feat: support specifying timezone

Amolith created 9 months ago

Add timezone configuration and validation to ensure the configured timezone is
valid on startup and during task creation. This includes adding a new `Timezone`
field to the `Config` struct and implementing a `loadLocation` function to
validate the timezone.

This change also updates the `handleCreateTask` function to use the configured
timezone when parsing natural language dates. Additionally, the default
configuration file creation has been updated to include the `Timezone` field
with a default value of "UTC".

BREAKING CHANGE: The `Timezone` field must be set in the configuration file. If
not set, the application will fail to start.

Change summary

main.go | 45 +++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 43 insertions(+), 2 deletions(-)

Detailed changes

main.go

@@ -48,6 +48,7 @@ type Config struct {
 	AccessToken string       `toml:"access_token"`
 	Areas       []Area       `toml:"areas"`
 	Server      ServerConfig `toml:"server"`
+	Timezone    string       `toml:"timezone"`
 }
 
 func main() {
@@ -84,6 +85,11 @@ func main() {
 		}
 	}
 
+	// Validate timezone config on startup
+	if _, err := loadLocation(config.Timezone); err != nil {
+		log.Fatalf("Timezone validation failed: %v", err)
+	}
+
 	mcpServer := NewMCPServer(&config)
 
 	baseURL := fmt.Sprintf("http://%s:%d", config.Server.Host, config.Server.Port)
@@ -95,6 +101,18 @@ func main() {
 	}
 }
 
+// loadLocation loads a timezone location string, returning a *time.Location or error
+func loadLocation(timezone string) (*time.Location, error) {
+	if timezone == "" {
+		return nil, fmt.Errorf("Timezone is not configured; please set the 'timezone' value in your config file (e.g. 'UTC' or 'America/New_York')")
+	}
+	loc, err := time.LoadLocation(timezone)
+	if err != nil {
+		return nil, fmt.Errorf("Could not load timezone '%s': %v", timezone, err)
+	}
+	return loc, nil
+}
+
 func NewMCPServer(config *Config) *server.MCPServer {
 	hooks := &server.Hooks{}
 
@@ -137,7 +155,11 @@ func NewMCPServer(config *Config) *server.MCPServer {
 		if !ok || natLangDate == "" {
 			return reportMCPError("Missing or invalid required argument: natural_language_date")
 		}
-		parsedTime, err := anytime.Parse(natLangDate, time.Now())
+		loc, err := loadLocation(config.Timezone)
+		if err != nil {
+			return reportMCPError(err.Error())
+		}
+		parsedTime, err := anytime.Parse(natLangDate, time.Now().In(loc))
 		if err != nil {
 			return reportMCPError(fmt.Sprintf("Could not parse natural language date: %v", err))
 		}
@@ -241,6 +263,11 @@ func handleCreateTask(
 ) (*mcp.CallToolResult, error) {
 	arguments := request.Params.Arguments
 
+	// Validate timezone before proceeding any further
+	if _, err := loadLocation(config.Timezone); err != nil {
+		return reportMCPError(err.Error())
+	}
+
 	areaID, ok := arguments["area_id"].(string)
 	if !ok || areaID == "" {
 		return reportMCPError("Missing or invalid required argument: area_id")
@@ -270,6 +297,19 @@ func handleCreateTask(
 		}
 	}
 
+	// Validate scheduled_on format if provided
+	if scheduledOnArg, exists := arguments["scheduled_on"]; exists {
+		if scheduledOnStr, ok := scheduledOnArg.(string); ok && scheduledOnStr != "" {
+			if _, err := time.Parse(time.RFC3339, scheduledOnStr); err != nil {
+				return reportMCPError(fmt.Sprintf("Invalid format for scheduled_on: '%s'. Must be RFC3339 timestamp (e.g., YYYY-MM-DDTHH:MM:SSZ). Use get_task_timestamp tool first.", scheduledOnStr))
+			}
+		} else if !ok {
+			// It exists but isn't a string, which shouldn't happen based on MCP schema but check anyway
+			return reportMCPError("Invalid type for scheduled_on argument: expected string.")
+		}
+		// If it's an empty string, it's handled by the API or omitempty later, no need to validate format.
+	}
+
 	var payload LunataskCreateTaskRequest
 	argBytes, err := json.Marshal(arguments)
 	if err != nil {
@@ -371,6 +411,7 @@ func createDefaultConfigFile(configPath string) {
 			Port: 8080,
 		},
 		AccessToken: "",
+		Timezone:    "UTC",
 		Areas: []Area{{
 			Name: "Example Area",
 			ID:   "area-id-placeholder",
@@ -388,6 +429,6 @@ func createDefaultConfigFile(configPath string) {
 	if err := toml.NewEncoder(file).Encode(defaultConfig); err != nil {
 		log.Fatalf("Failed to encode default config to %s: %v", configPath, err)
 	}
-	fmt.Printf("A default config has been created at %s.\nPlease edit it to provide your Lunatask access token and correct area/goal IDs, then restart the server.\n", configPath)
+	fmt.Printf("A default config has been created at %s.\nPlease edit it to provide your Lunatask access token, correct area/goal IDs, and your timezone (IANA/Olson format, e.g. 'America/New_York'), then restart the server.\n", configPath)
 	os.Exit(1)
 }