/**
 * @file Tests for the read-only MCP server (`mcp/server.js`): spawns it as a
 * child over stdio against a fake in-test dashboard API and drives the real
 * JSON-RPC exchange — initialize, tools/list, tools/call — plus the error
 * paths: a route the dashboard lacks (404, or the production SPA page), an API
 * error, an unreachable dashboard, unknown tools/methods and bad JSON.
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */

const { describe, it, before, after } = require("node:test");
const assert = require("node:assert/strict");
const http = require("node:http");
const path = require("node:path");
const readline = require("node:readline");
const { spawn } = require("node:child_process");

const SERVER = path.resolve(__dirname, "..", "..", "mcp", "server.js");

let api;
let apiUrl;
const seen = [];

/** Start the MCP server against `url`; returns `rpc(msg)` and `close()`. */
function startMcp(url) {
  const child = spawn(process.execPath, [SERVER], {
    env: { ...process.env, AGENTHUB_URL: url, DASHBOARD_TOKEN: "tok" },
    stdio: ["pipe", "pipe", "inherit"],
  });
  const waiting = new Map();
  const unsolicited = [];
  readline.createInterface({ input: child.stdout }).on("line", (line) => {
    const msg = JSON.parse(line);
    const w = waiting.get(msg.id);
    if (w) {
      waiting.delete(msg.id);
      w(msg);
    } else unsolicited.push(msg);
  });
  let next = 1;
  return {
    unsolicited,
    rpc(method, params) {
      const id = next++;
      child.stdin.write(JSON.stringify({ jsonrpc: "2.0", id, method, params }) + "\n");
      return new Promise((resolve) => waiting.set(id, resolve));
    },
    raw(line) {
      child.stdin.write(line + "\n");
    },
    close() {
      child.stdin.end();
      return new Promise((resolve) => child.on("exit", resolve));
    },
  };
}

const text = (res) => res.result.content[0].text;

describe("mcp/server.js", () => {
  let mcp;

  before(async () => {
    api = http.createServer((req, res) => {
      seen.push({ url: req.url, auth: req.headers.authorization });
      const send = (status, body, type = "application/json") => {
        res.writeHead(status, { "Content-Type": type });
        res.end(typeof body === "string" ? body : JSON.stringify(body));
      };
      const p = req.url.split("?")[0];
      if (p === "/api/stats") return send(200, { total_sessions: 3 });
      if (p === "/api/sessions/s%2F1") return send(200, { session: { id: "s/1" } });
      if (p === "/api/sessions/gone") {
        return send(404, { error: { code: "NOT_FOUND", message: "Session not found" } });
      }
      if (p === "/api/pricing/cost") return send(200, { total_cost: 1.5, daily_costs: [] });
      if (p === "/api/analytics") return send(500, { error: { message: "boom" } });
      if (p === "/api/lanes") return send(200, "<!doctype html><html></html>", "text/html");
      return send(404, "Cannot GET " + p, "text/html");
    });
    await new Promise((r) => api.listen(0, "127.0.0.1", r));
    apiUrl = `http://127.0.0.1:${api.address().port}`;
    mcp = startMcp(apiUrl);
  });

  after(async () => {
    await mcp.close();
    api.close();
  });

  it("initializes, echoing a supported protocol version", async () => {
    const res = await mcp.rpc("initialize", {
      protocolVersion: "2025-03-26",
      capabilities: {},
      clientInfo: { name: "test", version: "0" },
    });
    assert.equal(res.result.protocolVersion, "2025-03-26");
    assert.deepEqual(res.result.capabilities, { tools: {} });
    assert.equal(res.result.serverInfo.name, "agenthub");
    // A notification gets no answer.
    mcp.raw(JSON.stringify({ jsonrpc: "2.0", method: "notifications/initialized" }));
    const unknownVersion = await mcp.rpc("initialize", { protocolVersion: "1999-01-01" });
    assert.match(unknownVersion.result.protocolVersion, /^\d{4}-\d{2}-\d{2}$/);
    assert.notEqual(unknownVersion.result.protocolVersion, "1999-01-01");
  });

