import {z} from 'zod'

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

export const methodParameter = z.object({name: z.string(), description: z.string(), constraints: z.object({allow_empty_string: z.boolean(), allow_whitespace_string: z.boolean(), max_length: z.number().int(), min_length: z.number().int(), regex: z.string(), not_regex: z.string(), select: z.array(z.string())}), type: z.enum(["String", "HereString"])});

export const methods = z.object({id: z.string(), name: z.string(), version: z.string(), category: z.string(), desc: z.string(), documentation: z.string(), parameters: z.array(methodParameter), agents: z.array(z.string()), condition: z.object({prefix: z.string().optional(), parameter: z.string().optional()}), deprecated: z.object({info: z.string().optional(), replacedBy: z.string().optional()})});

export const getApiMethodsResponse = z.object({result: z.enum(["success", "error"]), action: z.literal("listTechniques"), data: z.object({methods: methods})});

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 methods
 * 
 * GET /methods
 */
export const getApiMethods = async (options?: GetApiMethodsOptions) => {
const {baseUrl = "https://rudder.example.com/rudder/api/latest", fetch: fetchFn = fetch, APITokens} = options ?? {}

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

if (APITokens !== undefined) headers.set("X-API-Token", APITokens)

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