import {z} from 'zod'

export type GetApiV1AnalyticsSessionsTurnDepthArgs = {start_date: string, end_date: string};

export type GetApiV1AnalyticsSessionsTurnDepthOptions = {baseUrl: string, APIKeyHeader?: string | undefined, fetch?: typeof fetch | undefined};

export const turnDepthRow = z.object({total_sessions: z.number().int(), avg_turns_per_session: z.number(), single_turn_rate_pct: z.number(), p50_turns: z.number(), p90_turns: z.number(), p95_turns: z.number()});

export const getApiV1AnalyticsSessionsTurnDepthResponse = z.array(turnDepthRow);

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
};

/**
 * Turn-depth summary (avg / single-turn rate / quantiles)
 * 
 * GET /v1/analytics/sessions/turn-depth
 */
export const getApiV1AnalyticsSessionsTurnDepth = async (args: GetApiV1AnalyticsSessionsTurnDepthArgs, options: GetApiV1AnalyticsSessionsTurnDepthOptions) => {
const {baseUrl, fetch: fetchFn = fetch, APIKeyHeader} = options ?? {}

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

if (args.start_date != null) query.append("start_date", String(args.start_date))
if (args.end_date != null) query.append("end_date", String(args.end_date))
if (APIKeyHeader !== undefined) headers.set("x-api-key", APIKeyHeader)

const url = `${baseUrl.replace(/\/+$/, '')}/v1/analytics/sessions/turn-depth${query.size > 0 ? `?${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(getApiV1AnalyticsSessionsTurnDepthResponse, await res.json())
};