import {z} from 'zod'

export type GetApiV1ItemsItemIdUnitOfMeasureConversionCheckArgs = {itemId: number, targetUnit: string, Account: unknown};

export type GetApiV1ItemsItemIdUnitOfMeasureConversionCheckOptions = {baseUrl: string, OAuth2?: string | undefined, fetch?: typeof fetch | undefined};

export const gapReason = z.union([z.literal(0), z.literal(1)]);

export const unitConversionGap = z.object({fromUnitId: z.string().nullable().optional(), toUnitId: z.string().nullable().optional(), reason: gapReason.optional()});

export const unitOfMeasureChangeValidationResponse = z.object({canChange: z.boolean().optional(), missingConversions: z.array(unitConversionGap).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
};

/**
 * Validate whether an item's inventory (base) unit can be changed to a target unit. Reports
 * the source units (sales/purch/barcode) that lack a usable conversion to the target so the
 * caller can create them before committing. Read-only; changes nothing.
 * 
 * GET /v1/Items/{itemId}/unit-of-measure/conversion-check
 */
export const getApiV1ItemsItemIdUnitOfMeasureConversionCheck = async (args: GetApiV1ItemsItemIdUnitOfMeasureConversionCheckArgs, options: GetApiV1ItemsItemIdUnitOfMeasureConversionCheckOptions) => {
const {baseUrl, fetch: fetchFn = fetch, OAuth2} = options ?? {}

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

if (args.targetUnit != null) query.append("targetUnit", String(args.targetUnit))
if (args.Account != null) query.append("Account", String(args.Account))
if (OAuth2 !== undefined) headers.set('authorization', `Bearer ${OAuth2}`)

const url = `${baseUrl.replace(/\/+$/, '')}/v1/Items/${encodeURIComponent(String(args.itemId))}/unit-of-measure/conversion-check${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(unitOfMeasureChangeValidationResponse, await res.json())
};