fix: update error handling

Changes:

- Move InvalidListRepliesPolicyError, InvalidTimelineCategory,
  InvalidStatusVisibility and InvalidStatusContentTypeError type to the
  model package.
- Clean up some code in regards to the parsing of the Enum types.
- Clean up the error messages sent back to the user.
- Use colons instead of semicolons when unwrapping error messages.
- Print errors to Standard Error (os.Stderr)

cmd/enbas/main.go

@@ -39,7 +39,7 @@ var (
 
 func main() {
 	if err := run(); err != nil {
-		fmt.Printf("ERROR: %v.\n", err)
+		fmt.Fprintf(os.Stderr, "ERROR: %v.\n", err)
 		os.Exit(1)
 	}
 }
@@ -71,7 +71,7 @@ func run() error {
 	flag.BoolFunc("no-color", "disable ANSI colour output when displaying text on screen", func(value string) error {
 		boolVal, err := strconv.ParseBool(value)
 		if err != nil {
-			return fmt.Errorf("unable to parse %q as a boolean; %w", value, err)
+			return fmt.Errorf("unable to parse %q as a boolean: %w", value, err)
 		}
 
 		topLevelFlags.NoColor = new(bool)
@@ -200,7 +200,7 @@ func run() error {
 	}
 
 	if err != nil {
-		return fmt.Errorf("received an error executing the command; %w", err)
+		return fmt.Errorf("(%s) %w", command, err)
 	}
 
 	return nil

internal/client/accounts.go

@@ -20,7 +20,7 @@ func (g *Client) VerifyCredentials() (model.Account, error) {
 	var account model.Account
 
 	if err := g.sendRequest(http.MethodGet, url, nil, &account); err != nil {
-		return model.Account{}, fmt.Errorf("received an error after sending the request to verify the credentials; %w", err)
+		return model.Account{}, fmt.Errorf("received an error after sending the request to verify the credentials: %w", err)
 	}
 
 	return account, nil
@@ -33,7 +33,7 @@ func (g *Client) GetAccount(accountURI string) (model.Account, error) {
 	var account model.Account
 
 	if err := g.sendRequest(http.MethodGet, url, nil, &account); err != nil {
-		return model.Account{}, fmt.Errorf("received an error after sending the request to get the account information; %w", err)
+		return model.Account{}, fmt.Errorf("received an error after sending the request to get the account information: %w", err)
 	}
 
 	return account, nil
@@ -46,11 +46,11 @@ func (g *Client) GetAccountRelationship(accountID string) (model.AccountRelation
 	var relationships []model.AccountRelationship
 
 	if err := g.sendRequest(http.MethodGet, url, nil, &relationships); err != nil {
-		return model.AccountRelationship{}, fmt.Errorf("received an error after sending the request to get the account relationship; %w", err)
+		return model.AccountRelationship{}, fmt.Errorf("received an error after sending the request to get the account relationship: %w", err)
 	}
 
 	if len(relationships) != 1 {
-		return model.AccountRelationship{}, fmt.Errorf("unexpected number of account relationships returned; want 1, got %d", len(relationships))
+		return model.AccountRelationship{}, fmt.Errorf("unexpected number of account relationships returned: want 1, got %d", len(relationships))
 	}
 
 	return relationships[0], nil
@@ -65,14 +65,14 @@ type FollowAccountForm struct {
 func (g *Client) FollowAccount(form FollowAccountForm) error {
 	data, err := json.Marshal(form)
 	if err != nil {
-		return fmt.Errorf("unable to marshal the form; %w", err)
+		return fmt.Errorf("unable to marshal the form: %w", err)
 	}
 
 	requestBody := bytes.NewBuffer(data)
 	url := g.Authentication.Instance + fmt.Sprintf("/api/v1/accounts/%s/follow", form.AccountID)
 
 	if err := g.sendRequest(http.MethodPost, url, requestBody, nil); err != nil {
-		return fmt.Errorf("received an error after sending the follow request; %w", err)
+		return fmt.Errorf("received an error after sending the follow request: %w", err)
 	}
 
 	return nil
@@ -82,7 +82,7 @@ func (g *Client) UnfollowAccount(accountID string) error {
 	url := g.Authentication.Instance + fmt.Sprintf("/api/v1/accounts/%s/unfollow", accountID)
 
 	if err := g.sendRequest(http.MethodPost, url, nil, nil); err != nil {
-		return fmt.Errorf("received an error after sending the request to unfollow the account; %w", err)
+		return fmt.Errorf("received an error after sending the request to unfollow the account: %w", err)
 	}
 
 	return nil
@@ -94,7 +94,7 @@ func (g *Client) GetFollowers(accountID string, limit int) (model.AccountList, e
 	accounts := make([]model.Account, limit)
 
 	if err := g.sendRequest(http.MethodGet, url, nil, &accounts); err != nil {
-		return model.AccountList{}, fmt.Errorf("received an error after sending the request to get the list of followers; %w", err)
+		return model.AccountList{}, fmt.Errorf("received an error after sending the request to get the list of followers: %w", err)
 	}
 
 	followers := model.AccountList{
@@ -111,7 +111,7 @@ func (g *Client) GetFollowing(accountID string, limit int) (model.AccountList, e
 	accounts := make([]model.Account, limit)
 
 	if err := g.sendRequest(http.MethodGet, url, nil, &accounts); err != nil {
-		return model.AccountList{}, fmt.Errorf("received an error after sending the request to get the list of followed accounts; %w", err)
+		return model.AccountList{}, fmt.Errorf("received an error after sending the request to get the list of followed accounts: %w", err)
 	}
 
 	following := model.AccountList{
@@ -126,7 +126,7 @@ func (g *Client) BlockAccount(accountID string) error {
 	url := g.Authentication.Instance + fmt.Sprintf("/api/v1/accounts/%s/block", accountID)
 
 	if err := g.sendRequest(http.MethodPost, url, nil, nil); err != nil {
-		return fmt.Errorf("received an error after sending the request to block the account; %w", err)
+		return fmt.Errorf("received an error after sending the request to block the account: %w", err)
 	}
 
 	return nil
@@ -136,7 +136,7 @@ func (g *Client) UnblockAccount(accountID string) error {
 	url := g.Authentication.Instance + fmt.Sprintf("/api/v1/accounts/%s/unblock", accountID)
 
 	if err := g.sendRequest(http.MethodPost, url, nil, nil); err != nil {
-		return fmt.Errorf("received an error after sending the request to unblock the account; %w", err)
+		return fmt.Errorf("received an error after sending the request to unblock the account: %w", err)
 	}
 
 	return nil
@@ -148,7 +148,7 @@ func (g *Client) GetBlockedAccounts(limit int) (model.AccountList, error) {
 	accounts := make([]model.Account, limit)
 
 	if err := g.sendRequest(http.MethodGet, url, nil, &accounts); err != nil {
-		return model.AccountList{}, fmt.Errorf("received an error after sending the request to get the list of blocked accounts; %w", err)
+		return model.AccountList{}, fmt.Errorf("received an error after sending the request to get the list of blocked accounts: %w", err)
 	}
 
 	blocked := model.AccountList{
@@ -168,14 +168,14 @@ func (g *Client) SetPrivateNote(accountID, note string) error {
 
 	data, err := json.Marshal(form)
 	if err != nil {
-		return fmt.Errorf("unable to marshal the form; %w", err)
+		return fmt.Errorf("unable to marshal the form: %w", err)
 	}
 
 	requestBody := bytes.NewBuffer(data)
 	url := g.Authentication.Instance + fmt.Sprintf("/api/v1/accounts/%s/note", accountID)
 
 	if err := g.sendRequest(http.MethodPost, url, requestBody, nil); err != nil {
-		return fmt.Errorf("received an error after sending the request to set the private note; %w", err)
+		return fmt.Errorf("received an error after sending the request to set the private note: %w", err)
 	}
 
