feat: add Google Calendar data source

Co-authored-by: Ona <no-reply@ona.com>

packages/aris-source-google-calendar/src/google-calendar-api.ts

@@ -0,0 +1,122 @@
+// Google Calendar REST API v3 client
+// https://developers.google.com/calendar/api/v3/reference/events/list
+
+import { type } from "arktype"
+
+import type {
+	ApiCalendarEvent,
+	GoogleCalendarClient,
+	GoogleOAuthProvider,
+	ListEventsOptions,
+} from "./types"
+
+import { EventStatus } from "./types"
+
+const eventStatusSchema = type.enumerated(
+	EventStatus.Confirmed,
+	EventStatus.Tentative,
+	EventStatus.Cancelled,
+)
+
+const eventDateTimeSchema = type({
+	"dateTime?": "string",
+	"date?": "string",
+	"timeZone?": "string",
+})
+
+const eventSchema = type({
+	id: "string",
+	status: eventStatusSchema,
+	htmlLink: "string",
+	"summary?": "string",
+	"description?": "string",
+	"location?": "string",
+	start: eventDateTimeSchema,
+	end: eventDateTimeSchema,
+})
+
+const calendarListEntrySchema = type({
+	id: "string",
+})
+
+const calendarListResponseSchema = type({
+	"items?": calendarListEntrySchema.array(),
+	"nextPageToken?": "string",
+})
+
+const eventsResponseSchema = type({
+	"items?": eventSchema.array(),
+	"nextPageToken?": "string",
+})
+
+export class DefaultGoogleCalendarClient implements GoogleCalendarClient {
+	private static readonly API_BASE = "https://www.googleapis.com/calendar/v3"
+
+	private readonly oauthProvider: GoogleOAuthProvider
+
+	constructor(oauthProvider: GoogleOAuthProvider) {
+		this.oauthProvider = oauthProvider
+	}
+
+	async listCalendarIds(): Promise<string[]> {
+		const url = `${DefaultGoogleCalendarClient.API_BASE}/users/me/calendarList?fields=items(id)`
+		const json = await this.request(url)
+		const result = calendarListResponseSchema(json)
+
+		if (result instanceof type.errors) {
+			throw new Error(`Google Calendar API response validation failed: ${result.summary}`)
+		}
+
+		if (!result.items) {
+			return []
+		}
+		return result.items.map((entry) => entry.id)
+	}
+
+	async listEvents(options: ListEventsOptions): Promise<ApiCalendarEvent[]> {
+		const url = new URL(
+			`${DefaultGoogleCalendarClient.API_BASE}/calendars/${encodeURIComponent(options.calendarId)}/events`,
+		)
+		url.searchParams.set("timeMin", options.timeMin.toISOString())
+		url.searchParams.set("timeMax", options.timeMax.toISOString())
+		url.searchParams.set("singleEvents", "true")
+		url.searchParams.set("orderBy", "startTime")
+
+		const json = await this.request(url.toString())
+		const result = eventsResponseSchema(json)
+
+		if (result instanceof type.errors) {
+			throw new Error(`Google Calendar API response validation failed: ${result.summary}`)
+		}
+
+		if (!result.items) {
+			return []
+		}
+
+		return result.items
+	}
+
+	/** Authenticated GET with auto token refresh on 401. */
+	private async request(url: string): Promise<unknown> {
+		const token = await this.oauthProvider.fetchAccessToken()
+		let response = await fetch(url, {
+			headers: { Authorization: `Bearer ${token}` },
+		})
+
+		if (response.status === 401) {
+			const newToken = await this.oauthProvider.refresh()
+			response = await fetch(url, {
+				headers: { Authorization: `Bearer ${newToken}` },
+			})
+		}
+
+		if (!response.ok) {
+			const body = await response.text()
+			throw new Error(
+				`Google Calendar API error: ${response.status} ${response.statusText}: ${body}`,
+			)
+		}
+
+		return response.json()
+	}
+}