Some kind of refactoring

src/services/stack_preview.rs

@@ -0,0 +1,106 @@
+use arc_swap::ArcSwap;
+use parking_lot::Mutex;
+use std::collections::hash_map::DefaultHasher;
+use std::collections::HashMap;
+use std::hash::{Hash, Hasher};
+use std::sync::Arc;
+
+use rand::rngs::StdRng;
+use rand::SeedableRng;
+
+use crate::model::{ScriptEngine, StepContext, Value};
+use crate::state::{EditorContext, StackCache};
+
+pub fn update_cache(editor_ctx: &EditorContext) {
+    let lines = editor_ctx.editor.lines();
+    let cursor_line = editor_ctx.editor.cursor().0;
+
+    let mut hasher = DefaultHasher::new();
+    for (i, line) in lines.iter().enumerate() {
+        if i > cursor_line {
+            break;
+        }
+        line.hash(&mut hasher);
+    }
+    let lines_hash = hasher.finish();
+
+    if let Some(ref c) = *editor_ctx.stack_cache.borrow() {
+        if c.cursor_line == cursor_line && c.lines_hash == lines_hash {
+            return;
+        }
+    }
+
+    let partial: Vec<&str> = lines
+        .iter()
+        .take(cursor_line + 1)
+        .map(|s| s.as_str())
+        .collect();
+    let script = partial.join("\n");
+
+    let result = if script.trim().is_empty() {
+        "Stack: []".to_string()
+    } else {
+        let vars = Arc::new(ArcSwap::from_pointee(HashMap::new()));
+        let dict = Arc::new(Mutex::new(HashMap::new()));
+        let rng = Arc::new(Mutex::new(StdRng::seed_from_u64(42)));
+        let engine = ScriptEngine::new(vars, dict, rng);
+
+        let ctx = StepContext {
+            step: 0,
+            beat: 0.0,
+            bank: 0,
+            pattern: 0,
+            tempo: 120.0,
+            phase: 0.0,
+            slot: 0,
+            runs: 0,
+            iter: 0,
+            speed: 1.0,
+            fill: false,
+            nudge_secs: 0.0,
+            cc_access: None,
+            speed_key: "",
+            chain_key: "",
+            #[cfg(feature = "desktop")]
+            mouse_x: 0.5,
+            #[cfg(feature = "desktop")]
+            mouse_y: 0.5,
+            #[cfg(feature = "desktop")]
+            mouse_down: 0.0,
+        };
+
+        match engine.evaluate(&script, &ctx) {
+            Ok(_) => {
+                let stack = engine.stack();
+                let formatted: Vec<String> = stack.iter().map(format_value).collect();
+                format!("Stack: [{}]", formatted.join(" "))
+            }
+            Err(e) => format!("Error: {e}"),
+        }
+    };
+
+    *editor_ctx.stack_cache.borrow_mut() = Some(StackCache {
+        cursor_line,
+        lines_hash,
+        result,
+    });
+}
+
+fn format_value(v: &Value) -> String {
+    match v {
+        Value::Int(n, _) => n.to_string(),
+        Value::Float(f, _) => {
+            if f.fract() == 0.0 && f.abs() < 1_000_000.0 {
+                format!("{f:.1}")
+            } else {
+                format!("{f:.4}")
+            }
+        }
+        Value::Str(s, _) => format!("\"{s}\""),
+        Value::Quotation(..) => "[...]".to_string(),
+        Value::CycleList(items) => {
+            let inner: Vec<String> = items.iter().map(format_value).collect();
+            format!("({})", inner.join(" "))
+        }
+    }
+}