feat: add --indent flag to control line indentation in remind output

- Introduces an 'indent' integer flag to the CLI for specifying the
  number of spaces to indent lines in the remind output.
- Updates Task.ToRemind to accept an indent parameter and apply heading
  spaces accordingly.
- Adjusts main.go to pass the indent value from the flag to ToRemind.

internal/parser/parser.go

@@ -23,10 +23,10 @@ type Task struct {
 	Description    string              `json:"description"`        // description with projects/contexts/metadata removed
 	Projects       []string            `json:"projects"`
 	Contexts       []string            `json:"contexts"`
-	Metadata       map[string]string `json:"metadata"`
+	Metadata       map[string][]string `json:"metadata"`
 }
 
-func (t Task) ToRemind() string {
+func (t Task) ToRemind(indent int) string {
 	var sb strings.Builder
 	sb.WriteString("REM TODO ")
 	if t.DueDate == nil {
@@ -37,13 +37,19 @@ func (t Task) ToRemind() string {
 	sb.WriteString(" ++5 INFO \"Calendar: TODO.TX\" ")
 
 	if len(t.Metadata) > 0 {
-		for k, v := range t.Metadata {
+		for k, values := range t.Metadata {
 			if k == "due" {
 				continue
 			}
 			// k must have the first letter uppercase for Remind
-			k = strings.ToUpper(k[:1]) + k[1:]
+			kUpper := strings.ToUpper(k[:1]) + k[1:]
-			sb.WriteString(fmt.Sprintf("INFO \"%s: %s\" ", k, v))
+			if len(values) == 1 {
+				sb.WriteString(fmt.Sprintf("INFO \"%s: %s\" ", kUpper, values[0]))
+			} else {
+				for i, v := range values {
+					sb.WriteString(fmt.Sprintf("INFO \"%s%d: %s\" ", kUpper, i+1, v))
+				}
+			}
 		}
 	}
 
@@ -81,14 +87,23 @@ func (t Task) ToRemind() string {
 		sb.WriteString(" (%b)")
 	}
 
+	headingSpaces := strings.Repeat(" ", indent)
+
 	if len(t.Metadata) > 0 {
-		for k := range t.Metadata {
+		for k, values := range t.Metadata {
 			if k == "due" {
 				continue
 			}
 			// uppercase first letter for Remind
-			k = strings.ToUpper(k[:1]) + k[1:]
+			kUpper := strings.ToUpper(k[:1]) + k[1:]
-			sb.WriteString(fmt.Sprintf("%%_%s: %%<%s>", k, k))
+			if len(values) == 1 {
+				sb.WriteString(fmt.Sprintf("%%_%s%s: %%<%s>", headingSpaces, kUpper, kUpper))
+			} else {
+				for i := range values {
+					kNumbered := fmt.Sprintf("%s%d", kUpper, i+1)
+					sb.WriteString(fmt.Sprintf("%%_%s%s: %%<%s>", headingSpaces, kNumbered, kNumbered))
+				}
+			}
 		}
 	}
 
@@ -181,7 +196,7 @@ func ParseReader(r io.Reader) ([]Task, []error) {
 func ParseLine(line string) (Task, error) {
 	t := Task{
 		Raw:      line,
-		Metadata: make(map[string]string),
+		Metadata: make(map[string][]string),
 	}
 
 	working := strings.TrimSpace(line)
@@ -262,14 +277,14 @@ func ParseLine(line string) (Task, error) {
 				}
 				val += " " + toks[i]
 			}
-			t.Metadata["location"] = val
+			t.Metadata["location"] = append(t.Metadata["location"], val)
 			continue
 		}
 		if !strings.ContainsAny(tok, " \t") && strings.Contains(tok, ":") {
 			parts := strings.SplitN(tok, ":", 2)
 			k, v := parts[0], parts[1]
 			if k != "" && v != "" && !isProtocolKey(k) {
-				t.Metadata[k] = v
+				t.Metadata[k] = append(t.Metadata[k], v)
 				if k == "due" && dateRe.MatchString(v) {
 					if dt, err := time.Parse(dateLayout, v); err == nil {
 						t.DueDate = &dt
@@ -277,6 +292,7 @@ func ParseLine(line string) (Task, error) {
 				}
 				continue
 			}
+
 		}
 		descParts = append(descParts, tok)
 	}

main.go

@@ -14,7 +14,8 @@ var (
 	inputFile  string
 	outputFile string
 	debug      bool
-	version    = "v2"
+	indent     int
+	version    = "v3.0.0"
 )
 
 func main() {
@@ -59,7 +60,7 @@ func main() {
 			}
 
 			for _, t := range tasks {
-				rem := t.ToRemind()
+				rem := t.ToRemind(indent)
 				if rem == "" {
 					continue
 				}
@@ -71,6 +72,7 @@ func main() {
 	rootCmd.Flags().StringVarP(&inputFile, "input", "i", "", "Input file (default: stdin)")
 	rootCmd.Flags().StringVarP(&outputFile, "output", "o", "", "Output file (default: stdout)")
 	rootCmd.Flags().BoolVar(&debug, "debug", false, "Print intermediate JSON to stderr")
+	rootCmd.Flags().IntVar(&indent, "indent", 0, "Number of spaces to indent lines (from second line onward)")
 	rootCmd.Version = version
 	rootCmd.Flags().BoolP("version", "v", false, "Show version and exit")
 	rootCmd.SetVersionTemplate(fmt.Sprintf("todotxt2remind version %s\n", version))