import { join, relative, isAbsolute } from 'path';
import { winPath } from 'umi-utils';
import { cloneDeep } from 'lodash';

let targetLevel = null;
let level = 0;

export default (routes, service) => {
  if (process.env.CODE_SPLITTING_LEVEL) {
    targetLevel = process.env.CODE_SPLITTING_LEVEL;
  } else {
    targetLevel = 1;
    const routesHaveChild = routes.filter(route => route.routes && route.routes.length);
    if (routesHaveChild.length) {
      targetLevel = 2;
    }
  }

  const { applyPlugins, paths } = service;
  const clonedRoutes = cloneDeep(routes);
  patchRoutes(clonedRoutes);

  return JSON.stringify(
    clonedRoutes,
    (key, value) => {
      switch (key) {
        case 'component': {
          if (value.startsWith('() =>')) {
            return value;
          }

          const [component, webpackChunkName] = value.split('^^');
          const importPath = isAbsolute(component)
            ? component
            : winPath(relative(paths.tmpDirPath, component));

          let ret = `require('${importPath}').default`;
          if (applyPlugins) {
            ret = applyPlugins.call(service, 'modifyRouteComponent', {
              initialValue: ret,
              args: {
                importPath,
                webpackChunkName,
                component,
              },
            });
          }

          return ret;
        }
        case 'Routes':
          return `[${value
            .map(
              v =>
                `require('${winPath(
                  precedingDot(relative(paths.absTmpDirPath, join(paths.cwd, v))),
                )}').default`,
            )
            .join(', ')}]`;
        default:
          return value;
      }
    },
    2,
  );
};

function patchRoutes(routes, webpackChunkName) {
  level += 1;
  routes.forEach(route => {
    patchRoute(route, webpackChunkName);
  });
  level -= 1;
}

function precedingDot(p) {
  return p.startsWith('.') ? p : `./${p}`;
}

export function normalizeEntry(entry) {
  return entry
    .replace(/^.(\/|\\)/, '')
    .replace(/(\/|\\)/g, '__')
    .replace(/\.jsx?$/, '')
    .replace(/\.tsx?$/, '');
}

function patchRoute(route, webpackChunkName) {
  if (route.component && !route.component.startsWith('() =>')) {
    if (!webpackChunkName || level <= targetLevel) {
      webpackChunkName = normalizeEntry(route.component || 'common_component')
        .replace(/^src__/, '')
        .replace(/^pages__/, 'p__')
        .replace(/^page__/, 'p__')
        .replace(/\$/g, '_');
    }
    route.component = [route.component || 'common_component', webpackChunkName, route.path].join(
      '^^',
    );
  }
  if (route.routes) {
    // 只在一级路由做按需编译
    patchRoutes(route.routes, webpackChunkName);
  }
}