import {z} from 'zod'

export type GetApiFlagsDefinitionsArgs = {token?: string | undefined, project_id: number};

export type GetApiFlagsDefinitionsOptions = {baseUrl?: string | undefined, ProjectSecret?: {username: string, password: string} | undefined, fetch?: typeof fetch | undefined};

export const variant = z.object({key: z.string(), value: z.union([z.string(), z.number(), z.boolean(), z.object({})]), is_control: z.boolean(), is_sticky: z.boolean().optional(), split: z.number()});

export const variantOverride = z.object({key: z.string().optional()});

export const rollout = z.object({rollout_percentage: z.number(), cohort_hash: z.string().optional(), runtime_evaluation_rule: z.record(z.string(), z.unknown()).optional(), runtime_evaluation_definition: z.record(z.string(), z.unknown()).optional(), variant_splits: z.record(z.string(), z.number()).optional(), variant_override: variantOverride.optional()});

export const testUsers = z.object({users: z.record(z.string(), z.string()).optional()});

export const ruleSet = z.object({variants: z.array(variant), rollout: z.array(rollout), test: testUsers.optional()});

export const experimentationFlagMetadata = z.object({id: z.string(), name: z.string(), key: z.string(), status: z.enum(["enabled", "disabled", "archived"]), project_id: z.number().int(), workspace_id: z.number().int(), ruleset: ruleSet, context: z.string(), experiment_id: z.string().optional(), is_experiment_active: z.boolean().optional()});

export const flagDefinitionsResponse = z.object({flags: z.array(experimentationFlagMetadata)});

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 Feature Flag Definitions
 * 
 * GET /flags/definitions
 * 
 * Also accepts auth: ServiceAccount
 */
export const getApiFlagsDefinitions = async (args: GetApiFlagsDefinitionsArgs, options?: GetApiFlagsDefinitionsOptions) => {
const {baseUrl = "https://mixpanel.com/api/query", fetch: fetchFn = fetch, ProjectSecret} = options ?? {}

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

if (args.token != null) query.append("token", String(args.token))
if (ProjectSecret !== undefined) headers.set('authorization', `Basic ${btoa(`${ProjectSecret.username}:${ProjectSecret.password}`)}`)

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