feat(core): add built-in calculator provider

crates/owlry-core/src/providers/calculator.rs

@@ -0,0 +1,237 @@
+use super::{DynamicProvider, LaunchItem, ProviderType};
+
+/// Built-in calculator provider. Evaluates mathematical expressions via `meval`.
+///
+/// Triggered by:
+/// - `= expr` / `=expr` / `calc expr` (explicit prefix)
+/// - Raw math expressions containing operators or known functions (auto-detect)
+pub(crate) struct CalculatorProvider;
+
+impl DynamicProvider for CalculatorProvider {
+    fn name(&self) -> &str {
+        "Calculator"
+    }
+
+    fn provider_type(&self) -> ProviderType {
+        ProviderType::Plugin("calc".into())
+    }
+
+    fn priority(&self) -> u32 {
+        10_000
+    }
+
+    fn query(&self, query: &str) -> Vec<LaunchItem> {
+        let expr = match extract_expression(query) {
+            Some(e) if !e.is_empty() => e,
+            _ => return Vec::new(),
+        };
+
+        match meval::eval_str(expr) {
+            Ok(result) => {
+                let display = format_result(result);
+                let copy_cmd = format!(
+                    "printf '%s' '{}' | wl-copy",
+                    display.replace('\'', "'\\''")
+                );
+                vec![LaunchItem {
+                    id: format!("calc:{}", expr),
+                    name: display.clone(),
+                    description: Some(format!("= {}", expr)),
+                    icon: Some("accessories-calculator".into()),
+                    provider: ProviderType::Plugin("calc".into()),
+                    command: copy_cmd,
+                    terminal: false,
+                    tags: vec!["math".into(), "calculator".into()],
+                }]
+            }
+            Err(_) => Vec::new(),
+        }
+    }
+}
+
+/// Extract the math expression from a query string.
+///
+/// Handles:
+/// - `= expr` and `=expr` (explicit calculator prefix)
+/// - `calc expr` (word prefix)
+/// - Raw expressions if they look like math (auto-detect)
+///
+/// Returns `None` only when input is empty after trimming.
+fn extract_expression(query: &str) -> Option<&str> {
+    let trimmed = query.trim();
+    if trimmed.is_empty() {
+        return None;
+    }
+
+    // Explicit prefixes
+    if let Some(rest) = trimmed.strip_prefix("= ") {
+        return Some(rest.trim());
+    }
+    if let Some(rest) = trimmed.strip_prefix('=') {
+        return Some(rest.trim());
+    }
+    if let Some(rest) = trimmed.strip_prefix("calc ") {
+        return Some(rest.trim());
+    }
+
+    // Auto-detect: only forward if the expression looks like math.
+    // Plain words like "firefox" should not reach meval.
+    if looks_like_math(trimmed) {
+        Some(trimmed)
+    } else {
+        None
+    }
+}
+
+/// Heuristic: does this string look like a math expression?
+///
+/// Returns true when the string contains binary operators, digits mixed with
+/// operators, or known function names. Plain alphabetic words return false.
+fn looks_like_math(s: &str) -> bool {
+    // Must contain at least one digit or a known constant/function name
+    let has_digit = s.chars().any(|c| c.is_ascii_digit());
+    let has_operator = s.contains('+')
+        || s.contains('*')
+        || s.contains('/')
+        || s.contains('^')
+        || s.contains('%');
+    // Subtraction/negation is ambiguous; only count it as an operator when
+    // there are already digits present to avoid matching bare words with hyphens.
+    let has_minus_operator = has_digit && s.contains('-');
+
+    // Known math functions that are safe to auto-evaluate
+    const MATH_FUNCTIONS: &[&str] = &[
+        "sqrt", "sin", "cos", "tan", "log", "ln", "abs", "floor", "ceil", "round",
+    ];
+    let has_function = MATH_FUNCTIONS.iter().any(|f| s.contains(f));
+
+    has_digit && (has_operator || has_minus_operator) || has_function
+}
+
+/// Format a floating-point result for display.
+///
+/// Integer-valued results are shown as integers with thousands separators.
+/// Non-integer results are shown with up to 10 decimal places, trailing zeros trimmed.
+fn format_result(result: f64) -> String {
+    if result.fract() == 0.0 && result.abs() < 1e15 {
+        format_integer_with_separators(result as i64)
+    } else {
+        let formatted = format!("{:.10}", result);
+        formatted
+            .trim_end_matches('0')
+            .trim_end_matches('.')
+            .to_string()
+    }
+}
+
+fn format_integer_with_separators(n: i64) -> String {
+    let s = n.unsigned_abs().to_string();
+    let with_commas = s
+        .as_bytes()
+        .rchunks(3)
+        .rev()
+        .map(|chunk| std::str::from_utf8(chunk).unwrap())
+        .collect::<Vec<_>>()
+        .join(",");
+
+    if n < 0 {
+        format!("-{}", with_commas)
+    } else {
+        with_commas
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn query(q: &str) -> Vec<LaunchItem> {
+        CalculatorProvider.query(q)
+    }
+
+    // --- Trigger prefix tests ---
+
+    #[test]
+    fn equals_prefix_addition() {
+        let results = query("= 5+3");
+        assert_eq!(results.len(), 1);
+        assert_eq!(results[0].name, "8");
+    }
+
+    #[test]
+    fn calc_prefix_multiplication() {
+        let results = query("calc 10*2");
+        assert_eq!(results.len(), 1);
+        assert_eq!(results[0].name, "20");
+    }
+
+    // --- Auto-detect tests ---
+
+    #[test]
+    fn auto_detect_addition() {
+        let results = query("5+3");
+        assert_eq!(results.len(), 1);
+        assert_eq!(results[0].name, "8");
+    }
+
+    #[test]
+    fn equals_prefix_complex_expression() {
+        let results = query("= sqrt(16) + 2^3");
+        assert_eq!(results.len(), 1);
+        assert_eq!(results[0].name, "12");
+    }
+
+    #[test]
+    fn decimal_result() {
+        let results = query("= 10/3");
+        assert_eq!(results.len(), 1);
+        assert!(
+            results[0].name.starts_with("3.333"),
+            "expected result starting with 3.333, got: {}",
+            results[0].name
+        );
+    }
+
+    #[test]
+    fn large_integer_thousands_separators() {
+        let results = query("= 1000000");
+        assert_eq!(results.len(), 1);
+        assert_eq!(results[0].name, "1,000,000");
+    }
+
+    // --- Invalid / non-math input ---
+
+    #[test]
+    fn invalid_expression_returns_empty() {
+        let results = query("= 5 +");
+        assert!(results.is_empty());
+    }
+
+    #[test]
+    fn plain_text_returns_empty() {
+        let results = query("firefox");
+        assert!(results.is_empty());
+    }
+
+    // --- Metadata tests ---
+
+    #[test]
+    fn provider_type_is_calc_plugin() {
+        assert_eq!(
+            CalculatorProvider.provider_type(),
+            ProviderType::Plugin("calc".into())
+        );
+    }
+
+    #[test]
+    fn description_shows_expression() {
+        let results = query("= 5+3");
+        assert_eq!(results[0].description.as_deref(), Some("= 5+3"));
+    }
+
+    #[test]
+    fn copy_command_contains_wl_copy() {
+        let results = query("= 5+3");
+        assert!(results[0].command.contains("wl-copy"));
+    }
+}

crates/owlry-core/src/providers/mod.rs

@@ -1,6 +1,7 @@
 // Core providers (no plugin equivalents)
 mod application;
 mod command;
+pub(crate) mod calculator;
 
 // Native plugin bridge
 pub mod native_provider;