 	return nil

internal/client/client.go

@@ -27,7 +27,7 @@ type Client struct {
 func NewClientFromConfig(configDir string) (*Client, error) {
 	config, err := config.NewCredentialsConfigFromFile(configDir)
 	if err != nil {
-		return nil, fmt.Errorf("unable to get the authentication configuration; %w", err)
+		return nil, fmt.Errorf("unable to get the authentication configuration: %w", err)
 	}
 
 	currentAuthentication := config.Credentials[config.CurrentAccount]
@@ -79,14 +79,14 @@ func (g *Client) sendRequest(method string, url string, requestBody io.Reader, o
 
 	response, err := g.HTTPClient.Do(request)
 	if err != nil {
-		return fmt.Errorf("received an error after sending the request; %w", err)
+		return fmt.Errorf("received an error after sending the request: %w", err)
 	}
 
 	defer response.Body.Close()
 
 	if response.StatusCode < http.StatusOK || response.StatusCode >= http.StatusBadRequest {
 		return fmt.Errorf(
-			"did not receive an OK response from the GoToSocial server; got %d",
+			"did not receive an OK response from the GoToSocial server: got %d",
 			response.StatusCode,
 		)
 	}
@@ -97,7 +97,7 @@ func (g *Client) sendRequest(method string, url string, requestBody io.Reader, o
 
 	if err := json.NewDecoder(response.Body).Decode(object); err != nil {
 		return fmt.Errorf(
-			"unable to decode the response from the GoToSocial server; %w",
+			"unable to decode the response from the GoToSocial server: %w",
 			err,
 		)
 	}

internal/client/instance.go

@@ -18,7 +18,7 @@ func (g *Client) GetInstance() (model.InstanceV2, error) {
 	var instance model.InstanceV2
 
 	if err := g.sendRequest(http.MethodGet, url, nil, &instance); err != nil {
-		return model.InstanceV2{}, fmt.Errorf("received an error after sending the request to get the instance details; %w", err)
+		return model.InstanceV2{}, fmt.Errorf("received an error after sending the request to get the instance details: %w", err)
 	}
 
 	return instance, nil

internal/client/lists.go

@@ -24,7 +24,7 @@ func (g *Client) GetAllLists() (model.Lists, error) {
 
 	if err := g.sendRequest(http.MethodGet, url, nil, &lists); err != nil {
 		return nil, fmt.Errorf(
-			"received an error after sending the request to get the list of lists; %w",
+			"received an error after sending the request to get the list of lists: %w",
 			err,
 		)
 	}
@@ -39,7 +39,7 @@ func (g *Client) GetList(listID string) (model.List, error) {
 
 	if err := g.sendRequest(http.MethodGet, url, nil, &list); err != nil {
 		return model.List{}, fmt.Errorf(
-			"received an error after sending the request to get the list; %w",
+			"received an error after sending the request to get the list: %w",
 			err,
 		)
 	}
@@ -55,7 +55,7 @@ type CreateListForm struct {
 func (g *Client) CreateList(form CreateListForm) (model.List, error) {
 	data, err := json.Marshal(form)
 	if err != nil {
-		return model.List{}, fmt.Errorf("unable to marshal the form; %w", err)
+		return model.List{}, fmt.Errorf("unable to marshal the form: %w", err)
 	}
 
 	requestBody := bytes.NewBuffer(data)
@@ -65,7 +65,7 @@ func (g *Client) CreateList(form CreateListForm) (model.List, error) {
 
 	if err := g.sendRequest(http.MethodPost, url, requestBody, &list); err != nil {
 		return model.List{}, fmt.Errorf(
-			"received an error after sending the request to create the list; %w",
+			"received an error after sending the request to create the list: %w",
 			err,
 		)
 	}
@@ -84,7 +84,7 @@ func (g *Client) UpdateList(listToUpdate model.List) (model.List, error) {
 
 	data, err := json.Marshal(form)
 	if err != nil {
-		return model.List{}, fmt.Errorf("unable to marshal the form; %w", err)
+		return model.List{}, fmt.Errorf("unable to marshal the form: %w", err)
 	}
 
 	requestBody := bytes.NewBuffer(data)
@@ -94,7 +94,7 @@ func (g *Client) UpdateList(listToUpdate model.List) (model.List, error) {
 
 	if err := g.sendRequest(http.MethodPut, url, requestBody, &updatedList); err != nil {
 		return model.List{}, fmt.Errorf(
-			"received an error after sending the request to update the list; %w",
+			"received an error after sending the request to update the list: %w",
 			err,
 		)
 	}
@@ -117,7 +117,7 @@ func (g *Client) AddAccountsToList(listID string, accountIDs []string) error {
 
 	data, err := json.Marshal(form)
 	if err != nil {
-		return fmt.Errorf("unable to marshal the form; %w", err)
+		return fmt.Errorf("unable to marshal the form: %w", err)
 	}
 
 	requestBody := bytes.NewBuffer(data)
@@ -125,7 +125,7 @@ func (g *Client) AddAccountsToList(listID string, accountIDs []string) error {
 
 	if err := g.sendRequest(http.MethodPost, url, requestBody, nil); err != nil {
 		return fmt.Errorf(
-			"received an error after sending the request to add the accounts to the list; %w",
+			"received an error after sending the request to add the accounts to the list: %w",
 			err,
 		)
 	}
@@ -142,7 +142,7 @@ func (g *Client) RemoveAccountsFromList(listID string, accountIDs []string) erro
 
 	data, err := json.Marshal(form)
 	if err != nil {
-		return fmt.Errorf("unable to marshal the form; %w", err)
+		return fmt.Errorf("unable to marshal the form: %w", err)
 	}
 
 	requestBody := bytes.NewBuffer(data)
@@ -150,7 +150,7 @@ func (g *Client) RemoveAccountsFromList(listID string, accountIDs []string) erro
 
 	if err := g.sendRequest(http.MethodDelete, url, requestBody, nil); err != nil {
 		return fmt.Errorf(
-			"received an error after sending the request to remove the accounts from the list; %w",
+			"received an error after sending the request to remove the accounts from the list: %w",
 			err,
 		)
 	}
@@ -166,7 +166,7 @@ func (g *Client) GetAccountsFromList(listID string, limit int) ([]model.Account,
 
 	if err := g.sendRequest(http.MethodGet, url, nil, &accounts); err != nil {
 		return nil, fmt.Errorf(
-			"received an error after sending the request to get the accounts from the list; %w",
+			"received an error after sending the request to get the accounts from the list: %w",
 			err,
 		)
 	}

internal/client/preferences.go

@@ -17,7 +17,7 @@ func (g *Client) GetUserPreferences() (model.Preferences, error) {
 	var preferences model.Preferences
 
 	if err := g.sendRequest(http.MethodGet, url, nil, &preferences); err != nil {
-		return model.Preferences{}, fmt.Errorf("received an error after sending the request to get the user preferences; %w", err)
+		return model.Preferences{}, fmt.Errorf("received an error after sending the request to get the user preferences: %w", err)
 	}
 
 	return preferences, nil

internal/client/register.go

@@ -31,7 +31,7 @@ func (g *Client) Register() error {
 
 	data, err := json.Marshal(params)
 	if err != nil {
-		return fmt.Errorf("unable to marshal the request body; %w", err)
+		return fmt.Errorf("unable to marshal the request body: %w", err)
 	}
 
 	requestBody := bytes.NewBuffer(data)
@@ -40,7 +40,7 @@ func (g *Client) Register() error {
 	var app model.Application
 
 	if err := g.sendRequest(http.MethodPost, url, requestBody, &app); err != nil {
-		return fmt.Errorf("received an error after sending the registration request; %w", err)
+		return fmt.Errorf("received an error after sending the registration request: %w", err)
 	}
 
