#!/usr/bin/env node
// SharePoint Lists MCP server.
//
// Wraps the SAME core client the skill uses (graph.mjs) and exposes it as MCP
// tools. App-only Microsoft Graph auth; credentials come from the environment
// (or an mcp-server/.env file — git-ignored).
//
// Transports:
//   stdio (default)                         — local Claude apps (Desktop/Code/Cowork)
//   Streamable HTTP (--http | MCP_TRANSPORT=http) — for hosting in a container
//
// The HTTP endpoint is guarded by a shared bearer token (MCP_AUTH_TOKEN). App-only
// auth means any caller has full access to the granted SharePoint sites, so do not
// run the HTTP transport without a token outside a trusted network.
//
// Env:
//   SP_TENANT_ID, SP_CLIENT_ID, SP_CLIENT_SECRET   (required)
//   SP_SITE_URL      optional default site so the `site` arg can be omitted
//   SP_READONLY      if "true"/"1", write tools (create/update/delete) are NOT registered
//   MCP_AUTH_TOKEN   (HTTP only) shared bearer token required on /mcp; empty = unauthenticated
//   PORT             (HTTP only) listen port, default 3838

import { readFileSync, existsSync } from "node:fs";
import { dirname, join } from "node:path";
import { fileURLToPath } from "node:url";
import { createHash, timingSafeEqual } from "node:crypto";
import { z } from "zod";
import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
import { StreamableHTTPServerTransport } from "@modelcontextprotocol/sdk/server/streamableHttp.js";
// Single source of truth — the same client the skill's CLI uses.
import { SharePointListsClient, GraphError, secretExpiryStatus } from "../.claude/skills/sharepoint-lists/scripts/lib/graph.mjs";

const __dirname = dirname(fileURLToPath(import.meta.url));
loadDotEnv();

const READONLY = /^(1|true|yes)$/i.test(process.env.SP_READONLY ?? "");

const client = new SharePointListsClient({
  tenantId: process.env.SP_TENANT_ID,
  clientId: process.env.SP_CLIENT_ID,
  clientSecret: process.env.SP_CLIENT_SECRET,
});

// Self-reported client-secret expiry (SP_SECRET_EXPIRES=YYYY-MM-DD) — warn
// loudly before auth starts failing with an opaque 401. Computed fresh on each
// use so a long-running container keeps counting down.
const secretExpiry = () => secretExpiryStatus(process.env.SP_SECRET_EXPIRES);
{
  const s = secretExpiry();
  if (s?.message) console.error(`[sharepoint-lists] ⚠ ${s.message}`);
}

// ---- helpers --------------------------------------------------------------

const ok = (data) => ({
  content: [{ type: "text", text: JSON.stringify(data, null, 2) }],
});
const fail = (err) => ({
  content: [
    {
      type: "text",
      text:
        err instanceof GraphError
          ? `Graph error (${err.status}${err.code ? " " + err.code : ""}): ${err.message}`
          : `Error: ${err.message}`,
    },
  ],
  isError: true,
});

/** Constant-time token comparison (hash first so lengths never leak / throw). */
function tokenMatches(got, expected) {
  const h = (s) => createHash("sha256").update(String(s)).digest();
  return timingSafeEqual(h(got), h(expected));
}

/** Resolve the site arg (or SP_SITE_URL default) to a Graph site id. */
async function siteId(site) {
  const s = site || process.env.SP_SITE_URL;
  if (!s) throw new Error("No `site` provided and SP_SITE_URL is not set.");
  return client.resolveSiteId(s);
}

const SITE = z
  .string()
  .optional()
  .describe(
    "SharePoint site URL, e.g. https://contoso.sharepoint.com/sites/Marketing. Omit to use the SP_SITE_URL default.",
  );
const LIST = z.string().describe("List display name, internal name, or GUID.");

