Commit: 1cf0824faf225a446bdf7447b36d08fabd142c86
Author: Vi Grey
Date: 2023-08-05 00:49 UTC
Summary: Initial commit

 .gitignore         |   1 +
 CHANGELOG.md       |  10 ++++
 LICENSE            |  24 ++++++++
 Makefile           |  12 ++++
 README.txt         |  37 ++++++++++++
 go.mod             |   3 +
 src/conversions.go | 108 +++++++++++++++++++++++++++++++++++
 src/weather-nws.go | 241 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 8 files changed, 436 insertions(+)


diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..567609b
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+build/
diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..6ea27a5
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,10 @@
+# Change Log
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
+
+## [0.0.0] - 2023-08-04
+
+### Added
+
+- Initial release
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..91c0826
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,24 @@
+Copyright (C) 2023, Vi Grey
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
+
+    1. Redistributions of source code must retain the above copyright
+       notice, this list of conditions and the following disclaimer.
+    2. Redistributions in binary form must reproduce the above copyright
+       notice, this list of conditions and the following disclaimer in the
+       documentation and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGE.
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..5c99ede
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,12 @@
+PKG_NAME := weather-nws
+CURRENTDIR := $(dir $(realpath $(firstword $(MAKEFILE_LIST))))
+
+all:
+	mkdir -p $(CURRENTDIR)build/bin; \
+	cd $(CURRENTDIR)src; \
+	go build -ldflags="-s -w" -o $(CURRENTDIR)build/bin/$(PKG_NAME); \
+	cd $(CURRENTDIR); \
+	#upx --brute $(CURRENTDIR)build/bin/$(PKG_NAME)
+
+clean:
+	rm -rf -- $(CURRENTDIR)build
diff --git a/README.txt b/README.txt
new file mode 100644
index 0000000..da4f997
--- /dev/null
+++ b/README.txt
@@ -0,0 +1,37 @@
+# Weather-NWS
+
+Get weather data in the US from the National Weather Service
+
+## Build Dependencies
+
+- go >= 1.20
+
+
+## Build
+
+To build weather-nws, use the following command in the root directory
+of this repository
+
+```
+make
+```
+
+The resulting binary file will be located at `build/bin/weather-nws
+
+
+## Usage
+
+```
+weather-nws [STATION_ID] [LAT,LON]
+```
+
+STATION_ID: 4 letter NWS station ID (example: KVGT for North Las Vegas
+                                     Airport)
+LAT,LON: Comma seperated latitude and longitude of a particular
+         location to get weather alerts.  South and West are negative.
+
+### Example:
+
+```
+weather-nws KVGT 36.1881,-115.1764
+```
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..ac4ddaf
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module weather-nws
+
+go 1.20
diff --git a/src/conversions.go b/src/conversions.go
new file mode 100644
index 0000000..52ba162
--- /dev/null
+++ b/src/conversions.go
@@ -0,0 +1,108 @@
+package main
+
+import (
+	"math"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+var (
+	metarRegex       = regexp.MustCompile(` (\d+)(\d{2})G?(\d{2})?KT .* ([M|-]?\d{2})/([M|-]?\d{2}) `)
+	weatherRegex     = regexp.MustCompile(`\/land\/(day|night)\/([^?]*)`)
