import type { Where } from 'payload/types'
import type { ParsedQs } from 'qs'

import QueryString from 'qs'

import type { SanitizedConfig } from '../../packages/payload/src/config/types'

import { GRAPHQL_POST as createGraphqlPOST } from '../../packages/next/src/routes/graphql'
import {
  DELETE as createDELETE,
  GET as createGET,
  PATCH as createPATCH,
  POST as createPOST,
} from '../../packages/next/src/routes/rest'
import { devUser } from '../credentials'

type ValidPath = `/${string}`
type RequestOptions = {
  auth?: boolean
  file?: boolean
  query?: {
    depth?: number
    fallbackLocale?: string
    limit?: number
    locale?: string
    page?: number
    sort?: string
    where?: Where
  }
}

function generateQueryString(query: RequestOptions['query'], params: ParsedQs): string {
  return QueryString.stringify(
    {
      ...(params || {}),
      ...(query || {}),
    },
    {
      addQueryPrefix: true,
    },
  )
}

export class NextRESTClient {
  private _DELETE: (request: Request, args: { params: { slug: string[] } }) => Promise<Response>

  private _GET: (request: Request, args: { params: { slug: string[] } }) => Promise<Response>

  private _GRAPHQL_POST: (request: Request) => Promise<Response>

  private _PATCH: (request: Request, args: { params: { slug: string[] } }) => Promise<Response>

  private _POST: (request: Request, args: { params: { slug: string[] } }) => Promise<Response>

  private readonly config: SanitizedConfig

  private token: string

  serverURL: string = 'http://localhost:3000'

  constructor(config: SanitizedConfig) {
    this.config = config
    if (config?.serverURL) this.serverURL = config.serverURL
    this._GET = createGET(config)
    this._POST = createPOST(config)
    this._DELETE = createDELETE(config)
    this._PATCH = createPATCH(config)
    this._GRAPHQL_POST = createGraphqlPOST(config)
  }

  private buildHeaders(options: RequestInit & RequestOptions): Headers {
    const defaultHeaders = {
      'Content-Type': 'application/json',
    }
    const headers = new Headers({
      ...(options?.file ? {} : defaultHeaders),
      ...(options?.headers || {}),
    })

    if (options.auth !== false && this.token) {
      headers.set('Authorization', `JWT ${this.token}`)
    }

    return headers
  }

  private generateRequestParts(path: ValidPath): {
    params?: ParsedQs
    slug: string[]
    url: string
  } {
    const [slugs, params] = path.slice(1).split('?')
    const url = `${this.serverURL}${this.config.routes.api}/${slugs}`

    return {
      url,
      slug: slugs.split('/'),
      params: params ? QueryString.parse(params) : undefined,
    }
  }

  async DELETE(path: ValidPath, options: RequestInit & RequestOptions = {}): Promise<Response> {
    const { url, slug, params } = this.generateRequestParts(path)
    const { query, ...rest } = options || {}
    const queryParams = generateQueryString(query, params)

    const request = new Request(`${url}${queryParams}`, {
      ...rest,
      method: 'DELETE',
      headers: this.buildHeaders(options),
    })
    return this._DELETE(request, { params: { slug } })
  }

  async GET(
    path: ValidPath,
    options: Omit<RequestInit, 'body'> & RequestOptions = {},
  ): Promise<Response> {
    const { url, slug, params } = this.generateRequestParts(path)
    const { query, ...rest } = options || {}
    const queryParams = generateQueryString(query, params)

    const request = new Request(`${url}${queryParams}`, {
      ...rest,
      method: 'GET',
      headers: this.buildHeaders(options),
    })
    return this._GET(request, { params: { slug } })
  }

  async GRAPHQL_POST(options: RequestInit & RequestOptions): Promise<Response> {
    const { query, ...rest } = options
    const queryParams = generateQueryString(query, {})
    const request = new Request(
      `${this.serverURL}${this.config.routes.api}${this.config.routes.graphQL}${queryParams}`,
      {
        ...rest,
        method: 'POST',
        headers: this.buildHeaders(options),
      },
    )
    return this._GRAPHQL_POST(request)
  }

  async PATCH(path: ValidPath, options: RequestInit & RequestOptions): Promise<Response> {
    const { url, slug, params } = this.generateRequestParts(path)
    const { query, ...rest } = options
    const queryParams = generateQueryString(query, params)

    const request = new Request(`${url}${queryParams}`, {
      ...rest,
      method: 'PATCH',
      headers: this.buildHeaders(options),
    })
    return this._PATCH(request, { params: { slug } })
  }

  async POST(path: ValidPath, options: RequestInit & { file?: boolean } = {}): Promise<Response> {
    const { url, slug, params } = this.generateRequestParts(path)
    const queryParams = generateQueryString({}, params)

    const request = new Request(`${url}${queryParams}`, {
      ...options,
      method: 'POST',
      headers: this.buildHeaders(options),
    })
    return this._POST(request, { params: { slug } })
  }

  async login({
    slug,
    credentials,
  }: {
    credentials?: {
      email: string
      password: string
    }
    slug: string
  }): Promise<string> {
    this.token = await this.POST(`/${slug}/login`, {
      body: JSON.stringify(
        credentials ? { ...credentials } : { email: devUser.email, password: devUser.password },
      ),
    })
      .then((res) => res.json())
      .then((data) => data.token)

    return this.token
  }
}