add ghostty_config_trigger C API to find a trigger for an action

include/ghostty.h

@@ -230,6 +230,12 @@ typedef enum {
     GHOSTTY_KEY_RIGHT_SUPER,
 } ghostty_input_key_e;
 
+typedef struct {
+    ghostty_input_key_e key;
+    ghostty_input_mods_e mods;
+    bool physical;
+} ghostty_input_trigger_s;
+
 // Fully defined types. This MUST be kept in sync with equivalent Zig
 // structs. To find the Zig struct, grep for this type name. The documentation
 // for all of these types is available in the Zig source.
@@ -282,6 +288,7 @@ void ghostty_config_load_string(ghostty_config_t, const char *, uintptr_t);
 void ghostty_config_load_default_files(ghostty_config_t);
 void ghostty_config_load_recursive_files(ghostty_config_t);
 void ghostty_config_finalize(ghostty_config_t);
+ghostty_input_trigger_s ghostty_config_trigger(ghostty_config_t, const char *, uintptr_t);
 
 ghostty_app_t ghostty_app_new(const ghostty_runtime_config_s *, ghostty_config_t);
 void ghostty_app_free(ghostty_app_t);

src/config.zig

@@ -1559,6 +1559,25 @@ pub const CAPI = struct {
             log.err("error finalizing config err={}", .{err});
         };
     }
+
+    export fn ghostty_config_trigger(
+        self: *Config,
+        str: [*]const u8,
+        len: usize,
+    ) inputpkg.Binding.Trigger {
+        return config_trigger_(self, str[0..len]) catch |err| err: {
+            log.err("error finding trigger err={}", .{err});
+            break :err .{};
+        };
+    }
+
+    fn config_trigger_(
+        self: *Config,
+        str: []const u8,
+    ) !inputpkg.Binding.Trigger {
+        const action = try inputpkg.Binding.Action.parse(str);
+        return self.keybind.set.getTrigger(action) orelse .{};
+    }
 };
 
 test {

src/input/Binding.zig

@@ -282,7 +282,10 @@ pub const Key = enum(c_int) {
 };
 
 /// Trigger is the associated key state that can trigger an action.
-pub const Trigger = struct {
+/// This is an extern struct because this is also used in the C API.
+///
+/// This must be kept in sync with include/ghostty.h ghostty_input_trigger_s
+pub const Trigger = extern struct {
     /// The key that has to be pressed for a binding to take action.
     key: key.Key = .invalid,
 
@@ -342,6 +345,22 @@ pub const Set = struct {
         return self.bindings.get(t);
     }
 
+    /// Get a trigger for the given action. An action can have multiple
+    /// triggers so this will return the first one found.
+    pub fn getTrigger(self: Set, a: Action) ?Trigger {
+        // Note: iterating over the full set each time is not ideal but
+        // we don't expect to have that many bindings. If this becomes
+        // a problem we can add a reverse map.
+        var it = self.bindings.iterator();
+        while (it.next()) |entry| {
+            if (std.meta.eql(entry.value_ptr.*, a)) {
+                return entry.key_ptr.*;
+            }
+        }
+
+        return null;
+    }
+
     /// Remove a binding for a given trigger.
     pub fn remove(self: *Set, t: Trigger) void {
         _ = self.bindings.remove(t);