// ---- server factory (a fresh instance per stdio process / per HTTP request) -

function buildServer() {
  const server = new McpServer({ name: "sharepoint-lists", version: "1.0.0" });

  server.registerTool(
    "sharepoint_test",
    {
      title: "Test SharePoint connectivity",
      description:
        "Verify app-only credentials work. With a site, also lists the lists in that site. Use this first when troubleshooting.",
      inputSchema: { site: SITE },
      annotations: { readOnlyHint: true },
    },
    async ({ site }) => {
      try {
        const result = await client.test(site || process.env.SP_SITE_URL);
        const s = secretExpiry();
        if (s) result.secretExpiry = s;
        return ok(result);
      } catch (e) {
        return fail(e);
      }
    },
  );

  server.registerTool(
    "sharepoint_list_lists",
    {
      title: "List the lists in a site",
      description: "Enumerate all SharePoint Lists in a site (name, displayName, id, webUrl).",
      inputSchema: { site: SITE },
      annotations: { readOnlyHint: true },
    },
    async ({ site }) => {
      try {
        return ok(await client.listLists(await siteId(site)));
      } catch (e) {
        return fail(e);
      }
    },
  );

  server.registerTool(
    "sharepoint_get_columns",
    {
      title: "Get a list's columns",
      description:
        "Show a list's column definitions (internal name, display name, type). Internal names differ from display names — call this before writing items.",
      inputSchema: { site: SITE, list: LIST },
      annotations: { readOnlyHint: true },
    },
    async ({ site, list }) => {
      try {
        return ok(await client.getColumns(await siteId(site), list));
      } catch (e) {
        return fail(e);
      }
    },
  );

  server.registerTool(
    "sharepoint_list_items",
    {
      title: "Query list items",
      description:
        "Query items in a list. Filter/orderby use the fields/ prefix, e.g. filter \"fields/Status eq 'Open'\", orderby \"fields/DueDate asc\". select is a comma list of internal field names. Set all=true to fetch every page.",
      inputSchema: {
        site: SITE,
        list: LIST,
        filter: z.string().optional().describe("OData $filter, e.g. fields/Status eq 'Open'"),
        select: z.string().optional().describe("Comma-separated internal field names to return"),
        orderby: z.string().optional().describe("OData $orderby, e.g. fields/DueDate asc"),
        top: z.number().int().positive().optional().describe("Page size / max items"),
        all: z.boolean().optional().describe("Follow pagination and return all items"),
      },
      annotations: { readOnlyHint: true },
    },
    async ({ site, list, filter, select, orderby, top, all }) => {
      try {
        return ok(
          await client.listItems(await siteId(site), list, { filter, select, orderby, top, all }),
        );
      } catch (e) {
        return fail(e);
      }
    },
  );

  server.registerTool(
    "sharepoint_get_item",
    {
      title: "Get one item",
      description: "Fetch a single list item (with its fields) by item id.",
      inputSchema: { site: SITE, list: LIST, itemId: z.string().describe("The list item id.") },
      annotations: { readOnlyHint: true },
    },
    async ({ site, list, itemId }) => {
      try {
        return ok(await client.getItem(await siteId(site), list, itemId));
      } catch (e) {
        return fail(e);
      }
    },
  );

  if (!READONLY) {
    const FIELDS = z
      .record(z.any())
      .describe(
        "Map of INTERNAL column name -> value. Internal names come from sharepoint_get_columns. See the skill's references/graph-api.md for person/lookup/choice formats.",
      );

    server.registerTool(
      "sharepoint_create_item",
      {
        title: "Create an item",
        description: "Create a new list item. fields is a map of internal column name to value.",
        inputSchema: { site: SITE, list: LIST, fields: FIELDS },
        annotations: { readOnlyHint: false, destructiveHint: false },
      },
      async ({ site, list, fields }) => {
        try {
          return ok(await client.createItem(await siteId(site), list, fields));
        } catch (e) {
          return fail(e);
        }
      },
    );

    server.registerTool(
      "sharepoint_update_item",
      {
        title: "Update an item",
        description:
          "Update an existing item's fields (partial — only provided fields change). fields is a map of internal column name to value.",
        inputSchema: { site: SITE, list: LIST, itemId: z.string().describe("The list item id."), fields: FIELDS },
        annotations: { readOnlyHint: false, destructiveHint: false, idempotentHint: true },
      },
      async ({ site, list, itemId, fields }) => {
        try {
          return ok(await client.updateItem(await siteId(site), list, itemId, fields));
        } catch (e) {
          return fail(e);
        }
      },
    );

