Calculate and draw hour precipitation rate

web/src/harmonie/draw/precipitation.ts

@@ -1,6 +1,9 @@
+import moment from 'moment'
 import { valueToColorInterpolated, valueToColorThreshold } from '../../helpers/interpolateColors'
-import { MeteoConversion } from '../interfaces'
+import { GribMessage, MeteoConversion } from '../interfaces'
 import { PRECIPITATION } from './constants'
+import { fetchBuffer } from '../../helpers/fetch'
+import { apiHost } from '../../consts'
 
 
 export function precipitationColors(
@@ -8,10 +11,89 @@ export function precipitationColors(
     { reference, binaryScale, decimalScale}: MeteoConversion,
     isInterpolated = true,
 ): [number, number, number, number] {
-    // const rainMM = (reference + encodedValue * Math.pow(2, binaryScale)) * Math.pow(10, -decimalScale) / 1000
     const rainMM = (reference + encodedValue * Math.pow(2, binaryScale)) * Math.pow(10, -decimalScale)
 
     return isInterpolated
         ? valueToColorInterpolated(rainMM, PRECIPITATION)
         : valueToColorThreshold(rainMM, PRECIPITATION)
 }
+
+export function hourPrecipitationColors(
+    encodedValNow: number,
+    convNow: MeteoConversion,
+    encodedValPrev: number,
+    convPrev: MeteoConversion,
+    isInterpolated = true,
+): [number, number, number, number] {
+    const nowVal = (convNow.reference + encodedValNow * Math.pow(2, convNow.binaryScale)) * Math.pow(10, -convNow.decimalScale)
+    const prevVal = (convPrev.reference + encodedValPrev * Math.pow(2, convPrev.binaryScale)) * Math.pow(10, -convPrev.decimalScale)
+
+    const rainMM = nowVal - prevVal
+    return isInterpolated
+        ? valueToColorInterpolated(rainMM, PRECIPITATION)
+        : valueToColorThreshold(rainMM, PRECIPITATION)
+}
+
+export function fetchHourPrecipitationData(
+    customMessage: GribMessage,
+    gribArr: GribMessage[],
+): Promise<[GribMessage[], ArrayBuffer[], ArrayBuffer[]]> {
+    const totalPrecipitation = gribArr.find(g => isPrecipitation(g)
+        && g.time.referenceTime === customMessage.time.referenceTime
+        && g.time.forecastTime === customMessage.time.forecastTime
+    )
+    if (!totalPrecipitation) throw new Error('Not found total precipitation')
+
+    const { forecastTime } = totalPrecipitation.time
+    const prevForecastTime = moment(forecastTime.replace(/(\d{2})(\d{2})Z/, '$1:$2:00Z'))
+        .subtract(1, 'hours')
+        .utc()
+        .format("YYYY-MM-DDTHHmm")+'Z'
+
+    const prevTotalPrecipitation = gribArr.find(g => isPrecipitation(g)
+        && g.time.referenceTime === customMessage.time.referenceTime
+        && g.time.forecastTime === prevForecastTime
+    )
+    
+    const section7now = totalPrecipitation.sections.find(section => section.id === 7)
+    const section7prev = prevTotalPrecipitation?.sections.find(section => section.id === 7)
+    if (!section7now) throw new Error('Didnt found binary section for total precipitation')
+    
+    const nowBinaryOffset = section7now.offset + 5
+    const nowBinaryLength = section7now.size - 5
+    const nowFileName = `harmonie_${totalPrecipitation.time.referenceTime}_${totalPrecipitation.time.forecastTime}.grib`
+
+    // for oldest message there is no more -1h message
+    let prevPromise: Promise<ArrayBuffer> | undefined
+    if (prevTotalPrecipitation && section7prev) {
+        const prevBinaryOffset = section7prev.offset + 5
+        const prevBinaryLength = section7prev.size - 5
+        const prevFileName = `harmonie_${prevTotalPrecipitation.time.referenceTime}_${prevTotalPrecipitation.time.forecastTime}.grib`
+        prevPromise = fetchBuffer(`${apiHost}/api/grib/binary-chunk/${prevBinaryOffset}/${prevBinaryLength}/${prevFileName}`)
+    }
+    if (!prevPromise) prevPromise = new Promise(resolve => resolve(new Uint8Array(nowBinaryLength).buffer))
+
+    return Promise.all([
+            fetchBuffer(`${apiHost}/api/grib/binary-chunk/${nowBinaryOffset}/${nowBinaryLength}/${nowFileName}`),
+            prevPromise,
+        ]).then(([bufferNow, bufferPrev]) => {
+            const messages = [customMessage, totalPrecipitation, prevTotalPrecipitation ?? totalPrecipitation]
+            const buffers = [bufferNow, bufferNow, bufferPrev]
+            return [messages, buffers, []]
+        })
+}
+
+export function isPrecipitation(grib: GribMessage): boolean {
+    return grib.meteo.discipline === 0 && grib.meteo.category === 1 && grib.meteo.product === 52
+}
+
+export function isCalculatedHourPrecipitation(grib: GribMessage): boolean {
+    return grib.meteo.discipline === 0 && grib.meteo.category === 1 && grib.meteo.product === 236
+}
+
+export function getFakeHourPrecipitation(totalPrecipitation: GribMessage): GribMessage {
+    const modifiedPrecipitation = structuredClone(totalPrecipitation)
+    modifiedPrecipitation.meteo = {...modifiedPrecipitation.meteo, product: 236}
+    modifiedPrecipitation.title = 'meteorology, moisture, hour precipitation rate'
+    return modifiedPrecipitation
+}