import fs from "node:fs/promises";
import { createRequire } from "node:module";
import path from "node:path";

const require = createRequire(import.meta.url);
const SDK_SERVER_MCP_PATH = require.resolve("@modelcontextprotocol/sdk/server/mcp.js");
const SDK_SERVER_STDIO_PATH = require.resolve("@modelcontextprotocol/sdk/server/stdio.js");
const SDK_CLIENT_INDEX_PATH = require.resolve("@modelcontextprotocol/sdk/client/index.js");
const SDK_CLIENT_STDIO_PATH = require.resolve("@modelcontextprotocol/sdk/client/stdio.js");

export async function writeExecutable(filePath: string, content: string): Promise<void> {
  await fs.mkdir(path.dirname(filePath), { recursive: true });
  await fs.writeFile(filePath, content, { encoding: "utf-8", mode: 0o755 });
}

export async function writeBundleProbeMcpServer(filePath: string): Promise<void> {
  await writeExecutable(
    filePath,
    `#!/usr/bin/env node
import { McpServer } from ${JSON.stringify(SDK_SERVER_MCP_PATH)};
import { StdioServerTransport } from ${JSON.stringify(SDK_SERVER_STDIO_PATH)};

const server = new McpServer({ name: "bundle-probe", version: "1.0.0" });
server.tool("bundle_probe", "Bundle MCP probe", async () => {
  return {
    content: [{ type: "text", text: process.env.BUNDLE_PROBE_TEXT ?? "missing-probe-text" }],
  };
});

await server.connect(new StdioServerTransport());
`,
  );
}

export async function writeClaudeBundle(params: {
  pluginRoot: string;
  serverScriptPath: string;
}): Promise<void> {
  await fs.mkdir(path.join(params.pluginRoot, ".claude-plugin"), { recursive: true });
  await fs.writeFile(
    path.join(params.pluginRoot, ".claude-plugin", "plugin.json"),
    `${JSON.stringify({ name: "bundle-probe" }, null, 2)}\n`,
    "utf-8",
  );
  await fs.writeFile(
    path.join(params.pluginRoot, ".mcp.json"),
    `${JSON.stringify(
      {
        mcpServers: {
          bundleProbe: {
            command: "node",
            args: [path.relative(params.pluginRoot, params.serverScriptPath)],
            env: {
              BUNDLE_PROBE_TEXT: "FROM-BUNDLE",
            },
          },
        },
      },
      null,
      2,
    )}\n`,
    "utf-8",
  );
}

export async function writeFakeClaudeCli(filePath: string): Promise<void> {
  await writeExecutable(
    filePath,
    `#!/usr/bin/env node
import fs from "node:fs/promises";
import { randomUUID } from "node:crypto";
import { Client } from ${JSON.stringify(SDK_CLIENT_INDEX_PATH)};
import { StdioClientTransport } from ${JSON.stringify(SDK_CLIENT_STDIO_PATH)};

function readArg(name) {
  const args = process.argv.slice(2);
  for (let i = 0; i < args.length; i += 1) {
    const arg = args[i] ?? "";
    if (arg === name) {
      return args[i + 1];
    }
    if (arg.startsWith(name + "=")) {
      return arg.slice(name.length + 1);
    }
  }
  return undefined;
}

const mcpConfigPath = readArg("--mcp-config");
if (!mcpConfigPath) {
  throw new Error("missing --mcp-config");
}

const raw = JSON.parse(await fs.readFile(mcpConfigPath, "utf-8"));
const servers = raw?.mcpServers ?? raw?.servers ?? {};
const server = servers.bundleProbe ?? Object.values(servers)[0];
if (!server || typeof server !== "object") {
  throw new Error("missing bundleProbe MCP server");
}

const transport = new StdioClientTransport({
  command: server.command,
  args: Array.isArray(server.args) ? server.args : [],
  env: server.env && typeof server.env === "object" ? server.env : undefined,
  cwd:
    typeof server.cwd === "string"
      ? server.cwd
      : typeof server.workingDirectory === "string"
        ? server.workingDirectory
        : undefined,
});
const client = new Client({ name: "fake-claude", version: "1.0.0" });
await client.connect(transport);
const tools = await client.listTools();
if (!tools.tools.some((tool) => tool.name === "bundle_probe")) {
  throw new Error("bundle_probe tool not exposed");
}
const result = await client.callTool({ name: "bundle_probe", arguments: {} });
await transport.close();

const text = Array.isArray(result.content)
  ? result.content
      .filter((entry) => entry?.type === "text" && typeof entry.text === "string")
      .map((entry) => entry.text)
      .join("\\n")
  : "";

process.stdout.write(
  JSON.stringify({
    session_id: readArg("--session-id") ?? randomUUID(),
    message: "BUNDLE MCP OK " + text,
  }) + "\\n",
);
`,
  );
}