import {z} from 'zod'

export type GetApiUsageOptions = {baseUrl: string, bearerAuth?: string | undefined, fetch?: typeof fetch | undefined};

export const fileStorage = z.object({plan: z.string(), maxBytes: z.number().int().gte(0), usedBytes: z.number().int().gte(0), reservedBytes: z.number().int().gte(0), remainingBytes: z.number().int().gte(0), sandbox: z.object({maxBytes: z.number().int().gte(0), usedBytes: z.number().int().gte(0), reservedBytes: z.number().int().gte(0), remainingBytes: z.number().int().gte(0)}), maxBatchUploadBytes: z.number().int().gte(0), maxEvidenceAttachmentBytes: z.number().int().gte(0)});

export const monitoringForecast = z.object({generatedAt: z.string(), periodEnd: z.string(), dailyScreenings: z.number().gte(0), projectedRemainingScreenings: z.number().int().gte(0), effectiveLimit: z.number().int().gte(0), used: z.number().int().gte(0), reserved: z.number().int().gte(0), remaining: z.number().int().gte(0), projectedExhaustionAt: z.string().nullable()});

export const usage = z.object({environment: z.enum(["sandbox", "production"]), period: z.string(), used: z.number().int().gte(0), reserved: z.number().int().gte(0), limit: z.number().int().gte(0), planLimit: z.number().int().gte(0), spendingCap: z.number().int().gte(0), effectiveLimit: z.number().int().gte(0), remaining: z.number().int().gte(0), plan: z.string(), events: z.array(z.object({kind: z.string(), subjects: z.number().int().gte(0)})), fileStorage: fileStorage, monitoringForecast: monitoringForecast.nullable(), forecastUnavailable: z.string().nullable()});

export const getApiUsageResponse = z.object({data: usage});

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
};

/**
 * Read period allowance, used subjects and pending reservations
 * 
 * GET /usage
 */
export const getApiUsage = async (options: GetApiUsageOptions) => {
const {baseUrl, fetch: fetchFn = fetch, bearerAuth} = options ?? {}

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

if (bearerAuth !== undefined) headers.set('authorization', `Bearer ${bearerAuth}`)

const url = `${baseUrl.replace(/\/+$/, '')}/usage${query.size > 0 ? `?${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(getApiUsageResponse, await res.json())
};