[WIP] Add functionality to load presets from file system

src/ui/dialogs/__init__.py

@@ -1,6 +1,7 @@
 """Dialog components for the Plugin Configurator application."""
 
+from ui.dialogs.preset_load_dialog import PresetLoadDialog
 from ui.dialogs.preset_management_dialog import PresetManagementDialog
 from ui.dialogs.success_dialog import SuccessDialog
 
-__all__ = ["PresetManagementDialog", "SuccessDialog"]
+__all__ = ["PresetLoadDialog", "PresetManagementDialog", "SuccessDialog"]

src/ui/dialogs/preset_load_dialog.py

@@ -0,0 +1,200 @@
+"""Preset load dialog for selecting and loading an available preset."""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+from PySide6.QtCore import Qt, Slot
+from PySide6.QtWidgets import (
+    QDialog,
+    QDialogButtonBox,
+    QGroupBox,
+    QHBoxLayout,
+    QLabel,
+    QListWidget,
+    QListWidgetItem,
+    QMessageBox,
+    QSizePolicy,
+    QTextEdit,
+    QVBoxLayout,
+    QWidget,
+)
+
+if TYPE_CHECKING:
+    from core.config_manager import ConfigManager
+
+
+class PresetLoadDialog(QDialog):
+    """Dialog for browsing available presets and loading one into the configurator."""
+
+    def __init__(self, config_manager: ConfigManager, parent: QWidget | None = None) -> None:
+        super().__init__(parent)
+        self._config_manager = config_manager
+        self._selected_preset: str | None = None
+
+        self.setWindowTitle("Load Preset")
+        self.setMinimumSize(600, 400)
+        self.resize(700, 450)
+
+        self._setup_ui()
+        self._refresh_preset_list()
+
+    # ------------------------------------------------------------------
+    # Public API
+    # ------------------------------------------------------------------
+
+    def selected_preset_name(self) -> str | None:
+        """Return the name of the preset chosen by the user, or ``None``."""
+        return self._selected_preset
+
+    # ------------------------------------------------------------------
+    # UI construction
+    # ------------------------------------------------------------------
+
+    def _setup_ui(self) -> None:
+        """Build the dialog layout."""
+        main_layout = QHBoxLayout(self)
+
+        # ── Left panel: preset list ───────────────────────────────────
+        left_panel = QVBoxLayout()
+
+        presets_group = QGroupBox("Available Presets")
+        presets_group_layout = QVBoxLayout(presets_group)
+
+        self._preset_list = QListWidget()
+        self._preset_list.setAlternatingRowColors(True)
+        self._preset_list.currentRowChanged.connect(self._on_preset_selected)
+        self._preset_list.itemDoubleClicked.connect(self._on_load)
+        presets_group_layout.addWidget(self._preset_list)
+
+        left_panel.addWidget(presets_group)
+
+        # ── Right panel: metadata display ─────────────────────────────
+        right_panel = QVBoxLayout()
+
+        metadata_group = QGroupBox("Preset Details")
+        metadata_layout = QVBoxLayout(metadata_group)
+
+        name_header = QLabel("<b>Name</b>")
+        self._name_label = QLabel("—")
+        self._name_label.setWordWrap(True)
+        self._name_label.setSizePolicy(QSizePolicy.Policy.Expanding, QSizePolicy.Policy.Preferred)
+
+        desc_header = QLabel("<b>Description</b>")
+        self._desc_text = QTextEdit()
+        self._desc_text.setReadOnly(True)
+        self._desc_text.setPlaceholderText("No description available.")
+        self._desc_text.setMaximumHeight(120)
+
+        metadata_layout.addWidget(name_header)
+        metadata_layout.addWidget(self._name_label)
+        metadata_layout.addSpacing(4)
+        metadata_layout.addWidget(desc_header)
+        metadata_layout.addWidget(self._desc_text)
+        metadata_layout.addStretch()
+
+        right_panel.addWidget(metadata_group)
+
+        # ── Dialog buttons ────────────────────────────────────────────
+        self._button_box = QDialogButtonBox(
+            QDialogButtonBox.StandardButton.Ok | QDialogButtonBox.StandardButton.Cancel
+        )
+        self._load_btn = self._button_box.button(QDialogButtonBox.StandardButton.Ok)
+        self._load_btn.setText("Load")