 	g.Authentication.ClientID = app.ClientID

internal/client/statuses.go

@@ -21,7 +21,7 @@ func (g *Client) GetStatus(statusID string) (model.Status, error) {
 
 	if err := g.sendRequest(http.MethodGet, url, nil, &status); err != nil {
 		return model.Status{}, fmt.Errorf(
-			"received an error after sending the request to get the status information; %w",
+			"received an error after sending the request to get the status information: %w",
 			err,
 		)
 	}
@@ -45,7 +45,7 @@ type CreateStatusForm struct {
 func (g *Client) CreateStatus(form CreateStatusForm) (model.Status, error) {
 	data, err := json.Marshal(form)
 	if err != nil {
-		return model.Status{}, fmt.Errorf("unable to create the JSON form; %w", err)
+		return model.Status{}, fmt.Errorf("unable to create the JSON form: %w", err)
 	}
 
 	requestBody := bytes.NewBuffer(data)
@@ -55,7 +55,7 @@ func (g *Client) CreateStatus(form CreateStatusForm) (model.Status, error) {
 
 	if err := g.sendRequest(http.MethodPost, url, requestBody, &status); err != nil {
 		return model.Status{}, fmt.Errorf(
-			"received an error after sending the request to create the status; %w",
+			"received an error after sending the request to create the status: %w",
 			err,
 		)
 	}

internal/client/timelines.go

@@ -61,7 +61,7 @@ func (g *Client) getTimeline(path string, timeline model.Timeline) (model.Timeli
 	var statuses []model.Status
 
 	if err := g.sendRequest(http.MethodGet, url, nil, &statuses); err != nil {
-		return timeline, fmt.Errorf("received an error after sending the request to get the timeline; %w", err)
+		return timeline, fmt.Errorf("received an error after sending the request to get the timeline: %w", err)
 	}
 
 	timeline.Statuses = statuses

internal/client/token.go

@@ -42,7 +42,7 @@ func (g *Client) UpdateToken(code string) error {
 
 	data, err := json.Marshal(params)
 	if err != nil {
-		return fmt.Errorf("unable to marshal the request body; %w", err)
+		return fmt.Errorf("unable to marshal the request body: %w", err)
 	}
 
 	requestBody := bytes.NewBuffer(data)
@@ -51,7 +51,7 @@ func (g *Client) UpdateToken(code string) error {
 	var response tokenResponse
 
 	if err := g.sendRequest(http.MethodPost, url, requestBody, &response); err != nil {
-		return fmt.Errorf("received an error after sending the token request; %w", err)
+		return fmt.Errorf("received an error after sending the token request: %w", err)
 	}
 
 	if response.AccessToken == "" {

internal/config/credentials.go

@@ -42,7 +42,7 @@ func (e CredentialsNotFoundError) Error() string {
 // is not present, it will be created.
 func SaveCredentials(configDir, username string, credentials Credentials) (string, error) {
 	if err := ensureConfigDir(calculateConfigDir(configDir)); err != nil {
-		return "", fmt.Errorf("unable to ensure the configuration directory; %w", err)
+		return "", fmt.Errorf("unable to ensure the configuration directory: %w", err)
 	}
 
 	var authConfig CredentialsConfig
@@ -51,14 +51,14 @@ func SaveCredentials(configDir, username string, credentials Credentials) (strin
 
 	if _, err := os.Stat(filepath); err != nil {
 		if !errors.Is(err, os.ErrNotExist) {
-			return "", fmt.Errorf("unknown error received when running stat on %s; %w", filepath, err)
+			return "", fmt.Errorf("unknown error received when running stat on %s: %w", filepath, err)
 		}
 
 		authConfig.Credentials = make(map[string]Credentials)
 	} else {
 		authConfig, err = NewCredentialsConfigFromFile(configDir)
 		if err != nil {
-			return "", fmt.Errorf("unable to retrieve the existing authentication configuration; %w", err)
+			return "", fmt.Errorf("unable to retrieve the existing authentication configuration: %w", err)
 		}
 	}
 
@@ -77,7 +77,7 @@ func SaveCredentials(configDir, username string, credentials Credentials) (strin
 	authConfig.Credentials[authenticationName] = credentials
 
 	if err := saveCredentialsConfigFile(authConfig, configDir); err != nil {
-		return "", fmt.Errorf("unable to save the authentication configuration to file; %w", err)
+		return "", fmt.Errorf("unable to save the authentication configuration to file: %w", err)
 	}
 
 	return authenticationName, nil
@@ -86,7 +86,7 @@ func SaveCredentials(configDir, username string, credentials Credentials) (strin
 func UpdateCurrentAccount(account string, configDir string) error {
 	credentialsConfig, err := NewCredentialsConfigFromFile(configDir)
 	if err != nil {
-		return fmt.Errorf("unable to retrieve the existing authentication configuration; %w", err)
+		return fmt.Errorf("unable to retrieve the existing authentication configuration: %w", err)
 	}
 
 	if _, ok := credentialsConfig.Credentials[account]; !ok {
@@ -96,7 +96,7 @@ func UpdateCurrentAccount(account string, configDir string) error {
 	credentialsConfig.CurrentAccount = account
 
 	if err := saveCredentialsConfigFile(credentialsConfig, configDir); err != nil {
-		return fmt.Errorf("unable to save the authentication configuration to file; %w", err)
+		return fmt.Errorf("unable to save the authentication configuration to file: %w", err)
 	}
 
 	return nil
@@ -114,7 +114,7 @@ func NewCredentialsConfigFromFile(configDir string) (CredentialsConfig, error) {
 	var authConfig CredentialsConfig
 
 	if err := json.NewDecoder(file).Decode(&authConfig); err != nil {
-		return CredentialsConfig{}, fmt.Errorf("unable to decode the JSON data; %w", err)
+		return CredentialsConfig{}, fmt.Errorf("unable to decode the JSON data: %w", err)
 	}
 
 	return authConfig, nil
@@ -125,7 +125,7 @@ func saveCredentialsConfigFile(authConfig CredentialsConfig, configDir string) e
 
 	file, err := os.Create(path)
 	if err != nil {
-		return fmt.Errorf("unable to open %s; %w", path, err)
+		return fmt.Errorf("unable to open %s: %w", path, err)
 	}
 
 	defer file.Close()
@@ -134,7 +134,7 @@ func saveCredentialsConfigFile(authConfig CredentialsConfig, configDir string) e
 	encoder.SetIndent("", "    ")
 
 	if err := encoder.Encode(authConfig); err != nil {
-		return fmt.Errorf("unable to save the JSON data to the authentication config file; %w", err)
+		return fmt.Errorf("unable to save the JSON data to the authentication config file: %w", err)
 	}
 
 	return nil

internal/config/directory.go

@@ -30,10 +30,10 @@ func ensureConfigDir(configDir string) error {
 	if _, err := os.Stat(configDir); err != nil {
 		if errors.Is(err, os.ErrNotExist) {
 			if err := os.MkdirAll(configDir, 0o750); err != nil {
-				return fmt.Errorf("unable to create %s; %w", configDir, err)
+				return fmt.Errorf("unable to create %s: %w", configDir, err)
 			}
 		} else {
-			return fmt.Errorf("unknown error received when running stat on %s; %w", configDir, err)
+			return fmt.Errorf("unknown error received after getting the config directory information: %w", err)
 		}
 	}
 

