import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { z } from "zod";
import { Solar, Lunar } from "lunar-typescript";
export function register(server: McpServer): void {
server.tool(
"convert_calendar",
"Convert between Gregorian (solar) and Chinese Lunar calendar. Includes Ganzhi (天干地支), zodiac animal, solar terms, and festival information.",
{
direction: z.enum(["gregorian_to_lunar", "lunar_to_gregorian"]).describe("Conversion direction"),
year: z.number().int().describe("Year"),
month: z.number().int().min(1).max(12).describe("Month (1-12)"),
day: z.number().int().min(1).max(31).describe("Day"),
isLeapMonth: z.boolean().optional().describe("For lunar_to_gregorian: whether the month is a leap month (闰月). Defaults to false."),
},
async ({ direction, year, month, day, isLeapMonth }) => {
try {
if (direction === "gregorian_to_lunar") {
const solar = Solar.fromYmd(year, month, day);
const lunar = solar.getLunar();
const result = {
input: { type: "gregorian", year, month, day },
lunar: {
year: lunar.getYear(),
month: lunar.getMonth(),
day: lunar.getDay(),
yearInChinese: lunar.getYearInChinese(),
monthInChinese: lunar.getMonthInChinese(),
dayInChinese: lunar.getDayInChinese(),
yearGanZhi: lunar.getYearInGanZhi(),
monthGanZhi: lunar.getMonthInGanZhi(),
dayGanZhi: lunar.getDayInGanZhi(),
zodiac: lunar.getYearShengXiao(),
solarTerm: lunar.getJieQi() || null,
lunarFestivals: lunar.getFestivals(),
solarFestivals: solar.getFestivals(),
constellation: solar.getXingZuo(),
},
};
return {
content: [{ type: "text", text: JSON.stringify(result, null, 2) }],
};
} else {
// lunar_to_gregorian
// If isLeapMonth is true, use negative month number per lunar-typescript convention
const lunarMonth = isLeapMonth ? -month : month;
const lunar = Lunar.fromYmd(year, lunarMonth, day);
const solar = lunar.getSolar();
const result = {
input: { type: "lunar", year, month, day, isLeapMonth: isLeapMonth || false },
gregorian: {
year: solar.getYear(),
month: solar.getMonth(),
day: solar.getDay(),
iso: solar.toYmd(),
weekday: solar.getWeekInChinese(),
},
lunarInfo: {
yearGanZhi: lunar.getYearInGanZhi(),
monthGanZhi: lunar.getMonthInGanZhi(),
dayGanZhi: lunar.getDayInGanZhi(),
zodiac: lunar.getYearShengXiao(),
lunarFestivals: lunar.getFestivals(),
solarFestivals: solar.getFestivals(),
},
};
return {
content: [{ type: "text", text: JSON.stringify(result, null, 2) }],
};
}
} catch (e: any) {
return {
content: [{ type: "text", text: JSON.stringify({ error: e.message || String(e) }) }],
};
}
}
);
}
