import { defineConfig, type Plugin } from "vite";
import react from "@vitejs/plugin-react";
import { readFileSync } from "node:fs";
import { resolve, sep } from "node:path";

/**
 * 开发期源码服务：GET /__source?root=&file=&start=&end=
 * 按报告里的 location 从磁盘读取真实源码片段，实现「报告 → 代码库」绑定。
 * 仅用于本地开发；做了基本的路径穿越防护（结果路径必须落在 root 内）。
 */
function sourceServer(): Plugin {
  return {
    name: "code-visualize-source-server",
    configureServer(server) {
      server.middlewares.use("/__source", (req, res) => {
        try {
          const url = new URL(req.url ?? "", "http://localhost");
          const root = url.searchParams.get("root") ?? "";
          const file = url.searchParams.get("file") ?? "";
          const start = Number(url.searchParams.get("start") ?? "1");
          const end = Number(url.searchParams.get("end") ?? String(start));

          if (!root || !file) {
            res.statusCode = 400;
            res.end("missing root/file");
            return;
          }

          const rootResolved = resolve(root);
          const target = resolve(rootResolved, file);
          if (target !== rootResolved && !target.startsWith(rootResolved + sep)) {
            res.statusCode = 403;
            res.end("path escapes root");
            return;
          }

          const content = readFileSync(target, "utf-8");
          const allLines = content.split(/\r?\n/);
          const from = Math.max(1, start);
          const to = Math.min(allLines.length, Math.max(from, end));
          const code = allLines.slice(from - 1, to).join("\n");

          res.setHeader("Content-Type", "application/json; charset=utf-8");
          res.end(JSON.stringify({ file, startLine: from, endLine: to, code }));
        } catch (e) {
          res.statusCode = 404;
          res.end(e instanceof Error ? e.message : "read error");
        }
      });
    },
  };
}

export default defineConfig({
  plugins: [react(), sourceServer()],
  server: {
    port: 5300,
    open: true,
  },
});