internal/executor/account.go

@@ -22,12 +22,12 @@ func getAccountID(gtsClient *client.Client, myAccount bool, accountName, configD
 	case myAccount:
 		accountID, err = getMyAccountID(gtsClient, configDir)
 		if err != nil {
-			return "", fmt.Errorf("unable to get your account ID; %w", err)
+			return "", fmt.Errorf("unable to get your account ID: %w", err)
 		}
 	case accountName != "":
 		accountID, err = getTheirAccountID(gtsClient, accountName)
 		if err != nil {
-			return "", fmt.Errorf("unable to get their account ID; %w", err)
+			return "", fmt.Errorf("unable to get their account ID: %w", err)
 		}
 	default:
 		return "", NoAccountSpecifiedError{}
@@ -39,7 +39,7 @@ func getAccountID(gtsClient *client.Client, myAccount bool, accountName, configD
 func getTheirAccountID(gtsClient *client.Client, accountURI string) (string, error) {
 	account, err := getAccount(gtsClient, accountURI)
 	if err != nil {
-		return "", fmt.Errorf("unable to retrieve your account; %w", err)
+		return "", fmt.Errorf("unable to retrieve your account: %w", err)
 	}
 
 	return account.ID, nil
@@ -48,7 +48,7 @@ func getTheirAccountID(gtsClient *client.Client, accountURI string) (string, err
 func getMyAccountID(gtsClient *client.Client, configDir string) (string, error) {
 	account, err := getMyAccount(gtsClient, configDir)
 	if err != nil {
-		return "", fmt.Errorf("received an error while getting your account details; %w", err)
+		return "", fmt.Errorf("received an error while getting your account details: %w", err)
 	}
 
 	return account.ID, nil
@@ -57,14 +57,14 @@ func getMyAccountID(gtsClient *client.Client, configDir string) (string, error)
 func getMyAccount(gtsClient *client.Client, configDir string) (model.Account, error) {
 	authConfig, err := config.NewCredentialsConfigFromFile(configDir)
 	if err != nil {
-		return model.Account{}, fmt.Errorf("unable to retrieve the authentication configuration; %w", err)
+		return model.Account{}, fmt.Errorf("unable to retrieve the authentication configuration: %w", err)
 	}
 
 	accountURI := authConfig.CurrentAccount
 
 	account, err := getAccount(gtsClient, accountURI)
 	if err != nil {
-		return model.Account{}, fmt.Errorf("unable to retrieve your account; %w", err)
+		return model.Account{}, fmt.Errorf("unable to retrieve your account: %w", err)
 	}
 
 	return account, nil
@@ -73,7 +73,7 @@ func getMyAccount(gtsClient *client.Client, configDir string) (model.Account, er
 func getAccount(gtsClient *client.Client, accountURI string) (model.Account, error) {
 	account, err := gtsClient.GetAccount(accountURI)
 	if err != nil {
-		return model.Account{}, fmt.Errorf("unable to retrieve the account details; %w", err)
+		return model.Account{}, fmt.Errorf("unable to retrieve the account details: %w", err)
 	}
 
 	return account, nil

internal/executor/add.go

@@ -59,7 +59,7 @@ func (a *AddExecutor) Execute() error {
 
 	gtsClient, err := client.NewClientFromConfig(a.topLevelFlags.ConfigDir)
 	if err != nil {
-		return fmt.Errorf("unable to create the GoToSocial client; %w", err)
+		return fmt.Errorf("unable to create the GoToSocial client: %w", err)
 	}
 
 	return doFunc(gtsClient)
@@ -102,7 +102,7 @@ func (a *AddExecutor) addAccountsToList(gtsClient *client.Client) error {
 	}
 
 	if err := gtsClient.AddAccountsToList(a.listID, accountIDs); err != nil {
-		return fmt.Errorf("unable to add the accounts to the list; %w", err)
+		return fmt.Errorf("unable to add the accounts to the list: %w", err)
 	}
 
 	fmt.Println("Successfully added the account(s) to the list.")
@@ -128,12 +128,12 @@ func (a *AddExecutor) addToAccount(gtsClient *client.Client) error {
 
 func (a *AddExecutor) addNoteToAccount(gtsClient *client.Client) error {
 	if len(a.accountNames) != 1 {
-		return fmt.Errorf("unexpected number of accounts specified; want 1, got %d", len(a.accountNames))
+		return fmt.Errorf("unexpected number of accounts specified: want 1, got %d", len(a.accountNames))
 	}
 
 	accountID, err := getAccountID(gtsClient, false, a.accountNames[0], a.topLevelFlags.ConfigDir)
 	if err != nil {
-		return fmt.Errorf("received an error while getting the account ID; %w", err)
+		return fmt.Errorf("received an error while getting the account ID: %w", err)
 	}
 
 	if a.content == "" {
@@ -144,7 +144,7 @@ func (a *AddExecutor) addNoteToAccount(gtsClient *client.Client) error {
 	}
 
 	if err := gtsClient.SetPrivateNote(accountID, a.content); err != nil {
-		return fmt.Errorf("unable to add the private note to the account; %w", err)
+		return fmt.Errorf("unable to add the private note to the account: %w", err)
 	}
 
 	fmt.Println("Successfully added the private note to the account.")

internal/executor/block.go

@@ -48,7 +48,7 @@ func (b *BlockExecutor) Execute() error {
 
 	gtsClient, err := client.NewClientFromConfig(b.topLevelFlags.ConfigDir)
 	if err != nil {
-		return fmt.Errorf("unable to create the GoToSocial client; %w", err)
+		return fmt.Errorf("unable to create the GoToSocial client: %w", err)
 	}
 
 	return doFunc(gtsClient)
@@ -57,7 +57,7 @@ func (b *BlockExecutor) Execute() error {
 func (b *BlockExecutor) blockAccount(gtsClient *client.Client) error {
 	accountID, err := getAccountID(gtsClient, false, b.accountName, b.topLevelFlags.ConfigDir)
 	if err != nil {
-		return fmt.Errorf("received an error while getting the account ID; %w", err)
+		return fmt.Errorf("received an error while getting the account ID: %w", err)
 	}
 
 	if b.unblock {
@@ -65,7 +65,7 @@ func (b *BlockExecutor) blockAccount(gtsClient *client.Client) error {
 	}
 
 	if err := gtsClient.BlockAccount(accountID); err != nil {
-		return fmt.Errorf("unable to block the account; %w", err)
+		return fmt.Errorf("unable to block the account: %w", err)
 	}
 
 	fmt.Println("Successfully blocked the account.")
@@ -75,7 +75,7 @@ func (b *BlockExecutor) blockAccount(gtsClient *client.Client) error {
 
 func (b *BlockExecutor) unblockAccount(gtsClient *client.Client, accountID string) error {
 	if err := gtsClient.UnblockAccount(accountID); err != nil {
-		return fmt.Errorf("unable to unblock the account; %w", err)
+		return fmt.Errorf("unable to unblock the account: %w", err)
 	}
 
 	fmt.Println("Successfully unblocked the account.")

internal/executor/create.go

@@ -58,7 +58,7 @@ func NewCreateExecutor(tlf TopLevelFlags, name, summary string) *CreateExecutor
 	createExe.BoolFunc(flagSensitive, "specify if the status should be marked as sensitive", func(value string) error {
 		boolVal, err := strconv.ParseBool(value)
 		if err != nil {
-			return fmt.Errorf("unable to parse %q as a boolean value; %w", value, err)
+			return fmt.Errorf("unable to parse %q as a boolean value: %w", value, err)
 		}
 
 		createExe.sensitive = new(bool)
@@ -79,7 +79,7 @@ func (c *CreateExecutor) Execute() error {
 
 	gtsClient, err := client.NewClientFromConfig(c.topLevelFlags.ConfigDir)
 	if err != nil {
-		return fmt.Errorf("unable to create the GoToSocial client; %w", err)
+		return fmt.Errorf("unable to create the GoToSocial client: %w", err)
 	}
 
 	funcMap := map[string]func(*client.Client) error{
@@ -100,9 +100,9 @@ func (c *CreateExecutor) createList(gtsClient *client.Client) error {
 		return FlagNotSetError{flagText: flagListTitle}
 	}
 
