Adds TZ sorting option

README.md

@@ -171,7 +171,12 @@ The configuration is stored in `$XDG_CONFIG_HOME/gotz/config.json` (usually `~/.
     // Indicates whether to colorize the blocks
     "hours12": false,
     // Indicates whether to use 12-hour format
-    "live": false
+    "live": false,
+    // Selects the sorting of the timezones
+    // (one of 'name' - lexicographically, 'offset' - TZ offset, 'none' - user defined)
+    "sorting": "name",
+    // Indicates whether to keep the local timezone on top when using sorting
+    "sort_local_top": true
 }
 ```
 

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, sortLocalTop string
 	flag.StringVar(
 		&timezones,
 		"timezones",
@@ -69,6 +69,21 @@ 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,
+		"sorting",
+		SortingModeDefault,
+		"indicates how to sort the timezones (one of: "+
+			SortingModeNone+", "+
+			SortingModeOffset+", "+
+			SortingModeName+")",
+	)
+	flag.StringVar(
+		&sortLocalTop,
+		"sort-local-top",
+		"",
+		"indicates whether to keep the local timezone at the top (one of: true, false)",
+	)
 
 	// Define direct flags
 	var requestTime string
@@ -166,6 +181,23 @@ 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
+	}
+	if sortLocalTop != "" {
+		changed = true
+		if strings.ToLower(sortLocalTop) == "true" {
+			startConfig.SortLocalTop = true
+		} else if strings.ToLower(sortLocalTop) == "false" {
+			startConfig.SortLocalTop = false
+		} else {
+			return startConfig, rt, changed, fmt.Errorf("invalid value for sort-local-top: %s", sortLocalTop)
+		}
+	}
 
 	// Handle direct flags
 	if requestTime != "" {

core/auxiliary.go

@@ -10,17 +10,6 @@ import (
 	"golang.org/x/term"
 )
 
-// maxStringLength returns the length of the longest string in the given slice.
-func maxStringLength(s []string) int {
-	length := 0
-	for _, str := range s {
-		if len(str) > length {
-			length = len(str)
-		}
-	}
-	return length
-}
-
 // getTerminalWidth returns the width of the terminal.
 func getTerminalWidth() int {
 	width, _, err := term.GetSize(0)

core/configuration.go

@@ -38,6 +38,12 @@ type Config struct {
 
 	// Indicates whether to continuously update.
 	Live bool `json:"live"`
+
+	// Defines the mode for sorting the timezones.
+	Sorting string `json:"sorting"`
+	// SortLocalTop indicates whether the local timezone should be kept at the
+	// top (independent of the sorting mode).
+	SortLocalTop bool `json:"sort_local_top"`
 }
 
 // Location describes a timezone the user wants to display.

core/plot.go

@@ -329,36 +329,58 @@ 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
-	timeZones := make([]*time.Location, len(cfg.Timezones)+1)
-	descriptions := make([]string, len(cfg.Timezones)+1)
-	timeZones[0] = time.Local
-	descriptions[0] = "Local"
+func createTimeInfos(cfg Config, t time.Time) (timeInfos []string, timeZones []*time.Location, err error) {
+	// Prepare timezones for plotting
+	locations := make([]locationContainer, len(cfg.Timezones)+1)
+	now := time.Now()
+	_, localOffset := now.In(time.Local).Zone()
+	locations[0] = locationContainer{
+		location:    time.Local,
+		description: "Local",
+		offset:      localOffset,
+	}
 	for i, tz := range cfg.Timezones {
 		// Get timezone
 		loc, err := time.LoadLocation(tz.TZ)
 		if err != nil {
 			return nil, nil, fmt.Errorf("error loading timezone %s: %s", tz.TZ, err)
 		}
+		_, offset := now.In(loc).Zone()
 		// Store timezone
-		timeZones[i+1] = loc
-		descriptions[i+1] = tz.Name
+		locations[i+1] = locationContainer{
+			location:    loc,
+			description: tz.Name,
+			offset:      offset,
+		}
+	}
+
+	// Sort timezones and convert
+	if cfg.Sorting != SortingModeNone {
+		sortLocations(locations, cfg.Sorting, cfg.SortLocalTop)
 	}
-	descriptionLength := maxStringLength(descriptions)
 
-	for i := range timeZones {
+	// Determine max description length
+	descriptionLength := 0
+	for _, location := range locations {
+		if len(location.description) > descriptionLength {
+			descriptionLength = len(location.description)
+		}
+	}
+
+	timeInfos = make([]string, len(cfg.Timezones)+1)
+	timeZones = make([]*time.Location, len(cfg.Timezones)+1)
+	for i, location := range locations {
 		// Prepare location and time infos
-		timeInfo := fmt.Sprintf("%-*s", descriptionLength, descriptions[i])
+		timeInfo := fmt.Sprintf("%-*s", descriptionLength, location.description)
 		timeInfo = fmt.Sprintf(
 			"%s: %s %s",
 			timeInfo,
-			formatDay(cfg.Hours12, t.In(timeZones[i])),
-			formatTime(cfg.Hours12, true, t.In(timeZones[i])))
+			formatDay(cfg.Hours12, t.In(location.location)),
+			formatTime(cfg.Hours12, true, t.In(location.location)),
+		)
+		// Store time info and timezone
 		timeInfos[i] = timeInfo
+		timeZones[i] = location.location
 	}
 
 	return timeInfos, timeZones, nil

core/sorting.go

@@ -0,0 +1,59 @@
+package core
+
+import (
+	"sort"
+	"time"
+)
+
+// 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
+	}
+}
+
+// locationContainer is a container for a location with additional information.