+	whitespacesRegex = regexp.MustCompile(`[^\S\r\n]+`)
+)
+
+// Converts nautical miles into miles
+func nmToMi(n float64) float64 {
+	return n * 1.852 / 1.609344
+}
+
+// Converts kilometers into miles
+func kmToMi(n float64) float64 {
+	return n / 1.609344
+}
+
+// Converts miles per hour to meters per second
+func miphToMps(n float64) float64 {
+	return n * 1609.344 / 3600
+}
+
+// Convert Temperature (t) from Celcius into Fahrenheit
+func celciusToFahrenheit(c float64) float64 {
+	return c*9/5 + 32
+}
+
+// Temperature (t) MUST be in Celcius
+func vaporPressure(t float64) float64 {
+	return (6.1078 * math.Pow(10, (7.5*t)/(237.3+t)))
+}
+
+// Temperature (t) and Dew Point (d) MUST be in Celcius
+// Returns a percentage (between 0 and 100)
+func tempDewPointToRelativeHumidity(t, d float64) float64 {
+	return (vaporPressure(d) / vaporPressure(t) * 100)
+}
+
+func metarStringToWeatherData(m string) (w MetarWeather) {
+	metarMatch := metarRegex.FindStringSubmatch(strings.ToUpper(m))
+	if len(metarMatch) < 6 {
+		return
+	}
+	w.windDirection, _ = strconv.ParseFloat(metarMatch[1], 64)
+	w.windSpeed, _ = strconv.ParseFloat(metarMatch[2], 64)
+	w.windGustSpeed, _ = strconv.ParseFloat(metarMatch[3], 64)
+	w.temperature, _ = strconv.ParseFloat(strings.ReplaceAll(metarMatch[4], "M", "-"), 64)
+	w.dewPoint, _ = strconv.ParseFloat(strings.ReplaceAll(metarMatch[5], "M", "-"), 64)
+	return
+}
+
+func iconStringToWeatherIcon(w string) string {
+	weatherMatch := weatherRegex.FindStringSubmatch(strings.ToLower(w))
+	if len(weatherMatch) < 3 {
+		return weatherIcons[0]
+	}
+	for i := range weatherIconRef {
+		for _, icon := range weatherIconRef[i] {
+			if icon == weatherMatch[2] {
+				return weatherIcons[i]
+			}
+		}
+	}
+	return weatherIcons[0]
+}
+
+func getWindChill(t, ws float64) (wc float64) {
+	wc = t
+	if t <= 50 && ws > 3 {
+		wc = (35.74 + 0.6215*t -
+			34.75*math.Pow(ws, 0.16) +
+			0.4275*t*math.Pow(ws, 0.16))
+	}
+	return
+}
+
+func getHeatIndex(t, rh float64) (hi float64) {
+	hi = t
+	if t >= 80 {
+		hi = (-42.379 + 2.04901523*t + 10.14333127*rh -
+			0.22475541*t*rh - 0.00683783*t*t - 0.05481717*rh*rh +
+			0.00122874*t*t*rh + 0.00085282*t*rh*rh -
+			0.00000199*t*t*rh*rh)
+		if t <= 112 && rh < 13 {
+			hi -= (13 - rh) / 4 * math.Sqrt(17-math.Abs(t-95)/19)
+		} else if t <= 87 && rh >= 85 {
+			hi += (rh - 85) / 10 * (87 - t) / 5
+		}
+	}
+	return
+}
+
+func getApparentTemp(t, rh, ws float64) (at float64) {
+	e := (rh / 100) * 6.105 * math.Exp((17.27*t)/(237.7+t))
+	return t + 0.33*e - 0.7*ws - 4
+}
+
+func removeExtraWhitespaces(s string) string {
+	return whitespacesRegex.ReplaceAllString(s, " ")
+}
diff --git a/src/weather-nws.go b/src/weather-nws.go
new file mode 100644
index 0000000..0b0c636
--- /dev/null
+++ b/src/weather-nws.go
@@ -0,0 +1,241 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"strings"
+	"time"
+)
+
+var (
+	topBarFlag                     bool
+	stationID, latitude, longitude string
+	expectedANSIStart              = "\x1b[104;30m "
+	watchANSIStart                 = "\x1b[103;3;30m "
+	warningANSIStart               = "\x1b[41;30m "
+	ansiEnd                        = " \x1b[0m"
+	windDirections                 = []string{"N", "NNE", "NE", "ENE", "E", "ESE", "SE", "SSE",
+		"S", "SSW", "SW", "WSW", "W", "WNW", "N", "NNW"}
