import { createRouter, createWebHistory, type RouteLocationNormalized, type RouterHistory } from 'vue-router'
import { controllerIdFromParams } from './controllerRoutes'
import { activateStyles } from './pluginAssets'
import { runtime } from './runtime'
import { currentUser } from '../state/useAuth'
import { homePath } from '../state/useNavigation'
import LoginView from '../views/LoginView.vue'
import ListView from '../views/ListView.vue'
import FormView from '../views/FormView.vue'
import PreviewView from '../views/PreviewView.vue'
import ReorderView from '../views/ReorderView.vue'
import SettingsFormView from '../views/SettingsFormView.vue'
import SettingsIndexView from '../views/SettingsIndexView.vue'
import AccountView from '../views/AccountView.vue'
import NotFoundView from '../views/NotFoundView.vue'

declare module 'vue-router' {
  interface RouteMeta {
    /** Reachable without a session. */
    public?: boolean
    /** Rendered inside the navigation shell. */
    shell?: boolean
  }
}

/**
 * Accepts a post-login redirect only when it is an in-app path: it must start
 * with exactly one slash, which rejects absolute and protocol-relative URLs.
 */
export function safeRedirect(value: unknown): string | null {
  if (typeof value !== 'string' || value.length === 0) {
    return null
  }
  if (!value.startsWith('/') || value.startsWith('//') || value.startsWith('/\\')) {
    return null
  }
  return value
}

const CONTROLLER_ROUTES = new Set(['list', 'create', 'record', 'preview', 'reorder'])

/**
 * The controller a route shows, or '' for every other screen (settings,
 * login, not found). Plugin stylesheets follow it (D-16, T-10.1-16).
 */
export function routeControllerId(route: RouteLocationNormalized): string {
  if (typeof route.name !== 'string' || !CONTROLLER_ROUTES.has(route.name)) {
    return ''
  }
  const { vendor, plugin, controller } = route.params
  if (typeof vendor !== 'string' || typeof plugin !== 'string' || typeof controller !== 'string') {
    return ''
  }
  return controllerIdFromParams({ vendor, plugin, controller })
}

export function createAdminRouter(history: RouterHistory = createWebHistory(runtime.base)) {
  const router = createRouter({
    history,
    routes: [
      { path: '/login', name: 'login', component: LoginView, meta: { public: true } },
      {
        path: '/',
        name: 'home',
        component: NotFoundView,
        props: { home: true },
        meta: { shell: true },
        beforeEnter: () => homePath() ?? true,
      },
      { path: '/settings', name: 'settings', component: SettingsIndexView, meta: { shell: true } },
      { path: '/settings/:code', name: 'settings-form', component: SettingsFormView, meta: { shell: true } },
      // My account: the signed-in admin's own profile and password.
      { path: '/account', name: 'account', component: AccountView, meta: { shell: true } },
      { path: '/:vendor/:plugin/:controller', name: 'list', component: ListView, meta: { shell: true } },
      { path: '/:vendor/:plugin/:controller/create', name: 'create', component: FormView, meta: { shell: true } },
      // The tree reorder page of a list with config_reorder.yaml (D-09).
      { path: '/:vendor/:plugin/:controller/reorder', name: 'reorder', component: ReorderView, meta: { shell: true } },
      { path: '/:vendor/:plugin/:controller/:id(\\d+)', name: 'record', component: FormView, meta: { shell: true } },
      // The read-only record screen of a form with a preview block (D-11).
      {
        path: '/:vendor/:plugin/:controller/:id(\\d+)/preview',
        name: 'preview',
        component: PreviewView,
        meta: { shell: true },
      },
      { path: '/:pathMatch(.*)*', name: 'not-found', component: NotFoundView, meta: { shell: true } },
    ],
  })
  router.beforeEach((to) => {
    const signedIn = currentUser.value !== null
    if (to.meta.public) {
      if (signedIn && to.name === 'login') {
        return safeRedirect(to.query.redirect) ?? '/'
      }
      return true
    }
    if (!signedIn) {
      return { name: 'login', query: { redirect: to.fullPath } }
    }
    return true
  })
  // Plugin CSS is global: enable only the links of the controller on screen,
  // and none on any other screen (D-16, T-10.1-16).
  router.afterEach((to, _from, failure) => {
    if (!failure) {
      activateStyles(routeControllerId(to))
    }
  })
  return router
}