-	parsedListRepliesPolicy := model.ParseListRepliesPolicy(c.listRepliesPolicy)
+	parsedListRepliesPolicy, err := model.ParseListRepliesPolicy(c.listRepliesPolicy)
-	if parsedListRepliesPolicy == model.ListRepliesPolicyUnknown {
+	if err != nil {
-		return InvalidListRepliesPolicyError{Policy: c.listRepliesPolicy}
+		return err
 	}
 
 	form := client.CreateListForm{
@@ -112,7 +112,7 @@ func (c *CreateExecutor) createList(gtsClient *client.Client) error {
 
 	list, err := gtsClient.CreateList(form)
 	if err != nil {
-		return fmt.Errorf("unable to create the list; %w", err)
+		return fmt.Errorf("unable to create the list: %w", err)
 	}
 
 	fmt.Println("Successfully created the following list:")
@@ -136,7 +136,7 @@ func (c *CreateExecutor) createStatus(gtsClient *client.Client) error {
 	case c.fromFile != "":
 		content, err = utilities.ReadFile(c.fromFile)
 		if err != nil {
-			return fmt.Errorf("unable to get the status contents from %q; %w", c.fromFile, err)
+			return fmt.Errorf("unable to get the status contents from %q: %w", c.fromFile, err)
 		}
 	default:
 		return EmptyContentError{
@@ -147,7 +147,7 @@ func (c *CreateExecutor) createStatus(gtsClient *client.Client) error {
 
 	preferences, err := gtsClient.GetUserPreferences()
 	if err != nil {
-		fmt.Println("WARNING: Unable to get your posting preferences; %w", err)
+		fmt.Println("WARNING: Unable to get your posting preferences: %w", err)
 	}
 
 	if c.language != "" {
@@ -168,14 +168,14 @@ func (c *CreateExecutor) createStatus(gtsClient *client.Client) error {
 		sensitive = preferences.PostingDefaultSensitive
 	}
 
-	parsedVisibility := model.ParseStatusVisibility(visibility)
+	parsedVisibility, err := model.ParseStatusVisibility(visibility)
-	if parsedVisibility == model.StatusVisibilityUnknown {
+	if err != nil {
-		return InvalidStatusVisibilityError{Visibility: visibility}
+		return err
 	}
 
-	parsedContentType := model.ParseStatusContentType(c.contentType)
+	parsedContentType, err := model.ParseStatusContentType(c.contentType)
-	if parsedContentType == model.StatusContentTypeUnknown {
+	if err != nil {
-		return InvalidStatusContentTypeError{ContentType: c.contentType}
+		return err
 	}
 
 	form := client.CreateStatusForm{
@@ -193,7 +193,7 @@ func (c *CreateExecutor) createStatus(gtsClient *client.Client) error {
 
 	status, err := gtsClient.CreateStatus(form)
 	if err != nil {
-		return fmt.Errorf("unable to create the status; %w", err)
+		return fmt.Errorf("unable to create the status: %w", err)
 	}
 
 	fmt.Println("Successfully created the following status:")

internal/executor/delete.go

@@ -49,7 +49,7 @@ func (d *DeleteExecutor) Execute() error {
 
 	gtsClient, err := client.NewClientFromConfig(d.topLevelFlags.ConfigDir)
 	if err != nil {
-		return fmt.Errorf("unable to create the GoToSocial client; %w", err)
+		return fmt.Errorf("unable to create the GoToSocial client: %w", err)
 	}
 
 	return doFunc(gtsClient)
@@ -61,7 +61,7 @@ func (d *DeleteExecutor) deleteList(gtsClient *client.Client) error {
 	}
 
 	if err := gtsClient.DeleteList(d.listID); err != nil {
-		return fmt.Errorf("unable to delete the list; %w", err)
+		return fmt.Errorf("unable to delete the list: %w", err)
 	}
 
 	fmt.Println("The list was successfully deleted.")

internal/executor/edit.go

@@ -55,7 +55,7 @@ func (e *EditExecutor) Execute() error {
 
 	gtsClient, err := client.NewClientFromConfig(e.topLevelFlags.ConfigDir)
 	if err != nil {
-		return fmt.Errorf("unable to create the GoToSocial client; %w", err)
+		return fmt.Errorf("unable to create the GoToSocial client: %w", err)
 	}
 
 	return doFunc(gtsClient)
@@ -68,7 +68,7 @@ func (e *EditExecutor) editList(gtsClient *client.Client) error {
 
 	list, err := gtsClient.GetList(e.listID)
 	if err != nil {
-		return fmt.Errorf("unable to get the list; %w", err)
+		return fmt.Errorf("unable to get the list: %w", err)
 	}
 
 	if e.listTitle != "" {
@@ -76,9 +76,9 @@ func (e *EditExecutor) editList(gtsClient *client.Client) error {
 	}
 
 	if e.listRepliesPolicy != "" {
-		parsedListRepliesPolicy := model.ParseListRepliesPolicy(e.listRepliesPolicy)
+		parsedListRepliesPolicy, err := model.ParseListRepliesPolicy(e.listRepliesPolicy)
-		if parsedListRepliesPolicy == model.ListRepliesPolicyUnknown {
+		if err != nil {
-			return InvalidListRepliesPolicyError{Policy: e.listRepliesPolicy}
+			return err
 		}
 
 		list.RepliesPolicy = parsedListRepliesPolicy
@@ -86,7 +86,7 @@ func (e *EditExecutor) editList(gtsClient *client.Client) error {
 
 	updatedList, err := gtsClient.UpdateList(list)
 	if err != nil {
-		return fmt.Errorf("unable to update the list; %w", err)
+		return fmt.Errorf("unable to update the list: %w", err)
 	}
 
 	fmt.Println("Successfully updated the list.")

internal/executor/errors.go

@@ -9,7 +9,7 @@ type FlagNotSetError struct {
 }
 
 func (e FlagNotSetError) Error() string {
-	return "the flag '" + e.flagText + "' is not set"
+	return "please use the required --" + e.flagText + " flag"
 }
 
 type UnsupportedTypeError struct {
@@ -17,15 +17,7 @@ type UnsupportedTypeError struct {
 }
 
 func (e UnsupportedTypeError) Error() string {
-	return "unsupported resource type '" + e.resourceType + "'"
+	return "'" + e.resourceType + "' is not supported for this operation"
-}
-
-type InvalidTimelineCategoryError struct {
-	category string
-}
-
-func (e InvalidTimelineCategoryError) Error() string {
-	return "'" + e.category + "' is not a valid timeline category (please choose home, public, tag or list)"
 }
 
 type NoAccountSpecifiedError struct{}
@@ -52,7 +44,7 @@ func (e UnsupportedRemoveOperationError) Error() string {
 	return "removing '" + e.ResourceType + "' from '" + e.RemoveFromResourceType + "' is not supported"
 }
 
-type EmptyContentError struct{
+type EmptyContentError struct {
 	ResourceType string
 	Hint         string
 }
@@ -66,27 +58,3 @@ func (e EmptyContentError) Error() string {
 
 	return message
 }
-
-type InvalidStatusVisibilityError struct {
-	Visibility string
-}
-
-func (e InvalidStatusVisibilityError) Error() string {
-	return "'" + e.Visibility + "' is an invalid status visibility (valid values are public, unlisted, private, mutuals_only and direct)"
-}
-
-type InvalidStatusContentTypeError struct {
-	ContentType string
-}
-
-func (e InvalidStatusContentTypeError) Error() string {
-	return "'" + e.ContentType + "' is an invalid status content type (valid values are plain and markdown)"
-}
-
-type InvalidListRepliesPolicyError struct {
-	Policy string
-}
-
-func (e InvalidListRepliesPolicyError) Error() string {
-	return "'" + e.Policy + "' is an invalid list replies policy"
-}

internal/executor/executor.go

@@ -14,11 +14,11 @@ type Executor interface {
 
 func Execute(executor Executor, args []string) error {
 	if err := executor.Parse(args); err != nil {
-		return fmt.Errorf("unable to parse the command line flags; %w", err)
+		return fmt.Errorf("flag parsing error: %w", err)
 	}
 
