feat(features): added file options, fixed some things

src/main/kotlin/org/kargs/ArgType.kt

@@ -1,5 +1,7 @@
 package org.kargs
 
+import java.io.File
+
 /**
  * Sealed class representing different argument types with conversion and validation logic
  */
@@ -84,6 +86,42 @@ sealed class ArgType<T>(val typeName: String) {
         override fun getValidationDescription(): String = "optional value or flag"
     }
 
+    /**
+     * File path type with existence and permision validation
+     */
+    class FilePath(
+        val mustExist: Boolean = false,
+        val mustBeFile: Boolean = false,
+        val mustBeDirectory: Boolean = false,
+        val mustBeReadable: Boolean = false,
+        val mustBeWritable: Boolean = false
+    ) : ArgType<File>("File") {
+        override fun convert(value: String): File = File(value)
+
+        override fun validate(value: File): Boolean {
+            return when {
+                mustExist && !value.exists() -> false
+                mustBeFile && !value.isFile -> false
+                mustBeDirectory && !value.isDirectory -> false
+                mustBeReadable && !value.canRead() -> false
+                mustBeWritable && !value.canWrite() -> false
+                else -> true
+            }        
+        }
+
+        override fun getValidationDescription(): String {
+            val conditions = mutableListOf<String>()
+            if (mustExist) conditions.add("must exist")
+            if (mustBeFile) conditions.add("must be a file")
+            if (mustBeDirectory) conditions.add("must be a directory")
+            if (mustBeReadable) conditions.add("must be readable")
+            if (mustBeWritable) conditions.add("must be writable")
+
+            return if (conditions.isEmpty()) "file path" else "file path (${conditions.joinToString(", ")})"
+        }
+    }
+
+
     companion object {
         val String: ArgType<kotlin.String> = StringType
         val Int: ArgType<kotlin.Int> = IntType
@@ -104,5 +142,30 @@ sealed class ArgType<T>(val typeName: String) {
          * Create an optional value or flag
          */
         fun optionalValue(defaultWhenPresent: String = "true") = OptionalValue(defaultWhenPresent)
+
+        /**
+         * File that must exist and be a regular file
+         */
+        fun existingFile() = FilePath(mustExist = true, mustBeFile = true)
+
+        /**
+         * Directory that must exist
+         */
+        fun existingDirectory() = FilePath(mustExist = true, mustBeDirectory = true)
+
+        /**
+         * File that must exist and be readable
+         */
+        fun readableFile() = FilePath(mustExist = true, mustBeFile = true, mustBeReadable = true)
+
+        /**
+         * File that must be writable (can be created if doesn't exist)
+         */
+        fun writableFile() = FilePath(mustBeWritable = true)
+
+        /**
+         * Any file path (no validation)
+         */
+        fun filePath() = FilePath()
     }
 }

src/main/kotlin/org/kargs/Parser.kt

@@ -25,6 +25,10 @@ class Parser(
      * @param args Array of command-line arguments
      */
     fun parse(args: Array<String>) {
+        if (handleVersionFlag(args)) {
+            return // Exit after showing version
+        }
+
         if (args.isEmpty()) {
             if (config.helpOnEmpty) {
                 printGlobalHelp()
@@ -254,7 +258,8 @@ class Parser(
      * Print global help menu
      */
     private fun printGlobalHelp() {
-        println(colorize("Usage: $programName <command> [options]", Color.BOLD))
+        val versionInfo = config.programVersion?.let { " (v$it)" } ?: ""
+        println(colorize("Usage: $programName$versionInfo <command> [options]", Color.BOLD))
         println()
         println(colorize("Commands:", Color.BOLD))
         commands.forEach { cmd -> 
@@ -321,6 +326,31 @@ class Parser(
         // Exit gracefully instead of throwing
         // kotlin.system.exitProcess(1)
     }
+
+    /**
+     * Check if version flag is present and handle it
+     */
+    private fun handleVersionFlag(args: Array<String>): Boolean {
+        if (config.programVersion == null) return false
+
+        val versionFlags = listOf("--${config.versionLongName}", "-${config.versionShortName}")
+
+        if (args.any { it in versionFlags }) {
+            printVersion()
+            return true // Indicates version was shown, should exit
+        }
+
+        return false
+    }
+
+    /**
+     * Print version information
+     */
+    private fun printVersion() {
+        config.programVersion?.let { version -> 
+            println("$programName version $version")
+        }
+    }
 }
 
