import merge from 'lodash/merge'
import * as path from 'path'
import * as fs from 'fs'
import i18n, { i18n as I18n } from 'i18next'
import { FC } from 'react'

import { AdminJSOptionsWithDefault, AdminJSOptions } from './adminjs-options.interface'
import BaseResource from './backend/adapters/resource/base-resource'
import BaseDatabase from './backend/adapters/database/base-database'
import ConfigurationError from './backend/utils/errors/configuration-error'
import ResourcesFactory from './backend/utils/resources-factory/resources-factory'
import userComponentsBundler from './backend/bundler/user-components-bundler'
import { RecordActionResponse, Action, BulkActionResponse } from './backend/actions/action.interface'
import { DEFAULT_PATHS } from './constants'
import { ACTIONS } from './backend/actions'

import loginTemplate from './frontend/login-template'
import { ListActionResponse } from './backend/actions/list/list-action'
import { combineTranslations, Locale } from './locale/config'
import { locales } from './locale'
import { TranslateFunctions, createFunctions } from './utils/translate-functions.factory'
import { relativeFilePathResolver } from './utils/file-resolver'
import { getComponentHtml } from './backend/utils'
import { ComponentLoader } from './backend/utils/component-loader'
import { OverridableComponent } from './frontend'

const pkg = JSON.parse(fs.readFileSync(path.join(__dirname, '../package.json'), 'utf-8'))
export const VERSION = pkg.version

export const defaultOptions: AdminJSOptionsWithDefault = {
  rootPath: DEFAULT_PATHS.rootPath,
  logoutPath: DEFAULT_PATHS.logoutPath,
  loginPath: DEFAULT_PATHS.loginPath,
  databases: [],
  resources: [],
  dashboard: {},
  pages: {},
  bundler: {},
}

type ActionsMap = {
  show: Action<RecordActionResponse>;
  edit: Action<RecordActionResponse>;
  delete: Action<RecordActionResponse>;
  bulkDelete: Action<BulkActionResponse>;
  new: Action<RecordActionResponse>;
  list: Action<ListActionResponse>;
}

export type LoginOverride<T = Record<string, unknown>> = {
  component: FC<T>;
  props?: T;
}

export type Adapter = { Database: typeof BaseDatabase; Resource: typeof BaseResource }

/**
 * Main class for AdminJS extension. It takes {@link AdminJSOptions} as a
 * parameter and creates an admin instance.
 *
 * Its main responsibility is to fetch all the resources and/or databases given by a
 * user. Its instance is a currier - injected in all other classes.
 *
 * @example
 * const AdminJS = require('adminjs')
 * const admin = new AdminJS(AdminJSOptions)
 */
class AdminJS {
  public resources: Array<BaseResource>

  public options: AdminJSOptionsWithDefault

  public locale!: Locale

  public i18n!: I18n

  public translateFunctions!: TranslateFunctions

  public componentLoader: ComponentLoader

  /**
   * List of all default actions. If you want to change the behavior for all actions like:
   * _list_, _edit_, _show_, _delete_ and _bulkDelete_ you can do this here.
   *
   * @example <caption>Modifying accessibility rules for all show actions</caption>
   * const { ACTIONS } = require('adminjs')
   * ACTIONS.show.isAccessible = () => {...}
   */
  public static ACTIONS: ActionsMap

  /**
   * AdminJS version
   */
  public static VERSION: string

  /**
   * Login override
   */
  private loginOverride?: LoginOverride

  /**
   * @param   {AdminJSOptions} options      Options passed to AdminJS
   */
  constructor(options: AdminJSOptions = {}) {
    /**
     * @type {BaseResource[]}
     * @description List of all resources available for the AdminJS.
     * They can be fetched with the {@link AdminJS#findResource} method
     */
    this.resources = []

