import {z} from 'zod'

export type GetApiV1StocksTickerCorrelatedArgs = {ticker: string, scope?: string | undefined, days?: number | undefined, direction?: string | undefined, limit?: number | undefined};

export type GetApiV1StocksTickerCorrelatedOptions = {baseUrl?: string | undefined, ApiKey?: string | undefined, fetch?: typeof fetch | undefined};

export const correlatedStockDto = z.object({ticker: z.string().nullable().optional(), name: z.string().nullable().optional(), industry: z.string().nullable().optional(), sector: z.string().nullable().optional(), correlation: z.number().optional(), observations: z.number().int().optional(), marketCap: z.number().optional()});

export const correlatedStocksResponse = z.object({ticker: z.string().nullable().optional(), companyName: z.string().nullable().optional(), scope: z.string().nullable().optional(), direction: z.string().nullable().optional(), windowDays: z.number().int().optional(), method: z.string().nullable().optional(), universeSize: z.number().int().optional(), subjectObservations: z.number().int().optional(), note: z.string().nullable().optional(), data: z.array(correlatedStockDto).nullable().optional()});

export const validateResponse = async <Output>(
  schema: {
    readonly '~standard': {
      readonly validate: (value: unknown) => ({ readonly value: Output; readonly issues?: undefined } | { readonly issues: ReadonlyArray<{ readonly message: string; readonly path?: ReadonlyArray<PropertyKey | { readonly key: PropertyKey }> | undefined }> }) | Promise<{ readonly value: Output; readonly issues?: undefined } | { readonly issues: ReadonlyArray<{ readonly message: string; readonly path?: ReadonlyArray<PropertyKey | { readonly key: PropertyKey }> | undefined }> }>
    }
  },
  value: unknown
): Promise<Output> => {
  const result = await schema['~standard'].validate(value)

  if (result.issues !== undefined) {
    const detail = result.issues
      .map(({ message, path }) =>
        path?.length
          ? `${path.map((segment) => String(typeof segment === 'object' ? segment.key : segment)).join('.')}: ${message}`
          : message
      )
      .join('; ')

    throw new Error(`Response does not match the schema: ${detail}`, { cause: { issues: result.issues } })
  }

  return result.value
};

/**
 * Stocks whose daily price returns are most (or least) correlated with one stock —
 * Pearson correlation of daily log returns on raw closes inside each exact listing's
 * comparable post-split interval, computed over the trading days both stocks priced.
 * Dividends are excluded; correlations are never computed on price levels.
 * Candidates need a $100M market cap and enough overlapping trading days; each row
 * reports the observation count behind its coefficient.
 * 
 * GET /v1/stocks/{ticker}/correlated
 */
export const getApiV1StocksTickerCorrelated = async (args: GetApiV1StocksTickerCorrelatedArgs, options?: GetApiV1StocksTickerCorrelatedOptions) => {
const {baseUrl = "https://api.equibles.com", fetch: fetchFn = fetch, ApiKey} = options ?? {}

const query = new URLSearchParams()
const headers = new Headers()
headers.set('accept', "application/json")

if (args.scope != null) query.append("scope", String(args.scope))
if (args.days != null) query.append("days", String(args.days))
if (args.direction != null) query.append("direction", String(args.direction))
if (args.limit != null) query.append("limit", String(args.limit))
if (ApiKey !== undefined) headers.set('authorization', `Bearer ${ApiKey}`)

const url = `${baseUrl.replace(/\/+$/, '')}/v1/stocks/${encodeURIComponent(String(args.ticker))}/correlated${query.size > 0 ? `?${query}` : ''}`

const res = await fetchFn(url, {method: "GET", headers})

if (!res.ok) throw new Error(`Request failed with status ${res.status}`, {cause: {status: res.status, body: await res.text()}})

return validateResponse(correlatedStocksResponse, await res.json())
};