import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { z } from "zod";
import { DateTime } from "luxon";
import { getHolidays, type HolidayInfo } from "../data/holidays.js";
export function register(server: McpServer, dataDir: string): void {
server.tool(
"calculate_business_days",
"Calculate business days between two dates or add/subtract business days from a date. Skips weekends and optionally public holidays.",
{
action: z.enum(["count", "add"]).describe("'count': count business days between from and to. 'add': add N business days to from date."),
from: z.string().describe("Start date in YYYY-MM-DD format"),
to: z.string().optional().describe("End date in YYYY-MM-DD format (required for 'count' action)"),
business_days: z.number().int().optional().describe("Number of business days to add (required for 'add' action, negative to subtract)"),
country: z.string().optional().describe("Country code for public holidays (e.g. CN, US). If omitted, only weekends are skipped."),
timezone: z.string().optional().describe("IANA timezone. Defaults to UTC."),
},
async ({ action, from, to, business_days, country, timezone }) => {
try {
const tz = timezone || "UTC";
const fromDt = DateTime.fromISO(from, { zone: tz });
if (!fromDt.isValid) {
return { content: [{ type: "text", text: JSON.stringify({ error: `Invalid from date: ${fromDt.invalidExplanation}` }) }] };
}
// Load holidays if country specified
let holidayMap: Map<string, HolidayInfo> | undefined;
if (country) {
// Load holidays for relevant years
const allHolidays = new Map<string, HolidayInfo>();
const startYear = fromDt.year;
const endYear = to ? DateTime.fromISO(to, { zone: tz }).year : startYear + 1;
for (let y = startYear; y <= endYear; y++) {
const yearHolidays = await getHolidays(dataDir, country, y);
for (const [k, v] of yearHolidays) allHolidays.set(k, v);
}
holidayMap = allHolidays;
}
function isBusinessDay(dt: DateTime): { isBusiness: boolean; reason?: string } {
const weekday = dt.weekday; // 1=Mon, 7=Sun
const dateStr = dt.toISODate()!;
// Check holiday map first (it may have makeup workdays)
if (holidayMap) {
const holiday = holidayMap.get(dateStr);
if (holiday) {
if (holiday.type === "makeup_workday") {
// It's a makeup workday (even if weekend)
return { isBusiness: true };
}
if (holiday.isOffDay) {
return { isBusiness: false, reason: holiday.name };
}
}
}
if (weekday === 6 || weekday === 7) {
return { isBusiness: false, reason: "weekend" };
}
return { isBusiness: true };
}
if (action === "count") {
if (!to) {
return { content: [{ type: "text", text: JSON.stringify({ error: "'to' date is required for count action" }) }] };
}
const toDt = DateTime.fromISO(to, { zone: tz });
if (!toDt.isValid) {
return { content: [{ type: "text", text: JSON.stringify({ error: `Invalid to date: ${toDt.invalidExplanation}` }) }] };
}
let count = 0;
const excluded: { date: string; reason: string }[] = [];
let current = fromDt;
while (current < toDt) {
const check = isBusinessDay(current);
if (check.isBusiness) {
count++;
} else {
excluded.push({ date: current.toISODate()!, reason: check.reason || "non-business" });
}
current = current.plus({ days: 1 });
}
const totalCalendarDays = Math.floor(toDt.diff(fromDt, "days").days);
return {
content: [{
type: "text",
text: JSON.stringify({
from: fromDt.toISODate(),
to: toDt.toISODate(),
businessDays: count,
calendarDays: totalCalendarDays,
excludedDays: excluded.length,
excluded: excluded.slice(0, 50), // Limit to 50 entries
}, null, 2),
}],
};
} else {
// add
if (business_days === undefined) {
return { content: [{ type: "text", text: JSON.stringify({ error: "'business_days' is required for add action" }) }] };
}
const direction = business_days >= 0 ? 1 : -1;
let remaining = Math.abs(business_days);
let current = fromDt;
const excluded: { date: string; reason: string }[] = [];
while (remaining > 0) {
current = current.plus({ days: direction });
const check = isBusinessDay(current);
if (check.isBusiness) {
remaining--;
} else {
excluded.push({ date: current.toISODate()!, reason: check.reason || "non-business" });
}
}
return {
content: [{
type: "text",
text: JSON.stringify({
from: fromDt.toISODate(),
businessDaysAdded: business_days,
result: current.toISODate(),
weekday: current.weekdayLong,
excludedDays: excluded.length,
excluded: excluded.slice(0, 50),
}, null, 2),
}],
};
}
} catch (e: any) {
return { content: [{ type: "text", text: JSON.stringify({ error: e.message || String(e) }) }] };
}
}
);
}