 /**

src/main/kotlin/org/kargs/ParserConfig.kt

@@ -9,7 +9,11 @@ data class ParserConfig(
     val helpOnEmpty: Boolean = true, // Show help when no args provided
     val caseSensitive: Boolean = true,
     val allowAbbreviations: Boolean = false, // Allow partial option matching
-    val programVersion: String? = null // Adds --version and -v flag if set
+    val programVersion: String? = null, // Adds --version and -v flag if set
+
+    // Optional customize version flag names
+    val versionLongName: String = "version",
+    val versionShortName: String = "V" // Capital V to avoid conflicts with -v (verbose)
 ) {
     companion object {
         val DEFAULT = ParserConfig()

src/main/kotlin/org/kargs/Subcommand.kt

@@ -139,6 +139,7 @@ abstract class Subcommand(
             is ArgType.IntRange -> " <${type.min}-${type.max}>"
             is ArgType.Choice -> " <${type.choices.joinToString("|")}>"
             is ArgType.OptionalValue -> " [string]"
+            is ArgType.FilePath -> " <path>"
         }
     }
 }

src/test/kotlin/org/kargs/tests/ArgTypeTest.kt

@@ -7,6 +7,8 @@ import org.junit.jupiter.params.provider.ValueSource
 import org.kargs.ArgType
 import org.kargs.ArgumentParseException
 import kotlin.test.assertEquals
+import kotlin.io.path.createTempFile
+import kotlin.io.path.createTempDirectory
 
