import polyline from "@mapbox/polyline";
import { point, polygon } from "@turf/helpers";
import booleanPointInPolygon from "@turf/boolean-point-in-polygon";
import type { Coordinate } from "./tripgo";
/**
* @param coordinate
* @param polygon Encoded polygon of coverage area for the region, using Google's Encoded Polyline Algorithm. See https://developers.google.com/maps/documentation/utilities/polylinealgorithm.
*/
export function coordinateInPolygon(
coordinate: Coordinate,
encodedPolygon: string,
): boolean {
// Decode the polygon using Google's polyline decoding algorithm
const points = polyline.decode(encodedPolygon);
// Convert to GeoJSON format - Turf expects [lng, lat] order
const polygonCoords = points.map((coord) => [coord[1], coord[0]]);
// Close the polygon if it's not already closed
if (
polygonCoords[0][0] !== polygonCoords[polygonCoords.length - 1][0] ||
polygonCoords[0][1] !== polygonCoords[polygonCoords.length - 1][1]
) {
polygonCoords.push(polygonCoords[0]);
}
// Create Turf point and polygon objects
const turfPoint = point([coordinate.lng, coordinate.lat]);
const turfPolygon = polygon([polygonCoords]);
// Check if point is inside polygon
return booleanPointInPolygon(turfPoint, turfPolygon);
}
/**
* Native JS equivalent of date-fns-tz's zonedTimeToUtc
* Interprets a ISO date string with no timezone as being in the specified timezone and returns UTC Date.
* For instance, if `isoDateLocalString` is "2025-07-18T19:00:00" and `timezone` is "Australia/Sydney",
* it will interpret this as 7 PM on July 18, 2025 in Sydney time, and it will return a Date object in UTC
* representing that same moment in time.
* Assuming Sydney is in AEST (UTC+10) during July, then zonedTimeToUtc("2025-07-18T19:00:00", "Australia/Sydney").getTime()
* is exactly the same as new Date("2025-07-18T19:00:00T+10:00").getTime();
*/
export function zonedTimeToUtc(
isoDateLocalString: string,
timezone: string,
): Date {
// Parse the date string as if it were in UTC (to avoid local timezone interpretation)
const date = new Date(`${isoDateLocalString}Z`);
// Get what this UTC time would be when displayed in the target timezone
const targetTime = new Date(
date.toLocaleString("en-US", { timeZone: timezone }),
);
// Calculate the offset between UTC and the target timezone
const utcTime = new Date(date.toLocaleString("en-US", { timeZone: "UTC" }));
const offset = targetTime.getTime() - utcTime.getTime();
// Apply the reverse offset to get the UTC time that would display as the input in the target timezone
return new Date(date.getTime() - offset);
}
/**
* Native JS equivalent of date-fns-tz's utcToZonedTime
* Converts a UTC Date to how it would appear in the specified timezone
*/
export function utcToZonedTime(utcDate: Date, timezone: string): Date {
// Get the date as it would appear in the target timezone
const targetTimeString = utcDate.toLocaleString("en-CA", {
timeZone: timezone,
year: "numeric",
month: "2-digit",
day: "2-digit",
hour: "2-digit",
minute: "2-digit",
second: "2-digit",
hour12: false,
});
// Parse this as a local time (which will be interpreted in the server's timezone)
// But we want it to represent the time as it appears in the target timezone
const [datePart, timePart] = targetTimeString.split(", ");
const [year, month, day] = datePart.split("-");
const [hour, minute, second] = timePart.split(":");
// Create a new Date object with these components
return new Date(
Number.parseInt(year),
Number.parseInt(month) - 1, // Month is 0-indexed
Number.parseInt(day),
Number.parseInt(hour),
Number.parseInt(minute),
Number.parseInt(second),
);
}
/**
* Converts a UTC Date to ISO string in the specified timezone with timezone offset
*/
export function toISOStringInTimezone(utcDate: Date, timezone: string): string {
const formatter = new Intl.DateTimeFormat("en-US", {
timeZone: timezone,
year: "numeric",
month: "2-digit",
day: "2-digit",
hour: "2-digit",
minute: "2-digit",
second: "2-digit",
hour12: false,
timeZoneName: "longOffset",
});
const parts = formatter.formatToParts(utcDate);
const year = parts.find((p) => p.type === "year")?.value;
const month = parts.find((p) => p.type === "month")?.value;
const day = parts.find((p) => p.type === "day")?.value;
const hour = parts.find((p) => p.type === "hour")?.value;
const minute = parts.find((p) => p.type === "minute")?.value;
const second = parts.find((p) => p.type === "second")?.value;
const offsetPart =
parts.find((p) => p.type === "timeZoneName")?.value || "+00:00";
// Format as ISO string (YYYY-MM-DD format)
return `${year}-${month}-${day}T${hour}:${minute}:${second}${offsetPart}`;
}
