Add provider-aware diagnostics rail

src/leader.zig

@@ -14,6 +14,7 @@ pub const Feature = enum {
     search,
     panel_close,
     lsp,
+    diagnostics,
 };
 
 pub const Action = union(enum) {
@@ -28,6 +29,10 @@ pub const Action = union(enum) {
     hover,
     signature,
     expand_hover,
+    diagnostics_open,
+    diagnostics_next,
+    diagnostics_previous,
+    diagnostics_filter,
     repeat_rail,
     restore_last,
     not_built: Feature,
@@ -46,6 +51,7 @@ const Mode = enum {
     symbol_rail,
     search_rail,
     language_rail,
+    diagnostic_rail,
     open_prompt,
 };
 
@@ -71,6 +77,7 @@ pub const Leader = struct {
             .symbol_rail => return self.handleSymbolRail(event),
             .search_rail => return self.handleSearchRail(event),
             .language_rail => return self.handleLanguageRail(event),
+            .diagnostic_rail => return self.handleDiagnosticRail(event),
             .open_prompt => return self.handleOpenPrompt(event),
         }
     }
@@ -83,6 +90,7 @@ pub const Leader = struct {
             .symbol_rail => symbol_mod.rail_status,
             .search_rail => "search: f current file  p project  s symbols",
             .language_rail => "language: h hover  s signature  o open hover",
+            .diagnostic_rail => "diagnostics: d/open  n next  p previous  f filter-source",
             .open_prompt => "open: type path, Enter opens, Esc cancels",
         };
     }
@@ -131,6 +139,10 @@ pub const Leader = struct {
                     self.mode = .language_rail;
                     return .none;
                 }
+                if (std.mem.eql(u8, text, "d")) {
+                    self.mode = .diagnostic_rail;
+                    return .diagnostics_open;
+                }
                 if (std.mem.eql(u8, text, "q")) {
                     self.mode = .idle;
                     return .quit;
@@ -216,6 +228,50 @@ pub const Leader = struct {
         }
     }
 
+    fn handleDiagnosticRail(self: *Leader, event: input.Event) Action {
+        self.message = null;
+        switch (event) {
+            .text => |text| {
+                if (std.mem.eql(u8, text, "d")) {
+                    self.mode = .idle;
+                    return .diagnostics_open;
+                }
+                if (std.mem.eql(u8, text, "n")) {
+                    self.mode = .idle;
+                    return .diagnostics_next;
+                }
+                if (std.mem.eql(u8, text, "p")) {
+                    self.mode = .idle;
+                    return .diagnostics_previous;
+                }
+                if (std.mem.eql(u8, text, "f")) {
+                    self.mode = .idle;
+                    return .diagnostics_filter;
+                }
+                self.mode = .idle;
+                self.message = "unknown diagnostics key";
+                return .none;
+            },
+            .key => |key| switch (key) {
+                .escape, .backspace => {
+                    self.mode = .idle;
+                    self.message = "diagnostics cancelled";
+                    return .none;
+                },
+                else => {
+                    self.mode = .idle;
+                    self.message = "unknown diagnostics key";
+                    return .none;
+                },
+            },
+            .unknown => {
+                self.mode = .idle;
+                self.message = "unknown diagnostics key";
+                return .none;
+            },
+        }
+    }
+
     fn handleSearchRail(self: *Leader, event: input.Event) Action {
         self.message = null;
         switch (event) {