumericValue,
  units: z.string().optional(),
});

export type EiaNaturalGasRow = z.infer<typeof eiaNaturalGasRowSchema>;

/**
 * EIA petroleum/crude oil price row.
 * Endpoint: /v2/petroleum/pri/spt/data/
 * Series: RWTC (WTI Cushing Oklahoma Spot Price)
 */
export const eiaWtiCrudeRowSchema = z.object({
  period: z.string(),
  'series-description': z.string().optional(),
  value: eiaNumericValue,
  units: z.string().optional(),
});

export type EiaWtiCrudeRow = z.infer<typeof eiaWtiCrudeRowSchema>;

/**
 * Parsed commodity price data point (from EIA/FRED/GPR).
 */
export interface CommodityPricePoint {
  timestamp: Date;
  commodity: CommodityType;
  price: number | null;
  unit: string;
  source: string;
}

/**
 * Generic EIA API response wrapper for commodity endpoints.
 */
export function eiaCommodityResponseSchema<T extends z.ZodType>(dataRowSchema: T) {
  return z.object({
    response: z.object({
      total: z.union([z.string(), z.number()]).transform(Number),
      data: z.array(dataRowSchema),
    }),
  });
}

export const eiaNaturalGasResponseSchema = eiaCommodityResponseSchema(eiaNaturalGasRowSchema);
export const eiaWtiCrudeResponseSchema = eiaCommodityResponseSchema(eiaWtiCrudeRowSchema);

export type EiaNaturalGasResponse = z.infer<typeof eiaNaturalGasResponseSchema>;
export type EiaWtiCrudeResponse = z.infer<typeof eiaWtiCrudeResponseSchema>;

/**
 * Parse an EIA daily period string to a UTC Date.
 * Commodity data uses daily format: "2026-02-02"
 */
export function parseEiaCommodityPeriod(period: string): Date {
  if (/^\d{4}-\d{2}-\d{2}$/.test(period)) {
    return new Date(`${period}T00:00:00Z`);
  }
  return new Date(period);
}