Feature enhancement: Adding -f/--format

* Adding the --format flag to leave it to the users to format their
queries
* Adding an --extra-information flag to print out some advanced
information
* Variable name change to make it more accurate, it's an affix

README.md

@@ -36,8 +36,10 @@ Flags:
   -P, --png                Download a weather PNG image
       --v2                 Use the v2 endpoint
   -t, --transparency=0     Set transparency level (0-100) (PNG only)
+  -f, --format=FORMAT      Query format (overrides everything else)
   -L, --location=LOCATION  Specify explicite location
   -l, --language=LANGUAGE  Specify explicite language
+      --extra-information  Print extra information
       --version            Show application version.
 ```
 

main.go

@@ -36,6 +36,7 @@ const (
 	NOCOLORS
 	ADDFRAME
 	MIDTRANSPARENCY
+	FORMAT
 	LOCATION
 	LANGUAGE
 	PNG
@@ -144,6 +145,7 @@ func getWheather(url string, headers map[string]string, download bool) {
 type cmdParams struct {
 	Flags        int
 	Transparency int
+	Format       string
 	Location     string
 	Language     string
 }
@@ -154,9 +156,14 @@ type cmdParams struct {
 // as well.
 func (cmdP *cmdParams) generateParamFormat() (string, bool, error) {
 	var params []string
-	var prefix []string
+	var affix []string
 	var download bool
-	prefix = append(prefix, "?")
+	affix = append(affix, "?")
+
+	// If --format is specified, let's not bother and simply return it
+	if cmdP.Flags&FORMAT == FORMAT {
+		return cmdP.Format, false, nil
+	}
 
 	if cmdP.Flags&METRIC == METRIC {
 		params = append(params, MetricSwitch)
@@ -211,7 +218,7 @@ func (cmdP *cmdParams) generateParamFormat() (string, bool, error) {
 	}
 
 	if cmdP.Flags&PNG == PNG {
-		prefix[0] = "_"
+		affix[0] = "_"
 
 		if cmdP.Flags&MIDTRANSPARENCY == MIDTRANSPARENCY {
 			params = append(params, MidTransparencySwitch)
@@ -225,7 +232,7 @@ func (cmdP *cmdParams) generateParamFormat() (string, bool, error) {
 		download = true
 	}
 
-	params = append(prefix, strings.Join(params, ""))
+	params = append(affix, strings.Join(params, ""))
 
 	return strings.Join(params, ""), download, nil
 }
@@ -250,10 +257,40 @@ var (
 	png              = app.Flag("png", "Download a weather PNG image").Short('P').Default("false").Bool()
 	v2               = app.Flag("v2", "Use the v2 endpoint").Default("false").Bool()
 	transparency     = app.Flag("transparency", "Set transparency level (0-100) (PNG only)").Short('t').Default("0").Int()
+	format           = app.Flag("format", "Query format (overrides everything else)").Short('f').OverrideDefaultFromEnvar("GO_CMW_FORMAT").String()
 	location         = app.Flag("location", "Specify explicite location").Short('L').OverrideDefaultFromEnvar("GO_CMW_LOCATION").String()
 	language         = app.Flag("language", "Specify explicite language").Short('l').OverrideDefaultFromEnvar("GO_CMW_LANGUAGE").String()
+	extraInformation = app.Flag("extra-information", "Print extra information").Default("false").Bool()
 )
 
+// Special help menu
+func printExtraInformation() {
+	eInfo := `
+Supported Location Types
+------------------------
+City name:                  Paris
+Unicode name:               Москва
+Airport code (3 letters):   muc
+Domain name:                @stackoverflow.com
+Area code:                  94107
+GPS coordinates:            -78.46,106.79
+
+Special Location
+----------------
+Moon phase (add ,+US or
+,+France for these cities): moon
+Moon phase for a date:      moon@2016-10-25
+
+Supported languages
+-------------------
+
+Supported: af da de el et fr fa hu id it nb nl
+           pl pt-br ro ru tr uk vi
+	`
+
+	println(eInfo)
+}
+
 // Create a function to parse all the command line parameters
 // provided and save them in the parameter struct.
 func flagParser(cmdP *cmdParams) {
@@ -263,6 +300,10 @@ func flagParser(cmdP *cmdParams) {
 
 	kingpin.MustParse(app.Parse(os.Args[1:]))
 
+	if *extraInformation {
+		printExtraInformation()
+		os.Exit(0)
+	}
 	// Windows does not have color encoding
 	// so let's make sure windows users are happy
 	term := os.Getenv("TERM")
@@ -338,6 +379,11 @@ func flagParser(cmdP *cmdParams) {
 		cmdP.Flags += VTWO
 	}
 
+	if *format != "" {
+		cmdP.Flags += FORMAT
+		cmdP.Format = *format
+	}
+
 	if *location != "" {
 		cmdP.Flags += LOCATION
 		cmdP.Location = *location
@@ -351,7 +397,7 @@ func flagParser(cmdP *cmdParams) {
 }
 
 // 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) {
+func generateURL(domain string, v2 bool, location string, lang string, affix string) ([]string, map[string]string) {
 	var link []string
 	var headers = make(map[string]string)
 
@@ -367,8 +413,8 @@ func generateURL(domain string, v2 bool, location string, lang string, format st
 		link = append(link, location)
 	}
 
-	if format != "" {
-		link = append(link, format)
+	if affix != "" {
+		link = append(link, affix)
 	}
 
 	if lang != "" {
@@ -383,7 +429,7 @@ 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)
+	affix, download, _ := params.generateParamFormat()
+	link, headers := generateURL(domain, params.Flags&VTWO == VTWO, params.Location, params.Language, affix)
 	getWheather(strings.Join(link, ""), headers, download)
 }