+type locationContainer struct {
+	location    *time.Location
+	description string
+	offset      int
+}
+
+// sortLocations sorts the given locations based on the given sorting mode.
+func sortLocations(locations []locationContainer, sortingMode string, localTop bool) {
+	sort.Slice(locations, func(i, j int) bool {
+		// If the local timezone should be kept at the top, check if one of the
+		// locations is the local timezone.
+		if localTop {
+			if locations[i].location == time.Local {
+				return true
+			} else if locations[j].location == time.Local {
+				return false
+			}
+		}
+		// Sort based on the sorting mode
+		switch sortingMode {
+		case SortingModeOffset:
+			return locations[i].offset < locations[j].offset
+		case SortingModeName:
+			return locations[i].description < locations[j].description
+		default:
+			return i < j
+		}
+	})
+}

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

tests/testdata/static_sort.golden

@@ -0,0 +1,11 @@
+                                now v 16:00
+Local   : Sat 24 Aug 1985 14:00     |
+            ▒▒▒▒▒▒██████████████████|███████████▒▒▒▒▒▒▒▒▒▒▒▒            
+Berlin  : Sat 24 Aug 1985 16:00     |
+      ▒▒▒▒▒▒████████████████████████|█████▒▒▒▒▒▒▒▒▒▒▒▒                  
+New York: Sat 24 Aug 1985 10:00     |
+                        ▒▒▒▒▒▒██████|███████████████████████▒▒▒▒▒▒▒▒▒▒▒▒
+Shanghai: Sat 24 Aug 1985 22:00     |
+████████████████████████▒▒▒▒▒▒▒▒▒▒▒▒|                       ▒▒▒▒▒▒██████
+Sydney  : Sun 25 Aug 1985 00:00     |
+██████████████████▒▒▒▒▒▒▒▒▒▒▒▒      |                 ▒▒▒▒▒▒████████████

tests/testdata/static_sort.json

@@ -0,0 +1,50 @@
+{
+  "config_version": "1.0",
+  "timezones": [
+    {
+      "Name": "New York",
+      "TZ": "America/New_York"
+    },
+    {
+      "Name": "Berlin",
+      "TZ": "Europe/Berlin"
+    },
+    {
+      "Name": "Shanghai",
+      "TZ": "Asia/Shanghai"
+    },
+    {
+      "Name": "Sydney",
+      "TZ": "Australia/Sydney"
+    }
+  ],
+  "style": {
+    "symbols": "rectangles",
+    "colorize": false,
+    "day_segments": {
+      "morning": 6,
+      "day": 8,
+      "evening": 18,
+      "night": 22
+    },
+    "coloring": {
+      "StaticColorMorning": "red",
+      "StaticColorDay": "yellow",
+      "StaticColorEvening": "red",
+      "StaticColorNight": "blue",
+      "StaticColorForeground": "",
+      "DynamicColorMorning": "red",
+      "DynamicColorDay": "yellow",
+      "DynamicColorEvening": "red",
+      "DynamicColorNight": "blue",
+      "DynamicColorForeground": "",
+      "DynamicColorBackground": ""
+    }
+  },
+  "tics": false,
+  "stretch": true,
+  "hours12": false,
+  "live": false,
+  "sorting": "name",
+  "sort_local_top": true
+}