+
+	weatherIconRef = [][]string{
+		[]string{"skc", "wind_skc"},
+		[]string{"tsra", "tsra_sct", "tsra_hi"},
+		[]string{"rain", "rain_showers", "rain_showers_hi"},
+		[]string{"rain_snow", "rain_sleet", "snow_sleet", "fzra", "rain_fzra", "snow_fzra", "sleet"},
+		[]string{"snow", "blizzard"},
+		[]string{"dust", "smoke", "haze", "fog"},
+		[]string{"few", "sct", "wind_few", "wind_sct"},
+		[]string{"bkn", "ovc", "wind_bkn", "wind_ovc"},
+	}
+	weatherIcons = []string{"CLR", "TS", "RA", "RASN", "SN", "FG", "SCT", "OVC"}
+)
+
+type MetarWeather struct {
+	windDirection float64
+	windSpeed     float64
+	windGustSpeed float64
+	temperature   float64
+	dewPoint      float64
+}
+
+type WeatherResponse struct {
+	Properties Weather `json:"properties"`
+	ID         string  `json:"id"`
+	Type       string  `json:"type"`
+	Status     int     `json:"status"`
+}
+
+type Weather struct {
+	Station         string     `json:"station"`
+	RawMessage      string     `json:"rawMessage"`
+	TextDescription string     `json:"textDescription"`
+	Icon            string     `json:"icon"`
+	Temperature     WeatherVal `json:"temperature"`
+	Dewpoint        WeatherVal `json:"dewpoint"`
+	WindDirection   WeatherVal `json:"windDirection"`
+	WindSpeed       WeatherVal `json:"windSpeed"`
+	WindGust        WeatherVal `json:"windGust"`
+	Timestamp       time.Time  `json:"timestamp"`
+}
+
+type WeatherVal struct {
+	Value    *float64 `json:"value"`
+	UnitCode string   `json:"unitCode"`
+}
+
+type AlertsResponse struct {
+	Features []Feature `json:"features"`
+	Status   int       `json:"status"`
+}
+
+type Feature struct {
+	Properties Alert `json:"properties"`
+}
+
+type Alert struct {
+	Ends        time.Time `json:"ends"`
+	Expires     time.Time `json:"expires"`
+	Urgency     string    `json:"urgency"`
+	Event       string    `json:"event"`
+	Headline    string    `json:"headline"`
+	Description string    `json:"description"`
+}
+
+func getWeather() (w WeatherResponse) {
+	client := http.Client{}
+	weatherEndPoint := fmt.Sprintf("https://api.weather.gov/stations/%s/observations/latest",
+		stationID)
+	req, err := http.NewRequest("GET", weatherEndPoint, nil)
+	if err != nil {
+		return
+	}
+	req.Header = http.Header{
+		"Accept":     []string{"application/geo+json"},
+		"User-Agent": []string{"(Weather Info, vigrey.com/git/weather, vi@vigrey.com)"},
+	}
+	resp, err := client.Do(req)
+	if err != nil {
+		return
+	}
+	respBody, _ := io.ReadAll(resp.Body)
+	json.Unmarshal(respBody, &w)
+	return
+}
+
+func getWeatherStr(w Weather, mw MetarWeather) (weatherStr string) {
+	temp := celciusToFahrenheit(mw.temperature)
+	tempC := *w.Temperature.Value
+	dp := celciusToFahrenheit(mw.dewPoint)
+	rh := tempDewPointToRelativeHumidity(mw.temperature, mw.dewPoint)
+	wd := windDirections[int((mw.windDirection*2/45)+0.5)%16]
+	ws := nmToMi(mw.windSpeed)
+	wsM := miphToMps(ws)
+	wg := nmToMi(mw.windGustSpeed)
+	hi := getHeatIndex(temp, rh)
+	wc := getWindChill(temp, ws)
+	at := celciusToFahrenheit(getApparentTemp(tempC, rh, wsM))
+	if topBarFlag {
+		weatherStr = fmt.Sprintf("%.0f", temp)
+		if int(at+0.5) != int(temp+0.5) {
+			weatherStr += fmt.Sprintf(" (A%.0f)", at)
+		}
+		if int(hi+0.5) > int(temp+0.5) {
+			weatherStr += fmt.Sprintf(" (H%.0f)", hi)
+		} else if int(wc+0.5) < int(temp+0.5) {