+        self._load_btn.setEnabled(False)
+        self._button_box.accepted.connect(self._on_load)
+        self._button_box.rejected.connect(self.reject)
+
+        right_panel.addWidget(self._button_box)
+
+        # ── Assemble panels ───────────────────────────────────────────
+        left_widget = QWidget()
+        left_widget.setLayout(left_panel)
+        left_widget.setMinimumWidth(260)
+
+        right_widget = QWidget()
+        right_widget.setLayout(right_panel)
+
+        main_layout.addWidget(left_widget, 2)
+        main_layout.addWidget(right_widget, 3)
+
+    # ------------------------------------------------------------------
+    # Internal helpers
+    # ------------------------------------------------------------------
+
+    def _refresh_preset_list(self) -> None:
+        """Reload the preset list from disk.
+
+        The first preset in the sorted list is automatically selected so that
+        the metadata panel is populated immediately on dialog open.
+        """
+        self._preset_list.clear()
+        for preset_name in self._config_manager.get_available_presets():
+            self._preset_list.addItem(QListWidgetItem(preset_name))
+
+        # Auto-select the first item so the metadata panel is populated right away.
+        if self._preset_list.count() > 0:
+            self._preset_list.setCurrentRow(0)
+
+        self._update_load_button()
+
+    def _update_load_button(self) -> None:
+        """Enable the Load button only when a preset is selected."""
+        self._load_btn.setEnabled(self._preset_list.currentItem() is not None)
+
+    def _current_preset_name(self) -> str | None:
+        """Return the currently selected preset name, or ``None``."""
+        item = self._preset_list.currentItem()
+        return item.text() if item is not None else None
+
+    def _load_metadata(self, preset_name: str) -> dict:
+        """Return the ``meta`` section of *preset_name*, or an empty dict on error."""
+        try:
+            config = self._config_manager.load_preset(preset_name)
+            meta: dict = config.get("meta", {})
+            return meta
+        except (ValueError, OSError):
+            return {}
+
+    # ------------------------------------------------------------------
+    # Slots
+    # ------------------------------------------------------------------
+
+    @Slot(int)
+    def _on_preset_selected(self, row: int) -> None:
+        """Update the metadata panel when the user selects a preset."""
+        self._update_load_button()
+
+        if row < 0:
+            self._name_label.setText("—")
+            self._desc_text.setPlainText("")
+            return
+
+        preset_name = self._current_preset_name()
+        if preset_name is None:
+            return
+
+        meta = self._load_metadata(preset_name)
+        self._name_label.setText(meta.get("name") or preset_name)
+        self._desc_text.setPlainText(meta.get("description", ""))
+
+    @Slot()
+    def _on_load(self) -> None:
+        """Validate the selected preset and accept the dialog."""
+        preset_name = self._current_preset_name()
+        if preset_name is None:
+            return
+
+        is_valid, errors = self._config_manager.validate_preset_file(
+            self._config_manager.preset_dir / f"{preset_name}.xml"
+        )
+        if not is_valid:
+            QMessageBox.warning(
+                self,
+                "Invalid Preset",
+                "The selected preset is not valid:\n\n" + "\n".join(errors),
+            )
+            return
+
+        self._selected_preset = preset_name
+        self.accept()

src/ui/main_window.py

@@ -14,7 +14,7 @@
 
 from core.config_manager import ConfigManager
 from ui.components import FileTreePreview
-from ui.dialogs import PresetManagementDialog
+from ui.dialogs import PresetLoadDialog, PresetManagementDialog
 from ui.tabs.configuration_tab import ConfigurationTab
 from ui.tabs.development_workflow_tab import DevelopmentWorkflowTab
 from ui.tabs.generate_tab import GenerateTab
@@ -122,6 +122,10 @@ def setup_menu(self):
         new_action.setShortcut("Ctrl+N")
         new_action.triggered.connect(self.new_project)
 
