Working on tz sorting

Author: merschformann

core/args.go

@@ -16,7 +16,7 @@ func ParseFlags(startConfig Config, appVersion string) (Config, time.Time, bool,
 	// Check for any changes
 	var changed bool
 	// Define configuration flags
-	var timezones, symbols, tics, stretch, inline, colorize, hours12, live string
+	var timezones, symbols, tics, stretch, inline, colorize, hours12, live, sorting string
 	flag.StringVar(
 		&timezones,
 		"timezones",
@@ -69,6 +69,15 @@ func ParseFlags(startConfig Config, appVersion string) (Config, time.Time, bool,
 		"",
 		"indicates whether to display time live (quit via 'q' or 'Ctrl+C') (one of: true, false)",
 	)
+	flag.StringVar(
+		&sorting,
+		"",
+		SortingModeDefault,
+		"indicates how to sort the timezones (one of: "+
+			SortingModeNone+", "+
+			SortingModeOffset+", "+
+			SortingModeName+")",
+	)
 
 	// Define direct flags
 	var requestTime string
@@ -166,6 +175,13 @@ func ParseFlags(startConfig Config, appVersion string) (Config, time.Time, bool,
 			return startConfig, rt, changed, fmt.Errorf("invalid value for live: %s", live)
 		}
 	}
+	if sorting != "" {
+		changed = true
+		if isValidSortingMode(sorting) {
+			return startConfig, rt, changed, fmt.Errorf("invalid sorting mode: %s", sorting)
+		}
+		startConfig.Sorting = sorting
+	}
 
 	// Handle direct flags
 	if requestTime != "" {

core/configuration.go

@@ -38,6 +38,9 @@ type Config struct {
 
 	// Indicates whether to continuously update.
 	Live bool `json:"live"`
+
+	// Defines the mode for sorting the timezones.
+	Sorting string `json:"sorting"`
 }
 
 // Location describes a timezone the user wants to display.

core/plot.go

@@ -330,15 +330,22 @@ func PlotTime(plt Plotter, cfg Config, t time.Time) error {
 
 // createTimeInfos creates the time info strings for all locations.
 func createTimeInfos(cfg Config, t time.Time) (timeInfos []string, times []*time.Location, err error) {
-	// Init
-	timeInfos = make([]string, len(cfg.Timezones)+1)
-
-	// Prepare timeZones to plot
+	// Sort timezones and convert
 	timeZones := make([]*time.Location, len(cfg.Timezones)+1)
 	descriptions := make([]string, len(cfg.Timezones)+1)
+	sortedTimeZones := sortLocations(cfg.Timezones, cfg.Sorting)
+
+	// Prepare timeZones to plot
 	timeZones[0] = time.Local
 	descriptions[0] = "Local"
-	for i, tz := range cfg.Timezones {
+	sortedZones := cfg.Timezones
+	switch cfg.Sorting {
+	case SortingModeOffset:
+		sortedZones = sortByOffset(cfg.Timezones)
+	case SortingModeName:
+		sortedZones = sortByName(cfg.Timezones)
+	}
+	for i, tz := range sortedZones {
 		// Get timezone
 		loc, err := time.LoadLocation(tz.TZ)
 		if err != nil {
@@ -350,6 +357,7 @@ func createTimeInfos(cfg Config, t time.Time) (timeInfos []string, times []*time
 	}
 	descriptionLength := maxStringLength(descriptions)
 
+	timeInfos = make([]string, len(cfg.Timezones)+1)
 	for i := range timeZones {
 		// Prepare location and time infos
 		timeInfo := fmt.Sprintf("%-*s", descriptionLength, descriptions[i])

core/sorting.go

@@ -0,0 +1,32 @@
+package core
+
+import "sort"
+
+// Define sorting modes
+const (
+	// SortingModeNone keeps the order of the timezones as they are defined.
+	SortingModeNone = "none"
+	// SortingModeOffset sorts the timezones by their offset.
+	SortingModeOffset = "offset"
+	// SortingModeName sorts the timezones by their name.
+	SortingModeName = "name"
+	// SortingModeDefault is the default sorting mode.
+	SortingModeDefault = SortingModeNone
+)
+
+// isValidSortingMode checks if the given sorting mode is defined and valid.
+func isValidSortingMode(mode string) bool {
+	switch mode {
+	case SortingModeNone, SortingModeOffset, SortingModeName:
+		return true
+	default:
+		return false
+	}
+}
+
+// sortByOffset sorts the given locations by their offset.
+func sortByOffset(locations []Location) {
+	sort.Slice(locations, func(i, j int) bool {
+		return locations[i].
+	})
+}

go.mod

@@ -1,6 +1,6 @@
 module github.com/merschformann/gotz
 
-go 1.17
+go 1.23.0
 
 require (
 	github.com/adrg/xdg v0.4.0