feat(commands/config.ts): add support for 'describe' mode to print detailed help for config parameters

fix(commands/config.ts): improve error handling for 'get' and 'set' modes when no config keys are provided

The changes in this commit add a new 'describe' mode to the config command, which allows users to get detailed information about the available configuration parameters. This includes a description of each parameter and the accepted values.

The 'describe' mode can be used in two ways:

1. To print help for all available config parameters:
   ```
   oco config describe
   ```

2. To print help for specific config parameters:
   ```
   oco config describe OCO_MODEL OCO_API_KEY
   ```

Additionally, the commit fixes the error handling for the 'get' and 'set' modes, ensuring that an error is thrown if no config keys are provided.

These changes improve the usability and discoverability of the configuration system, making it easier for users to understand and manage their opencommit settings.

Author: benleibowitz

README.md

@@ -132,6 +132,18 @@ Simply set any of the variables above like this:
 oco config set OCO_MODEL=gpt-4o-mini
 ```
 
+To see all available configuration parameters and their accepted values:
+
+```sh
+oco config describe
+```
+
+To see details for a specific parameter:
+
+```sh
+oco config describe OCO_MODEL
+```
+
 Configure [GitMoji](https://gitmoji.dev/) to preface a message.
 
 ```sh

src/commands/config.ts

@@ -31,7 +31,8 @@ export enum CONFIG_KEYS {
 
 export enum CONFIG_MODES {
   get = 'get',
-  set = 'set'
+  set = 'set',
+  describe = 'describe'
 }
 
 export const MODEL_LIST = {
@@ -603,28 +604,154 @@ export const setConfig = (
   outro(`${chalk.green('✔')} config successfully set`);
 };
 
+// --- HELP MESSAGE GENERATION ---
+function getConfigKeyDetails(key) {
+  switch (key) {
+    case CONFIG_KEYS.OCO_MODEL:
+      return {
+        description: 'The AI model to use for generating commit messages',
+        values: MODEL_LIST
+      };
+    case CONFIG_KEYS.OCO_AI_PROVIDER:
+      return {
+        description: 'The AI provider to use',
+        values: Object.values(OCO_AI_PROVIDER_ENUM)
+      };
+    case CONFIG_KEYS.OCO_PROMPT_MODULE:
+      return {
+        description: 'The prompt module to use for commit message generation',
+        values: Object.values(OCO_PROMPT_MODULE_ENUM)
+      };
+    case CONFIG_KEYS.OCO_LANGUAGE:
+      return {
+        description: 'The language to use for commit messages',
+        values: Object.keys(i18n)
+      };
+    case CONFIG_KEYS.OCO_TEST_MOCK_TYPE:
+      return {
+        description: 'The type of test mock to use',
+        values: ['commit-message', 'prompt-module-commitlint-config']
+      };
+    case CONFIG_KEYS.OCO_DESCRIPTION:
+    case CONFIG_KEYS.OCO_EMOJI:
+    case CONFIG_KEYS.OCO_WHY:
+    case CONFIG_KEYS.OCO_ONE_LINE_COMMIT:
+    case CONFIG_KEYS.OCO_OMIT_SCOPE:
+    case CONFIG_KEYS.OCO_GITPUSH:
+      return {
+        description: 'Boolean flag',
+        values: ['true', 'false']
+      };
+    case CONFIG_KEYS.OCO_TOKENS_MAX_INPUT:
+    case CONFIG_KEYS.OCO_TOKENS_MAX_OUTPUT:
+      return {
+        description: 'Integer number',
+        values: ['Any positive integer']
+      };
+    case CONFIG_KEYS.OCO_API_KEY:
+      return {
+        description: 'API key for the selected provider',
+        values: ['String (required for most providers)']
+      };
+    case CONFIG_KEYS.OCO_API_URL:
+      return {
+        description: 'Custom API URL',
+        values: ["URL string (must start with 'http://' or 'https://')"]
+      };
+    case CONFIG_KEYS.OCO_MESSAGE_TEMPLATE_PLACEHOLDER:
+      return {
+        description: 'Template placeholder for commit messages',
+        values: ["String (must start with $)"]
+      };
+    default:
+      return {
+        description: 'String value',
+        values: ['Any string']
+      };
+  }
+}
+
+function printConfigKeyHelp(param) {
+  if (!Object.values(CONFIG_KEYS).includes(param)) {
+    console.log(chalk.red(`Unknown config parameter: ${param}`));
+    return;
+  }
+
+  const details = getConfigKeyDetails(param as CONFIG_KEYS);
+  
+  console.log(chalk.bold(`\n${param}:`));
+  console.log(chalk.gray(`  Description: ${details.description}`));
+  
+  if (Array.isArray(details.values)) {
+    console.log(chalk.gray('  Accepted values:'));
+    details.values.forEach(value => {
+      console.log(chalk.gray(`    - ${value}`));
+    });
+  } else {
+    console.log(chalk.gray('  Accepted values by provider:'));
+    Object.entries(details.values).forEach(([provider, values]) => {
+      console.log(chalk.gray(`    ${provider}:`));
+      (values as string[]).forEach(value => {
+        console.log(chalk.gray(`      - ${value}`));
+      });
+    });
+  }
+}
+
+function printAllConfigHelp() {
+  console.log(chalk.bold('Available config parameters:'));
+  for (const key of Object.values(CONFIG_KEYS)) {
+    printConfigKeyHelp(key);
+  }
+  console.log(chalk.gray('\nFor more help, see https://github.com/di-sukharev/opencommit'));
+}
+
 export const configCommand = command(
   {
     name: COMMANDS.config,
-    parameters: ['<mode>', '<key=values...>']
+    parameters: ['<mode>', '[key=values...]'],
+    help: {
+      description: 'Configure opencommit settings',
+      examples: [
+        'Describe all config parameters: oco config describe',
+        'Describe a specific parameter: oco config describe OCO_MODEL',
+        'Get a config value: oco config get OCO_MODEL',
+        'Set a config value: oco config set OCO_MODEL=gpt-4'
+      ]
+    }
   },
   async (argv) => {
     try {
       const { mode, keyValues } = argv._;
       intro(`COMMAND: config ${mode} ${keyValues}`);
 
-      if (mode === CONFIG_MODES.get) {
+      if (mode === CONFIG_MODES.describe) {
+        if (!keyValues || keyValues.length === 0) {
+          printAllConfigHelp();
+        } else {
+          for (const key of keyValues) {
+            printConfigKeyHelp(key);
+          }
+        }
+        process.exit(0);
+      } else if (mode === CONFIG_MODES.get) {
+        if (!keyValues || keyValues.length === 0) {
+          throw new Error('No config keys specified for get mode');
+        }
         const config = getConfig() || {};
         for (const key of keyValues) {
           outro(`${key}=${config[key as keyof typeof config]}`);
         }
       } else if (mode === CONFIG_MODES.set) {
+        if (!keyValues || keyValues.length === 0) {
+          throw new Error('No config keys specified for set mode');
+        }
         await setConfig(
           keyValues.map((keyValue) => keyValue.split('=') as [string, string])
         );
       } else {
         throw new Error(
-          `Unsupported mode: ${mode}. Valid modes are: "set" and "get"`
+          `Unsupported mode: ${mode}. Valid modes are: "set", "get", and "describe"`
         );
       }
     } catch (error) {