+        load_preset_action = QAction("&Load Preset…", self)
+        load_preset_action.setShortcut("Ctrl+L")
+        load_preset_action.triggered.connect(self.show_load_preset_dialog)
+
         save_preset_action = QAction("&Save as Preset", self)
         save_preset_action.setShortcut("Ctrl+S")
         save_preset_action.triggered.connect(self.save_current_as_preset)
@@ -140,6 +144,7 @@ def setup_menu(self):
 
         # Add actions to file menu
         file_menu.addAction(new_action)
+        file_menu.addAction(load_preset_action)
         file_menu.addAction(save_preset_action)
         file_menu.addAction(manage_presets_action)
         file_menu.addAction(generate_action)
@@ -232,6 +237,30 @@ def show_preset_management(self):
         dialog = PresetManagementDialog(self._config_manager, parent=self)
         dialog.exec()
 
+    @Slot()
+    def show_load_preset_dialog(self):
+        """Open the preset load dialog and apply the chosen preset to all tabs."""
+        dialog = PresetLoadDialog(self._config_manager, parent=self)
+        if not dialog.exec():
+            return
+
+        preset_name = dialog.selected_preset_name()
+        if preset_name is None:
+            return
+
+        try:
+            config = self._config_manager.load_preset(preset_name)
+        except ValueError as exc:
+            QMessageBox.warning(
+                self,
+                "Load Preset Failed",
+                f'Could not load preset "{preset_name}":\n{exc}',
+            )
+            return
+
+        self.load_preset_to_all_tabs(config)
+        self.status_bar.showMessage(f'Preset "{preset_name}" loaded')
+
     @Slot()
     def generate_project(self):
         """Start the project generation process"""

src/ui/tabs/project_info_tab.py

@@ -300,8 +300,13 @@ def setup_ui(self):
             "Skip the detailed steps and jump straight to Review & Generate with sensible defaults."
         )
         quick_actions_layout = QHBoxLayout()
+        self.load_preset_button = QPushButton("Load Preset…")
+        self.load_preset_button.setToolTip(
+            "Browse and load a saved preset to populate all configuration tabs."
+        )
         self.review_generate_button = QPushButton("Review & Generate")
         self.review_generate_button.setEnabled(False)
+        quick_actions_layout.addWidget(self.load_preset_button)
         quick_actions_layout.addWidget(self.review_generate_button)
         quick_actions_layout.addStretch()
         quick_start_layout.addWidget(self.quick_start_checkbox)
@@ -378,6 +383,7 @@ def setup_connections(self):
         self.project_name.textChanged.connect(self.update_file_tree)
         self.quick_start_checkbox.toggled.connect(self._on_quick_start_toggled)
         self.review_generate_button.clicked.connect(self._on_review_generate_clicked)
+        self.load_preset_button.clicked.connect(self._on_load_preset_clicked)
         for spin in [self.fx_wet_dry, self.fx_latency, self.instrument_polyphony]:
             spin.valueChanged.connect(self._on_plugin_type_option_changed)
         for checkbox in [self.fx_sidechain, self.instrument_midi_input]:
@@ -856,6 +862,13 @@ def _on_review_generate_clicked(self):
             main_window.quick_start_review_generate()
         self._update_quick_start_button_state()
 
+    @Slot()
+    def _on_load_preset_clicked(self):
+        """Open the preset load dialog and apply the chosen preset to all tabs."""
+        main_window = self.window()
+        if hasattr(main_window, "show_load_preset_dialog"):
+            main_window.show_load_preset_dialog()
+
     def _has_required_quick_start_data(self) -> bool:
         """Check required fields without showing dialogs for button state."""
         return self._validate_required_fields(show_messages=False)