feat: add Export/Import character as JSON (Closes #29) (#72)

sharedUI/src/commonMain/kotlin/org/shahondin1624/App.kt

@@ -320,7 +320,12 @@ private fun MainScaffold(
                     )
                 }
                 composable(AppRoutes.SETTINGS) {
-                    SettingsPage()
+                    SettingsPage(
+                        character = character,
+                        onImportCharacter = { imported ->
+                            characterViewModel.setCharacter(imported)
+                        }
+                    )
                 }
             }
         }

sharedUI/src/commonMain/kotlin/org/shahondin1624/lib/components/TestTags.kt

@@ -75,6 +75,20 @@ object TestTags {
     const val SETTINGS_THEME_SYSTEM = "settings_theme_system"
     const val SETTINGS_THEME_LIGHT = "settings_theme_light"
     const val SETTINGS_THEME_DARK = "settings_theme_dark"
+    const val SETTINGS_EXPORT_BUTTON = "settings_export_button"
+    const val SETTINGS_IMPORT_BUTTON = "settings_import_button"
+
+    // --- Export dialog ---
+    const val EXPORT_DIALOG = "export_dialog"
+    const val EXPORT_JSON_TEXT = "export_json_text"
+    const val EXPORT_DISMISS = "export_dismiss"
+
+    // --- Import dialog ---
+    const val IMPORT_DIALOG = "import_dialog"
+    const val IMPORT_JSON_INPUT = "import_json_input"
+    const val IMPORT_CONFIRM = "import_confirm"
+    const val IMPORT_DISMISS = "import_dismiss"
+    const val IMPORT_ERROR = "import_error"
 
     // --- Top app bar ---
     const val TOP_APP_BAR = "top_app_bar"

sharedUI/src/commonMain/kotlin/org/shahondin1624/lib/components/settings/ExportCharacterDialog.kt

@@ -0,0 +1,65 @@
+package org.shahondin1624.lib.components.settings
+
+import androidx.compose.foundation.horizontalScroll
+import androidx.compose.foundation.layout.*
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material3.*
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.testTag
+import androidx.compose.ui.text.font.FontFamily
+import androidx.compose.ui.unit.dp
+import org.shahondin1624.lib.components.TestTags
+
+/**
+ * Dialog displaying the character JSON for export.
+ * The user can select and copy the text manually.
+ */
+@Composable
+fun ExportCharacterDialog(
+    json: String,
+    onDismiss: () -> Unit
+) {
+    AlertDialog(
+        onDismissRequest = onDismiss,
+        modifier = Modifier.testTag(TestTags.EXPORT_DIALOG),
+        title = { Text("Export Character") },
+        text = {
+            Column {
+                Text(
+                    text = "Copy the JSON below to save your character:",
+                    style = MaterialTheme.typography.bodyMedium,
+                    modifier = Modifier.padding(bottom = 8.dp)
+                )
+                Surface(
+                    color = MaterialTheme.colorScheme.surfaceContainerHighest,
+                    shape = MaterialTheme.shapes.small,
+                    modifier = Modifier
+                        .fillMaxWidth()
+                        .heightIn(max = 300.dp)
+                ) {
+                    Text(
+                        text = json,
+                        style = MaterialTheme.typography.bodySmall.copy(
+                            fontFamily = FontFamily.Monospace
+                        ),
+                        modifier = Modifier
+                            .verticalScroll(rememberScrollState())
+                            .horizontalScroll(rememberScrollState())
+                            .padding(8.dp)
+                            .testTag(TestTags.EXPORT_JSON_TEXT)
+                    )
+                }
+            }
+        },
+        confirmButton = {
+            TextButton(
+                onClick = onDismiss,
+                modifier = Modifier.testTag(TestTags.EXPORT_DISMISS)
+            ) {
+                Text("Close")
+            }
+        }
+    )
+}

sharedUI/src/commonMain/kotlin/org/shahondin1624/lib/components/settings/ImportCharacterDialog.kt

@@ -0,0 +1,87 @@
+package org.shahondin1624.lib.components.settings
+
+import androidx.compose.foundation.layout.*
+import androidx.compose.material3.*
+import androidx.compose.runtime.*
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.testTag
+import androidx.compose.ui.unit.dp
+import org.shahondin1624.lib.components.TestTags
+import org.shahondin1624.lib.functions.DataLoader
+import org.shahondin1624.model.charactermodel.ShadowrunCharacter
+
+/**
+ * Dialog for importing a character from pasted JSON.
+ * Validates the JSON and shows an error message for invalid input.
+ */
+@Composable
+fun ImportCharacterDialog(
+    onImport: (ShadowrunCharacter) -> Unit,
+    onDismiss: () -> Unit
+) {
+    var jsonText by remember { mutableStateOf("") }
+    var errorMessage by remember { mutableStateOf<String?>(null) }
+
+    AlertDialog(
+        onDismissRequest = onDismiss,
+        modifier = Modifier.testTag(TestTags.IMPORT_DIALOG),
+        title = { Text("Import Character") },
+        text = {
+            Column {
+                Text(
+                    text = "Paste the character JSON below:",
+                    style = MaterialTheme.typography.bodyMedium,
+                    modifier = Modifier.padding(bottom = 8.dp)
+                )
+                OutlinedTextField(
+                    value = jsonText,
+                    onValueChange = {
+                        jsonText = it
+                        errorMessage = null
+                    },
+                    modifier = Modifier
+                        .fillMaxWidth()
+                        .heightIn(min = 150.dp, max = 300.dp)
+                        .testTag(TestTags.IMPORT_JSON_INPUT),
+                    placeholder = { Text("{ \"characterData\": ... }") },
+                    isError = errorMessage != null,
+                    maxLines = Int.MAX_VALUE
+                )
+                if (errorMessage != null) {
+                    Text(
+                        text = errorMessage!!,
+                        color = MaterialTheme.colorScheme.error,
+                        style = MaterialTheme.typography.bodySmall,
+                        modifier = Modifier
+                            .padding(top = 4.dp)
+                            .testTag(TestTags.IMPORT_ERROR)
+                    )
+                }
+            }
+        },
+        confirmButton = {
+            TextButton(
+                onClick = {
+                    try {
+                        val character = DataLoader.deserialize(jsonText)
+                        onImport(character)
+                    } catch (e: Exception) {
+                        errorMessage = "Invalid JSON: ${e.message?.take(100) ?: "unknown error"}"
+                    }
+                },
+                modifier = Modifier.testTag(TestTags.IMPORT_CONFIRM),
+                enabled = jsonText.isNotBlank()
+            ) {
+                Text("Import")
+            }
+        },
+        dismissButton = {
+            TextButton(
+                onClick = onDismiss,
+                modifier = Modifier.testTag(TestTags.IMPORT_DISMISS)
+            ) {
+                Text("Cancel")
+            }
+        }
+    )
+}