+			weatherStr += fmt.Sprintf(" (W%.0f)", wc)
+		}
+		weatherStr += "F "
+		return
+	}
+	weatherStr = fmt.Sprintf("Weather Station: %s\nTime: %s\n\n"+
+		"Temperature: %.2fF\nApparent Temperature %.2fF\n", stationID,
+		w.Timestamp.Format(time.RFC1123), temp, at)
+	if int(hi+0.5) != int(temp+0.5) {
+		weatherStr += fmt.Sprintf("Heat Index: %.2fF\n", hi)
+	} else if int(wc+0.5) != int(temp+0.5) {
+		weatherStr += fmt.Sprintf("Wind Chill: %.2fF\n", wc)
+	}
+	weatherStr += fmt.Sprintf("\n%s\n\nDewPoint: %.2fF\nRelative Humidity: %.2f%%\n"+
+		"Wind: %.2f mph %s", w.TextDescription, dp, rh, ws, wd)
+	if wg > 0 {
+		weatherStr += fmt.Sprintf("\nWind Gusts: %.2f mph", wg)
+	}
+	return
+}
+
+func getWeatherAlerts() (a AlertsResponse) {
+	client := http.Client{}
+	alertEndPoint := fmt.Sprintf("https://api.weather.gov/alerts/active?point=%s,%s",
+		latitude, longitude)
+	req, err := http.NewRequest("GET", alertEndPoint, nil)
+	if err != nil {
+		return
+	}
+	req.Header = http.Header{
+		"Accept":     []string{"application/geo+json"},
+		"User-Agent": []string{"(Vi Grey Weather Info, vi@vigrey.com)"},
+	}
+	resp, err := client.Do(req)
+	if err != nil {
+		return
+	}
+	respBody, _ := io.ReadAll(resp.Body)
+	json.Unmarshal(respBody, &a)
+	return
+}
+
+func getAlertStr(a Alert) (alertStr string) {
+	var ansiStart string
+	if strings.ToLower(a.Urgency) == "immediate" {
+		ansiStart = warningANSIStart
+	} else if strings.ToLower(a.Urgency) == "future" {
+		ansiStart = watchANSIStart
+	} else if strings.ToLower(a.Urgency) == "expected" {
+		ansiStart = expectedANSIStart
+	}
+	alertStr = ansiStart + a.Event + ansiEnd + "\n"
+	if a.Expires.After(a.Ends) {
+		alertStr += "Expires at " + a.Expires.Format("Jan _2 3:04PM") + "\n\n"
+	} else {
+		alertStr += "Ends at " + a.Ends.Format("Jan _2 3:04PM") + "\n\n"
+	}
+	alertStr += (a.Headline + "\n\n" +
+		removeExtraWhitespaces(a.Description))
+	return
+}
+
+func handleFlags(flags []string) {
+	for _, flag := range flags {
+		if strings.ToLower(flag) == "--topbar" {
+			topBarFlag = true
+		} else if len(strings.ToLower(flag)) == 4 {
+			stationID = strings.ToUpper(flag)
+		} else if strings.Contains(flag, ",") {
+			flagSplit := strings.Split(flag, ",")
+			latitude = flagSplit[0]
+			longitude = flagSplit[1]
+		}
+	}
+}
+
+func validNWSWeather(m string) bool {
+	return m != ""
+}
+
+func main() {
+	handleFlags(os.Args[1:])
+	if stationID == "" && latitude == "" && longitude == "" {
+		return
+	}
+	if stationID != "" {
+		w := getWeather()
+		if w.Status == 0 || w.Status == 200 {
+			mw := metarStringToWeatherData(w.Properties.RawMessage)
+			var weatherStr string
+			weatherStr = getWeatherStr(w.Properties, mw)
+			if topBarFlag {
+				iconStr := iconStringToWeatherIcon(w.Properties.Icon)
+				fmt.Printf("  %s %s\n", iconStr, weatherStr)
+				return
+			}
+			fmt.Println(weatherStr)
+		}
+	}
+	if latitude != "" && longitude != "" {
+		alerts := getWeatherAlerts()
+		if alerts.Status == 0 || alerts.Status == 200 {
+			if len(alerts.Features) > 0 && stationID != "" {
+				fmt.Println("\n--------------------\n\nAlerts:\n")
+			}
+			for x, a := range alerts.Features {
+				fmt.Println(getAlertStr(a.Properties))
+				if x != len(alerts.Features)-1 {
+					fmt.Println("\n")
+				}
+			}
+		}
+	}
+}