import {z} from 'zod'

export type UsageRequest = {granularity: 'monthly' | 'yearly' | 'custom', date_start?: (string | null) | undefined, date_end?: (string | null) | undefined};

export type CreateApiLlmCostArgs = {cookie_name?: (string | null) | undefined, tenant_id?: number | undefined, body: UsageRequest};

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

export const timeseriesPoint = z.object({date: z.string(), cost: z.number()});

export const timeseriesResponse = z.object({total_cost: z.number(), timeseries: z.record(z.string(), z.array(timeseriesPoint))});

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
};

/**
 * Get LLM cost metrics
 * 
 * POST /llm/cost
 */
export const createApiLlmCost = async (args: CreateApiLlmCostArgs, options?: CreateApiLlmCostOptions) => {
const {baseUrl = "https://api.your-domain.com", fetch: fetchFn = fetch, APIKeyHeader} = options ?? {}

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

if (args.cookie_name != null) query.append("cookie_name", String(args.cookie_name))
if (args.tenant_id != null) query.append("tenant_id", String(args.tenant_id))
if (APIKeyHeader !== undefined) headers.set("X-API-KEY", APIKeyHeader)

const url = `${baseUrl.replace(/\/+$/, '')}/llm/cost${query.size > 0 ? `?${query}` : ''}`

const res = await fetchFn(url, {method: "POST", headers, body: JSON.stringify(args.body)})

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

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