import { deprecate } from 'umi-utils';
import { remove } from 'lodash';

let redirects;

export default (routes, config = {}, isProduction, onPatchRoute) => {
  redirects = [];
  patchRoutes(routes, config, isProduction, onPatchRoute);
  if (!config.disableRedirectHoist) {
    routes.unshift(...redirects);
  }
  return routes;
};

function patchRoutes(routes, config, isProduction, onPatchRoute) {
  let notFoundIndex = null;
  let rootIndex = null;

  routes.forEach((route, index) => {
    patchRoute(route, config, isProduction, onPatchRoute);
    if (route.path === '/404') {
      notFoundIndex = index;
    }
    if (config.exportStatic && route.path === '/' && route.exact) {
      rootIndex = index;
    }
  });

  // Transform /404 to fallback route in production and exportStatic is not set
  if (notFoundIndex !== null && isProduction && !config.exportStatic) {
    const notFoundRoute = routes.slice(notFoundIndex, notFoundIndex + 1)[0];
    if (notFoundRoute.component) {
      routes.push({ component: notFoundRoute.component });
    } else if (notFoundRoute.redirect) {
      routes.push({ redirect: notFoundRoute.redirect });
    } else {
      throw new Error('Invalid route config for /404');
    }
  }

  if (rootIndex !== null) {
    routes.splice(rootIndex, 0, {
      ...routes[rootIndex],
      path: '/index.html',
    });
  }

  if (!config.disableRedirectHoist) {
    const removedRoutes = remove(routes, route => {
      return route.redirect;
    });
    redirects = redirects.concat(removedRoutes);
  }
}

function patchRoute(route, config, isProduction, onPatchRoute) {
  const isDynamicRoute = route.path && route.path.indexOf('/:') > -1;
  if (config.exportStatic && isDynamicRoute) {
    throw new Error(`you should not use exportStatic with dynamic route: ${route.path}`);
  }

  // /path -> /path.html
  if (route.path && config.exportStatic && config.exportStatic.htmlSuffix) {
    route.path = addHtmlSuffix(route.path, !!route.routes);
  }

  // 权限路由
  // TODO: use config from config.routes
  if (config.pages && config.pages[route.path] && config.pages[route.path].Route) {
    route.Route = config.pages[route.path].Route;
  }

  // Compatible the meta.Route and warn deprecated
  if (route.meta && route.meta.Route) {
    deprecate('route.meta.Route', 'use route.Route instead');
    route.Route = route.meta.Route;
    delete route.meta;
  }

  if (onPatchRoute) onPatchRoute(route);
  if (route.routes) {
    patchRoutes(route.routes, config, isProduction, onPatchRoute);
  }
}

function addHtmlSuffix(path, hasRoutes) {
  if (path === '/') return path;
  if (hasRoutes) {
    return path.endsWith('/') ? path : `${path}(.html)?`;
  } else {
    return path.endsWith('/') ? `${path.slice(0, -1)}.html` : `${path}.html`;
  }
}