sharedUI/src/commonMain/kotlin/org/shahondin1624/lib/components/settings/Settings.kt

@@ -1,12 +1,15 @@
 package org.shahondin1624.lib.components.settings
 
 import androidx.compose.foundation.layout.*
+import androidx.compose.foundation.rememberScrollState
 import androidx.compose.foundation.selection.selectable
 import androidx.compose.foundation.selection.selectableGroup
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Download
+import androidx.compose.material.icons.filled.Upload
 import androidx.compose.material3.*
-import androidx.compose.runtime.Composable
-import androidx.compose.runtime.getValue
-import androidx.compose.runtime.setValue
+import androidx.compose.runtime.*
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.testTag
@@ -14,23 +17,52 @@ import androidx.compose.ui.semantics.Role
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.dp
 import org.shahondin1624.lib.components.TestTags
+import org.shahondin1624.lib.functions.DataLoader
+import org.shahondin1624.model.charactermodel.ShadowrunCharacter
 import org.shahondin1624.theme.LocalThemePreference
 import org.shahondin1624.theme.ThemePreference
 
 /**
- * Settings page with theme selection (Light / Dark / System Default).
+ * Settings page with theme selection and character export/import.
  */
 @Composable
-fun SettingsPage() {
+fun SettingsPage(
+    character: ShadowrunCharacter? = null,
+    onImportCharacter: ((ShadowrunCharacter) -> Unit)? = null
+) {
     var themePreference by LocalThemePreference.current
+    var showExportDialog by remember { mutableStateOf(false) }
+    var showImportDialog by remember { mutableStateOf(false) }
+
+    // Export dialog
+    if (showExportDialog && character != null) {
+        val json = remember(character) { DataLoader.serialize(character) }
+        ExportCharacterDialog(
+            json = json,
+            onDismiss = { showExportDialog = false }
+        )
+    }
+
+    // Import dialog
+    if (showImportDialog && onImportCharacter != null) {
+        ImportCharacterDialog(
+            onImport = { importedCharacter ->
+                onImportCharacter(importedCharacter)
+                showImportDialog = false
+            },
+            onDismiss = { showImportDialog = false }
+        )
+    }
 
     Column(
         modifier = Modifier
             .fillMaxSize()
+            .verticalScroll(rememberScrollState())
             .padding(16.dp)
             .testTag(TestTags.SETTINGS_PAGE),
         verticalArrangement = Arrangement.spacedBy(16.dp)
     ) {
+        // --- Appearance section ---
         Text(
             text = "Appearance",
             style = MaterialTheme.typography.titleMedium,
@@ -78,6 +110,62 @@ fun SettingsPage() {
                 )
             }
         }
+
+        // --- Character Data section ---
+        if (character != null && onImportCharacter != null) {
+            Text(
+                text = "Character Data",
+                style = MaterialTheme.typography.titleMedium,
+                fontWeight = FontWeight.Bold
+            )
+
+            Card(
+                modifier = Modifier.fillMaxWidth()
+            ) {
+                Column(
+                    modifier = Modifier
+                        .fillMaxWidth()
+                        .padding(vertical = 8.dp)
+                ) {
+                    Row(
+                        modifier = Modifier
+                            .fillMaxWidth()
+                            .padding(horizontal = 16.dp, vertical = 8.dp),
+                        verticalAlignment = Alignment.CenterVertically,
+                        horizontalArrangement = Arrangement.spacedBy(12.dp)
+                    ) {
+                        Button(
+                            onClick = { showExportDialog = true },
+                            modifier = Modifier
+                                .weight(1f)
+                                .testTag(TestTags.SETTINGS_EXPORT_BUTTON)
+                        ) {
+                            Icon(
+                                Icons.Default.Upload,
+                                contentDescription = null,
+                                modifier = Modifier.size(18.dp)
+                            )
+                            Spacer(Modifier.width(8.dp))
+                            Text("Export")
+                        }
+                        OutlinedButton(
+                            onClick = { showImportDialog = true },
+                            modifier = Modifier
+                                .weight(1f)
+                                .testTag(TestTags.SETTINGS_IMPORT_BUTTON)
+                        ) {
+                            Icon(
+                                Icons.Default.Download,
+                                contentDescription = null,
+                                modifier = Modifier.size(18.dp)
+                            )
+                            Spacer(Modifier.width(8.dp))
+                            Text("Import")
+                        }
+                    }
+                }
+            }
+        }
     }
 }