 	if err := executor.Execute(); err != nil {
-		return fmt.Errorf("unable to execute the command %q; %w", executor.Name(), err)
+		return fmt.Errorf("execution error: %w", err)
 	}
 
 	return nil

internal/executor/follow.go

@@ -51,7 +51,7 @@ func (c *FollowExecutor) Execute() error {
 
 	gtsClient, err := client.NewClientFromConfig(c.topLevelFlags.ConfigDir)
 	if err != nil {
-		return fmt.Errorf("unable to create the GoToSocial client; %w", err)
+		return fmt.Errorf("unable to create the GoToSocial client: %w", err)
 	}
 
 	return doFunc(gtsClient)
@@ -60,7 +60,7 @@ func (c *FollowExecutor) Execute() error {
 func (c *FollowExecutor) followAccount(gtsClient *client.Client) error {
 	accountID, err := getAccountID(gtsClient, false, c.accountName, c.topLevelFlags.ConfigDir)
 	if err != nil {
-		return fmt.Errorf("received an error while getting the account ID; %w", err)
+		return fmt.Errorf("received an error while getting the account ID: %w", err)
 	}
 
 	if c.unfollow {
@@ -74,7 +74,7 @@ func (c *FollowExecutor) followAccount(gtsClient *client.Client) error {
 	}
 
 	if err := gtsClient.FollowAccount(form); err != nil {
-		return fmt.Errorf("unable to follow the account; %w", err)
+		return fmt.Errorf("unable to follow the account: %w", err)
 	}
 
 	fmt.Println("The follow request was sent successfully.")
@@ -84,7 +84,7 @@ func (c *FollowExecutor) followAccount(gtsClient *client.Client) error {
 
 func (c *FollowExecutor) unfollowAccount(gtsClient *client.Client, accountID string) error {
 	if err := gtsClient.UnfollowAccount(accountID); err != nil {
-		return fmt.Errorf("unable to unfollow the account; %w", err)
+		return fmt.Errorf("unable to unfollow the account: %w", err)
 	}
 
 	fmt.Println("Successfully unfollowed the account.")

internal/executor/login.go

@@ -59,7 +59,7 @@ func (c *LoginExecutor) Execute() error {
 	gtsClient := client.NewClient(credentials)
 
 	if err := gtsClient.Register(); err != nil {
-		return fmt.Errorf("unable to register the application; %w", err)
+		return fmt.Errorf("unable to register the application: %w", err)
 	}
 
 	consentPageURL := gtsClient.AuthCodeURL()
@@ -83,21 +83,21 @@ Once you have the code please copy and paste it below.
 	fmt.Print("Out-of-band token: ")
 
 	if _, err := fmt.Scanln(&code); err != nil {
-		return fmt.Errorf("failed to read access code; %w", err)
+		return fmt.Errorf("failed to read access code: %w", err)
 	}
 
 	if err := gtsClient.UpdateToken(code); err != nil {
-		return fmt.Errorf("unable to update the client's access token; %w", err)
+		return fmt.Errorf("unable to update the client's access token: %w", err)
 	}
 
 	account, err := gtsClient.VerifyCredentials()
 	if err != nil {
-		return fmt.Errorf("unable to verify the credentials; %w", err)
+		return fmt.Errorf("unable to verify the credentials: %w", err)
 	}
 
 	loginName, err := config.SaveCredentials(c.topLevelFlags.ConfigDir, account.Username, gtsClient.Authentication)
 	if err != nil {
-		return fmt.Errorf("unable to save the authentication details; %w", err)
+		return fmt.Errorf("unable to save the authentication details: %w", err)
 	}
 
 	fmt.Printf("Successfully logged into %s\n", loginName)

internal/executor/remove.go

@@ -57,7 +57,7 @@ func (r *RemoveExecutor) Execute() error {
 
 	gtsClient, err := client.NewClientFromConfig(r.topLevelFlags.ConfigDir)
 	if err != nil {
-		return fmt.Errorf("unable to create the GoToSocial client; %w", err)
+		return fmt.Errorf("unable to create the GoToSocial client: %w", err)
 	}
 
 	return doFunc(gtsClient)
@@ -100,7 +100,7 @@ func (r *RemoveExecutor) removeAccountsFromList(gtsClient *client.Client) error
 	}
 
 	if err := gtsClient.RemoveAccountsFromList(r.listID, accountIDs); err != nil {
-		return fmt.Errorf("unable to remove the accounts from the list; %w", err)
+		return fmt.Errorf("unable to remove the accounts from the list: %w", err)
 	}
 
 	fmt.Println("Successfully removed the account(s) from the list.")
@@ -126,16 +126,16 @@ func (r *RemoveExecutor) removeFromAccount(gtsClient *client.Client) error {
 
 func (r *RemoveExecutor) removeNoteFromAccount(gtsClient *client.Client) error {
 	if len(r.accountNames) != 1 {
-		return fmt.Errorf("unexpected number of accounts specified; want 1, got %d", len(r.accountNames))
+		return fmt.Errorf("unexpected number of accounts specified: want 1, got %d", len(r.accountNames))
 	}
 
 	accountID, err := getAccountID(gtsClient, false, r.accountNames[0], r.topLevelFlags.ConfigDir)
 	if err != nil {
-		return fmt.Errorf("received an error while getting the account ID; %w", err)
+		return fmt.Errorf("received an error while getting the account ID: %w", err)
 	}
 
 	if err := gtsClient.SetPrivateNote(accountID, ""); err != nil {
-		return fmt.Errorf("unable to remove the private note from the account; %w", err)
+		return fmt.Errorf("unable to remove the private note from the account: %w", err)
 	}
 
 	fmt.Println("Successfully removed the private note from the account.")

internal/executor/show.go

@@ -42,7 +42,7 @@ func NewShowExecutor(tlf TopLevelFlags, name, summary string) *ShowExecutor {
 	command.StringVar(&command.resourceType, flagType, "", "specify the type of resource to display")
 	command.StringVar(&command.accountName, flagAccountName, "", "specify the account name in full (username@domain)")
 	command.StringVar(&command.statusID, flagStatusID, "", "specify the ID of the status to display")
-	command.StringVar(&command.timelineCategory, flagTimelineCategory, "home", "specify the type of timeline to display (valid values are home, public, list and tag)")
+	command.StringVar(&command.timelineCategory, flagTimelineCategory, model.TimelineCategoryHome, "specify the timeline category to view")
 	command.StringVar(&command.listID, flagListID, "", "specify the ID of the list to display")
 	command.StringVar(&command.tag, flagTag, "", "specify the name of the tag to use")
 	command.IntVar(&command.limit, flagLimit, 20, "specify the limit of items to display")
@@ -75,7 +75,7 @@ func (c *ShowExecutor) Execute() error {
 
 	gtsClient, err := client.NewClientFromConfig(c.topLevelFlags.ConfigDir)
 	if err != nil {
-		return fmt.Errorf("unable to create the GoToSocial client; %w", err)
+		return fmt.Errorf("unable to create the GoToSocial client: %w", err)
 	}
 
 	return doFunc(gtsClient)
@@ -84,7 +84,7 @@ func (c *ShowExecutor) Execute() error {
 func (c *ShowExecutor) showInstance(gtsClient *client.Client) error {
 	instance, err := gtsClient.GetInstance()
 	if err != nil {
-		return fmt.Errorf("unable to retrieve the instance details; %w", err)
+		return fmt.Errorf("unable to retrieve the instance details: %w", err)
 	}
 
 	utilities.Display(instance, *c.topLevelFlags.NoColor)
@@ -101,7 +101,7 @@ func (c *ShowExecutor) showAccount(gtsClient *client.Client) error {
 	if c.myAccount {
 		account, err = getMyAccount(gtsClient, c.topLevelFlags.ConfigDir)
 		if err != nil {
-			return fmt.Errorf("received an error while getting the account details; %w", err)
+			return fmt.Errorf("received an error while getting the account details: %w", err)
 		}
 	} else {
 		if c.accountName == "" {
@@ -110,7 +110,7 @@ func (c *ShowExecutor) showAccount(gtsClient *client.Client) error {
 
 		account, err = getAccount(gtsClient, c.accountName)
 		if err != nil {
-			return fmt.Errorf("received an error while getting the account details; %w", err)
+			return fmt.Errorf("received an error while getting the account details: %w", err)
 		}
 	}
 