  it("lists ~15 read-only tools with object schemas", async () => {
    const res = await mcp.rpc("tools/list", {});
    const names = res.result.tools.map((t) => t.name);
    for (const n of [
      "get_stats",
      "get_total_cost",
      "get_session_cost",
      "list_sessions",
      "get_session",
      "get_session_stats",
      "get_analytics",
      "get_workflows",
      "list_alerts",
      "list_lanes",
      "get_lane_cost",
      "list_pricing",
      "get_health",
      "get_info",
      "get_budget_status",
    ]) {
      assert.ok(names.includes(n), n);
    }
    for (const t of res.result.tools) {
      assert.equal(t.inputSchema.type, "object");
      assert.equal(t.annotations.readOnlyHint, true);
    }
  });

  it("calls a tool: pretty JSON text, bearer token, query passed through", async () => {
    seen.length = 0;
    const res = await mcp.rpc("tools/call", {
      name: "get_total_cost",
      arguments: { tz_offset: -420, lane: 7, tool: "codex" },
    });
    assert.equal(res.result.isError, undefined);
    assert.deepEqual(JSON.parse(text(res)), { total_cost: 1.5, daily_costs: [] });
    assert.equal(seen[0].url, "/api/pricing/cost?tz_offset=-420&lane=7&tool=codex");
    assert.equal(seen[0].auth, "Bearer tok");
  });

  it("defaults tz_offset to this machine's and encodes path ids", async () => {
    seen.length = 0;
    await mcp.rpc("tools/call", { name: "get_stats", arguments: {} });
    assert.equal(seen[0].url, `/api/stats?tz_offset=${new Date().getTimezoneOffset()}`);
    const res = await mcp.rpc("tools/call", {
      name: "get_session",
      arguments: { session_id: "s/1" },
    });
    assert.equal(JSON.parse(text(res)).session.id, "s/1");
    assert.equal(seen[1].url, "/api/sessions/s%2F1?events=0");
  });

  it("reports a missing route as not available (404 and SPA page)", async () => {
    const budgets = await mcp.rpc("tools/call", { name: "get_budget_status", arguments: {} });
    assert.equal(budgets.result.isError, true);
    assert.match(text(budgets), /Not available on this dashboard/);
    const spa = await mcp.rpc("tools/call", { name: "list_lanes", arguments: {} });
    assert.match(text(spa), /Not available on this dashboard/);
  });

  it("returns API errors and bad calls as isError results", async () => {
    const notFound = await mcp.rpc("tools/call", {
      name: "get_session_stats",
      arguments: { session_id: "gone" },
    });
    // JSON 404 from a real route is the API's own answer, not a missing route.
    const gone = await mcp.rpc("tools/call", {
      name: "get_session",
      arguments: { session_id: "gone" },
    });
    assert.match(text(gone), /HTTP 404: Session not found/);
    assert.equal(notFound.result.isError, true);
    const boom = await mcp.rpc("tools/call", { name: "get_analytics", arguments: {} });
    assert.equal(boom.result.isError, true);
    assert.match(text(boom), /HTTP 500: boom/);
    const missing = await mcp.rpc("tools/call", { name: "get_session_cost", arguments: {} });
    assert.match(text(missing), /Missing required argument\(s\): session_id/);
    const unknown = await mcp.rpc("tools/call", { name: "drop_tables", arguments: {} });
    assert.match(text(unknown), /Unknown tool/);
  });

  it("answers unknown methods and bad JSON with JSON-RPC errors", async () => {
    const res = await mcp.rpc("resources/list", {});
    assert.equal(res.error.code, -32601);
    const before = mcp.unsolicited.length;
    mcp.raw("{not json");
    await mcp.rpc("ping", {}); // ordering barrier
    assert.equal(mcp.unsolicited[before].error.code, -32700);
  });

  it("says so when the dashboard is down", async () => {
    const dead = http.createServer();
    await new Promise((r) => dead.listen(0, "127.0.0.1", r));
    const port = dead.address().port;
    await new Promise((r) => dead.close(r));
    const down = startMcp(`http://127.0.0.1:${port}`);
    const res = await down.rpc("tools/call", { name: "get_health", arguments: {} });
    assert.equal(res.result.isError, true);
    assert.match(text(res), /not reachable/);
    await down.close();
  });
});