fix: implement missing UI features (file picker, color preview, filters, bulk ops)

app/src/main/java/com/example/printer/ui/ConfigurationField.kt

@@ -1,5 +1,8 @@
 package com.example.printer.ui
 
+import android.net.Uri
+import androidx.activity.compose.rememberLauncherForActivityResult
+import androidx.activity.result.contract.ActivityResultContracts
 import androidx.compose.foundation.background
 import androidx.compose.foundation.layout.*
 import androidx.compose.foundation.rememberScrollState
@@ -10,6 +13,8 @@ import androidx.compose.material3.*
 import androidx.compose.runtime.*
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.input.KeyboardType
 import androidx.compose.ui.unit.dp
@@ -157,6 +162,15 @@ fun ConfigurationField(
             }
 
             FieldType.FILE -> {
+                val filePickerLauncher = rememberLauncherForActivityResult(
+                    contract = ActivityResultContracts.GetContent()
+                ) { uri: Uri? ->
+                    uri?.let {
+                        val filePath = it.toString()
+                        onValueChange(filePath)
+                    }
+                }
+
                 OutlinedTextField(
                     value = currentValue?.toString() ?: field.defaultValue?.toString() ?: "",
                     onValueChange = { onValueChange(it) },
@@ -166,7 +180,9 @@ fun ConfigurationField(
                     },
                     trailingIcon = {
                         TextButton(
-                            onClick = { /* TODO: File picker */ }
+                            onClick = { 
+                                filePickerLauncher.launch("*/*")
+                            }
                         ) {
                             Text("Browse")
                         }
@@ -175,14 +191,31 @@ fun ConfigurationField(
             }
 
             FieldType.COLOR -> {
+                val colorString = currentValue?.toString() ?: field.defaultValue?.toString() ?: "#000000"
+                val parsedColor = remember(colorString) {
+                    try {
+                        parseHexColor(colorString)
+                    } catch (e: Exception) {
+                        Color.Gray
+                    }
+                }
+
                 Row(
                     modifier = Modifier.fillMaxWidth(),
                     horizontalArrangement = Arrangement.spacedBy(8.dp),
                     verticalAlignment = Alignment.CenterVertically
                 ) {
                     OutlinedTextField(
-                        value = currentValue?.toString() ?: field.defaultValue?.toString() ?: "#000000",
-                        onValueChange = { onValueChange(it) },
+                        value = colorString,
+                        onValueChange = { 
+                            val trimmed = it.trim()
+                            if (trimmed.startsWith("#") || trimmed.matches(Regex("^[0-9A-Fa-f]{6}$"))) {
+                                val formatted = if (trimmed.startsWith("#")) trimmed else "#$trimmed"
+                                onValueChange(formatted)
+                            } else if (trimmed.isEmpty()) {
+                                onValueChange("#000000")
+                            }
+                        },
                         modifier = Modifier.weight(1f),
                         placeholder = {
                             Text("#RRGGBB")
@@ -192,12 +225,28 @@ fun ConfigurationField(
                         modifier = Modifier
                             .size(40.dp)
                             .background(
-                                color = androidx.compose.ui.graphics.Color.Gray, // TODO: Parse color
+                                color = parsedColor,
                                 shape = RoundedCornerShape(8.dp)
                             )
                     )
                 }
             }
         }
     }
+}
+
+/**
+ * Parses a hex color string (e.g., "#RRGGBB" or "RRGGBB") into a Color object
+ */
+private fun parseHexColor(hex: String): Color {
+    val cleanHex = hex.trim().removePrefix("#")
+    if (cleanHex.length != 6) {
+        throw IllegalArgumentException("Invalid hex color format: $hex")
+    }
+
+    val r = cleanHex.substring(0, 2).toInt(16)
+    val g = cleanHex.substring(2, 4).toInt(16)
+    val b = cleanHex.substring(4, 6).toInt(16)
+
+    return Color(r, g, b)
 }