Convert to represent dates instead of numbers

- Add HistDate class
- Adapt TimeLine and BaseLine to work with HistDates
- For own-size-watching components, add onMounted() hook to run before
  ResizeObserver is set up

1 files changed, 207 insertions, 6 deletions

diff --git a/src/lib.ts b/src/lib.ts
index 28994f1..9bd23a5 100644
--- a/src/lib.ts
+++ b/src/lib.ts
@@ -2,16 +2,217 @@
  * Project-wide globals
  */
 
-export const MIN_DATE = -1000;
-export const MAX_DATE = 1000;
-export const SCALES = [200, 50, 10, 1, 0.2]; // Timeline gets divided into units of SCALES[0], then SCALES[1], etc
-
+export const DEBUG = true;
 export const WRITING_MODE_HORZ =
 	window.getComputedStyle(document.body)['writing-mode' as any].startsWith('horizontal');
 	// Used with ResizeObserver callbacks, to determine which resized dimensions are width and height
 
+// For calendar conversion. Same as in backend/hist_data/cal.py
+export function gregorianToJdn(year: number, month: number, day: number): number {
+	if (year < 0){
+		year += 1;
+	}
+	const x = Math.trunc((month - 14) / 12);
+	let jdn = Math.trunc(1461 * (year + 4800 + x) / 4);
+	jdn += Math.trunc((367 * (month - 2 - 12 * x)) / 12);
+	jdn -= Math.trunc((3 * Math.trunc((year + 4900 + x) / 100)) / 4);
+	jdn += day - 32075;
+	return jdn;
+}
+export function julianToJdn(year: number, month: number, day: number): number {
+	if (year < 0){
+		year += 1;
+	}
+	let jdn = 367 * year;
+	jdn -= Math.trunc(7 * (year + 5001 + Math.trunc((month - 9) / 7)) / 4);
+	jdn += Math.trunc(275 * month / 9);
+	jdn += day + 1729777;
+	return jdn;
+}
+export function jdnToGregorian(jdn: number): [number, number, number] {
+	const f = jdn + 1401 + Math.trunc((Math.trunc((4 * jdn + 274277) / 146097) * 3) / 4) - 38;
+	const e = 4 * f + 3;
+	const g = Math.trunc((e % 1461) / 4);
+	const h = 5 * g + 2;
+	const D = Math.trunc((h % 153) / 5) + 1;
+	const M = (Math.trunc(h / 153) + 2) % 12 + 1;
+	let Y = Math.trunc(e / 1461) - 4716 + Math.trunc((12 + 2 - M) / 12);
+	if (Y <= 0){
+		Y -= 1;
+	}
+	return [Y, M, D];
+}
+export function jdnToJulian(jdn: number): [number, number, number] {
+	const f = jdn + 1401;
+	const e = 4 * f + 3;
+	const g = Math.trunc((e % 1461) / 4);
+	const h = 5 * g + 2;
+	const D = Math.trunc((h % 153) / 5) + 1;
+	const M = (Math.trunc(h / 153) + 2) % 12 + 1;
+	let Y = Math.trunc(e / 1461) - 4716 + Math.trunc((12 + 2 - M) / 12);
+	if (Y <= 0){
+		Y -= 1;
+	}
+	return [Y, M, D];
+}
+export function julianToGregorian(year: number, month: number, day: number): [number, number, number] {
+	return jdnToGregorian(julianToJdn(year, month, day));
+}
+export function gregorianToJulian(year: number, month: number, day: number): [number, number, number] {
+	return jdnToJulian(gregorianToJdn(year, month, day));
+}
+
+// For date representation
+export class HistDate {
+	year: number;
+	month: number;
+	day: number;
+	constructor(year: number, month=1, day=1){
+		this.year = year;
+		this.month = month;
+		this.day = day;
+	}
+	equals(other: HistDate, scale=DAY_SCALE){
+		if (scale == DAY_SCALE){
+			return this.year == other.year && this.month == other.month && this.day == other.day;
+		} else if (scale == MONTH_SCALE){
+			return this.year == other.year && this.month == other.month;
+		} else {
+			return Math.floor(this.year / scale) == Math.floor(other.year / scale);
+		}
+	}
+	isEarlier(other: HistDate, scale=DAY_SCALE){
+		const yearlyScale = scale != DAY_SCALE && scale != MONTH_SCALE;
+		const thisYear = yearlyScale ? Math.floor(this.year / scale) : this.year;
+		const otherYear = yearlyScale ? Math.floor(other.year / scale) : other.year;
+		if (yearlyScale || thisYear != otherYear){
+			return thisYear < otherYear;
+		} else {
+			if (scale == MONTH_SCALE || this.month != other.month){
