Adding the initial code

LICENSE

@@ -0,0 +1,25 @@
+BSD 2-Clause License
+
+Copyright (c) 2020, Elia el Lazkani
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright notice, this
+  list of conditions and the following disclaimer.
+
+* 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 THE COPYRIGHT HOLDERS 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 THE COPYRIGHT HOLDER 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.

main.go

@@ -0,0 +1,348 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"os"
+	"strings"
+
+	flag "github.com/spf13/pflag"
+)
+
+// Create a list of constants to figure out
+// the command line flags and translate them
+// into uri flags.
+const (
+	METRIC = 1 << iota
+	USCS
+	METERSECOND
+	ZERO
+	ONE
+	TWO
+	IGNOREUSERAGENT
+	FOLLOWLINK
+	NARROW
+	QUIET
+	SUPERQUIET
+	NOCOLORS
+	ADDFRAME
+	MIDTRANSPARENCY
+	TRANSPARENCY
+	LOCATION
+	LANGUAGE
+	PNG
+	VTWO
+)
+
+// Create a list of constants to define
+// uri switches by flag.
+const (
+	MetricSwitch          = "m"
+	UscsSwitch            = "u"
+	MeterSecondSwitch     = "M"
+	ZeroSwitch            = "0"
+	OneSwitch             = "1"
+	TwoSwitch             = "2"
+	IgnoreUserAgentSwitch = "A"
+	FollowLinkSwitch      = "F"
+	NarrowSwitch          = "n"
+	QuietSwitch           = "q"
+	SuperQuietSwitch      = "Q"
+	NoColorsSwitch        = "T"
+	AddFrameSwitch        = "p"
+	MidTransparencySwitch = "T"
+)
+
+// Define a command parameters struct.
+// This will hold all the configurations
+// set by the command line parameters provided.
+type cmdParams struct {
+	Flags             int
+	TransparencyLevel int
+	Location          string
+	Language          string
+}
+
+// Create a method to figure out the command parameters
+// provided and translate them into uri parameters.
+// This will figure out if we need to download the PNG image
+// as well.
+func (cmdP *cmdParams) generateParamFormat() (string, bool, error) {
+	var params []string
+	var prefix []string
+	var download bool
+	prefix = append(prefix, "?")
+
+	if cmdP.Flags&METRIC == METRIC {
+		params = append(params, MetricSwitch)
+	}
+
+	if cmdP.Flags&USCS == USCS {
+		params = append(params, UscsSwitch)
+	}
+
+	if cmdP.Flags&METERSECOND == METERSECOND {
+		params = append(params, MeterSecondSwitch)
+	}
+
+	if cmdP.Flags&ZERO == ZERO {
+		params = append(params, ZeroSwitch)
+	}
+
+	if cmdP.Flags&ONE == ONE {
+		params = append(params, OneSwitch)
+	}
+
+	if cmdP.Flags&TWO == TWO {
+		params = append(params, TwoSwitch)
+	}
+
+	if cmdP.Flags&IGNOREUSERAGENT == IGNOREUSERAGENT {
+		params = append(params, IgnoreUserAgentSwitch)
+	}
+
+	if cmdP.Flags&FOLLOWLINK == FOLLOWLINK {
+		params = append(params, FollowLinkSwitch)
+	}
+
+	if cmdP.Flags&NARROW == NARROW {
+		params = append(params, NarrowSwitch)
+	}
+
+	if cmdP.Flags&QUIET == QUIET {
+		params = append(params, QuietSwitch)
+	}
+
+	if cmdP.Flags&SUPERQUIET == SUPERQUIET {
+		params = append(params, SuperQuietSwitch)
+	}
+
+	if cmdP.Flags&NOCOLORS == NOCOLORS {
+		params = append(params, NoColorsSwitch)
+	}
+
+	if cmdP.Flags&ADDFRAME == ADDFRAME {
+		params = append(params, AddFrameSwitch)
+	}
+
+	if cmdP.Flags&MIDTRANSPARENCY == MIDTRANSPARENCY {
+		params = append(params, MidTransparencySwitch)
+	}
+
+	if cmdP.Flags&PNG == PNG {
+		prefix[0] = "_"
+
+		if cmdP.Flags&TRANSPARENCY == TRANSPARENCY && cmdP.TransparencyLevel >= 0 && cmdP.TransparencyLevel <= 100 {
+			params = append(params, strings.Join([]string{"_transparency=", string(cmdP.TransparencyLevel)}, ""))
+		}
+
+		params = append(params, ".png")
+		download = true
+	}
+
+	params = append(prefix, strings.Join(params, ""))
+
+	return strings.Join(params, ""), download, nil
+}
+
+// TODO:
+//   * Fix the description for help
+//
+// Create a function to parse all the command line parameters
+// provided and save them in the parameter struct.
+func flagParser(cmdP *cmdParams) {
+	metric := flag.Bool("metric", false, "Display weather in metric")
+	uscs := flag.Bool("uscs", false, "Display weather Imperial")
+	meterSecond := flag.Bool("meter-second", false, "Display wind in m/s")
+	zero := flag.Bool("zero", false, "Show the weather now")
+	one := flag.Bool("one", false, "Show the weather for one day")
+	two := flag.Bool("two", false, "Show the weather for two days")