@@ -125,7 +125,7 @@ func (c *ShowExecutor) showAccount(gtsClient *client.Client) error {
 	if !c.myAccount && !c.skipAccountRelationship {
 		relationship, err := gtsClient.GetAccountRelationship(account.ID)
 		if err != nil {
-			return fmt.Errorf("unable to retrieve the relationship to this account; %w", err)
+			return fmt.Errorf("unable to retrieve the relationship to this account: %w", err)
 		}
 
 		utilities.Display(relationship, *c.topLevelFlags.NoColor)
@@ -134,7 +134,7 @@ func (c *ShowExecutor) showAccount(gtsClient *client.Client) error {
 	if c.myAccount && c.showUserPreferences {
 		preferences, err := gtsClient.GetUserPreferences()
 		if err != nil {
-			return fmt.Errorf("unable to retrieve the user preferences; %w", err)
+			return fmt.Errorf("unable to retrieve the user preferences: %w", err)
 		}
 
 		utilities.Display(preferences, *c.topLevelFlags.NoColor)
@@ -150,7 +150,7 @@ func (c *ShowExecutor) showStatus(gtsClient *client.Client) error {
 
 	status, err := gtsClient.GetStatus(c.statusID)
 	if err != nil {
-		return fmt.Errorf("unable to retrieve the status; %w", err)
+		return fmt.Errorf("unable to retrieve the status: %w", err)
 	}
 
 	if c.showInBrowser {
@@ -171,28 +171,28 @@ func (c *ShowExecutor) showTimeline(gtsClient *client.Client) error {
 	)
 
 	switch c.timelineCategory {
-	case "home":
+	case model.TimelineCategoryHome:
 		timeline, err = gtsClient.GetHomeTimeline(c.limit)
-	case "public":
+	case model.TimelineCategoryPublic:
 		timeline, err = gtsClient.GetPublicTimeline(c.limit)
-	case "list":
+	case model.TimelineCategoryList:
 		if c.listID == "" {
 			return FlagNotSetError{flagText: flagListID}
 		}
 
 		timeline, err = gtsClient.GetListTimeline(c.listID, c.limit)
-	case "tag":
+	case model.TimelineCategoryTag:
 		if c.tag == "" {
 			return FlagNotSetError{flagText: flagTag}
 		}
 
 		timeline, err = gtsClient.GetTagTimeline(c.tag, c.limit)
 	default:
-		return InvalidTimelineCategoryError{category: c.timelineCategory}
+		return model.InvalidTimelineCategoryError{Value: c.timelineCategory}
 	}
 
 	if err != nil {
-		return fmt.Errorf("unable to retrieve the %s timeline; %w", c.timelineCategory, err)
+		return fmt.Errorf("unable to retrieve the %s timeline: %w", c.timelineCategory, err)
 	}
 
 	if len(timeline.Statuses) == 0 {
@@ -213,12 +213,12 @@ func (c *ShowExecutor) showList(gtsClient *client.Client) error {
 
 	list, err := gtsClient.GetList(c.listID)
 	if err != nil {
-		return fmt.Errorf("unable to retrieve the list; %w", err)
+		return fmt.Errorf("unable to retrieve the list: %w", err)
 	}
 
 	accounts, err := gtsClient.GetAccountsFromList(c.listID, 0)
 	if err != nil {
-		return fmt.Errorf("unable to retrieve the accounts from the list; %w", err)
+		return fmt.Errorf("unable to retrieve the accounts from the list: %w", err)
 	}
 
 	if len(accounts) > 0 {
@@ -238,7 +238,7 @@ func (c *ShowExecutor) showList(gtsClient *client.Client) error {
 func (c *ShowExecutor) showLists(gtsClient *client.Client) error {
 	lists, err := gtsClient.GetAllLists()
 	if err != nil {
-		return fmt.Errorf("unable to retrieve the lists; %w", err)
+		return fmt.Errorf("unable to retrieve the lists: %w", err)
 	}
 
 	if len(lists) == 0 {
@@ -255,12 +255,12 @@ func (c *ShowExecutor) showLists(gtsClient *client.Client) error {
 func (c *ShowExecutor) showFollowers(gtsClient *client.Client) error {
 	accountID, err := getAccountID(gtsClient, c.myAccount, c.accountName, c.topLevelFlags.ConfigDir)
 	if err != nil {
-		return fmt.Errorf("received an error while getting the account ID; %w", err)
+		return fmt.Errorf("received an error while getting the account ID: %w", err)
 	}
 
 	followers, err := gtsClient.GetFollowers(accountID, c.limit)
 	if err != nil {
-		return fmt.Errorf("unable to retrieve the list of followers; %w", err)
+		return fmt.Errorf("unable to retrieve the list of followers: %w", err)
 	}
 
 	if len(followers.Accounts) > 0 {
@@ -275,12 +275,12 @@ func (c *ShowExecutor) showFollowers(gtsClient *client.Client) error {
 func (c *ShowExecutor) showFollowing(gtsClient *client.Client) error {
 	accountID, err := getAccountID(gtsClient, c.myAccount, c.accountName, c.topLevelFlags.ConfigDir)
 	if err != nil {
-		return fmt.Errorf("received an error while getting the account ID; %w", err)
+		return fmt.Errorf("received an error while getting the account ID: %w", err)
 	}
 
 	following, err := gtsClient.GetFollowing(accountID, c.limit)
 	if err != nil {
-		return fmt.Errorf("unable to retrieve the list of followed accounts; %w", err)
+		return fmt.Errorf("unable to retrieve the list of followed accounts: %w", err)
 	}
 
 	if len(following.Accounts) > 0 {
@@ -295,7 +295,7 @@ func (c *ShowExecutor) showFollowing(gtsClient *client.Client) error {
 func (c *ShowExecutor) showBlocked(gtsClient *client.Client) error {
 	blocked, err := gtsClient.GetBlockedAccounts(c.limit)
 	if err != nil {
-		return fmt.Errorf("unable to retrieve the list of blocked accounts; %w", err)
+		return fmt.Errorf("unable to retrieve the list of blocked accounts: %w", err)
 	}
 
 	if len(blocked.Accounts) > 0 {

internal/executor/switch.go

@@ -52,7 +52,7 @@ func (s *SwitchExecutor) switchToAccount() error {
 	}
 
 	if err := config.UpdateCurrentAccount(s.accountName, s.topLevelFlags.ConfigDir); err != nil {
-		return fmt.Errorf("unable to switch account to the account; %w", err)
+		return fmt.Errorf("unable to switch account to the account: %w", err)
 	}
 
 	fmt.Printf("The current account is now set to %q.\n", s.accountName)

internal/executor/whoami.go

@@ -31,7 +31,7 @@ func NewWhoAmIExecutor(tlf TopLevelFlags, name, summary string) *WhoAmIExecutor
 func (c *WhoAmIExecutor) Execute() error {
 	config, err := config.NewCredentialsConfigFromFile(c.topLevelFlags.ConfigDir)
 	if err != nil {
-		return fmt.Errorf("unable to load the credential config; %w", err)
+		return fmt.Errorf("unable to load the credential config: %w", err)
 	}
 
 	fmt.Printf("You are logged in as %q.\n", config.CurrentAccount)

internal/model/list.go

@@ -41,7 +41,7 @@ func (l ListRepliesPolicy) String() string {
 	return output
 }
 