 class ArgTypeTest {
 
@@ -103,5 +105,192 @@ class ArgTypeTest {
         val type = ArgType.choice("apple", "banana", "cherry")
         assertEquals("one of: apple, banana, cherry", type.getValidationDescription())
     }
+
+    @Test
+    fun `FilePath converts string to File`() {
+        val type = ArgType.filePath()
+        val result = type.convert("/path/to/file.txt")
+        assertEquals("/path/to/file.txt", result.path)
+    }
+
+    @Test
+    fun `FilePath with no constraints allows any path`() {
+        val type = ArgType.filePath()
+        // Should not throw for non-existent files
+        val result = type.convert("/non/existent/path")
+        assertEquals("/non/existent/path", result.path)
+        assertEquals(true, type.validate(result))
+    }
+
+    @Test
+    fun `existingFile validates file exists and is file`() {
+        val type = ArgType.existingFile()
+
+        // Create a temporary file for testing
+        val tempFile = kotlin.io.path.createTempFile().toFile()
+        tempFile.writeText("test content")
+
+        try {
+            // Should work with existing file
+            val result = type.convert(tempFile.absolutePath)
+            assertEquals(true, type.validate(result))
+
+            // Should fail with non-existent file
+            val nonExistent = type.convert("/non/existent/file.txt")
+            assertEquals(false, type.validate(nonExistent))
+
+        } finally {
+            tempFile.delete()
+        }
+    }
+
+    @Test
+    fun `existingFile fails validation on directory`() {
+        val type = ArgType.existingFile()
+
+        // Create a temporary directory
+        val tempDir = kotlin.io.path.createTempDirectory().toFile()
+
+        try {
+            val result = type.convert(tempDir.absolutePath)
+            assertEquals(false, type.validate(result)) // Should fail because it's a directory, not a file
+
+        } finally {
+            tempDir.delete()
+        }
+    }
+
+    @Test
+    fun `existingDirectory validates directory exists and is directory`() {
+        val type = ArgType.existingDirectory()
+
+        // Create a temporary directory
+        val tempDir = kotlin.io.path.createTempDirectory().toFile()
+
+        try {
+            // Should work with existing directory
+            val result = type.convert(tempDir.absolutePath)
+            assertEquals(true, type.validate(result))
+
+            // Should fail with non-existent directory
+            val nonExistent = type.convert("/non/existent/directory")
+            assertEquals(false, type.validate(nonExistent))
+
+        } finally {
+            tempDir.delete()
+        }
+    }
+
+    @Test
+    fun `existingDirectory fails validation on file`() {
+        val type = ArgType.existingDirectory()
+
+        // Create a temporary file
+        val tempFile = kotlin.io.path.createTempFile().toFile()
+        tempFile.writeText("test")
+
+        try {
+            val result = type.convert(tempFile.absolutePath)
+            assertEquals(false, type.validate(result)) // Should fail because it's a file, not a directory
+
+        } finally {
+            tempFile.delete()
+        }
+    }
+
+    @Test
+    fun `readableFile validates file is readable`() {
+        val type = ArgType.readableFile()
+
+        // Create a temporary file
+        val tempFile = kotlin.io.path.createTempFile().toFile()
+        tempFile.writeText("test content")
+
+        try {
+            // Should work with readable file
+            val result = type.convert(tempFile.absolutePath)
+            assertEquals(true, type.validate(result))
+
+            // Make file unreadable (this might not work on all systems)
+            tempFile.setReadable(false)
+            assertEquals(false, type.validate(result))
+
+        } finally {
+            tempFile.setReadable(true) // Restore permissions
+            tempFile.delete()
+        }
+    }
+
+    @Test
+    fun `writableFile validates file is writable`() {
+        val type = ArgType.writableFile()
+
+        // Create a temporary file
+        val tempFile = kotlin.io.path.createTempFile().toFile()
+        tempFile.writeText("test content")
+
+        try {
+            // Should work with writable file
+            val result = type.convert(tempFile.absolutePath)
+            assertEquals(true, type.validate(result))
+
+            // Make file read-only (this might not work on all systems)
+            tempFile.setWritable(false)
+            assertEquals(false, type.validate(result))
+
+        } finally {
+            tempFile.setWritable(true) // Restore permissions
+            tempFile.delete()
+        }
+    }
+
+    @Test
+    fun `FilePath validation description includes constraints`() {
+        assertEquals("file path", ArgType.filePath().getValidationDescription())
+        assertEquals("file path (must exist, must be a file)", ArgType.existingFile().getValidationDescription())
+        assertEquals("file path (must exist, must be a directory)", ArgType.existingDirectory().getValidationDescription())
+        assertEquals("file path (must exist, must be a file, must be readable)", ArgType.readableFile().getValidationDescription())
+        assertEquals("file path (must be writable)", ArgType.writableFile().getValidationDescription())
+    }
+
+    @Test
+    fun `FilePath with multiple constraints`() {
+        val type = ArgType.FilePath(
+            mustExist = true,
+            mustBeFile = true,
+            mustBeReadable = true,
+            mustBeWritable = true
+        )
+
+        val tempFile = kotlin.io.path.createTempFile().toFile()
+        tempFile.writeText("test")
+
+        try {
+            val result = type.convert(tempFile.absolutePath)
+            assertEquals(true, type.validate(result))
+
+            assertEquals(
+                "file path (must exist, must be a file, must be readable, must be writable)",
+                type.getValidationDescription()
+            )
+
+        } finally {
+            tempFile.delete()
+        }
+    }
+
+    @Test
+    fun `FilePath handles non-existent parent directories`() {
+        val type = ArgType.writableFile()
+
+        // Path with non-existent parent directory
+        val result = type.convert("/non/existent/parent/file.txt")
+
+        // Should convert fine (validation happens separately)
+        assertEquals("/non/existent/parent/file.txt", result.path)
+
+        // Validation should fail because parent doesn't exist
+        assertEquals(false, type.validate(result))
+    }
 }