+	ignoreUserAgent := flag.Bool("ignore-user-agent", false, "Request ignoring the user agent")
+	followLink := flag.Bool("follow-link", true, "Follow link redirect")
+	narrow := flag.Bool("narrow", false, "Display weather in narrow view")
+	quiet := flag.Bool("quiet", false, "Add the quiet flag")
+	superQuiet := flag.Bool("super-quiet", false, "Add the super quiet flag")
+	noColors := flag.Bool("no-colors", false, "Disable displaying colors")
+	addFrame := flag.Bool("add-frame", false, "Add a frame to the output")
+	midTransparency := flag.Bool("mid-transparency", false, "Enable mid-transparency (PNG only)")
+	transparency := flag.Bool("transparency", false, "Enable transparency (PNG only)")
+	png := flag.Bool("png", false, "Download a weather PNG image")
+	v2 := flag.Bool("v2", false, "Use the v2 endpoint")
+	transparencyLevel := flag.Int("transparency-level", 0, "Set transparency level between 0 and 100 ")
+	location := flag.String("location", "", "Specify explicite location")
+	language := flag.String("language", "", "Speficy explicite language")
+
+	flag.Parse()
+
+	if *metric {
+		cmdP.Flags += METRIC
+	}
+
+	if *uscs {
+		cmdP.Flags += USCS
+	}
+
+	if *meterSecond {
+		cmdP.Flags += METERSECOND
+	}
+
+	if *zero {
+		cmdP.Flags += ZERO
+	}
+
+	if *one {
+		cmdP.Flags += ONE
+	}
+
+	if *two {
+		cmdP.Flags += TWO
+	}
+
+	if *ignoreUserAgent {
+		cmdP.Flags += IGNOREUSERAGENT
+	}
+
+	if *followLink {
+		cmdP.Flags += FOLLOWLINK
+	}
+
+	if *narrow {
+		cmdP.Flags += NARROW
+	}
+
+	if *quiet {
+		cmdP.Flags += QUIET
+	}
+
+	if *superQuiet {
+		cmdP.Flags += SUPERQUIET
+	}
+
+	if *noColors {
+		cmdP.Flags += NOCOLORS
+	}
+
+	if *addFrame {
+		cmdP.Flags += ADDFRAME
+	}
+
+	if *midTransparency {
+		cmdP.Flags += MIDTRANSPARENCY
+	}
+
+	if *transparency {
+		cmdP.Flags += TRANSPARENCY
+		cmdP.TransparencyLevel = *transparencyLevel
+	}
+
+	if *png {
+		cmdP.Flags += PNG
+	}
+
+	if *v2 {
+		cmdP.Flags += VTWO
+	}
+
+	if *location != "" {
+		cmdP.Flags += LOCATION
+		cmdP.Location = *location
+	}
+
+	if *language != "" {
+		cmdP.Flags += LANGUAGE
+		cmdP.Language = *language
+	}
+
+}
+
+// Create a function to generate the url that we'll be calling shortly.
+func generateURL(domain string, v2 bool, location string, lang string, format string) ([]string, map[string]string) {
+	var link []string
+	var headers = make(map[string]string)
+
+	link = append(link, "https://")
+
+	if v2 {
+		link = append(link, "v2.")
+	}
+
+	link = append(link, domain, "/")
+
+	if location != "" {
+		link = append(link, location)
+	}
+
+	if format != "" {
+		link = append(link, format)
+	}
+
+	if lang != "" {
+		headers["Accept-Language"] = lang
+	}
+
+	return link, headers
+}
+
+// TODO:
+//   * Create interfaces to print and save and migrate code to them
+//
+// Figure out if we need to print or download a PNG image
+// and call the server accordingly.
+func getWheather(url string, headers map[string]string, download bool) {
+
+	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		log.Fatal("Error reading request. ", err)
+	}
+
+	req.Header.Set("Content-Type", "text/plain; charset=utf-8")
+	// I had to read the wttr.in code to figure this one out.
+	// It wasn't Golang, it was 2 wasted hours that I won't be getting back.
+	req.Header.Set("User-Agent", "curl")
+
+	for key, value := range headers {
+		req.Header.Add(key, value)
+	}
+
+	client := &http.Client{}
+	client.Jar = nil
+
+	resp, err := client.Do(req)
+	if err != nil {
+		log.Fatal("Error reading response. ", err)
+	}
+	defer resp.Body.Close()
+
+	if download {
+		splitURL := strings.Split(url, "/")
+		filename := splitURL[len(splitURL)-1]
+
+		f, err := os.Create(filename)
+		if err != nil {
+			return
+		}
+		defer f.Close()
+
+		_, err = io.Copy(f, resp.Body)
+	} else {
+
+		body, err := ioutil.ReadAll(resp.Body)
+		if err != nil {
+			log.Fatal("Error reading body. ", err)
+		}
+		fmt.Printf("%s\n", body)
+	}
+}
+
+// This is the main function that glues everything together.
+func main() {
+	var params cmdParams = cmdParams{}
+	var domain string = "wttr.in"
+	flagParser(&params)
+	format, download, _ := params.generateParamFormat()
+	link, headers := generateURL(domain, params.Flags&VTWO == VTWO, params.Location, params.Language, format)
+	getWheather(strings.Join(link, ""), headers, download)
+}