    server.registerTool(
      "sharepoint_delete_item",
      {
        title: "Delete an item",
        description:
          "Delete a list item by id. IRREVERSIBLE (item goes to the site Recycle Bin). Confirm the id before calling.",
        inputSchema: { site: SITE, list: LIST, itemId: z.string().describe("The list item id.") },
        annotations: { readOnlyHint: false, destructiveHint: true },
      },
      async ({ site, list, itemId }) => {
        try {
          await client.deleteItem(await siteId(site), list, itemId);
          return ok({ ok: true, deleted: itemId });
        } catch (e) {
          return fail(e);
        }
      },
    );
  }

  return server;
}

// ---- transports -----------------------------------------------------------

async function runStdio() {
  const server = buildServer();
  await server.connect(new StdioServerTransport());
  console.error(
    `[sharepoint-lists] MCP server ready on stdio (${READONLY ? "read-only" : "read/write"}).`,
  );
}

async function runHttp() {
  const { default: express } = await import("express");
  const app = express();
  app.use(express.json({ limit: "4mb" }));

  const TOKEN = process.env.MCP_AUTH_TOKEN || "";
  if (!TOKEN) {
    console.error(
      "[sharepoint-lists] WARNING: MCP_AUTH_TOKEN is not set — the /mcp endpoint is UNAUTHENTICATED.",
    );
  }
  const requireAuth = (req, res, next) => {
    if (!TOKEN) return next();
    const m = /^Bearer\s+(.+)$/i.exec(req.headers.authorization || "");
    if (m && tokenMatches(m[1], TOKEN)) return next();
    res.status(401).json({ error: "Unauthorized" });
  };

  // Liveness probe (no secrets — expiry days-left only) — intentionally
  // unauthenticated so healthchecks/monitors can watch it.
  app.get("/health", (_req, res) => {
    const s = secretExpiry();
    res.json({
      ok: true,
      readonly: READONLY,
      ...(s ? { secretExpiry: { level: s.level, daysLeft: s.daysLeft, expiresAt: s.expiresAt } } : {}),
    });
  });

  // Stateless: a fresh server + transport per request.
  app.post("/mcp", requireAuth, async (req, res) => {
    const server = buildServer();
    const transport = new StreamableHTTPServerTransport({ sessionIdGenerator: undefined });
    res.on("close", () => {
      transport.close();
      server.close();
    });
    try {
      await server.connect(transport);
      await transport.handleRequest(req, res, req.body);
    } catch (e) {
      console.error("[sharepoint-lists] request error:", e);
      if (!res.headersSent) res.status(500).json({ error: String(e?.message || e) });
    }
  });
  app.get("/mcp", requireAuth, (_req, res) => res.status(405).json({ error: "Method Not Allowed" }));
  app.delete("/mcp", requireAuth, (_req, res) => res.status(405).json({ error: "Method Not Allowed" }));

  const port = Number(process.env.PORT) || 3838;
  app.listen(port, () => {
    console.error(
      `[sharepoint-lists] HTTP MCP server on :${port}/mcp (${READONLY ? "read-only" : "read/write"}, auth ${TOKEN ? "on" : "OFF"}).`,
    );
  });
}

const useHttp = process.argv.includes("--http") || /^http$/i.test(process.env.MCP_TRANSPORT ?? "");
(useHttp ? runHttp() : runStdio()).catch((e) => {
  console.error("[sharepoint-lists] fatal:", e);
  process.exit(1);
});

// ---- minimal .env loader (no dependency) ----------------------------------

function loadDotEnv() {
  for (const dir of [__dirname, join(__dirname, ".."), process.cwd()]) {
    const file = join(dir, ".env");
    if (!existsSync(file)) continue;
    for (const line of readFileSync(file, "utf8").split("\n")) {
      const m = line.match(/^\s*([A-Z0-9_]+)\s*=\s*(.*)\s*$/i);
      if (!m) continue;
      let val = m[2].trim();
      if ((val.startsWith('"') && val.endsWith('"')) || (val.startsWith("'") && val.endsWith("'"))) {
        val = val.slice(1, -1);
      }
      if (process.env[m[1]] === undefined) process.env[m[1]] = val;
    }
  }
}