Add GTK app shell with wizard navigation, step indicator, and actions

pixstrip-gtk/src/wizard.rs

@@ -0,0 +1,88 @@
+pub struct WizardState {
+    pub current_step: usize,
+    pub total_steps: usize,
+    pub visited: Vec<bool>,
+    names: Vec<String>,
+}
+
+impl WizardState {
+    pub fn new() -> Self {
+        let names = vec![
+            "Workflow".into(),
+            "Images".into(),
+            "Resize".into(),
+            "Convert".into(),
+            "Compress".into(),
+            "Metadata".into(),
+            "Output".into(),
+        ];
+        let total = names.len();
+        let mut visited = vec![false; total];
+        visited[0] = true;
+
+        Self {
+            current_step: 0,
+            total_steps: total,
+            visited,
+            names,
+        }
+    }
+
+    pub fn step_names(&self) -> Vec<String> {
+        self.names.clone()
+    }
+
+    pub fn can_go_next(&self) -> bool {
+        self.current_step < self.total_steps - 1
+    }
+
+    pub fn can_go_back(&self) -> bool {
+        self.current_step > 0
+    }
+
+    pub fn is_last_step(&self) -> bool {
+        self.current_step == self.total_steps - 1
+    }
+
+    pub fn go_next(&mut self) {
+        if self.can_go_next() {
+            self.current_step += 1;
+            self.visited[self.current_step] = true;
+        }
+    }
+
+    pub fn go_back(&mut self) {
+        if self.can_go_back() {
+            self.current_step -= 1;
+        }
+    }
+}
+
+pub fn build_wizard_pages() -> Vec<adw::NavigationPage> {
+    let steps = [
+        ("step-workflow", "Choose a Workflow", "image-x-generic-symbolic", "Select a preset or build a custom workflow"),
+        ("step-images", "Add Images", "folder-pictures-symbolic", "Drop images here or click Browse"),
+        ("step-resize", "Resize", "view-fullscreen-symbolic", "Set output dimensions"),
+        ("step-convert", "Convert", "document-save-symbolic", "Choose output format"),
+        ("step-compress", "Compress", "system-file-manager-symbolic", "Set compression quality"),
+        ("step-metadata", "Metadata", "security-high-symbolic", "Control metadata privacy"),
+        ("step-output", "Output & Process", "emblem-ok-symbolic", "Review and process"),
+    ];
+
+    steps
+        .iter()
+        .map(|(tag, title, icon, description)| {
+            let status_page = adw::StatusPage::builder()
+                .title(*title)
+                .description(*description)
+                .icon_name(*icon)
+                .build();
+
+            adw::NavigationPage::builder()
+                .title(*title)
+                .tag(*tag)
+                .child(&status_page)
+                .build()
+        })
+        .collect()
+}