    /**
     * @type {AdminJSOptions}
     * @description Options given by a user
     */
    this.options = merge({}, defaultOptions, options)

    this.resolveBabelConfigPath()

    this.initI18n()

    const { databases, resources } = this.options

    this.componentLoader = options.componentLoader ?? new ComponentLoader()

    const resourcesFactory = new ResourcesFactory(this, global.RegisteredAdapters || [])
    this.resources = resourcesFactory.buildResources({ databases, resources })
  }

  initI18n(): void {
    const language = this.options.locale?.language || locales.en.language
    const defaultTranslations = locales[language]?.translations || locales.en.translations
    this.locale = {
      translations: combineTranslations(defaultTranslations, this.options.locale?.translations),
      language,
    }
    if (i18n.isInitialized) {
      i18n.addResourceBundle(this.locale.language, 'translation', this.locale.translations)
    } else {
      i18n.init({
        lng: this.locale.language,
        initImmediate: false, // loads translations immediately
        resources: {
          [this.locale.language]: {
            translation: this.locale.translations,
          },
        },
      })
    }

    // mixin translate functions to AdminJS instance so users will be able to
    // call AdminJS.translateMessage(...)
    this.translateFunctions = createFunctions(i18n)
    Object.getOwnPropertyNames(this.translateFunctions).forEach((translateFunctionName) => {
      this[translateFunctionName] = this.translateFunctions[translateFunctionName]
    })
  }

  /**
   * Registers various database adapters written for AdminJS.
   *
   * @example
   * const AdminJS = require('adminjs')
   * const MongooseAdapter = require('adminjs-mongoose')
   * AdminJS.registerAdapter(MongooseAdapter)
   *
   * @param  {Object}       options
   * @param  {typeof BaseDatabase} options.Database subclass of {@link BaseDatabase}
   * @param  {typeof BaseResource} options.Resource subclass of {@link BaseResource}
   */
  static registerAdapter({ Database, Resource }: {
    Database: typeof BaseDatabase;
    Resource: typeof BaseResource;
  }): void {
    if (!Database || !Resource) {
      throw new Error('Adapter has to have both Database and Resource')
    }

    // TODO: check if this is actually valid because "isAdapterFor" is always defined.
    // checking if both Database and Resource have at least isAdapterFor method
    // @ts-ignore
    if (Database.isAdapterFor && Resource.isAdapterFor) {
      global.RegisteredAdapters = global.RegisteredAdapters || []
      global.RegisteredAdapters.push({ Database, Resource })
    } else {
      throw new Error('Adapter elements have to be a subclass of AdminJS.BaseResource and AdminJS.BaseDatabase')
    }
  }

  /**
   * Initializes AdminJS instance in production. This function should be called by
   * all external plugins.
   */
  async initialize(): Promise<void> {
    if (process.env.NODE_ENV === 'production'
        && !(process.env.ADMIN_JS_SKIP_BUNDLE === 'true')) {
      // eslint-disable-next-line no-console
      console.log('AdminJS: bundling user components...')
      await userComponentsBundler(this, { write: true })
    }
  }

  /**
   * Watches for local changes in files imported via {@link ComponentLoader}.
   * It doesn't work on production environment.
   *
   * @return  {Promise<never>}
   */
  async watch(): Promise<string | undefined> {
    if (process.env.NODE_ENV !== 'production') {
      return userComponentsBundler(this, { write: true, watch: true })
    }
    return undefined
  }

  /**
   * Allows you to override the default login view by providing your React components
   * and custom props.
   *
   * @param  {Object} options
   * @param  {String} options.component       Custom React component
   * @param  {String} [options.props]         Props to be passed to React component
   * @return {Promise<void>}
   */
  overrideLogin({ component, props }: LoginOverride): void {
    this.loginOverride = { component, props: props ?? {} }
  }

  /**
   * Renders an entire login page with email and password fields
   * using {@link Renderer}.
   *
   * Used by external plugins
   *
   * @param  {Object} options
   * @param  {String} options.action          Login form action url - it could be
   *                                          '/admin/login'
   * @param  {String} [options.errorMessage]  Optional error message. When set,
   *                                          renderer will print this message in
   *                                          the form
   * @return {Promise<string>}                HTML of the rendered page
   */
  async renderLogin({ action, errorMessage }): Promise<string> {
    if (this.loginOverride) {
      const { component, props = {} } = this.loginOverride
      const mergedProps = {
        action,
        message: errorMessage,
        ...props,
      }
      return getComponentHtml(component, mergedProps, this)
    }
    return loginTemplate(this, { action, errorMessage })
  }

