import { transformSync } from '@babel/core';
import path from 'path';
import { Context } from 'koa';
import { Plugin } from '@web/dev-server-core';
import * as BabelTypes from '@babel/types';
import { NodePath } from '@babel/traverse';
import { cwkState } from '../utils/CwkStateSingleton';

interface PluginOptions {
  opts: {
    url: string;
  };
}

export function queryTimestampModulesPlugin(dir: string): Plugin {
  return {
    name: 'query-timestamp-modules',
    transform(context: Context) {
      let rewrittenBody = context.body as string;

      if (
        context.status === 200 &&
        context.response.is('js') &&
        cwkState.state.queryTimestamps &&
        context.cookies.get('participant_name')
      ) {
        // Get participant name from browser path
        const normalizedPath = context.path.endsWith('/')
          ? `${context.path}index.html`
          : context.path;
        const participantName = path.basename(path.dirname(decodeURI(normalizedPath)));
        const timestamp = cwkState.state.queryTimestamps[participantName];

        if (timestamp) {
          try {
            rewrittenBody =
              transformSync(rewrittenBody, {
                plugins: [
                  [
                    ({ types: t }) => ({
                      visitor: {
                        ImportDeclaration(
                          astPath: NodePath<BabelTypes.ImportDeclaration>,
                          state: PluginOptions,
                        ) {
                          if (
                            astPath.node.source.value.startsWith('.') ||
                            astPath.node.source.value.startsWith('/')
                          ) {
                            const participantFolderRelativeToServer = `${dir}/participants`.split(
                              process.cwd(),
                            )[1];

                            const importAbsoluteToServer = path.resolve(
                              state.opts.url,
                              '../',
                              astPath.node.source.value,
                            );

                            if (
                              importAbsoluteToServer.startsWith(participantFolderRelativeToServer)
                            ) {
                              // eslint-disable-next-line no-param-reassign
                              astPath.node.source = t.stringLiteral(
                                `${astPath.node.source.value}?mtime=${timestamp}`,
                              );
                            }
                          }
                        },
                      },
                    }),
                    { url: decodeURI(context.url) },
                  ],
                ],
              })?.code || rewrittenBody;
          } catch (e) {
            // WDS will already throw this error to the browser because it also tries to do babel parsing on it
          }
        }
      }

      return { body: rewrittenBody, transformCache: false };
    },
  };
}