import path from 'node:path';
import { init, parse } from 'es-module-lexer';
import MagicString from 'magic-string';
import { BARE_IMPORT_RE, CLIENT_PUBLIC_PATH, PRE_BUNDLE_DIR } from '../constants';
import { cleanUrl, getShortName, isInternalRequest, isJSRequest } from '../utils';
import type { Plugin } from '../plugin';
import type { ServerContext } from '../server/index';

export function importAnalysisPlugin(): Plugin {
  let serverContext: ServerContext;
  return {
    name: 'ranite:import-analysis',
    configureServer(s) {
      serverContext = s;
    },
    async transform(code: string, id: string) {
      if (!isJSRequest(id) || isInternalRequest(id)) {
        return null;
      }
      await init;
      const importedModules = new Set<string>();
      const [imports] = parse(code);
      const ms = new MagicString(code);
      const { moduleGraph } = serverContext;
      const curMod = moduleGraph.getModuleById(id)!;
      const resolve = async (id: string, importer?: string) => {
        const resolved = await serverContext.pluginContainer.resolveId(id, importer);
        if (!resolved) {
          return;
        }
        const cleanedId = cleanUrl(resolved.id);
        const mod = moduleGraph.getModuleById(cleanedId);
        const resolvedId = `/${getShortName(resolved.id, serverContext.root)}`;
        if (mod && mod.lastHMRTimestamp > 0) {
          // resolvedId += "?t=" + mod.lastHMRTimestamp;
        }
        return resolvedId;
      };

      for (const importInfo of imports) {
        const { s: modStart, e: modEnd, n: modSource } = importInfo;
        if (!modSource || isInternalRequest(modSource)) continue;
        // 静态资源
        if (modSource.endsWith('.svg')) {
          // 加上 ?import 后缀
          const resolvedUrl = path.join(path.dirname(id), modSource);
          ms.overwrite(modStart, modEnd, `${resolvedUrl}?import`);
          continue;
        }
        // 第三方库: 路径重写到预构建产物的路径
        if (BARE_IMPORT_RE.test(modSource)) {
          const bundlePath = path.join(serverContext.root, PRE_BUNDLE_DIR, `${modSource}.js`);
          ms.overwrite(modStart, modEnd, bundlePath);
          importedModules.add(bundlePath);
        } else if (modSource.startsWith('.') || modSource.startsWith('/')) {
          const resolved = await resolve(modSource, id);
          if (resolved) {
            ms.overwrite(modStart, modEnd, resolved);
            importedModules.add(resolved);
          }
        }
      }
      // 只对业务源码注入
      if (!id.includes('node_modules')) {
        // 注入 HMR 相关的工具函数
        ms.prepend(
          `import { createHotContext as __ranite__createHotContext } from "${CLIENT_PUBLIC_PATH}";` +
            `import.meta.hot = __ranite__createHotContext(${JSON.stringify(cleanUrl(curMod.url))});`,
        );
      }

      moduleGraph.updateModuleInfo(curMod, importedModules);

      return {
        code: ms.toString(),
        map: ms.generateMap(),
      };
    },
  };
}