  /**
   * Returns resource base on its ID
   *
   * @example
   * const User = admin.findResource('users')
   * await User.findOne(userId)
   *
   * @param  {String} resourceId    ID of a resource defined under {@link BaseResource#id}
   * @return {BaseResource}         found resource
   * @throws {Error}                When resource with given id cannot be found
   */
  findResource(resourceId): BaseResource {
    const resource = this.resources.find((m) => m._decorated?.id() === resourceId)
    if (!resource) {
      throw new Error([
        `There are no resources with given id: "${resourceId}"`,
        'This is the list of all registered resources you can use:',
        this.resources.map((r) => r._decorated?.id() || r.id()).join(', '),
      ].join('\n'))
    }
    return resource
  }

  /**
   * Resolve babel config file path,
   * and load configuration to this.options.bundler.babelConfig.
   */
  resolveBabelConfigPath(): void {
    if (typeof this.options?.bundler?.babelConfig !== 'string') {
      return
    }
    let filePath = ''
    let config = this.options?.bundler?.babelConfig
    if (config[0] === '/') {
      filePath = config
    } else {
      filePath = relativeFilePathResolver(config, /new AdminJS/)
    }

    if (!fs.existsSync(filePath)) {
      throw new ConfigurationError(`Given babel config "${filePath}", doesn't exist.`, 'AdminJS.html')
    }
    if (path.extname(filePath) === '.js') {
      // eslint-disable-next-line
      const configModule = require(filePath)
      config = configModule && configModule.__esModule
        ? configModule.default || undefined
        : configModule
      if (!config || typeof config !== 'object' || Array.isArray(config)) {
        throw new Error(
          `${filePath}: Configuration should be an exported JavaScript object.`,
        )
      }
    } else {
      try {
        config = JSON.parse(fs.readFileSync(filePath, 'utf8'))
      } catch (err) {
        throw new Error(`${filePath}: Error while parsing config - ${err.message}`)
      }
      if (!config) throw new Error(`${filePath}: No config detected`)
      if (typeof config !== 'object') {
        throw new Error(`${filePath}: Config returned typeof ${typeof config}`)
      }
      if (Array.isArray(config)) {
        throw new Error(`${filePath}: Expected config object but found array`)
      }
    }
    this.options.bundler.babelConfig = config
  }

  /**
   * Requires given `.jsx/.tsx` file, that it can be bundled to the frontend.
   * It will be available under AdminJS.UserComponents[componentId].
   *
   * @param   {String}  src  Path to a file containing react component.
   *
   * @param  {OverridableComponent}  [componentName] - name of the component which you want
   *                                  to override
   * @returns {String}                componentId - uniq id of a component
   *
   * @example <caption>Passing custom components in AdminJS options</caption>
   * const adminJsOptions = {
   *   dashboard: {
   *     component: AdminJS.bundle('./path/to/component'),
   *   }
   * }
   * @example <caption>Overriding AdminJS core components</caption>
   * // somewhere in the code
   * AdminJS.bundle('./path/to/new-sidebar/component', 'SidebarFooter')
   *
   * @deprecated since version 6.5.0, use {@link ComponentLoader} instead
   */
  public static bundle(src: string, componentName?: OverridableComponent): string {
    // eslint-disable-next-line no-plusplus
    const name = componentName ?? `Component${this.__unsafe_componentIndex++}`
    this.__unsafe_staticComponentLoader.__unsafe_addWithoutChecks(name, src, 'bundle')
    return name
  }

  private static __unsafe_componentIndex = 0

  public static __unsafe_staticComponentLoader = new ComponentLoader()
}

AdminJS.VERSION = VERSION
AdminJS.ACTIONS = ACTIONS

// eslint-disable-next-line @typescript-eslint/no-empty-interface
interface AdminJS extends TranslateFunctions {}

export const { registerAdapter } = AdminJS

export default AdminJS