import {z} from 'zod'

export type FraudScoreRequest = {email: string};

export type CreateApiFraudScoreArgs = {body: FraudScoreRequest};

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

export const fraudFlag = z.object({code: z.string(), label: z.string(), category: z.enum(["rights", "account_integrity", "content", "distribution", "streaming", "behavior", "abuse"]), severity: z.enum(["low", "medium", "high", "critical"]), triggered: z.boolean(), points: z.number().int()});

export const fraudScoreResponse = z.object({email: z.string(), score: z.number().int(), maxScore: z.number().int(), severity: z.enum(["none", "low", "medium", "high", "critical"]), computedAt: z.string().nullable().optional(), flags: z.array(fraudFlag)});

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
};

/**
 * ONCE Fraud API — risk score and flags for an email
 * 
 * POST /fraud/score
 */
export const createApiFraudScore = async (args: CreateApiFraudScoreArgs, options?: CreateApiFraudScoreOptions) => {
const {baseUrl = "https://once.app/v1", fetch: fetchFn = fetch, bearerAuth} = options ?? {}

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

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

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