import {z} from 'zod'

export type GetApiChangesSinceDateArgs = {date: string};

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

export const premisAgent = z.object({agentType: z.string(), agentName: z.string(), agentRole: z.string().optional()});

export const premisObject = z.object({objectIdentifier: z.string(), objectCategory: z.enum(["software", "hardware"]), objectDescription: z.string()});

export const premisEvent = z.object({eventType: z.string(), eventDateTime: z.string(), eventDetail: z.string(), eventOutcomeInformation: z.string().optional(), linkedAgent: premisAgent.optional(), linkedObject: premisObject.optional()});

export const changeLog = z.object({versionNr: z.string(), typesOfChanges: z.array(z.enum(["Unavailability", "Interface change", "Functionality change", "Behavioural change"])), description: z.string(), systemChanges: z.object({softwareChanges: z.array(premisEvent).optional(), hardwareChanges: z.array(premisEvent).optional()}).optional()});

export const getApiChangesSinceDateResponse = z.array(changeLog);

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
};

/**
 * List of changes to the web service
 * 
 * GET /changesSince/{date}
 */
export const getApiChangesSinceDate = async (args: GetApiChangesSinceDateArgs, options: GetApiChangesSinceDateOptions) => {
const {baseUrl, fetch: fetchFn = fetch} = options ?? {}

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

const url = `${baseUrl.replace(/\/+$/, '')}/changesSince/${encodeURIComponent(String(args.date))}${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(getApiChangesSinceDateResponse, await res.json())
};