+				return this.month < other.month;
+			} else {
+				return this.day < other.day;
+			}
+		}
+	}
+	toInt(){
+		return this.day + this.month * 50 + this.year * 1000;
+	}
+	toString(){
+		return `${this.year}-${this.month}-${this.day}`;
+	}
+	getDayDiff(other: HistDate){
+		const jdn2 = gregorianToJdn(this.year, this.month, this.day);
+		const jdn1 = gregorianToJdn(other.year, other.month, other.day);
+		return Math.abs(jdn1 - jdn2);
+	}
+	getMonthDiff(other: HistDate){
+		// Determine earlier date
+		let earlier = this as HistDate;
+		let later = other;
+		if (other.year < this.year || other.year == this.year && other.month < this.month){
+			earlier = other;
+			later = this as HistDate;
+		}
+		//
+		const yearDiff = later.year - earlier.year;
+		if (yearDiff == 0){
+			return later.month - earlier.month;
+		} else {
+			return (13 - earlier.month) + (yearDiff * 12) + later.month - 1;
+		}
+	}
+	clone(){
+		return new HistDate(this.year, this.month, this.day);
+	}
+}
+
+// Timeline parameters
+const currentDate = new Date();
+export const MIN_DATE = new HistDate(-13.8e9);
+export const MAX_DATE = new HistDate(currentDate.getFullYear(), currentDate.getMonth() + 1, currentDate.getDate());
+export const MONTH_SCALE = -1;
+export const DAY_SCALE = -2;
+export const SCALES = [1e9, 1e8, 1e7, 1e6, 1e5, 1e4, 1e3, 100, 10, 1, MONTH_SCALE, DAY_SCALE];
+	// The timeline will be divided into units of SCALES[0], then SCALES[1], etc
+	// Positive ints represent numbers of years, -1 represents 1 month, -2 represents 1 day
+if (DEBUG){
+	if (SCALES[SCALES.length - 1] != DAY_SCALE
+			|| SCALES[SCALES.length - 2] != MONTH_SCALE
+			|| SCALES[SCALES.length - 3] != 1){
+		throw new Error('SCALES must end with [1, MONTH_SCALE, DAY_SCALE]');
+	}
+	for (let i = 1; i < SCALES.length - 2; i++){
+		if (SCALES[i] <= 0){
+			throw new Error('SCALES must only have positive ints before MONTH_SCALE');
+		}
+		if (SCALES[i-1] <= SCALES[i]){
+			throw new Error('SCALES must hold decreasing values');
+		}
+		if (SCALES[i-1] % SCALES[i] > 0){
+			throw new Error('Each positive int in SCALES must divide the previous int');
+		}
+	}
+}
+export function stepDate(date: HistDate, scale: number, {forward=true, count=1, inplace=false} = {}): HistDate {
+	const newDate = inplace ? date : date.clone();
+	for (let i = 0; i < count; i++){
+		if (scale == DAY_SCALE){
+			if (forward && newDate.day < 28){
+				newDate.day += 1;
+			} else if (!forward && newDate.day > 1){
+				newDate.day -= 1
+			} else {
+				let jdn = gregorianToJdn(newDate.year, newDate.month, newDate.day)
+				jdn += forward ? 1 : -1;
+				const [year, month, day] = jdnToGregorian(jdn);
+				newDate.year = year;
+				newDate.month = month;
+				newDate.day = day;
+			}
+		} else if (scale == MONTH_SCALE){
+			if (forward){
+				if (newDate.month < 12){
+					newDate.month += 1;
+				} else {
+					newDate.year += 1;
+					newDate.month = 1;
+				}
+			} else {
+				if (newDate.month > 1){
+					newDate.month -= 1;
+				} else {
+					newDate.year -= 1;
+					newDate.month = 12;
+				}
+			}
+		} else {
+			newDate.year += forward ? scale : -scale;
+		}
+	}
+	return newDate;
+}
+export function inDateScale(date: HistDate, scale: number): boolean {
+	if (scale == DAY_SCALE){
+		return true;
+	} else if (scale == MONTH_SCALE){
+		return date.day == 1;
+	} else {
+		return date.year % scale == 0 && date.month == 1 && date.day == 1;
+	}
+}
+
+// For sending timeline-bound data to BaseLine
 export type TimelineRange = {
 	id: number,
-	start: number,
-	end: number,
+	start: HistDate,
+	end: HistDate,
+};
+
+export type HistEvent = {
+	title: string,
+	start: HistDate,
+	startUpper: HistDate | null,
+	end: HistDate,
+	endUpper: HistDate | null,
 };