-func ParseListRepliesPolicy(value string) ListRepliesPolicy {
+func ParseListRepliesPolicy(value string) (ListRepliesPolicy, error) {
 	mapped := map[string]ListRepliesPolicy{
 		listRepliesPolicyFollowedValue: ListRepliesPolicyFollowed,
 		listRepliesPolicyListValue:     ListRepliesPolicyList,
@@ -50,19 +50,24 @@ func ParseListRepliesPolicy(value string) ListRepliesPolicy {
 
 	output, ok := mapped[value]
 	if !ok {
-		return ListRepliesPolicyUnknown
+		return ListRepliesPolicyUnknown, InvalidListRepliesPolicyError{value}
 	}
 
-	return output
+	return output, nil
 }
 
 func (l ListRepliesPolicy) MarshalJSON() ([]byte, error) {
 	value := l.String()
 	if value == unknownValue {
-		return nil, fmt.Errorf("%q is not a valid list replies policy")
+		return nil, InvalidListRepliesPolicyError{value}
 	}
 
-	return json.Marshal(value)
+	data, err := json.Marshal(value)
+	if err != nil {
+		return nil, fmt.Errorf("unable to encode %s to JSON: %w", value, err)
+	}
+
+	return data, nil
 }
 
 func (l *ListRepliesPolicy) UnmarshalJSON(data []byte) error {
@@ -72,14 +77,30 @@ func (l *ListRepliesPolicy) UnmarshalJSON(data []byte) error {
 	)
 
 	if err = json.Unmarshal(data, &value); err != nil {
-		return fmt.Errorf("unable to unmarshal the data; %w", err)
+		return fmt.Errorf("unable to decode the JSON data: %w", err)
 	}
 
-	*l = ParseListRepliesPolicy(value)
+	*l, err = ParseListRepliesPolicy(value)
+	if err != nil {
+		return err
+	}
 
 	return nil
 }
 
+type InvalidListRepliesPolicyError struct {
+	Value string
+}
+
+func (e InvalidListRepliesPolicyError) Error() string {
+	return "'" +
+		e.Value +
+		"' is not a valid list replies policy: valid values are " +
+		listRepliesPolicyFollowedValue + ", " +
+		listRepliesPolicyListValue + ", " +
+		listRepliesPolicyNoneValue
+}
+
 type List struct {
 	ID            string            `json:"id"`
 	RepliesPolicy ListRepliesPolicy `json:"replies_policy"`

internal/model/status_content_type.go

@@ -38,22 +38,37 @@ func (s StatusContentType) String() string {
 	return output
 }
 
-func ParseStatusContentType(value string) StatusContentType {
+func ParseStatusContentType(value string) (StatusContentType, error) {
 	switch value {
 	case statusContentTypePlainValue, statusContentTypeTextPlainValue:
-		return StatusContentTypePlainText
+		return StatusContentTypePlainText, nil
 	case statusContentTypeMarkdownValue, statusContentTypeTextMarkdownValue:
-		return StatusContentTypeMarkdown
+		return StatusContentTypeMarkdown, nil
 	}
 
-	return StatusContentTypeUnknown
+	return StatusContentTypeUnknown, InvalidStatusContentTypeError{Value: value}
 }
 
 func (s StatusContentType) MarshalJSON() ([]byte, error) {
 	value := s.String()
 	if value == unknownValue {
-		return nil, fmt.Errorf("%q is not a valid status content type", value)
+		return nil, InvalidStatusContentTypeError{Value: value}
 	}
 
-	return json.Marshal(value)
+	data, err := json.Marshal(value)
+	if err != nil {
+		return nil, fmt.Errorf("unable to encode %s to JSON: %w", value, err)
+	}
+
+	return data, nil
+}
+
+type InvalidStatusContentTypeError struct {
+	Value string
+}
+
+func (e InvalidStatusContentTypeError) Error() string {
+	return "'" + e.Value + "' is an invalid status content type: valid values are " +
+		statusContentTypePlainValue + " or " + statusContentTypeTextPlainValue + " for plain text, or " +
+		statusContentTypeMarkdownValue + " or " + statusContentTypeTextMarkdownValue + " for Markdown"
 }

internal/model/status_visibility.go

@@ -45,7 +45,7 @@ func (s StatusVisibility) String() string {
 	return output
 }
 
-func ParseStatusVisibility(value string) StatusVisibility {
+func ParseStatusVisibility(value string) (StatusVisibility, error) {
 	mapped := map[string]StatusVisibility{
 		statusVisibilityPublicValue:      StatusVisibilityPublic,
 		statusVisibilityPrivateValue:     StatusVisibilityPrivate,
@@ -56,19 +56,24 @@ func ParseStatusVisibility(value string) StatusVisibility {
 
 	output, ok := mapped[value]
 	if !ok {
-		return StatusVisibilityUnknown
+		return StatusVisibilityUnknown, InvalidStatusVisibilityError{Value: value}
 	}
 
-	return output
+	return output, nil
 }
 
 func (s StatusVisibility) MarshalJSON() ([]byte, error) {
 	value := s.String()
 	if value == unknownValue {
-		return nil, fmt.Errorf("%q is not a valid status visibility", value)
+		return nil, InvalidStatusVisibilityError{Value: value}
 	}
 
-	return json.Marshal(value)
+	data, err := json.Marshal(value)
+	if err != nil {
+		return nil, fmt.Errorf("unable to encode %s to JSON: %w", value, err)
+	}
+
+	return data, nil
 }
 
 func (s *StatusVisibility) UnmarshalJSON(data []byte) error {
@@ -78,10 +83,25 @@ func (s *StatusVisibility) UnmarshalJSON(data []byte) error {
 	)
 
 	if err = json.Unmarshal(data, &value); err != nil {
-		return fmt.Errorf("unable to unmarshal the data; %w", err)
+		return fmt.Errorf("unable to decode the JSON data: %w", err)
 	}
 
-	*s = ParseStatusVisibility(value)
+	// Ignore the error if the visibility from another service is
+	// not known by enbas. It will be replaced with 'unknown'.
+	*s, _ = ParseStatusVisibility(value)
 
 	return nil
 }
+
+type InvalidStatusVisibilityError struct {
+	Value string
+}
+
+func (e InvalidStatusVisibilityError) Error() string {
+	return "'" + e.Value + "' is not a valid status visibility value: valid values are " +
+		statusVisibilityPublicValue + ", " +
+		statusVisibilityUnlistedValue + ", " +
+		statusVisibilityPrivateValue + ", " +
+		statusVisibilityMutualsOnlyValue + ", " +
+		statusVisibilityDirectValue
+}

internal/model/timeline.go

@@ -10,6 +10,27 @@ import (
 	"codeflow.dananglin.me.uk/apollo/enbas/internal/utilities"
 )
 
+const (
+	TimelineCategoryHome   = "home"
+	TimelineCategoryPublic = "public"
+	TimelineCategoryTag    = "tag"
+	TimelineCategoryList   = "list"
+)
+
+type InvalidTimelineCategoryError struct {
+	Value string
+}
+
+func (e InvalidTimelineCategoryError) Error() string {
+	return "'" +
+		e.Value +
+		"' is not a valid timeline category (valid values are " +
+		TimelineCategoryHome + ", " +
+		TimelineCategoryPublic + ", " +
+		TimelineCategoryTag + ", " +
+		TimelineCategoryList + ")"
+}
+
 type Timeline struct {
 	Name     string
 	Statuses []Status

internal/utilities/file.go

@@ -12,7 +12,7 @@ import (
 func ReadFile(path string) (string, error) {
 	data, err := os.ReadFile(path)
 	if err != nil {
-		return "", fmt.Errorf("unable to read the data from the file; %w", err)
+		return "", fmt.Errorf("unable to read the data from the file: %w", err)
 	}
 
 	return string(data), nil