import type { Config, Plugin } from 'payload'

import type { IpalOptions } from './types.js'

import { buildCookieSettings } from './globals/CookieSettings/index.js'
import { buildNotifications } from './globals/Notifications/index.js'
import { buildSiteIntegrations } from './globals/SiteIntegrations/index.js'
import { buildSiteSettings } from './globals/SiteSettings/index.js'
import { injectRoles } from './modules/access/index.js'
import { buildArchiveFields } from './modules/content/index.js'
import { testEmailEndpoint } from './modules/email/test/testEmailEndpoint.js'
import { buildFormsPlugin } from './modules/forms/formsPluginConfig.js'
import { buildLocalizationConfig, validateI18nConfig } from './modules/i18n/index.js'
import { buildSystemPagesFields } from './modules/pages/index.js'
import { buildSeoPlugin, injectAutoFillMeta, injectSeoTabs } from './modules/seo/index.js'

/**
 * IPAL (Intecion Payload Advanced Library) plugin for Payload CMS 3.
 *
 * @example
 * ```ts
 * import { ipalKit } from 'ipal-kit'
 *
 * export default buildConfig({
 *   plugins: [
 *     ipalKit({
 *       i18n: {
 *         locales: [
 *           { code: 'pl', label: 'Polski' },
 *           { code: 'en', label: 'English' },
 *         ],
 *         defaultLocale: 'pl',
 *       },
 *       access: { authCollection: 'users' },
 *     }),
 *   ],
 * })
 * ```
 */
export const ipalKit = (options: IpalOptions): Plugin => {
  // Validate eagerly — fail fast before Payload boots
  validateI18nConfig(options.i18n)

  return async (incomingConfig: Config): Promise<Config> => {
    // Early return when disabled — schema stays, behavior off
    if (options.enabled === false) {
      return incomingConfig
    }

    let config = { ...incomingConfig }

    // --- i18n ---
    config.localization = buildLocalizationConfig(options.i18n)

    // --- access: inject roles into the client's auth collection ---
    if (options.access) {
      config = injectRoles(config, options.access)
    }

    // --- seo: apply @payloadcms/plugin-seo directly ---
    // NOTE: apply the plugin function to the config immediately rather than
    // pushing it onto config.plugins. Payload has already iterated the plugins
    // array by the time IPAL runs, so nested plugins added to that list are
    // never executed. Calling the plugin as (config) => config applies its
    // transform now.
    if (options.seo) {
      config = await buildSeoPlugin({ seo: options.seo })(config)
      // Auto-fill empty meta from document content on save
      config = injectAutoFillMeta(config, options.seo)
      // Wrap fields into Content + SEO tabs (replaces plugin-seo's tabbedUI,
      // which breaks when other fields already exist in the collection)
      config = injectSeoTabs(config, options.seo)
    }

    // --- forms: apply @payloadcms/plugin-form-builder directly ---
    if (options.forms) {
      config = await buildFormsPlugin(options.forms)(config)
    }

    // --- globals ---
    // The System Pages tab collects every "which page plays this role"
    // assignment. Composing it here keeps SiteSettings unaware of which modules
    // are enabled — it just renders the fields it's given.
    const systemPageFields = [
      ...(options.pages ? buildSystemPagesFields(options.pages) : []),
      ...(options.content && options.pages
        ? buildArchiveFields(options.content, options.pages.slug)
        : []),
    ]

    config.globals = [
      ...(config.globals ?? []),
      buildSiteSettings({
        additionalFields: options.siteSettingsFields,
        systemPageFields,
      }),
      buildSiteIntegrations({ additionalFields: options.integrationsFields }),
      buildCookieSettings(),
      buildNotifications(),
    ]

    // --- endpoints ---
    // Test-email endpoint (admin-only): POST /api/ipal/test-email sends a probe
    // message through the currently selected transport, so the panel's "send
    // test" button can confirm delivery without leaving the admin UI.
    config.endpoints = [...(config.endpoints ?? []), testEmailEndpoint]

    // --- hooks: onInit ---
    const incomingOnInit = config.onInit
    config.onInit = async (payload) => {
      if (incomingOnInit) {
        await incomingOnInit(payload)
      }
      payload.logger.info('[ipal] Plugin initialized.')
    }

    return config
  }
}