feat(parser): support multiple values per metadata key in Task

BREAKING CHANGE: The Task struct's Metadata field now maps to slices of
strings (map[string][]string) instead of single strings. This allows
tasks to have multiple values for the same metadata key. All code
interacting with Metadata must be updated to handle slices. Version
bumped to v3.0.0.

internal/parser/parser.go

@@ -14,16 +14,16 @@ import (
 
 // Task represents a parsed todo item.
 type Task struct {
-	Raw            string            `json:"raw"`
-	Completed      bool              `json:"completed"`
-	CompletionDate *time.Time        `json:"completion_date,omitempty"`
-	Priority       *rune             `json:"priority,omitempty"` // 'A'..'Z'
-	CreationDate   *time.Time        `json:"creation_date,omitempty"`
-	DueDate        *time.Time        `json:"due_date,omitempty"` // parsed from due:YYYY-MM-DD
-	Description    string            `json:"description"`        // description with projects/contexts/metadata removed
-	Projects       []string          `json:"projects"`
-	Contexts       []string          `json:"contexts"`
-	Metadata       map[string]string `json:"metadata"`
+	Raw            string              `json:"raw"`
+	Completed      bool                `json:"completed"`
+	CompletionDate *time.Time          `json:"completion_date,omitempty"`
+	Priority       *rune               `json:"priority,omitempty"` // 'A'..'Z'
+	CreationDate   *time.Time          `json:"creation_date,omitempty"`
+	DueDate        *time.Time          `json:"due_date,omitempty"` // parsed from due:YYYY-MM-DD
+	Description    string              `json:"description"`        // description with projects/contexts/metadata removed
+	Projects       []string            `json:"projects"`
+	Contexts       []string            `json:"contexts"`
+	Metadata       map[string][]string `json:"metadata"`
 }
 
 func (t Task) ToRemind() string {
@@ -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:]
-			sb.WriteString(fmt.Sprintf("INFO \"%s: %s\" ", k, v))
+			kUpper := strings.ToUpper(k[:1]) + k[1:]
+			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))
+				}
+			}
 		}
 	}
 
@@ -82,13 +88,20 @@ func (t Task) ToRemind() string {
 	}
 
 	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:]
-			sb.WriteString(fmt.Sprintf("%%_%s: %%<%s>", k, k))
+			kUpper := strings.ToUpper(k[:1]) + k[1:]
+			if len(values) == 1 {
+				sb.WriteString(fmt.Sprintf("%%_%s: %%<%s>", kUpper, kUpper))
+			} else {
+				for i := range values {
+					kNumbered := fmt.Sprintf("%s%d", kUpper, i+1)
+					sb.WriteString(fmt.Sprintf("%%_%s: %%<%s>", kNumbered, kNumbered))
+				}
+			}
 		}
 	}
 
@@ -181,7 +194,7 @@ 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 +275,14 @@ 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 +290,7 @@ func ParseLine(line string) (Task, error) {
 				}
 				continue
 			}
+
 		}
 		descParts = append(descParts, tok)
 	}

main.go

@@ -14,7 +14,7 @@ var (
 	inputFile  string
 	outputFile string
 	debug      bool
-	version    = "v2.0.0"
+	version    = "v3.0.0"
 )
 
 func main() {