import {z} from 'zod'

export type GetApiV2CoursesOptions = {baseUrl?: string | undefined, BearerAuth?: string | undefined, fetch?: typeof fetch | undefined};

export const courseEnrollmentRole = z.enum(["student", "viewer", "teacher", "collaborator"]);

export const themeColors = z.object({light: z.string(), dark: z.string()});

export const symbol = z.object({label: z.string().optional(), color: z.union([z.string(), themeColors]).optional(), icon: z.string().optional()});

export const courseModule = z.object({id: z.number().int().nullable(), shortcode: z.string(), name: z.string(), teachingPeriod: z.string(), teacherId: z.number().int().nullable(), teacherName: z.string().nullable(), isOverBooking: z.boolean(), category: z.string(), enrollmentRole: courseEnrollmentRole, year: z.string(), style: symbol.nullable()});

export const courseOverview = courseModule;

export const getApiV2CoursesResponse = z.object({data: z.array(courseOverview)});

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 courses | Elenca corsi
 * 
 * GET /v2/courses
 */
export const getApiV2Courses = async (options?: GetApiV2CoursesOptions) => {
const {baseUrl = "https://app.didattica.polito.it/api", fetch: fetchFn = fetch, BearerAuth} = options ?? {}

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

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

const url = `${baseUrl.replace(/\/+$/, '')}/v2/courses${query.size > 0 ? `?${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(getApiV2CoursesResponse, await res.json())
};